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OUTLINE Organism History Epidemiology Transmission Clinical Signs Diagnosis and Treatment Prevention


Coccidian protozoa Obligate intramembranous pathogen Primarily infects small intestine Forms oocysts Resistant to disinfection Killed by ozone, desiccation Oocysts may also be killed with 5% ammonia solution. CRYPTOSPORIDIUM


Genus ------- Cryptosporidium Family ------- Cryptosporidiidae Order- -------- Eucoccidiorida Subclass ------ Coccidiasina Class ----------- Sporozoasida Phylum -------- Apicomplexa . TAXONOMY


Currently, there are 18 ‘valid’ species namely: C. hominis found primarily in humans (previously known as C. parvum Type 1) C. parvum found in humans and other mammals (previously known as C. parvum Type 2) C. andersoni and C. bovis in cattle C. canis in dogs C. muris in mice C. felis in cats C. wrairi in guinea-pigs C. suis in pigs SPECIES


C. fayeri in red kangaroo C. macropodum in grey kangaroo C. meleagridis in turkeys and humans C. baileyi in chickens C. galli in adult hens and some wild birds C. varanii in emerald monitor lizards C. serpentis in snakes and lizards C. molnari in fish In livestock, C. parvum, C. andersoni, C. baileyi and C. meleagridis have been reported to cause morbidity and outbreaks of disease.


HISTORY In 1907, Tyzzer was the first to discover the genus Cryptosporidium who described it as a coccidian- like organism in the stomach of mice, which he named Cryptosporidium muris. Later, Tyzzer discovered second organism from small intestine of mice, which he named Cryptosporidium parvum. Cryptosporidium associated Diarrhoea in young turkeys ( C. meleagridis ) in the 1950s, and with large outbreaks of diarrhoea in calves ( C. parvum ) in the 1970s. E.E. Tyzzer


In Humans:- 1987 Carroll County Cryptosporidiosis outbreak 13,000 of the 65,000 residents suffered intestinal illness 1993: Milwaukee, WI Largest known water supply outbreak 40,000 persons became ill 1997: Minnesota Zoo Decorative water fountain 369 cases Most cases in children <10 years old 1998 Sydney water crisis

Epidemology and Risk Factors:

Epidemology and Risk Factors Cryptosporidium can be spread: By putting something in mouth or accidentally swallowing something that has come in contact with the stool of a person or animal infected with Cryptosporidium . By swallowing  recreational water  contaminated with Cryptosporidium . By swallowing water or beverages contaminated by stool from infected humans or animals. By eating uncooked food contaminated with Cryptosporidium.


By touching mouth with contaminated hands. Hands can become contaminated through a variety of activities, such as: Touching surfaces (e.g., toys, bathroom fixtures, changing tables, diaper pails) that have been contaminated by stool from an infected person. Caring for an infected person . Handling an infected cow or calf .


International travelers Backpackers, hikers, and campers who drink unfiltered, untreated water People who drink from untreated shallow, unprotected wells People, including swimmers, who swallow water from contaminated sources People who handle infected cattle People exposed to human faeces through sexual contact


50% infective dose (ID50) of C. parvum is only 132 oocysts ( Resistant to chlorine treatment) North America 2% of population infected 80% previously exposed Worldwide Prevalence lower in developed countries, higher in developing countries Animals Morbidity high, mortality low


Transmission Fecal-oral route Person-to-person Person-to-animal Waterborne Food borne Mechanical Aerosol (rare)


Phase contrast photograph of sporozoite release from the Cryptosporidium oocyst


Pathogenesis Upon oocyst excystation , four sporozoites are released which adhere their apical ends to the surface of the intestinal mucosa A sporozoite -specific lectin adherence factor has been identified Following attachment cytokines are released from Epithelial cells which activates macrophages


Activated macrophages release histamine, serotonin, adenosine, prostaglandins, leukotrienes, and platelet-activating factor which induce loss of fluid and electrolytes.


Epithelial cells are damaged Cell death is a direct result of parasite invasion, multiplication, and extrusion . 2. Cell damage could occur through T cell-mediated inflammation,producing villus atrophy and crypt hyperplasia. Both results in distortion of villus architecture results in nutrient malabsorption and diarrhoea

Disease in Animals:

Disease in Animals All mammals Common in calves and lambs Other species Pigs Birds Dogs (rare) Cats (rare) Horses (rare)


Incubation period ~ 4 days in calves Clinical signs: Anorexia Diarrhea Tenesmus Weight loss

Post Mortem Lesions:

Post Mortem Lesions Gross lesions Hyperemia of intestinal mucosa Yellowish intestinal contents Microscopic lesions Mild to severe villous atrophy Spherical organisms in the brush border Shortening of microvilli and sloughing of enterocytes

Samples :

Samples Mainly feacal samples and intestinal necropsy samples collected. Ideally, transportation systems should be selected to ensure that specimens arrive at the laboratory within 24 hours. If prompt examination for Cryptosporidium cannot be carried out, the deterioration of protozoan morphology and their overgrowth by other microorganisms, can be reduced by the addition of 10% aqueous (v/v) formalin, although 10% formalin can interfere with PCR tests.


Both oocyst morphology for microscopic identification and sporozoite DNA for PCR testing can usually be preserved for long periods at 4°C without formalinisation. Faeces can be stored frozen for over 2 years without affecting the ability to extract Cryptosporidium DNA for molecular analysis. Repeated freeze–thawing of frozen faecal samples is not recommended as the released DNA will degrade.


Diagnosis Diagnostic tests Fecal flotation Acid-fast staining Immunofluorescence Differentials Giardia, Isospora Microsporidia Salmonella Rotavirus


C. parvum - Cysts in stool Acid fast Source:


A scanning electron micrograph of a broken meront of Cryptosporidium showing the merozoites within.  (From: Gardiner et al., 1988,An Atlas of Protozoan Parasites in Animal Tissues, USDA Agriculture Handbook No.651)


A scanning electron micrograph of Cryptosporidium lining the intestinal tract . ( From: Gardiner et al., 1988,An Atlas of Protozoan Parasites in Animal Tissues, USDA Agriculture Handbook No.651 )


Source: Cryptosporidium parvum : Oocysts of Cryptosporidium parvum , in wet mount. The oocysts are rounded, 4.2 µm - 5.4 µm in diameter.  Sporozoites are visible inside the oocysts


Source: Oocysts of Cryptosporidium parvum stained by the modified acid-fast method. Sporozoites are visible inside the two oocysts to the right.


Source: “ghosts” modified acid-fast method non acid-fast oocysts “ghosts”  


Source: Oocysts of Cryptosporidium parvum stained with the fluorescent stain auramine-rhodamine


Giardia cyst C. parvum Source: Oocysts of C. parvum (upper left) and cysts of Giardia intestinalis (lower right) labeled with immunofluorescent antibodies

Treatment :

Treatment No specific treatment Supportive care Rehydration Correction of acidosis Maintenance of energy requirements No vaccine Center for Food Security and Public Health, Iowa State University, 2011

Disease in Humans:

Disease in Humans Similar to disease in animals Parasite is accidentally swallowed Contaminated water, food, hands, stool People affected: Children Immunosuppressed Travelers Swimmers Center for Food Security and Public Health, Iowa State University, 2011

Disease in Humans:

Disease in Humans Incubation period: 1 to 12 days Clinical signs Profuse, watery diarrhea Abdominal pains Anorexia Self-limiting in healthy people May become serious in immunocompromised people Center for Food Security and Public Health, Iowa State University, 2011


Diagnosis Differential diagnosis Similar to animals Diagnostic tests Fecal flotation Acid-fast staining Immunofluorescence Antigen capture rapid diagnostic kits Center for Food Security and Public Health, Iowa State University, 2011


Duodenal biopsy sample from a patient with AIDS and cryptosporidiosis. Source:http ://

Prevention and Control:

Prevention and Control

Prevention in Animals:

Prevention in Animals Keep sick away from healthy animals Clean and disinfect (5% ammonia solution) pens Good nutrition Center for Food Security and Public Health, Iowa State University, 2011

Prevention in Humans:

Prevention in Humans Wash hands Wash fruits/vegetables Don’t swallow water from: Lakes Streams Public pools Minimize contact with young and sick animals Center for Food Security and Public Health, Iowa State University, 2011


Resources World Organization for Animal Health (OIE) U.S. Department of Agriculture (USDA) Center for Food Security and Public Health Centers for Disease Control and Prevention / Center for Food Security and Public Health, Iowa State University, 2011


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