• Prevention of exposure
• Prevention of disease
• Prevention of recurrence
• Children

2. HIV-infected persons should avoid contact with human and animal feces. They should be advised to wash their hands after contact with human feces (e.g., diaper changing), after handling pets, and after gardening or other contact with soil. HIV-infected persons should avoid sexual practices that might result in oral exposure to feces (e.g., oral-anal contact) (BIII).

3. HIV-infected persons should be advised that newborn and very young pets might pose a small risk for transmitting cryptosporidial infection, but they should not be advised to destroy or give away healthy pets. Persons contemplating the acquisition of a new pet should avoid bringing any animal that has diarrhea into their households, should avoid purchasing a dog or cat aged less than 6 months, and should not adopt stray pets. HIV-infected persons who wish to assume the small risk for acquiring a puppy or kitten aged less than 6 months should request that their veterinarian examine the animal's stool for Cryptosporidium before they have contact with the animal (BIII).

4. HIV-infected persons should avoid exposure to calves and lambs and to premises where these animals are raised (BII).

5. HIV-infected persons should not drink water directly from lakes or rivers (AIII).

6. Waterborne infection also might result from swallowing water during recreational activities. HIV-infected persons should be aware that many lakes, rivers, and salt-water beaches and some swimming pools, recreational water parks, and ornamental water fountains might be contaminated with human or animal waste that contains Cryptosporidium. They should avoid swimming in water that is likely to be contaminated and should avoid swallowing water while swimming or playing in recreational waters (BIII).

7. Several outbreaks of cryptosporidiosis have been linked to municipal water supplies. During outbreaks or in other situations in which a community "boil-water" advisory is issued, boiling water for 1 minute will eliminate the risk for cryptosporidiosis (AI). Use of submicron personal-use water filters* (home/office types) and/or bottled water** also might reduce the risk (CIII). The magnitude of the risk for acquiring cryptosporidiosis from drinking water in a nonoutbreak setting is uncertain, and current data are inadequate to recommend that all HIV-infected persons boil water or avoid drinking tap water in nonoutbreak settings. However, HIV-infected persons who wish to take independent action to reduce the risk for waterborne cryptosporidiosis may choose to take precautions similar to those recommended during outbreaks. Such decisions should be made in conjunction with health-care providers. Persons who opt for a personal-use filter or bottled water should be aware of the complexities involved in selecting appropriate products, the lack of enforceable standards for the destruction or removal of oocysts, the cost of the products, and the logistic difficulty of using these products consistently.

8. Patients who take precautions to avoid acquiring cryptosporidiosis from drinking water should be advised that ice made from contaminated tap water also can be a source of infection (BII). Such persons also should be aware that fountain beverages served in restaurants, bars, theaters, and other places also might pose a risk because these beverages, as well as the ice they contain, are made from tap water. Nationally distributed brands of bottled or canned carbonated soft drinks are safe to drink. Commercially packaged noncarbonated soft drinks and fruit juices that do not require refrigeration until after they are opened (i.e., those that can be stored unrefrigerated on grocery shelves) also are safe. Nationally distributed brands of frozen fruit juice concentrate are safe if they are reconstituted by the user with water from a safe source. Fruit juices that must be kept refrigerated from the time they are processed to the time of consumption might be either fresh (unpasteurized) or heat-treated (pasteurized); only those juices labeled as pasteurized should be considered free of risk from Cryptosporidium. Other pasteurized beverages and beers also are considered safe to drink (BII). No data are available concerning survival of Cryptosporidium oocysts in wine.

9. HIV-infected persons should avoid eating raw oysters because cryptosporidial oocysts can survive in oysters for more than 2 months and have been found in oysters taken from some commercial oyster beds (BIII). Cryptosporidium-infected patients should not work as food handlers, especially if the food to be handled is intended to be eaten without cooking (BII). Because most foodborne outbreaks of cryptosporidiosis are believed to have been caused by infected food handlers, more specific recommendations to avoid exposure to contaminated food cannot be made.

10. In a hospital, standard precautions (i.e., use of gloves and hand washing after removal of gloves) should be sufficient to prevent transmission of cryptosporidiosis from an infected patient to a susceptible HIV-infected person (BII). However, because of the potential for fomite transmission, some experts recommend that HIV-infected persons, especially those who are severely immunocompromised, should not share a room with a patient with cryptosporidiosis (CIII).

Prevention of Exposure
11. No agents have been proven to be effective as chemoprophylaxis against cryptosporidiosis. Rifabutin or clarithromycin, when taken for Mycobacterium avium complex prophylaxis, were associated with a reduced risk for cryptosporidiosis in one study (37), but data are insufficient to warrant a recommendation for using these drugs.

Prevention of Recurrence
12. No drug regimens are known to be effective in preventing the recurrence of cryptosporidiosis.

Special Considerations
Children
13. At present, no data indicate that formula-preparation practices for infants should be altered in an effort to prevent cryptosporidiosis (CIII). However, in the event of a "boil-water" advisory, similar precautions for the preparation of infant formula should be taken as for drinking water for adults (AII).

* Only filters capable of removing particles 1 µm in diameter should be considered. Filters that provide the greatest assurance of oocyst removal include those that operate by reverse osmosis, those labeled as absolute 1-µm filters, and those labeled as meeting NSF (National Sanitation Foundation) standard no. 53 for cyst removal. The nominal 1-µm filter rating is not standardized, and many filters in this category might not be capable of removing 99% of oocysts.

** Sources of bottled water (e.g., wells, springs, municipal tap-water supplies, rivers, and lakes) and methods for its disinfection differ; therefore, all brands should not be presumed to be free of cryptosporidial oocysts. Water from wells and springs is much less likely to be contaminated by oocysts than water from rivers or lakes. Treatment of bottled water by distillation or reverse osmosis ensures oocyst removal. Water passed through an absolute 1-µm filter or a filter labeled as meeting NSF standard no. 53 for cyst removal before bottling will provide nearly the same level of protection. Use of nominal 1-µm filters by bottlers as the only barrier to Cryptosporidia might not result in the removal of 99% of oocysts.

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