What Is Cryptosporidiosis?
Cryptosporidiosis is a disease caused by infection of humans and other
animals by one or more species of Cryptosporidium protozoans. At least 15
different species of Cryptosporidium can cause the disease in humans and
other animals. Cryptosporidium hominis is the only species that uses only humans as a
host. The disease causes diarrhea and mainly affects children.
What Causes Cryptosporidiosis?
The causes of cryptosporidiosis are protozoan parasites that reproduce in the
epithelial cells lining the distal small intestine tract and, if the host is
immunocompromised, parasites may reproduce almost anywhere in the G.I. tract and
in the lungs. C. hominis and C. parvum are the two species that mainly infect
humans although other species may participate.
Is Cryptosporidiosis Contagious?
Cryptosporidiosis is highly contagious, and many outbreaks can occur from
fecal-oral route. Transmission of the infections often are by person-to-person contact. However, humans can get the disease from parasites excreted by
humans, animals, and the environment.
Life cycle of Cryptosporidium; image courtesy of the CDC
Bacterial Infections 101: Types, Symptoms, and Treatments
What Are Risk Factors for Cryptosporidiosis?
Risk factors for cryptosporidiosis include poor environmental sanitation,
contaminated public water supply systems, including swimming pools, ingestion of
contaminated food, and close human-animal contacts. Unfortunately,
Cryptosporidium species can resist chlorination and survive for long
periods in the environment. For example, in 1993, Milwaukee, Wis., had a
significant outbreak documented to be caused by contamination in the
treatment processing of the city's drinking water. Apparently, thousands of
citizens developed symptoms. The city health department eventually determined
that Cryptosporidium was in the tap water. People had to destroy food and drinks,
and the city's population had to boil water and clean all foods. This
outbreak was the largest documented waterborne disease in U.S. history.
What Is the Incubation Period for Cryptosporidiosis?
The incubation period ranges from about two to 10 days, with the average being
seven days after exposure to the parasite. A few patients may not develop
symptoms for as long as 28 days.
What Are Cryptosporidiosis Symptoms and Signs?
The first signs and symptoms of the disease often are watery diarrhea and fever. The patient can develop lack of appetite, stomach cramps, dehydration, weight loss, nausea, and/or vomiting. Symptoms last about five to 10 days but may persist longer in immunosuppressed individuals.
How Do Medical Professionals Diagnose Cryptosporidiosis?
Testing stool samples can diagnose the disease. Most laboratories do
not routinely test for Cryptosporidium parasites. However, medical
professionals may rarely utilize tests such as acid-fast staining of stool specimens, fluorescent antibody tests, and other
immunoassays to diagnose the disease.
What Is the Treatment for Cryptosporidiosis?
Most individuals who have normal, healthy immune systems recover without treatment. However, young children and pregnant women are susceptible to dehydration, which could become life threatening. Consequently, patients need to be well hydrated. Doctors suggest a lactose-free diet to avoid malnutrition since the tips of the villi that process lactose are often lost for the duration of the illness. The FDA approved nitazoxanide for cryptosporidiosis diarrhea. Physicians have prescribed paromomycin and azithromycin used alone and together with some effect. Infected individuals may use over-the-counter treatments to suppress diarrhea and reduce symptoms of fever and nausea. An infectious disease consultant is often helpful in the management of immunosuppressed patients with this disease.
What Is the Prognosis for Cryptosporidiosis?
In healthy individuals, the prognosis is good because the disease is usually
self-limiting and does not require special treatment. However, individuals who are immunocompromised (for example, patients with AIDS) have a prognosis that
may vary from fair to poor depending upon how they respond to supportive care
and treatment. Complications of cryptosporidiosis can be persistent diarrhea,
malnutrition, dehydration, respiratory problems, pancreatitis, and gallbladder
problems (acalculous cholecystitis). Some patients may have persistent pain in
the head, joints, eyes, and may have problems with cognition.
Is It Possible to Prevent Cryptosporidiosis?
It is possible to reduce the chance of getting cryptosporidiosis by maintaining good personal hygiene, avoiding food and drinks that may be contaminated, by not swimming in natural sources of water (especially after heavy downpours), and not sharing linens or towels or other items touched by an infected person. Because Cryptosporidium parasites are resistant to chlorination, health officials recommend boiling water for drinking for prevention of the disease in areas that may have outbreaks. People may use special filters to purify water. Although research is ongoing to develop a vaccine, there is currently no commercially available vaccine for humans.
Cabada, M. "Cryptosporidiosis." Medscape.com. Aug. 24, 2018. <https://emedicine.medscape.com/article/215490-overview>.