Control Tools

• Diagnostics availability

• Commercial diagnostic kits available worldwide

  A variety of antibody-based commercial detection kits are available for rapid screening, all of which rely on the detection of Cryptosporidium antigens from concentrated or unconcentrated oocysts in faeces samples. These include immunofluorescent, enzyme-linked immunosorbent assay (ELISA), and immunochromatography based kits. For detection of Cryptosporidium DNA, commercial molecular diagnostic, quantitative real time PCR (qPCR) kits, are also available. List of commercially available diagnostics (Diagnostics for Animals)

• Diagnostic kits validated by International, European or National Standards

  No.

  No. Detection and characterisation of Cryptosporidium at the species level by PCR-Restriction Fragment Length Polymorphism (RFLP) is validated and accredited (Accredia) at the European Union Reference Laboratory for Parasites (EURLP), Italy. Commercially available diagnostic kits likely have some sort of accreditation.

• Diagnostic method(s) described by International, European or National standards

  No (the chapter on Cryptosporidiosis was removed from the WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals). The archived chapter is still available online and describes routine methods involving: 1. Demonstration of Cryptosporidium oocysts in faeces 2. Immunological methods to demonstrate Cryptosporidium-specific antigens in faecal samples a) Direct immunofluorescence microscopy b) ELISA c) Immunochromatography (Lateral Flow Tests) 3. Nucleic acid recognition methods a) PCR b) Quantitative real-time PCR c) Loop-mediated isothermal amplification (LAMP)

  GAPS

  Lack of evaluation of existing diagnostic assays for each specific diagnostic target: clinical, subclinical or epidemiological diagnosis, in order to define preferred assay for each diagnostic target, in terms of the value of the additional info obtained versus the cost.

• Commercial potential for diagnostic kits worldwide

  Current diagnosis is based on detecting oocysts, antigens, or DNA in faeces samples. Kits for all these methods are available. qPCR kits are numerous and are more sensitive than other methods.

  GAPS

  Diagnostic tests that are designed to differentiate between species may be of commercial potential, as not all Cryptosporidium species represent the same zoonotic risk and not all species infecting animal hosts are associated with disease or the same extent/severity of disease.

• DIVA tests required and/or available

  Not required and not available.

• Opportunities for new developments

  Microscopy is still the most commonly used diagnostic assay and is validated for clinical diagnosis. Commercial kits are available (ELISA and immunochromographic lateral flow assays), but the cost is high.

  Furthermore, none of these assays allows the identification of the species/genotypes of the parasite.

  GAPS:

  1. Further reduce cost of ELISA and/or immunochromographic lateral flow assays in cassette and/or dipstick format to make these tools available to veterinarians and farmers

  2. Develop molecular-based platforms for routine detection, including species identification

  3. Improve and standardize assays for the detection of carriers

  4. Develop ISO standards

  5. Investigate the efficacy of using cell-mediated immune based assays using specific Cryptosporidium antigens and induction of interferon gamma as a diagnostic test in people

  6. Examine duration of this type of response in symptomatic animal models and in infected people

  7. Develop multi-pathogen diagnostic tools

• Vaccines availability

• Commercial vaccines availability (globally)

  Bovilis Cryptium® from MSD has been introduced for vaccination of bovines but is apparently not available globally (e.g., apparently not available in USA). Further details: Bovilis Cryptium is indicated for the active immunization of pregnant cows and heifers to raise antibodies in colostrum against the Gp40 antigen of Cryptosporidium parvum. Calves receive passive immunity by ingesting colostrum from vaccinated dams, which helps reduce the severity and duration of neonatal diarrhoea caused by C. parvum Production: The vaccine is a ready-to-use, inactivated water-in-oil emulsion. It contains 1.5 AU/dose of the inactivated antigen and is manufactured under the Bovilis brand by MSD Animal Health Administration:
  • Route: Subcutaneous injection (s.c.)
  • Primary vaccination: Two 2 mL doses—first between 12 to 6 weeks before calving, second 3–6 weeks later and 2–3 weeks before calving.
  • Revaccination: One 2 mL dose during each pregnancy, 8–3 weeks before calving.
  • Injection sites: Neck, dewlap, or ischiorectal fossa.
  • Colostrum feeding: It is recommended to feed calves colostrum and/or transition milk for at least 5 days to ensure effective immunity
  Geographic availability: Bovilis Cryptium is licensed in the European Union and is available EU-wide and in other countries including:
  • United Kingdom, Switzerland, Chile, Norway, Israel,
  Another vaccine is licensed in the US (Medgene) since May 2025 (although introduced incorrectly as the first and only vaccine on the market); the only information available indicates a similar mode of action to that of Bovilis Cryptium.

  GAPS

  1. Lack of information on whether current vaccine available can be effective in hosts that are not cattle and for species that are not C. parvum.
  2. Vaccines for additional species such as sheep, poultry and pigs (e.g. lambs are a major cause of zoonotic transmission), and for species other than C. parvum.

• Marker vaccines available worldwide

  No.

  The Gp40 antigen in the vaccine elicits a significantly higher Gp40 antibody response in cattle than is seen in infected, non-vaccinated animals.

• Effectiveness of vaccines / Main shortcomings of current vaccines

  For active immunisation of pregnant heifers and cows to raise antibodies in their colostrum against Gp40 of C. parvum, intended for passive immunisation of calves to reduce clinical signs (i.e. diarrhoea) caused by C. parvum. Onset of immunity: Passive immunity commences from the start of colostrum feeding. Duration of immunity: In calves that receive colostrum and transition milk as indicated and which were challenged at birth, passive immunity has been demonstrated until 2 weeks of age.

  Although oocyst shedding is reduced, it is not eliminated so the risk for further transmission, including to those handling calves and indirectly via water etc. remains even following treatment.

  GAP

  1. Lack of evaluation criteria for vaccines (e.g., level of reduction in oocyst excretion, (sub)clinical benefit).

• Commercial potential for vaccines

  There is clearly commercial potential for a vaccine, given the high prevalence of cryptosporidiosis, the clinical relevance in several animal species and the public health importance due to potential zoonotic transmission, especially from C. parvum. As the disease affects young, often unweaned, animals, the classic vaccination strategy (multiple challenges) cannot be applied. Thus, maternal (passive immunity) vaccines, e.g. Bovilis Cryptium, are a realistic alternative approach 1) Maternal (passive immunity) vaccines Advantages: Proven reduction in calf diarrhoea severity. Aligns with colostrum-based immunity practices already in place on farms. Weaknesses: Efficacy depends on proper colostrum management. Requires early planning and compliance with vaccination schedule. Particularities: Based on the successful Bovilis Rotavec Corona platform 2) Direct calf vaccines (Experimental/in development) Advantages: Potential for direct protection without relying on maternal transfer. May simplify logistics for farms with poor colostrum management. Weaknesses: Time to build up active immunity, while the major problem of Cryptosporidium, is in the first 2 weeks of life. 3) Recombinant/subunit vaccines (mostly in research phase) Advantages: High specificity and safety profile. Scalable production and potential for multivalent formulations. Weaknesses: Often lower immunogenicity; may require adjuvants or boosters. No commercial product yet; long development timelines. Particularities: Reverse vaccinology has identified promising antigens like Cp15, Cp23, and Gp40. Could be adapted for both human and veterinary use under One Health strategy.

• Regulatory and/or policy challenges to approval

  Use of genetically modified vaccines might be problematic in some countries.

  Field trials may need specific regulation regarding the release of GMOs into the environment.

  GAPS

  1.Need to identify potential vaccine candidates, the appropriate expression system and route of vaccination, taking regulatory constraints into account.

• Commercial feasibility (e.g manufacturing)

  Vaccines are already commercially available (see earlier points).

  GAPS

  We lack the results of a desktop cost-benefit analysis to evaluate whether this should be expanded upon (e.g., different species of livestock, different species of Cryptosporidium).

  Although vaccines are available, and Bovilis Cryptium reduces symptoms, it does not eliminate infection. We lack information on how much reduction in oocyst shedding is necessary to have an impact on transmission and environmental contamination.

• Opportunity for barrier protection

  No.

• Pharmaceutical availability

• Current therapy (curative and preventive)

  Halofuginone lactate is approved for use in newborn calves and can be used for the prevention (treatment within first 2 days) or treatment of scours (start treatment within 24 hours after onset of diarrhoea)

  Paromomycin is approved for use in newborn calves, lambs and goat kids and reduces oocyst shedding and disease. This drug is a non-absorbable aminoglycoside, which is normally indicated for the treatment of intestinal amoebiasis in humans and is also approved for the treatment of E. coli infection in ruminants and pigs.

  Paromomycin is very poorly absorbed and is excreted into the farm environment, which can lead to bacteria becoming resistant to paromomycin and neomycin.

  Various other compounds are known to reduce oocyst shedding and to control disease but are not approved for use in animals. Nitazoxanide, an orally administered nitrothiazole benzamide, is used in humans. It is approved by the US FDA and has been found to be effective in immunocompetent individuals. The effect in malnourished children is doubtful, and no effect shown in immunosuppressed individuals.

  As noted earlier, colostrum management is key in preventing neonatal diarrhoea in ruminants.

  GAPS

  Efficacy guidelines for evaluation of compounds against Cryptosporidium infection are lacking; in USA there are no pharmaceuticals approved for treating animals.

  Alternative treatment programmes (e.g., lower dosage, alternate day treatments) with existing compounds (halofuginone, paromomycin) in order to reduce potential side effects in terms of toxicity (environmental, user, animal) and potential spread of AMR have not been investigated.

  We lack knowledge on whether Cryptosporidium will develop resistance against the current (and future) treatments; in vitro studies may be of value.

• Future therapy

  Use of in vitro models (prior to in vivo models) for testing potential treatments is progressing, but is still problematic. Using current in vitro models, results are often more likely to indicate effect than are seen in subsequent in vivo trials.

  GAPS

  We lack knowledge on whether improved antiparasitic therapy could be used as a prophylactic, as well as curative, drug; further information on effects of pharmaceuticals on oocyst production, and development of treatments that last longer (therefore requiring fewer applications) could be of value.

  We lack knowledge of whether pro-/pre-biotics increase resistance to parasite proliferation in the gastrointestinal tract.

  Development of more robust, reliable, and informative in vitro models would be of value for improving and developing treatments.

• Commercial potential for pharmaceuticals

  Good potential as the disease is widespread, and of public health importance.

  GAP

  We lack a robust cost-benefit analysis. Studies to evaluate the impact of preventive animal treatment on outbreak-related costs would be of value.

• Regulatory and/or policy challenges to approval

  Antimicrobials used for treating humans may be restricted for use in animals; this may complicate obtaining drug approval.

  GAP

  1. There are no approved pharmaceuticals in the United States for treating Cryptosporidium infection in animals.

• Commercial feasibility (e.g manufacturing)

  Depends on demand and price.

  GAPS

  A desktop cost-benefit analysis is lacking

• New developments for diagnostic tests

• Requirements for diagnostics development

  Several diagnostic assays suitable for use in different economic settings, are available. In recent years, lateral flow tests and ELISA kits have become commercially available offering an apparently reliable and cheap on-site diagnosis option for the presence of Cryptosporidium spp. in faecal samples. A few qPCR kits for the detection and quantification of Cryptosporidium species in animals are also available.

  In humans, Cryptosporidium is part of commercially available multiplex protozoan-PCR kits, that have become routine part of diarrhoea diagnostics in high-income countries over the last decade. Fewer of these pathogen-panel kits are available for animal diagnostics.

  Microscopy-methods are also an option: auramine-phenol staining of stool smears can detect acid-fast oocysts by LED-microscopy. In high-income countries, immunofluorescent antibody tests (IFAT) are more likely to be used.

  GAPS

  Although cheap, reliable, on-site diagnostic kits for veterinary use are available, currently none are specific for C. parvum; such a kit could be of value

  Validation of lateral flow tests for different host species, such as poultry and/or pigs, is lacking

  There is a potential need for commercial PCR-based kits that can differentiate between different species/(sub)genotypes. Although this may not be a requirement in every day veterinary practice, such a tool could be of value in outbreak investigation and tracking of infection transmission.

• Time to develop new or improved diagnostics

  In general, development of tests is much faster and cheaper than developing vaccines. However, from development through validation to commercial availability is time consuming and can take years.

• Cost of developing new or improved diagnostics and their validation

  The development and validation of new tests is time consuming and labour intensive which is costly. Costs cannot be specified as they depend on the nature of the test and the cost of producing reagents and supplying reading or processing machines if necessary. External validation, if necessary, can also be expensive. Marketing is also an expense.

  GAPS

  Need to evaluate the existing diagnostic assays for each specific diagnostic target: clinical, subclinical or epidemiological diagnosis. Need to define the preferred diagnostic assay for each diagnostic target, in terms of the value of additional info that is procured versus the cost.

• Research requirements for new or improved diagnostics

  Whole genome sequencing (WGS) of relevant species and genotypes has enhanced our knowledge of the Cryptosporidium biology.

  GAPS

  It is currently difficult to generate WGS data from sub-clinical or asymptomatic infections, while this may be important to understand drivers of virulence. Genome-targeted enrichment technology shows potential in alleviating this. Additionally, WGS data is lacking for many species/genotypes.

• Technology to determine virus freedom in animals

  Not applicable.

• New developments for vaccines

• Requirements for vaccines development / main characteristics for improved vaccines

  A vaccine that achieves (close to) 100% reduction in disease development, and also a high reduction in oocyst excretion, is highly desirable.

  GAPS 1. A defined required reduction in oocyst excretion, taking the need for adaptive immune development into account, is lacking; an effective vaccine to significantly reduce shedding would be of immense benefit. Models development quantifying the shedding is required in order to have an impact on transmission and environmental contamination. 2. Clinical disease should be reduced so that there is no impact on growth of vaccinated animals when they become infected. 3. A vaccine for different domestic animal host species (sheep, pigs, poultry) and also humans is lacking.

• Time to develop new or improved vaccines

  Depending on when a candidate vaccine could be identified the timescale will be 5-10 years. This will involve development, clinical trials and licensing. Potential vaccines need to be identified and subjected to initial trials and depending on the outcome will depend the time to commercial availability.

• Cost of developing new or improved vaccines and their validation

  Expensive with the need to develop and undertake all the relevant tests to provide data to enable the product to be authorised. Field trials are expensive, and evaluating the results can be complicated.

• Research requirements for new or improved vaccines

  Bovilis Cryptium requires 2 doses when used for the first time during late gestation. Optimal administration routes and timings could be further investigated.

  GAPS

  We lack information on the Medgene vaccine.

  Identification of more potential vaccine targets, and of expression systems and adjuvants could be of value.

  We lack knowledge on the effective components (both antibody and cellular immune factors) of immune colostrum.

  The effect of particular antigenic components of the parasite on the stimulation of effective immune factors in the dams that can be transferred in the colostrum could be further investigated along with investigation of the composition of the colostrum and the subsequent transfer of these components to young livestock through immunological monitoring.

  Use of current and new vaccines in different host animals and for different species of Cryptosporidium requires further research.

• New developments for pharmaceuticals

• Requirements for pharmaceuticals development

  At present, data on the working mechanisms of the available compounds for treating Cryptosporidium infection are lacking or proprietary. Insights on the microorganism itself often impedes the development of other compounds.

  The development of genetically modified parasites expressing luciferase reporter proteins allowed large-scale screening of compound libraries in vitro to identify compounds that are active in vitro. Subsequent evaluations of these compounds using mouse and calf models have confirmed that they stopped oocyst shedding in both host species This study has confirmed that genetically modified C. parvum can be a useful tool for evaluating growth of the parasites in in vitro assays and in vivo models.

  GAPS

  Study the molecular targets and working mechanism for the different active compounds, in order to better understand and manipulate safety (environmental, animals, and person who gives treatment).

  Development of new pharmaceuticals that do not result in environmental contamination with antimicrobials (as paromomycin does).

• Time to develop new or improved pharmaceuticals

  Time to develop would depend on the product and the trials necessary to validate the efficacy and safety. Commercial production would then take further time. Five to 10 years seems a realistic timeframe.

• Cost of developing new or improved pharmaceuticals and their validation

  Likely expensive, but costs are difficult to assess as they depend on the product itself, the trials necessary to validate, and licensing and other related costs.

• Research requirements for new or improved pharmaceuticals

  As working mechanisms are not known, it is unclear at what stage of the lifecycle the compounds are effective.

  Whole genome sequencing with baits enrichment has enabled genomic analysis of many species and opened up future research on vaccines, diagnostics, and genotyping tools

  GAPS

  Improve knowledge on the Cryptosporidium lifecycle in terms of molecular pathways to identify potential targets for treatment.

  Improve knowledge on Cryptosporidium pathogenicity in terms of lifecycle in order to define the optimum treatment time to achieve maximum efficacy.

Disease details

• Description and characteristics

• Pathogen

  Cryptosporidiosis is caused by protozoan parasites belonging to the genus Cryptosporidium. Currently almost 50 species have been recognized as valid. Among these, C. parvum, C. andersoni, C. ubiquitum, C. scrofarum, C. suis, C. baileyi, C. meleagridis and C. galli have been reported to cause morbidity and/or outbreaks of disease in mammalian and avian livestock. C. parvum is particularly important, not only for its impact on livestock health, but because of its zoonotic potential. C. hominis is also an important human pathogen, and, in Scandinavia, C. mortiferum has become common in human infections and is associated with squirrels and possibly other wild animals. In addition to the recognized species, there are over 120 described genotypes and it is likely that some of these will be re-categorised as species. Our understanding of C. parvum and its subtypes, and their risk to animal and public health has benefited from multilocus genotyping schemes. Genome sequence data are available for many different species of Cryptosporidium, with the use of bait enrichment enabling additional data to be generated for species (and from samples) that were previously challenging.

  GAPS

  Improved sampling and testing methods may provide better occurrence and prevalence data across all host ages. Knowledge of the interactions between different Cryptosporidium species and our understanding of mixed species/genotypes infections could be improved. The risk for animal and public health posed by different Cryptosporidium species, subtypes and genotypes (including infectivity, pathogenesis and shedding profiles) could be improved on the basis of a combination of morphological, biological and genetic data.

• Variability of the disease

  Cryptosporidium parvum has a very wide host range of animals and is responsible for severe infection and/or disease in neonatal ruminants. Older animals are often infected, usually without disease, and serve as a source of infective oocysts. Different degrees of virulence and host specificity have been reported for distinct C. parvum isolates and subtypes.

  GAPS

  1. We lack detailed data on how disease progression and outcome are associated with pathogen and host characteristics. In addition, the influence of temporal, geographic, socio-economic and climatic variations on prevalence and clinical outcome are poorly described.
  2. Our knowledge on oocyst excretion patterns in different animal hosts infected with different Cryptosporidium species or subtypes and the potential implications for transmission are scanty.
  3. Information on the influence of mixed Cryptosporidium infections in the outcome of disease, and evolution of host specificity through genetic recombination events is minimal; in addition, whether the effects of co-infections with different diarrhoeal pathogens are additive (synergistic) or antagonistic has been only rarely investigated.

• Stability of the agent/pathogen in the environment

  Cryptosporidium oocysts are protected by a robust outer wall that allows them to survive for prolonged periods (>6 months) in moist, cool environments. They are, however, susceptible to desiccation and repeated freeze-thaw cycles. The oocysts are also very resistant to chlorine-based disinfectants at concentrations normally used. Currently, disinfectants based on phenols and hydrogen peroxide seem to be most effective against Cryptosporidium oocysts.

  GAPS Whether an oocyst viability assay can be used as a surrogate for infectivity remains unresolved. Although survival of oocysts in different matrices (water, faeces, soil, biofilms, food and feedstuffs etc) has been investigated, it could be revisited with new tools. How environmental factors (temperature, UV scale, predation by other microorganisms etc) and food/feed processing and preservation techniques affect oocyst survival requires investigation (how do lethal conditions affect the oocysts). Identification of novel, effective, cheap oocyst inactivation measures that do not affect the environment or the user would be of value.

• Species involved

• Animal infected/carrier/disease

  A wide range of domestic and wild animals are affected by cryptosporidiosis, but overt disease is primarily observed in calves, lambs, kids, foals, piglets, reptiles, turkeys, chicken and some other avian species. It is more difficult to identify severe impacts of cryptosporidiosis in wildlife, but they cannot be excluded and may be relevant for the survival of critically endangered species. Older animals are often infected asymptomatically, thus acting as carriers. The main (initial) source of infection in calves is often unknown (some studies have shown different genotypes in cow and progeny calves). Sterile immunity against Cryptosporidium infection does not seem to occur.

  GAPS

  Although we have considerable knowledge on the Cryptosporidium species/genotypes infecting animals, including wildlife, more information would be of value particularly for endangered species, and also regarding the likelihood of habitat fragmentation and reduced human/wildlife barriers resulting in spread of human/livestock infections to wildlife The effect of host factors (genetics, physiology, diet and supplements, age and host immunological status) on infection level and pathogenicity caused by different species/genotypes of Cryptosporidium, including mixed infections, is relatively poorly documented. The importance of asymptomatic carriers on transmission has been poorly investigated and would benefit from improved sampling and testing.

• Human infected/disease

  C. parvum and C. hominis are the most important species causing human infections, but other species and genotypes, most of which have zoonotic potential, have been reported. C. mortiferum appears to be emerging in Scandinavia. Immunocompetent humans normally recover from cryptosporidiosis within 1-2 weeks. Oocyst shedding can last one month. Cryptosporidiosis is the second most common cause of diarrhoeal disease in very young children in low-income countries. It is associated with increased risk of death, and also with malnutrition and reduced linear growth.

  GAPS

  We lack knowledge on the mechanisms associated with long-term health effects of infection. Sensitive diagnostic tests for detection of infection are lacking in many places where patients are likely to be most vulnerable and further tools to trace mixed infections at species and (sub)genotype level are also needed. Elucidation of the role of different species and subtypes in severity of human cryptosporidiosis is necessary. Strategies for effective anti-cryptosporidial drug interventions need to be developed and implemented, and identification of an effective vaccine for use in young children should be prioritised. Development of immunological tools to monitor humoral and cell-mediated responses following exposure to infection and the duration of these responses could be of value.

• Vector cyclical/non-cyclical

  Contamination of animal feed with oocysts by rodents and other host species is possible, as is transfer of oocysts from faeces by insects such as filth flies.

  GAPS

  We lack knowledge regarding the extent to which mechanical vectors (e.g. filth flies) play a role in transmission. We lack knowledge regarding the extent to which feed/waterborne transmission occurs to animals on farms, especially if private water supplies are used.

• Reservoir (animal, environment)

  Animals infected with Cryptosporidium spp. act as reservoirs for infection for other animals and humans. Wild animals can also be infected, but little is known about their potential role in the epidemiology of infection and the extent to which they play a role in transmitting infection to domestic animals or humans. Although data are available on the range of both host reservoirs and environmental reservoirs, this could be extended, and modelling could be used to determine the likely risk of transmitting disease. The effect of factors such as livestock movements and social contact on infection transmission is poorly understood.

  GAPS

  Although we have knowledge regarding interventions and biosecurity measures that reduce transmission via reservoirs, details regarding the efficacy are poorly understood; the extent to which water recycling/reuse on cattle farms contributes towards reducing the water footprint may contribute to oocyst transmission is also unknown.

• Description of infection & disease in natural hosts

• Transmissibility

  The usual transmission route is from oral ingestion of oocysts, which are infective when shed in the faeces and do not need to sporulate in the environment. Other routes of infection (aspiration, inhalation, mucosa) have been reported but are considered as rare in mammalian hosts. In poultry, respiratory cryptosporidiosis, particularly with C. baileyi, may be transmitted by inhalation or ingestion.

  GAPS

  • Although the minimum infective dose for some Cryptosporidium species and genotypes has been published, it would be of value to determine it for other Cryptosporidium species in a range of hosts.
  • We have limited data on the number and proportion of viable (infectious) oocysts of different Cryptosporidium species shed by different infected hosts at different time-points during infection. Determining the relevance of low-level shedding by older animals on transmission and environmental contamination would be of value.
  • Our knowledge on the importance of other routes of infection in different host species is generally poor.

• Pathogenic life cycle stages

  Sporulated oocysts are considered the infectious stage of Cryptosporidium. Following ingestion of the oocysts, excystation occurs and infective sporozoites are released and invade the epithelial cells, where they locate in a parasitophorous vacuole and undergo asexual multiplication followed by sexual multiplication (gametogony) producing male and female gametes. Following gamete fusion, oocysts develop and sporulate generating 4 sporozoites. This means the oocysts are fully infective upon excretion in the faeces. It has been reported that two types of oocysts are produced, thick-walled oocysts that are excreted in the faeces, whilst thin-walled oocysts are involved in auto-reinfection. Genetically modified Cryptosporidium parasites have been generated and used to confirm that sexual chromosome reassortment and recombination occur frequently in mammalian hosts. In addition, genetically modified parasites have been used to investigate sites of infection in the gut of mice and calves. Small animal laboratory models for studying cryptosporidiosis pathogenicity (and other aspects) have been developed and published and will be valuable for obtaining further information.

  GAPS

  The mechanisms of Cryptosporidium pathogenicity have been investigated, and this should be continued using relevant in vitro approaches. We lack knowledge on how host physiology and pathophysiological changes correlate with different Cryptosporidium species/genotypes. Studies on the invasion process and the host-pathogen interactions during parasite development in the gut have been investigated. Further research using proteomic and genomic techniques will be of value and may lead to the design of intervention strategies to reduce/prevent shedding by infected hosts. The involvement of the gut microbiota in the mechanisms of the pathogenesis of cryptosporidiosis is poorly understood.

• Signs/Morbidity

  Cryptosporidiosis is primarily a problem in neonates especially young ruminants up to the age of 4 weeks. Clinical disease is rare in older animals due to the development of immunity, and therefore may occur with concurrent immunosuppression. Severe watery diarrhoea, weight loss and loss of appetite are the main clinical signs, which may persist for several days. Some infected animals will not develop clinical signs but will excrete the parasite in their faeces. Cryptosporidiosis is commonly associated with other infections, such as rotavirus, which results in more severe disease. Piglets and foals can also be infected but disease is seen over a wider age range and it does not seem to be such an important pathogen in these species.

  GAPS

  Information on pathological changes in the mucosa are scanty and it would be relevant to determine whether chronic sequelae occur in animals (they are reported from humans and, as well as gastrointestinal issues, also include joint pain, eye pain and headache) and the significance for food production. The role of co-infections in pathogenicity is poorly understood. We have limited information on associations between virulence and specific subtypes of Cryptosporidium. The immunological correlates of protection are poorly described. The economic impact of cryptosporidiosis on livestock farmers and small-scale husbandry in different settings could be investigated (zDALY).

• Incubation period

  The incubation period is short (usually 3-12 days), but varies with host species and extent of exposure to infective oocysts.

  GAPS

  1. Whether the incubation period depends on the Cryptosporidium species/(sub)genotype and/or characteristics of infected host (species, immunological status, colostrum fed) has not been well described
  2. Determine if the incubation period depends on the Cryptosporidium species/(sub)genotype
  3. Determine if the incubation period depends on the infected host (immunological status, colostrum fed)

• Mortality

  In animals, generally low unless associated with concurrent infection with rotavirus or coronavirus, inadequate intake of colostrum, poor hygiene and a breakdown in biosecurity, high stocking density, failure to ensure adequate rehydration and energy intake or the impact of adverse weather conditions. In humans, cryptosporidiosis is one of the most important causes of diarrhoea in young children in areas with poor hygienic standards. It is associated with increased mortality in children in low-income countries, and in young animals in low-income countries mortality may be more likely to occur.

  GAPS

  1. We are not aware of whether fatalities are associated with particular genotypes, or host-related factors.
  2. The role of co-infections on mortality under controlled conditions has not been well investigated.
  3. The mechanisms for Cryptosporidium-related malnutrition and the impact on long-term mortality (and morbidity) has not been investigated in either livestock or people.

• Shedding kinetic patterns

  C. parvum can be shed by animals of any age although the highest oocyst concentrations are usually seen in very young calves/lambs. Large quantities of infective, fully sporulated oocysts are shed in the faeces for infected calves for 3 to 12 days. Weaned and adult animals do not usually exhibit clinical signs but can shed a relatively low number of oocysts per gram, thus totalling a significant daily output. In young children, oocyst shedding often last around one month, several weeks after diarrhoeal symptoms have ended. In an affected farm, there is often one predominant C. parvum subtype in the calf population, while in adult cattle on the same farm the C. parvum subtype diversity may be higher. In lambs, however, this pattern is not always seen.

  GAPS

  1. Data on oocyst shedding profiles (shedding levels and duration) in different animal hosts could be improved by using appropriate sampling and sensitive testing methods.
  2. The extent to which dead oocysts are shed during infection is unknown.
  3. The host correlates of protective immunity are not well known. It would be of value to determine the qualitative and quantitative nature of this response.

• Mechanism of pathogenicity

  Damage to host epithelial cells mainly occurs in the gastrointestinal tract where villous atrophy occurs in the small intestine. Increased intestinal barrier permeability and inflammatory responses are typically associated with cryptosporidiosis, as are alteration in the host gut microbiota composition.

  GAPS

  The mechanisms/factors that regulate invasion are poorly understood. The host factors, including gut microbiota, that contribute towards (or ameliorate) pathogenesis are poorly understood. Which Cryptosporidium proteins are involved in pathogenesis requires further elucidation.

• Zoonotic potential

• Reported incidence in humans

  Considered to be relatively common in children where it usually causes self-limiting diarrhoea. Can affect any age group. A higher incidence is reported in immunocompromised individuals. In the 2021 European Centre for Disease Control report the overall notification rate was 1.8 per 100,000, with higher rates in Ireland (16.7 per 100,000) and Finland (9.1 per 100,000). Children aged 0–4 years had the highest notification rate of 6.4 cases per 100,000 population. However, species and transmission route is not specified. Although human infection with C. parvum of known zoonotic subtypes occurs commonly in Europe, the distribution is not global and in many parts of Africa, Cryptosporidium is more likely C. hominis or C. parvum of non-zoonotic subtypes.

  GAPS

  1. Multilocus genotyping, e.g. multilocus variable number tandem repeats analysis (MLVA) scheme, should be applied more broadly for tracking infection sources and for identification of diffuse outbreaks.
  2. We have some information on the prevalence and distribution of zoonotic subtypes of C. parvum in different host species in different geographical situations, but further data would be of value. It would also be of value to investigate the prevalence and distribution of non-zoonotic subtypes of C. parvum that only cycle within humans.
  3. A better understanding of the occurrence of C. hominis in animals and the risk of onward transmission would be useful (can animals be considered a reservoir?). Current data support the existence of C. hominis variants that infect animals (mostly non-human primates and equines) and could perhaps be non-infectious to humans
  4. Whether species/subtype-specific immunity can develop in humans is of interest and unresolved. Valuable information could be obtained from animal models on long-lasting immunity against particular species/genotypes. Although lambs can be reinfected with the same subtype of Cryptosporidium, data for other animals are lacking.

• Risk of occurence in humans, populations at risk, specific risk factors

  Transmission follows a faecal-oral pathway. Robust oocysts are passed fully sporulated (immediately infective), allowing for either direct or indirect transmission. Some specific groups are at particular risk of exposure (mothers, veterinarians, farmers) and others at particular risk of infection if exposed (those with immunodeficiencies or who are otherwise immunosuppressed (e.g., transplant patients), those who have never been previously exposed (young children). Direct transmission:
  1. Person-to-person
  2. Animal contact (farm or domestic setting, potentially wildlife)
  Indirect transmission:
  1. Consumption of water contaminated with human or animal faeces, sewage or effluent where water treatment is inadequate.
  2. Consumption of food contaminated with infectious oocysts (via unhygienic handling, or during pre- or post-processing of produce).
  3. Contact with contaminated recreational or environmental water (e.g. swimming pools, splash zones, lakes and rivers).
  4. Contact with contaminated fomites (fences, clothes, footwear, pushchair wheels).
  5. Specific risk factors that are often linked to infections and outbreaks include petting farm visits, foreign travel, poor sanitary infrastructure and swimming pools, particularly those used by young children.

  GAPS

  1. The relative risk of different transmission routes is likely to vary according to geographical and socio-economic conditions (among other factors). Estimating these relative risks for different situations would be useful for determining where interventions would be most effective.
  2. Our understanding of prevalence and impact of infection in risk groups (immunodeficient or immunosuppressed) could be improved.
  3. Epidemiological questionnaires could probably be improved by interaction with social scientists. Knowledge exchange projects and educational programmes could be useful for reducing transmission.
  4. Specific questions require addressing: for example, why are most swimming pool outbreaks in UK caused by C. hominis and not in equal numbers with C. parvum, when the prevalence of both species is almost 50:50 within the human population in the UK? Could this indicate age-related factors?

• Symptoms described in humans

  Cryptosporidiosis is most common in children aged between 1 and 5 years. Watery diarrhoea, abdominal cramps, vomiting and loss of appetite are the predominant presenting symptoms. Around 50% will also have low-grade fever, aching muscles, and headache. The clinical picture can last for 5-6 weeks in some cases. Severe clinical signs can occur in immunocompromised individuals and in immunocompetent young children in low-income countries with significant contribution to morbidity and mortality. Long-term sequelae include gastrointestinal issues (chronic diarrhoea, weight loss, abdominal pain) along with joint pain, eye pain and headache.

  GAPS

  1. Although we have information on acute symptoms, detail is missing regarding: Do some cases have vomiting and not diarrhoea? Is vomit a risk for onward transmission?
  2. Although we have information on chronic sequelae following infection in industrialised countries, such information is generally lacking in low-income countries. Is such information available?
  3. Although information on the effect of paediatric cryptosporidiosis on parameters like height, weight and cognisance have been reported, data are patchy.
  4. Our understanding of the interaction with other conditions such as malnutrition, pregnancy and immunosuppression, and treatments, such as biologics for rheumatoid conditions, could be improved.

• Likelihood of spread in humans

  Spread is likely to occur in poor hygiene environments, but can also occur in good hygiene environments due to faecal accidents or because of high contact (e.g. among families, in schools, daycare, hospitals etc.). Swimming pools also present a high risk setting for increased spread.

  GAP

  1. While there have been some studies looking entirely at secondary spread, information is scanty and often not coupled to close analysis of potentially exacerbating factors. In which setting / households is this more likely?
  2. The duration and quality of immunity following exposure and disease have not been investigated much in people

• Impact on animal welfare and biodiversity

• Both disease and prevention/control measures related

  Paromomycin is poorly absorbed and about 97% is excreted into the environment. This leads to environmental contamination of an antimicrobial that can lead to resistance in bacteria to paromomycin and neomycin.

  GAP

  1. Knowledge of the risk factors (e.g., season, environment, climate) that facilitate or decrease Cryptosporidium transmission between wildlife and other populations (human and production animals) is superficial.
  2. It is worth considering whether changes in animal welfare legislation (requiring neonatal calves to spend more time with their dams) will affect Cryptosporidium transmission.

• Endangered wild species affected or not (estimation for Europe / worldwide)

  Data are limited but some apparent outbreaks (with mortalities) have been reported in some wildlife populations, particularly of wild birds (e.g., red grouse – red-listed in UK; African penguin (Spheniscus demersus) - considered critically endangered).

  GAP

  Knowledge on the impact of cryptosporidiosis on endangered wild species is poor, and largely driven by outbreak events. Focus should be on vulnerable groups such as neonates.

• Slaughter necessity according to EU rules or other regions

  No.

• Geographical distribution and spread

• Current occurence/distribution

  Worldwide, with geographical differences in the locally prevalent species and subtypes. In many countries in sub-Saharan Africa, C. parvum appears relatively uncommon in both people and livestock.

  GAPS

  1. Although there have been many genotyping and sub-genotyping surveys associated with people, livestock and wildlife, some questions remain unanswered, including the relative lack of C. parvum in many African countries, and differences in subtype predominance in different countries.
  2. Disease and source tracking studies. using dynamic and longitudinal study design (GIS) may provide further information

• Epizootic/endemic- if epidemic frequency of outbreaks

  Cryptosporidiosis is endemic in most countries. Outbreaks associated with contamination of water sources (in particular) have been widely documented, particularly from high-income countries, where the background infection rate is lower. Outbreaks associated with animal contact (particularly petting farms and veterinary students) are also well documented. That outbreaks are not documented in low-income countries does not mean they do not happen, although exposure in childhood and development of immunity may mean that outbreaks among adults occur less frequently.

  GAPS

  Breaking the transmission cycle and reducing environmental contamination remains key in control.

• Speed of spatial spread during an outbreak

  Rapid and easily spread between animals.

  GAPS

  Our understanding on how farm management practices influence disease spread is relatively poor. Gathering data on the effect of biosecurity measures and practices on farms such as quarantine of new stock and housing of birthing animals and young stock could be of value. Understand the role of mechanical vectors (e.g., filth flies and rodents) in disease spread.

• Transboundary potential of the disease

  Spread by domestic and wild animals, and also by people.

  GAP

  1. The role of wild animals in maintaining a reservoir of infection and the role of migratory birds in spreading Cryptosporidium is poorly defined.
  2. From a global perspective, the general absence of C. parvum infections in many (sub-Saharan) African countries, in either human or livestock, suggests the potential for introduction. Establishment of C. parvum in human and animal populations could be devastating in these countries and should be a matter of concern; investigation on why this species has apparently not yet established there would be of value.
  3. A similar concern has been expressed about the introduction of C. parvum IIa genotypes into China, where the IId genotypes currently predominate in cattle.

• Route of Transmission

• Usual mode of transmission (introduction, means of spread)

  Transmission of Cryptosporidium to a new host is predominantly via the oral ingestion of infective oocysts shed in the faeces of infected animals. Husbandry practices in relation to housing, feeding, lambing and calving patterns and facilities can all have an impact on the spread of disease. Disposal of waste, manure, animal faeces and human sewage can lead to contamination of watercourses that may be used for animals or humans.

  GAPS

  1. The relative importance of the different infection sources, including potential vectors and environment/food, probably varies by location and situation, and also for each population/host species in different settings. Data are currently scattered, with many gaps.
  2. It would be of value to investigate which husbandry practices are associated with reduced spread of infection and environmental contamination.
  3. We currently do not have guidelines/information on best practises for treating waste on farms to kill or inactivate oocysts.

• Occasional mode of transmission

  Inhalation is reported to occur. There is evidence for transmission from clinically normal dams to suckling calves or lambs, but the precise mechanism remains unknown. GAPS
  1. Investigate airborne transmission of cryptosporidiosis.
  2. Investigate faecal oral route with improved sampling and detection from dams.
  3. Investigate contamination of udders and milk ducts.

• Conditions that favour spread

  Environmental conditions: Poor sanitation, faecal contamination of animal feed or water, insufficient cleanliness of housing, and direct contact. Damp conditions favour oocyst survival. Management conditions: Overcrowding, group housing of young stock of different ages, prolonged lambing or calving seasons with opportunity for older animals to infection new-borns, stress and buying-in of animals.

  GAPS

  1. We have little information on how climate change will influence spread.
  2. Although information is available on the survival and viability of oocysts in different environmental matrices, this is a topic that would benefit from revisiting using appropriate sampling and methodologies.

• Detection and Immune response to infection

• Mechanism of host response

  Infection results in both humoral and cell mediated immunity. Both systemic and local antibody production in the gastrointestinal tract occurs, but cellular immunity seems most important for protection against symptomatic reinfection. Previous challenge does not result in sterile immunity; thus, animals can be reinfected with C. parvum (including with the same C. parvum subtype) leading to oocyst shedding.

  GAPS

  Further study on the mechanisms and effectors triggering a protective immune response would be of value. The mechanisms and effectors causing immune-mediated pathology is incompletely understood. Development of in vitro and in vivo models for studying immunity would be of value. Data on the duration of immunity following exposure and disease is lacking.

• Immunological basis of diagnosis

  As disease generally occurs in neonates, serum antibodies are npt present and therefore serological assays are not helpful. Immunodiagnostic assay for copro-antigen are commercially available.

  GAPS

  The usefulness of an assay of cell-mediated immunity based the induction of interferon gamma in response to specific antigens should be explored.

• Main means of prevention, detection and control

• Sanitary measures

  Cryptosporidiosis is difficult to control due to the low infectious dose and the high numbers of oocysts shed by infected animals (around 6 oocysts will lead to oocyst shedding and around 10 oocysts will result in diarrhoea in 50% of calves). Reducing the potential for ingestion of infected oocysts is the only effective measure to limit spread of the disease.

  GAPS

  1. Further information is needed on the best methods to treat farm waste in order to minimise environmental contamination with viable oocysts. It would be of value to develop and evaluate effective cleaning, disinfection and composting treatments that can be used at farm level and develop multi-barrier waste treatment (potentially including) solar insolation.
  2. We need to identify the barriers to uptake of effective measures within the farming community.
  3. In mixed farms, it is important to be able to limit contamination of vegetable production areas (potentially resulting in foodborne transmission).
  4. Farm-visit-related outbreaks of cryptosporidiosis continue to occur. We need further information on reasons and control.

• Mechanical and biological control

  Various control measures are used; the most important are listed below:
  1. Calving and lambing in a clean environment
  2. Increasing the bedding to reduce contamination
  3. Feed adequate amounts of good quality colostrum
  4. Isolate affected animals
  5. All-in all-out management systems (small groups with plenty of space)
  6. Individual housing
  7. Preventing faecal contamination of feed and water troughs
  8. Ensuring no run-off from pens affecting other calf pens, especially if calves are individually housed
  9. Decrease stocking density of animals
  10. Clean and disinfect all buildings with products that kill oocysts, using the correct disinfectant concentration and contact time
  11. Disposal of faeces and manure with care to avoid contamination of water.

  GAPS

  1. Knowledge on the relative importance of risk factors for infection spread could be strengthened with longitudinal, rather than cross-sectional, studies.
  2. Educational opportunities for farmers and other decision makers about effective strategies to minimise disease spread could be improved, and barriers to uptake of these measures should be identified.
  3. Appropriate guidelines aimed at minimising/ controlling disease (at regional, national, and/or European levels) could be useful
  4. Efforts to investigate colostrum quality (with regard to specific immunological components active against Cryptosporidium) and ensuring uptake of these components is enabled would be valuable.

• Diagnostic tools

  Detection of Cryptosporidium oocysts, specific antigens or nucleic acids present in faeces or other matrices. Acid-fast staining methods, with or without faecal concentration, are most frequently used in clinical laboratories globally but are not sensitive and liable to misinterpretation. Immunofluorescent antibody tests with fluorescence microscopy are also widely used and are more reliable. In recent years, the use of point-of-care (PoC) pen-side tests based on antigen detection (immunochromatography), detecting multiple pathogens, has become more common. These tools support disease control measures, such as treatment decisions, quarantine etc.

  GAPS

  Although molecular-based platforms for rapid detection at the genus level are established, they are not widely used in veterinary diagnostics; identification of species and (sub)genotype using such platforms would increase their usefulness. Cryptosporidiosis should be included in the standard testing of neonates for diarrhoeal diseases. Further development of sensitive cheap methods for diagnosing early infection would be of value, and tests that can monitor oocyst shedding accurately. Although pen-side PoC tests are available in some countries, national regulatory frameworks governing animal health products vary widely. Thus, these tests are available in many European countries, but not, for example in USA.

• Vaccines

  Bovilis Cryptium vaccine: In vitro infection assays show efficacy of high titre anti-Gp40 sera and monoclonal antibodies. Medgene vaccine: Although apparently available in USA from May 2025, there is no publicly available information on the mode of action. However, like the Bovilis Cryptium vaccine it is administered to cows and heifers before calving, and likely has a similar basis.

  GAPS

  The potential of adoptive transfer of protective immunity through colostrum from the dam could be investigated more closely, and protective components of immunity within colostrum (both humoral and cell-mediated) identified. Identify Cryptosporidium antigens involved in host-pathogen interactions and evaluate these as targets for vaccine development. Further exploration of vaccine-delivery tools and use of adjuvants would be of value. Whether the efficiency of current vaccines is affected by C. parvum subtype could be worthy of exploration.

• Therapeutics

  Halofuginone lactate and paromomycin are approved for use in newborn calves. Paromomycin is also licensed for use in lambs and goat kids in some EU countries (but not in other animals), for the prevention and reduction of diarrhoea due to cryptosporidiosis. Various other compounds are known to reduce oocyst excretion and control disease, but are either not approved for use in animals or not approved at the effective dose regimen. Plant-based products, prebiotics and probiotics have been investigated either individually or in combination for their potential to help prevent/reduce cryptosporidiosis, but further studies are required to give conclusive results. Nitazoxanide is approved for treatment of human infection by US FDA (for immunocompetent patients over 1 year old), but considered ineffective in immunocompromised and is of questionable efficacy in malnourished children.

  GAPS

  1. Additional products against cryptosporidiosis with emphasis on safety of the target animal, environment, and person who gives the medicine.
  2. Improving ease of use (a reduction in the frequency of necessary treatment) would be of value. In addition, decreasing the cost of existing drugs, while safeguarding efficacy, could be of importance.
  3. Further investigation is needed regarding the efficacy of plant-based products, prebiotics/probiotics with appropriate documentation of the impact on the parasite and the host.

• Biosecurity measures effective as a preventive measure

  Cryptosporidiosis is easily spread to humans. Those working on farms, especially during the calving and lambing periods, and those visiting petting farms should be advised about this. GAPS Biosecurity measures based on social contacts, and other effective interventions could be improved. The inclusion of Cryptosporidium in ‘on farm’ biosecurity, and, where possible, in wildlife management would contribute to limiting spread. It would be useful to develop educational material to advise on risks and how to minimise/avoid transmission. In addition, knowledge exchange events to investigate potential barriers to uptake of appropriate biosecurity and provide advice to help reduce transmission would be useful.

• Border/trade/movement control sufficient for control

  None.

• Prevention tools

  Good management and hygiene are critical for preventing outbreaks of cryptosporidiosis. Ensuring use of good quality colostrum.

  GAPS

  The need to emphasise good management and hygiene practices will always be there. It would be of value to identify active component(s) in colostrum that is / are effective in limiting disease. There has been no research on the effect of adding active component(s) or plant extracts to pooled colostrum sources.

• Surveillance

  Passive surveillance resulting from samples submitted to diagnostic laboratories. In addition, seroepidemiological surveys of exposure can be undertaken mostly using ELISA-based methods. Epidemiological data on human infection is gathered across Europe using the The European Surveillance System (TESSy). However not all countries report or gather data, and animal data are not included. Species and genotype data are not reported.

  GAPS

  1. Encouragement towards gathering epidemiological data from across Europe (and beyond) using passive surveillance, including species and genotype where possible, would be of value
  2. A web-based, publicly available database would be of value (and is already available in some countries).
  3. Surveillance on the duration of antibodies / protection in infected individuals and livestock species could provide useful information.
  4. If species/subtype specific antigens could be developed, then serological (or other immunological) tests could be used for surveillance for specific species/subtypes.
  5. Collecting multi-locus genotype information would be useful for source tracking and outbreak investigations.

• Past experiences on success (and failures) of prevention, control, eradication in regions outside Europe

  Good hygiene can be effective, and treatment and isolation of clinically affected animals is warranted. Eradication of the parasite is unlikely.

  GAPS

  1. Field studies to evaluate treatment and/or management/environmental measures under different management/climate conditions are lacking.
  2. Monitoring studies in water catchments near study farms where different measures are being implemented to reduce/prevent Cryptosporidium shedding or environmental contamination could provide useful information

• Costs of above measures

  Variable- impossible to provide a figure

• Disease information from the WOAH

• WOAH disease card available

  No.

  (https://www.woah.org/en/disease/cryptosporidiosis/)

• WOAH Terrestrial Animal Health Code

  No

• WOAH Terrestrial Manual

  No- Archived (click here for link)

• Socio-economic impact

• Zoonosis: impact on affected individuals and/or aggregated DALY figures

  The 2019 Global Burden of Disease study estimated cryptosporidiosis to result in 133,422 deaths and 8.2 million DALYs annually. These are higher values than those estimated for cholera in the same study.

• Zoonosis: cost of treatment and control of the disease in humans

  Unknown.

  GAP

  There are few economic impact studies are lacking.

• Direct impact (a) on production

  Poor husbandry will result in higher mortality. The cost of reduced growth rates has been calculated for a beef cattle herd in Scotland and Cryptosporidium affected calves at 6 months of age were on average 34 kg lighter than unaffected calves on the same farm, which was equated to £128 (€147) per calf. An economic study conducted on 57 dairy farms in The Netherlands, Belgium and France has calculated the loss per calf due to cryptosporidiosis to be €40. Another study calculated the costs of raising a heifer in a typical Dutch dairy farm with cryptosporidiosis to be €195 per successfully raised heifer.

  GAPS

  1. Further investigations on the short and long-term impact of both clinical and subclinical disease on productivity of different livestock are necessary.
  2. Currently we lack estimates of the costs for C. parvum and other species/genotypes known to be pathogenic and to cause outbreaks in livestock, farmed animals and wildlife
  3. It would be of value to investigate the effects of husbandry and nutrition on the economic impact of cryptosporidiosis.
  4. Economic impact assessments for dairy and beef cattle, sheep and goat farming in different areas, farming scales and husbandry are lacking. The same is true for poultry and wildlife, particularly game (e.g. red grouse).

• Direct impact (b) cost of private and public control measures

  In general, no public control measures are in place (so cost-free). However, outbreaks, particularly those associated with food and water have considerable costs.

  GAPS

  1. The direct costs of waterborne and foodborne outbreaks are seldom calculated and it is difficult to identify which costs are direct and which are indirect (as exemplified by an economic assessment after a waterborne cryptosporidiosis outbreak in Östersund, Sweden).
  2. Conduct a cost-benefit analysis of implementing effective prevention strategies.

• Indirect impact

  Indirect impacts of livestock cryptosporidiosis on farms include reduced production and impact on reputation. This is even more so if there is a farm-visit outbreak. The total costs (direct and indirect) of some outbreaks have been estimated. For example, a waterborne outbreak in Galway, Ireland with 242 lab-confirmed cases and a boil-water notice lasting 158 days was estimated to over 19 million Euros in 2007 (or around 120,000 Euros per day). A waterborne outbreak in Östersund, Sweden in 2011 resulting in an estimated 27,000 cases and with a boil-water notice lasting around 12 weeks is estimated to have costed 220 million Swedish kroner (~200 million Euro). More recently, a waterborne outbreak of cryptosporidiosis in Devon, UK in 2024, with more than 100 cases infected, was estimated to have cost the tourist industry £34m during the outbreak and a further £6m in subsequent months due to booking cancellations and reductions

  GAPS

  Cost-benefit estimates would provide impetus towards improving public health interventions. The cost of social effects (missed school etc.) are often neglected in these estimates.

• Trade implications

• Impact on international trade/exports from the EU

  None. There are no international standards for trade laid down by the WOAH.

• Impact on EU intra-community trade

  None. There are no EU standards related to trade in animals.

• Impact on national trade

  None. There is no control programme nor restriction on movements.

• Links to climate

  Seasonal cycle linked to climate

  Seasonal variation in transmission, influenced by housing density/quality and number of young animals and that they are immunologically naïve.

• Distribution of disease or vector linked to climate

  No.

• Outbreaks linked to extreme weather

  Although data are scarce, outbreaks associated with extreme weather events have been described (e.g., in Halle, Germany in 2013, associated with flooding).

  GAPS

  Although some studies on climate changes, including flooding, droughts, increased / decreased snow melt, have considered Cryptosporidium transmission, data are relatively scanty. Further modelling efforts, taking into account water supply and sewage treatment plants, could provide useful estimates on the effects of weather events spreading contaminated farm waste into the environment.

• Sensitivity of disease or vectors to the effects of global climate change (climate/environment/land use)

  No.

  GAP

  Further study on how exposure to increased solar irradiation and UV affects parasite survival, and whether different species/sub-types are more or less resistant would be relevant.

• Main perceived obstacles for effective prevention and control

  1. Endemic worldwide and a ubiquitous organism that cannot be eliminated:
  2. Very robust resistant oocysts present in high numbers in the environment that are shed in high quantities, but with a low infectious dose.
  3. Most disease and impacts occur in neonates, thus a classic vaccine approach is unlikely to be effective.
  4. Therefore, currently available vaccines rely on passive transfer of immunity from dam to offspring via colostrum.
  5. Important species (particularly C. parvum) are zoonotic and can infect a variety of animals. As well as posing a public health threat, it may also threaten species considered vulnerable, and reservoirs of infection may occur widely
  6. Costs and time constraints for farmers
  GAPS
  1. We lack a vaccine for people, and the approach used for cattle may not easily transfer to humans.
  2. Although in vitro culture of Cryptosporidium has been established, more effective culture approaches that cover the whole lifecycle would be of enormous benefit for exploring new treatment options.
  3. Effective and safe treatments that are cheap

• Main perceived facilitators for effective prevention and control

  Farmers awareness of the disease and how to combat it using good farm management, high levels of hygiene, careful and regular disposal of faeces, isolation of sick calves, and keeping stocking densities at appropriate levels.

  Pen-side diagnostics

  Availability of effective vaccines and therapeutics.

  Use of prophylactic therapeutics in the first few weeks of life.

  Vaccines for dams that stimulate production of colostral antibodies.

  GAPS

  1. Identify effective components (both antibody and cellular immune factors) of immune colostrum.
  2. Study the effect of particular antigenic components of the parasite on the stimulation of effective immune factors in the dams than cam be transferred in the colostrum.
  3. Study the composition of the colostrum and the subsequent transfer of these components to young livestock through immunological monitoring.

Risk

• Cryptosporidiosis remains a significant public health threat. The infection is the 4^th most important cause of gastrointestinal infection in developed countries (UK) and is on the increase. Can be a serious problem in developing countries where the contamination of watercourses, wells and drinking water poses a major risk of infection to vulnerable children and those who are immunocompromised with infections such as HIV.

Main critical gaps

• main critical gaps

  1. More effective drugs are needed that do not have a negative effect on the environment and are appropriately priced
  2. Vaccines for other species of animal and for humans not available.
  3. Incomplete understanding of host and parasite factors influencing virulence and disease outcome.

Conclusion

• A widespread zoonosis of major importance in the developing world. The discovery of new genes, biochemical pathways and protective antigens through mining of the Cryptosporidium genomes will help to develop novel therapies and/or vaccines for cryptosporidiosis.

  The development of vaccines to provide passive immunity to young animals would contribute to the reduction of the level of oocysts in the environment. Future controls could result form passive immunity derived from vaccinated dams and appropriate application of therapies such as nitazoxanide.

  The recent development of a method for the genetic manipulation of the parasite will allow robust testing of the biological role of potential vaccine candidates.

• Conclusion summary (s)

  All Cryptosporidium species have a complex lifecycle including both asexual and sexual reproduction. The asexual reproduction provides enormous replicative power, such that vast quantities of oocysts are shed from infected animals. The robustness of oocysts, the high excretion rate, and the low infectious dose all contribute to waterborne or foodborne transmission being important infection routes (as well as direct from host to host) and may result in disease outbreaks.

  Among the many Cryptosporidium species, specific subtypes of the species C. parvum are of particular relevance to livestock due to being particularly associated with ruminant (calves, sheep, goats) diarrhoea in neonates. This species is also zoonotic. However, other species are also important in different host species (poultry, humans, wildlife) and should not be overlooked. The increase of concentrated animal feeding operations in industrialized nations is having an impact on the evolution of the parasite, favouring the emergence of virulent strains, often through genetic recombination.

  Relevance to animals: Cryptosporidiosis remains an important disease of animals, with a global distribution. The infection is serious and potentially fatal for newborns. Preventing infection is difficult, but good farm-based biosecurity and hygiene, and good animal management have proven efficacy as control measures.

  The recent development of a passive immunization strategy that confers protection to calves through vaccination of dams and heifers with a C. parvum-specific antigen will contribute to a reduction in both clinical signs and excretion of infectious oocysts.

  Relevance to people: Human infection with Cryptosporidium is common, and in industrialised countries this is frequently with zoonotic C. parvum, although other species are also infectious to people; outbreaks have been often reported and may be associated with ingestion of contaminated water or food or with animal contact. In low-income countries, infection with non-zoonotic species often predominates, and the DALY burden is high and includes substantial mortalities.

  Recent developments in diagnostics: In human medicine, Cryptosporidium diagnostics in high-income countries have moved towards molecular detection through inclusion in gastrointestinal pathogen panels that screen for a wide variety of pathogens. However, molecular diagnostics are not yet common practice in the investigation of animal disease, nor in many low-income countries in human medicine, and methods that identify oocysts (microscopy methods, including IFAT) and antigens (including PoC pen-side tests) still predominate. The wide variety of animal hosts and the different Cryptosporidium species that may be involved are also relevant.

  Recent developments in multi-locus typing and whole genome processing have the potential to further our understanding of this parasite, its interactions, and the potential for improved diagnostics, vaccines and therapeutics.

  Recent developments in vaccines and therapeutics: Vaccines have recently begun appearing on the market and will contribute to our arsenal in combating this parasite. Further development of vaccines to provide passive immunity to young animals would contribute to reducing the level of oocysts in the environment. Future controls could result from passive immunity derived from vaccinated dams and appropriate application of drug therapies

  The discovery of new genes, biochemical pathways, and protective antigens through mining of the Cryptosporidium genomes will help to develop novel therapies and/or vaccines for cryptosporidiosis.

  Recent developments of tools for the genetic manipulation of the parasite, and the establishment of informative in vivo models of infection are allowing robust testing of the biological role of genes and proteins, including potential vaccine candidates. In addition, the use of genetically modified parasites in vitro infection models allows screening of active therapeutic compounds on a large scale, leading to the identification of new therapeutic compounds, which await commercialisation.

Sources of information

• Expert group composition

  Expert group members are included where permission has been given:

  Lucy Robertson, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Norway

  Simone M. Caccio, Department of Infectious Diseases, Istituto Superiore di Sanità, Italy

  Kurt Hanevik, University of Bergen, Norway

  Frank Katzer, Moredun Research Institute, United Kingdom

  Guy Robinson, Cryptosporidium Reference Unit, Public Health Wales, United Kingdom

  Monica Santin-Duran, United States Department of Agriculture, USA

  Karin Troell, Norwegian Veterinary Institute, Norway

  Mark van Roosmalen, MSD Animal Health

  Geert Vertenten, MSD Animal Health

• Date of submission by expert group

  18 December 2025

• References

  Please cite this chapter as: Robertson L., Caccio S.M., Hanevik K., Katzer K., Robinson G., Santin-Duran M., Troell K., van Roosmalen M., Vertenten G., 2026. DISCONTOOLS chapter on Cryptosporidiosis. https://www.discontools.eu/database/52-cryptosporidiosis.html.

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• Name of reviewers

  Project Management Board