CRYPTOSPORIDIUM SP

What is it?  Cryptosporidium is an emerging coccidian protozoan parasite  It is associated with municipal water supplies which causes diarrhea  Cryptosporidium parvum causes the disease Cryptosporidiosis.  During the past two decades, Cryptosporidium has become recognized as one of the most common causes of waterborne illness in the United States.

 Definitive Host: Human  Reservoir Hosts: kittens, puppies, goats, calves, mice,etc  It is a zoonotic disease and can travel from animals to humans, and also from human to human  Transmission : fecal oral route  food and water  Cryptosporidium parvum has been recognized as a human pathogen since What is it?

Prevalence  Found in most parts of the world  Most prevalent in Asia, Africa, Australia, South America  Antibody prevalence in Peru and Venezuela – 64%  32% in Peace Corps workers  More prevalent in rural areas of U.S.  More animal contact

Outbreak  In Milwaukee, WI water contamination from a sewage treatment plant killed 100 people and affected more than 400,000 in The parasite that caused the disease was determined to be cryptosporidium.

Infectivity & Life Cycle  C. parvum has a low ID 50 ( oocysts)  Can be infected by just one oocyst  10 billion oocysts per gram infected feces

Oocyst  Double walled, 4-6µm  Resistant to chlorine, drying, progressive freezing, salt water  Only stage in life cycle that can live ex vivo  Imbeds itself in gut epithelium and releases sporozoites  Reproduction continues sexually and asexually  Mature oocyst contain 4 sporozoites within

Site of infection  Epithelial cells of the gastrointestinal tract  Has affected other tissues such as respiratory tract tissues and conjunctiva of the eye.  Cell death is a direct result of parasite invasion, multiplication, and extrusion or  Cell damage could occur through T cell-mediated inflammation, producing microvilli death and Cryptosporidium excess growth

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.)

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

Symptoms Some individuals can be asymptomatic Incubation period: 2-10 days Symptoms include: Stomach cramps, pain, watery diarrhea, dehydration, weight loss, vomiting, fever. Immuno-competent individuals: 1-2 weeks Immuno-compromised individuals: longer (months, even years!) Patients excreting at least 2-25 liters of watery diarrhea per day  life threatening!

LAB DIAGNOSIS  Microscopic exam  Modified acid fast stain of stool sample  Endoscopic biopsy of small intestine

Cryptosporidium oocysts with acid-fast stain

LAB DIAGNOSIS  Immunodiagnosis  Immunofluorescence assay (IFA)  Enzyme linked immunoabsorbant assay (ELISA)  Polymerase Chain Reaction (PCR)  Test of choice

LAB DIAGNOSIS

Treatment  No effective therapy, currently researching for a suitable prophylactic drug.  Immuno-competent individuals will recover with fluid and electrolyte replacement.  Nitazoxande for treatment of diarrhea.  For individuals with AIDS, anti-retroviral therapy will reduce oocyst excretion and decreases diarrhea.

Control Methods Water purification and filtration Routine testing Use of 1 micron filter to remove cysts Boil water Drink bottled water when traveling abroad Educate public Wash hands frequently Avoid fecal matter during sexual activity

INTERESTING FACT  There were 6 outbreaks between 1984 and 1994 in the US.  Cryptosporidium is resistant to chlorine.  Not protected in chlorinated pool.  In MO there were 26 confirmed cases from motel pools in 1994.

INTERESTING FACT  Cattle alone produce about 4.57 tons of Cryptosporidium oocysts per year in the US BEWARE !