Avoiding Cryptosporidiosis

What the HIV-Positive Patient Needs to Know

Cryptosporidiosis (CRYPT-OH-spore-id-ee-oh-sis) is an uncommon but unpleasant AIDS-related opportunistic infection. It occurs in up to 20% of people who are infected with the human immunodeficiency virus, causing non-bloody, watery diarrhea and, less commonly, abdominal cramping and pain. Onset is generally rapid and fever is rare. Nausea, vomiting, tiredness, and jaundice -- a yellow discoloration of the skin and/or the whites of the eyes -- have been reported in some cases.

Cryptosporidium, the organism that causes this infection, gets into the intestinal tract when a person drinks contaminated water or eats unwashed or uncooked food. It can also be spread through direct contact with an infected individual, or indirectly through clothing they have worn, food they have prepared, and objects they have touched.

In HIV-positive individuals with CD4 counts -- also known as "T cell" counts -- above 200, cryptosporidiosis is a self-limiting condition that lasts from 5 to 14 days and resolves without medication, just as it does in HIV-negative individuals. The relapse rate is fairly high -- about 30% -- but these secondary flare-ups are less severe, and they usually last no more than a day or two.

In HIV-positive individuals with CD4 counts below 200, however, cryptosporidiosis is a considerably more serious affliction, one that can lead to permanent diarrheal illness. Over time, this unchecked diarrhea causes chronic malabsorption -- of fluids, nutrients, vitamins, and electrolytes. And malabsorption, in turn, leads to weight loss, wasting syndrome, and even death.

Many AIDS-related infections can cause diarrhea, among them cytomegalovirus and Mycobacterium avium complex, or MAC. All of these pathogens are a cause for concern, especially in individuals with advanced HIV disease, and persons with CD4 counts below 200 should consult a doctor if they develop diarrhea that persists for more than three days.

As a rule, a single stool specimen is usually sufficient to establish a diagnosis of cryptosporidiosis, although some physicians ask for up to three samples, each on a different day. There are no medications that will cure cryptosporidiosis once infection sets in, but Humatin® does suppress the effects of infection in most people. Zithromax® has also been used with some success in affected individuals. The recommended daily dose of Humatin® is 500 mg four times a day for a period of 14 to 28 days. The customary dose of Zithromax® is 600 mg daily for 14 to 28 days. Patients with particularly heavy infestations of cryptosporidia, those with CD4 counts below 50, and those who suffer relapses may require additional months of maintenance therapy.

With treatment, diarrhea usually abates, and for most patients it eventually ceases. As infection subsides, patients are often able to regain most or all of the weight they lost during the acute phase of infection. Humatin® and Zithromax® are not universally effective, however, and for that reason HIV-positive individuals with CD4 counts below 200 may want to take these simple precautions, which will dramatically reduce the likelihood that they will become infected with cryptosporidia:

  • Wash your hands carefully after you use the bathroom and after such activities as handling dirty laundry, playing with a pet, or changing a diaper.
  • Avoid contact with human and animal waste. This caution applies equally to cleaning litter boxes, gardening, and all sexual activities that involve oral-anal contact ("rimming").
  • Wash all fruits and vegetables well with distilled, bottled, boiled, or filtered water before you eat them. If your CD4 count is below 200, you may want to avoid eating raw vegetables and fruits in restaurants or other places where those items may not have been well washed.
  • Avoid swimming in fresh water (ponds, lakes, streams, and rivers), and do not use swimming pools -- because they can become contaminated, and chlorine does not kill the organism that causes cryptosporidiosis.
  • Before you adopt a pet, have the vet examine its stool for Cryptosporidium. Do not take in stray animals, and do not let any animal with diarrhea into your home.
Although the risk of acquiring cryptosporidiosis from drinking tap water is low, municipal water supplies can become contaminated. In 1993, for example, a waterborne outbreak in Milwaukee resulted in 400,000 cases of cryptosporidiosis in the population at large and hundreds of cases, some very serious, in HIV-infected individuals. To guard against waterborne infection, people with CD4 counts below 200 may want to consider these precautions:

  • Drink only tap water that has been boiled at a rolling boil for at least one minute, transferred to an airtight container, and refrigerated or allowed to cool to room temperature.

  • Drink distilled water or water that has been properly filtered. This means water that has been passed through a so-called absolute filter, one that filters out all organisms that are greater than one micron in size. Such filters -- which meet the National Sanitation Foundation's standard for cyst removal -- will eliminate any Cryptosporidium in the water.

  • Drink bottled water that has been distilled or filtered. Not all bottled waters meet these criteria, and water that has not been purified by one of these methods may not be safe.