Cryptosporidium Infection

1 What is Cryptosporidium Infection?

Cryptosporidium infection (cryptosporidiosis) is an intestinal infection caused by microscopic parasite cryptosporidium. The major signs of cryptosporidiosis are watery diarrhea and abdominal cramps. The infection is non-serious in healthy individuals and often symptoms like watery diarrhea subside within one or two weeks. However, in an individual with weakened immunity, it can be fatal if left untreated. As with other similar intestinal infections, you can prevent cryptosporidiosis by exercising good hygiene. You also need to take care not to swallow water from pools, recreational water parks, lakes and streams as the water can be contaminated with cryptosporidiosis parasite.

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2 Symptoms

It takes about a week for the parasite to produce apparent signs and symptoms of cryptosporidium infection that may include: 

Some people may not realize that they are infected because they may not notice any symptoms. In general, the symptoms last for up to two weeks while in some cases, they may appear and disappear randomly for up to a month. 

When to see a doctor? 

Consult your doctor if you develop watery diarrhea that persists for more than a few days.

3 Causes

Tiny cryptosporidium parasite is the main cause of cryptosporidium infection. Once ingested, these parasites take a tour of your intestinal tract before harboring in your intestinal walls. They grow in your intestine and are excreted in your feces, ingestion of which is the most likely cause of the infection. The microorganisms in your feces are very contagious and may infect you if you touch anything that contains small particles of the contaminated feces. The various modes of transmission are:

  • Drinking contaminated water 
  • Swimming in contaminated water 
  • Eating raw contaminated food 
  • Accidentally or unintendedly ingesting the microorganism while touching your mouth with a contaminated hand
  • Being close to an infected person or animal 

Your risk of having cryptosporidium infection increases if you have conditions that weaken your immune cells. It is often difficult to treat cryptosporidiosis because of:

  • Intense nature of the symptoms
  • Chronic, persistent nature of the infection
  • Resistance of cryptosporidium parasites to common disinfectants

Cryptosporidia is notorious for its ability to survive in harsh conditions such as varying temperature for many months. However, you can kill the parasite by freezing or boiling.

4 Making a Diagnosis

You can visit your primary physician to receive a diagnosis if you suspect being infected by cryptosporidiosis. You may be referred to a doctor who specializes in infectious diseases or a doctor who specializes in disorders of the gastrointestinal tract (gastroenterologist). 

How to prepare yourself for the visit?

Getting prepared for the visit can optimize the therapy and help make the visit more fruitful.

List out all the symptoms.

Write down your key medical information. 

Mention any recent travel.

Write down the names of all your medications, vitamins or supplements. 

Ask a friend or a family member to accompany you during the visit.

Make a list of the questions to ask your doctor. Some typical questions can be: 

  • What could be causing my symptoms?
  • What are the tests that I need? 
  • What are my treatment options? 
  • Do I need to follow any dietary restrictions?

What your doctor wants to know?

A clear talk with your doctor can optimize the therapy and improve the outcomes. Prepare yourself to answer some essential questions from your doctor. Your doctor might ask you typical questions like: 

  • When did the symptoms start appearing? 
  • How severe are your symptoms? 
  • Does anything improve or aggravate your symptoms? 
  • Do you swim? If yes, how often and where? 
  • Can you tell something about your recent travel history, if any? 

What you can do in the meantime? 

Take enough fluids to stay hydrated while you're waiting to see your doctor. 

Tests for Cryptosporidiosis include: 

  • Acid-staining test: It is a simple test in which a sample of cells from your stool is examined under a microscope to detect the presence of cryptosporidiosis parasite. If sample stool collection is not possible, your doctor may take a tissue sample (biopsy) from your intestine for the test. 
  • Stool culture: This is done to exclude other bacterial causes for the symptoms. 
  • Other tests: Once the diagnosis is confirmed, other tests may be done to detect if complications have developed. For example, liver and gallbladder functions may be checked to detect if the infection has spread. In case you are an AIDS patient and have cryptosporidiosis, you have to undergo a test that measures the level of immune cells in your blood, a T cell count. Your risk of complications increases if T cell count is below 100. 

5 Treatment

No one knows what works the best for cryptosporidium infection and the current treatments aim to reduce severity of the symptoms and enhance immune response. Recovery usually depends on how well your immune system is working. In most healthy people, cryptosporidiosis in non-serious and symptoms subside within two weeks on their own. However, it can cause complications like severe malnutrition if your immune system is weakened. The treatment options are: 

  • Antibiotics: Medications, such as nitazoxanide, can be given to reduce diarrhea. Another antibiotic azithromycin may be added to the drug regimen if you have weakened immunity. 
  • Anti-motility agents: These medications delay passage of contents down your intestines and promote absorption of fluids. They may be helpful to reduce diarrhea but you need to talk to your doctor prior to using any of the drugs such as loperamide and derivatives.
  • Fluid replacement: To replace the fluid and electrolytes lost during bouts of diarrhea, you may be given a combination of fluids and minerals by mouth or injection. It helps to keep you hydrated and prevents complications of dehydration
  • Antiretroviral therapies: Highly active antiretroviral therapy (HAART) is given to the patients who have HIV/AIDS. 

6 Prevention

Here are some tips to prevent the spread of cryptosporidium infection: 

  • Exercise good hygiene: Do not forget to properly wash your hands with soap and water after using the toilet and changing diapers, and before and after eating. 
  • Wash raw fruits and vegetables under running water for sufficient time. 
  • Do not eat food that might have been contaminated. 
  • Do not eat raw food during your stay in a developing country. 
  • Drink only purified water. You may boil it for at least one minute or filter it using 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. For bacteria and viruses, you will have to use other filters.
  • If your immunity is compromised, do not swim in lakes, streams and public swimming pools. If you are healthy, reduce the frequency. 
  • Do not indulge in oral-anal sexual activity. 
  • Exercise precautions when you handle newborn farm and domestic animals. Do not forget to wash your hands after you come in contact with them. 
  • Do not swim if you are having diarrhea. If your diagnosis is confirmed, don't go swimming for at least two weeks after your symptoms are over because you may still pass the infection to others.

7 Risks and Complications

There are several risks and complications associated with cryptosporidium infection.


  • Exposure to contaminated water 
  • Children in child care centers, especially those wearing diapers
  • Parents of infected children
  • Child care workers 
  • Animal handlers 
  • Engaging in oral-to-anal sexual activity 
  • Travelers, especially those traveling to developing countries 
  • Backpackers, hikers and campers who drink water from unknown source 
  • Swimmers who swallow water in pools, lakes and rivers 
  • People who drink water from shallow, unprotected wells


  • Malnutrition: Persistent diarrhea can cause poor absorption of nutrients from your intestinal tract (malabsorption) 
  • Severe dehydration 
  • Marked weight loss (wasting) 
  • Inflammation of a bile duct
  • Inflammation of your gallbladder, liver or pancreas 

Cryptosporidium infection itself isn't fatal but the associated complications in people who have had a transplant or have a compromised immune system, can be life-threatening.