A diarrheal disease caused by Cryptoporidium, an intracellular parasite of the phylum Apicomplexa.

Cryptosporidium hominis human genotype 1.

The parasite completes its life cycle in the host, starting with the ingestion of the oocyst forms.

Cryptosporidium parasites are spread through direct contact with infected people or animals or exposure to fecal contamination of water, soil, food, or the hands of exposed individuals.

The principle cryptosporidium species that in fact humans are C, parvum and C. hominis.

Molecular techniques are needed to distinguish between the two oocyst species.

Once ingested the parasite causes infection in the small intestine.
Rarely it can cause disease outside the G.I. tract.
The disease ranges from no symptoms to death in certain cases, and depends upon underlying health of the infected patient.
Occurs worldwide but is more common in regions with inadequate sanitation and hygiene.
These parasites are resistant to many common disinfectants including chlorine.

Oocysts rupture in the gastrointestinal tract releasing trophozoites, which adhere to and invade epithelial intestinal cells with asexual replication into merozoites.

Merozoites are released into the gastrointestinal lumen and can infect other mucosal cells or differentiate into gametocytes which produce sexually into oocysts restarting the process.

Oocysts are excreted into the feces.

Cryptosporidium is a chlorine resistant parasite and can cause illness after ingestion of as few as 10 oocysts.

Ingestion of oocysts by other hosts spreads the infection.

Spread by person-to-person contact, by infected water, food and animals.

1-2 cases per 100,000 population in the U.S. reported each year.

Spread by fecal-oral contact from oral-anal contact or poor hygiene and by fomites.

Infected ingested or recreational water a major source of outbreaks of infection.

Oocysts are hardy and require few to initiate infection.

Oocysts can be infectious for up to 6 months, if kept moist.

Oocysts are unaffected by chlorine treated water.

Can survive for days in recreational waters such as swimming pools and water parks.

Can cause large scale outbreaks in recreational water activities and child care centers.

Fecal-oral transmission of Cryptosporidium oocysts can occur via ingestion of contaminated recreational water, drinking water, or food, or through contact with infected persons or animals, most notably preweaned calves.

Treatment of water with filters, ultraviolet radiation and ozone required to remove or kill the parasitic organisms.

Primarily a gastrointestinal disease manifested by diarrhea.

Watery diarrhea lasts 1-3 weeks.

Diarrhea, stomach pain, nausea, vomiting, fever, and dehydration are the most common symptoms.

A self limited illness in immunocompetent patients.

Effects immunocompetent and immunocompromised individuals especially those with HIV.

It affects immunocompetent, mostly children under the age of five.

In immune competent persons the disease can range from asymptomatic infection to diarrhea that typically lasts 1 to 2 weeks.

Immunocompromised individuals may experience chronic and severe diarrhea which can lead to weight loss, malnutrition and potentially death.

In immunodeficient individuals, particularly in HIV patients, can be a life-threatening process.

Prevalence decreasing with the addition of highly active antiretroviral therapy.

Prior to the use of HAART 3-4% of patients with AIDS contracted this infection.

HAART therapy that improves CD4 count reduces the severity of the infection, but is not curative and the symptoms can remit when immune status worsens.

To control transmission hand washing with soap and using disposable towels or air dryers.

Alcohol-based hand sanitizes are not effective against Cryptosporidium.

Contact with preweaned calves should be limited.

Diagnosis is made by microscopic detection of cryptosporidium in stool samples.
Most patients with healthy immune systems recover with rest and fluids to prevent dehydration.
Anti-diarrheal medications can alleviate symptoms.
No reliable treatment for cryptosporidium enteritis.

Paromomycin, atovaquone, nitazoxanide,and azithromycin have only temporary effects.

Treatment is primarily supportive, and intravenous fluids may rarely be needed.

Antibiotics are not usually helpful, and are primarily reserved for persons with severe disease and immunosuppression.

Nitazoxamide an antiparasitic agent has been shown to be efficacious in immunocompetent patients.

Prevention by washing hands thoroughly with soap and water, as alcohol-based sanitizers do you not kill the parasite.
Toys and other surfaces in child care facility should be sanitized with soap and water.
Avoiding the ingestion of untreated water or ice particularly when traveling is efficacious.
Avoiding swallowing water in pools and other  the bodies of water.
Children with diarrhea should not be allowed to swim.

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