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 1976.

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 1993. The parasite that caused the disease was determined to be cryptosporidium.

Infectivity & Life Cycle C. parvum has a low ID50 (9-1000

oocysts) Can be infected by just one oocyst 10 billion oocysts per gram infected

feces

http://www.dpd.cdc.gov/dpdx/HTML/Cryptosporidiosis.htm

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

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 testingUse of 1 micron filter to remove cystsBoil 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 !