Cryptosporidiosis, is a parasitic disease caused by the parasite Cryptosporidium. It affects the distal small intestine and can affect the respiratory tract in both immunocompetent (i.e., individuals with a normal functioning immune system) and immunocompromised (e.g., persons with HIV/AIDS) individuals, resulting in watery diarrhea with or without an unexplained cough. In immunocompromised individuals, the symptoms are particularly severe and can be fatal. It is primarily spread through the fecal-oral route, often through contaminated water.
In most healthy people, cryptosporidium infection produces a bout of watery diarrhea and the infection usually goes away within a week or two. If you have a compromised immune system, a cryptosporidium infection can become life-threatening without proper treatment.
You can help prevent a cryptosporidium infection by practicing good hygiene and avoiding swallowing water from pools, recreational water parks, lakes and streams.
Symptoms appear from two to ten days after infection, with an average of 7 days, and last for up to two weeks, or in some cases, up to one month. The first signs and symptoms of cryptosporidium infection usually appear within a week after infection and may include:
- Watery diarrhea
- Lack of appetite
- Weight loss
- Stomach cramps or pain
Some people with cryptosporidium infection may have no symptoms.
Cryptosporidium infection begins when you ingest the one-celled cryptosporidium parasite. Some strains of cryptosporidium may cause more serious disease.
These parasites then travel to your intestinal tract, where they settle into the walls of your intestines. Eventually, more cells are produced and shed in massive quantities into your feces, where they are highly contagious.
You can become infected with cryptosporidia by touching anything that has come in contact with contaminated feces. Methods of infection include:
- Drinking contaminated water that contains cryptosporidium parasites
- Swimming in contaminated water that contains cryptosporidium parasites and accidentally swallowing some of it
- Eating uncooked, contaminated food that contains cryptosporidia
- Touching your hand to your mouth if your hand has been in contact with a contaminated surface or object
- Having close contact with other infected people or animals — especially their feces — which can allow the parasite to be transmitted from your hands to your mouth
If you have a compromised immune system from HIV/AIDS, you're more susceptible to illness from cryptosporidium parasites than is a person with a healthy immune system. People with HIV/AIDS can develop severe symptoms and a chronic, persistent form of disease that may be difficult to treat.
Cryptosporidium parasites are one of the most common causes of diarrhea in humans. This parasite is difficult to eradicate because it's resistant to many chlorine-based disinfectants and can't be effectively removed by many filters. Cryptosporidia can also survive in the environment for many months at varying temperatures, though the parasite can be destroyed by freezing or boiling.
People who are at increased risk of developing cryptosporidiosis include:
- Those who are exposed to contaminated water
- Children, particularly those wearing diapers, who attend child care centers
- Parents of infected children
- Child care workers
- Animal handlers
- Those who engage in oral-to-anal sexual activity
- International travelers, especially those traveling to developing countries
- Backpackers, hikers and campers who drink untreated, unfiltered water
- Swimmers who swallow water in pools, lakes and rivers
- People who drink water from shallow, unprotected wells
Cryptosporidium infection is contagious, so take precautions to avoid spreading the parasite to other people. There's no vaccine that can prevent cryptosporidium infection.
All preventive methods aim to reduce or prevent the transmission of the cryptosporidium germs that are shed in human and animal feces. Precautions are especially important for people with compromised immune systems. Follow these suggestions:
- Practice good hygiene. Wash your hands with soap and water after using the toilet and changing diapers, and before and after eating.
- Thoroughly wash with uncontaminated water all fruits and vegetables that you will eat raw, and avoid eating any food you suspect might be contaminated. If you're traveling in a developing country, avoid uncooked foods.
- Purify drinking water if you have a weakened immune system or are traveling in an area with a high risk of infection. Methods include boiling — at least one minute at a rolling boil — or filtering, although filtering may not be as effective as boiling. Be sure to use a filter that meets the National Safety Foundation Standard/American National Standards Institute (NSF/ANSI) standard 53 or 58 requirements for cyst and oocyst reduction. You'll need a separate water filter to for bacteria and viruses.
- Limit swimming activities in lakes, streams and public swimming pools, especially if the water is likely to be contaminated or if you have a compromised immune system.
- Avoid fecal exposure during sexual activity.
- Handle newborn farm and domestic animals with care. Be sure to wash your hands after handling the animals.
Always refrain from swimming anytime you're experiencing diarrhea. If you know you've had a cryptosporidium infection, don't go swimming for at least two weeks after your symptoms subside because you may still be contagious.
There are many diagnostic tests for Cryptosporidium. They include microscopy, staining, and detection of antibodies. Detecting antigens is yet another way to diagnose the disease. Polymerase chain reaction (PCR) is another way to diagnose cryptosporidiosis. It can even identify the specific species of Cryptosporidium. If the patient is thought to have biliary cryptosporidiosis, then an appropriate diagnostic technique is ultrasonography. If that returns normal results, the next step would be to perform endoscopic retrograde cholangiopancreatography.
The following tests to diagnose cryptosporidium infection:
- Acid-staining test. The simplest way to diagnose cryptosporidium infection is a method called an acid-staining test, which identifies cryptosporidium under a microscope. To obtain cells for the analysis, your doctor might ask for a stool sample, or in more extreme cases, take a tissue sample (biopsy) from your intestine for the test.
- Stool culture. Your doctor might also order a standard stool culture. Although this test cannot detect the presence of cryptosporidium, it may help rule out other bacterial pathogens.
- Other tests. Once it's clear that your infection is caused by cryptosporidium parasites, you may need further testing to check for development of serious complications. For example, checking liver and gallbladder function may determine whether the infection has spread.
If you have both AIDS and cryptosporidiosis, a T cell count — which measures the level of a certain white blood cell that's part of your immune system — can help predict the duration of the cryptosporidiosis. A T cell count under 100 cells per microliter means you're more likely to have complications.
The majority of individuals suffer a short (less than 2 weeks) self-limiting course that requires supportive care with rehydration and occasionally antidiarrhoeal medication, and ends with spontaneous recovery.
In immunocompromised individuals, such as AIDS/HIV patients, cryptosporidiosis resolves slowly or not at all, and frequently causes a particularly severe and permanent form of watery diarrhea coupled with a greatly decreased ability to absorb key nutrients through the intestinal tract. The result is progressively severe dehydration, electrolyte imbalances, malnutrition, wasting, and eventual death.
There's no commonly advised specific treatment for cryptosporidiosis, and recovery usually depends on the health of your immune system. Most healthy people recover within two weeks without medical attention.
If you have a compromised immune system, the illness can last and lead to significant malnutrition and wasting. The goal of treatment is to alleviate symptoms and improve your immune response. Cryptosporidiosis treatment options include:
- Anti-parasitic drugs. Medications, such as nitazoxanide (Alinia) approved to treat diarrhea caused by Cryptosporidium parvum and Giardia lamblia.
- Antibiotics: Azithromycin (Zithromax) may be given along with one of these medications in people with compromised immune systems.
- Anti-motility agents. These medications slow down the movements of your intestines and increase fluid absorption to relieve diarrhea and restore normal stools. Anti-motility drugs include loperamide and its derivatives (Imodium A-D, others). Talk with your doctor before taking any of these medications.
- Fluid replacement. You'll need either oral or intravenous replacement of fluids and electrolytes — minerals, such as sodium, potassium and calcium, that maintain the balance of fluids in your body — lost to persistent diarrhea. These precautions will help keep your body hydrated and functioning properly.
- Antiretroviral therapies. If you have HIV/AIDS, highly active antiretroviral therapy (HAART) can reduce the viral load in your body and boost your immune response. Restoring your immune system to a certain level may completely resolve symptoms of cryptosporidiosis.
Refer to research Publications.