Cryptosporidiosis
Prevention of Exposure
HIV-infected persons should be educated and counseled about the many
ways that Cryptosporidium can be transmitted. Modes of transmission include
contact with infected adults and diaper-aged children, contact with infected
animals, drinking contaminated water, and contact with contaminated water
during recreational activities.
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., during diaper changing), after handling pets, and after gardening
or other contact with soil. HIV-infected persons should avoid sexual practices
that may result in oral exposure to feces (e.g., oral-anal intercourse).
HIV-infected persons should be advised that newborn and very young pets
may pose a small risk of 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 <6 months
and should not adopt stray pets. HIV-infected persons who wish to assume
the small risk of acquiring a puppy or kitten aged <6 months should request
that their veterinarian examine the animal's stool for Cryptosporidium before
they have contact with the animal.
HIV-infected persons should avoid exposure to calves and lambs and to premises where these animals are raised.
HIV-infected persons should not drink water directly from lakes or rivers.
Waterborne infection may also result from swallowing water during
recreational activities. Patients should be aware that many lakes, rivers,
and salt-water beaches and some swimming pools and recreational water parks
may be contaminated with human or animal waste that contains Cryptosporidia.
Patients should avoid swimming in water that is likely to be contaminated
and should avoid swallowing water during swimming.
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 of cryptosporidiosis (AI). Use of submicron personal-use water filters*
(i.e., home/office types) and/or bottled water may reduce the risk.
The magnitude of the risk of acquiring cryptosporidiosis from drinking water
in a non-outbreak setting is uncertain, and current data are inadequate to
recommend that all HIV-infected persons boil water or avoid drinking tap
water in non-outbreak settings. However, HIV-infected persons who wish to
take independent action to reduce the risk of 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.
Patients who take precautions to avoid acquiring cryptosporidiosis from
drink-ing water should be advised that ice made from contaminated tap water
also can be a source of infection. Such persons also should be aware
that fountain beverages served in restaurants, bars, theaters, and other
places may also 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
non-carbonated soft drinks and fruit juices that do not require refrigeration
until after they are opened (e.g., 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 may 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.
No data are available concerning survival of Cryptosporidium oocysts in wine.
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. 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.
*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 may 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 may not result
in the removal of 99% of oocysts.
Prevention of Disease
No effective chemoprophylactic agents are available for cryptosporidiosis.
Prevention of Recurrence
No drug regimens are known to be effective in preventing the recurrence
of cryptosporidiosis.
Note:
Pediatric Note
At present, no data indicate that formula-preparation practices for
infants should be altered in an effort to prevent cryptosporidiosis.
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