BackgroundPatients with HIV are more susceptible than others to certain infections. Exposure to some of the opportunistic pathogens may be minimized or avoided if patients are aware of the possible dangers associated with them. Grouping transmissible infections by type of exposure is a useful way for patients and providers to conceptualize means of prevention. Sexual ExposuresPatients should use latex or polyurethane condoms during every act of sexual intercourse to reduce the risk of exposure to cytomegalovirus (CMV), herpes simplex virus, hepatitis C, human papillomavirus, and other sexually transmitted pathogens. Although polyurethane male and female condoms have not been tested as thoroughly as latex condoms, they can greatly reduce risk if properly used. Correct use of condoms and other effective barriers, such as latex dental dams or flexible plastic film (eg, plastic food wrap) during oral sex on women also will prevent the transmission of HIV. Avoiding sexual contact when herpetic lesions are present (on the mouth or genitals) may help to reduce herpes simplex transmission, although herpes can be transmitted when no lesions are visible. The most effective way to avoid the risk of sexually transmitted intestinal infections such as cryptosporidiosis, shigellosis, campylobacteriosis, amebiasis, and hepatitis A and B is to avoid sexual practices that may result in oral exposure to feces (eg, oral-anal contact, or "rimming"). Persons wishing to reduce their risk of exposure might consider using dental dams or other barrier methods (eg, plastic food wrap) for oral-anal contact; changing condoms after anal intercourse; and wearing latex, nitrile, or other intact waterproof gloves during digital-anal contact. Frequently washing hands and genitals with warm soapy water during and after activity that may bring them in contact with feces may further reduce the risk of illness. Consistent and correct use of condoms greatly reduces the risk of sexually transmitted infections. See chapter Preventing HIV Transmission/Prevention with Positives for specific information on the use of condoms. Injection Drug Use ExposuresInjection drug use with sharing of needles or other injection equipment puts HIV-infected persons at risk for infection with hepatitis C, additional strains of HIV (some of which may be drug-resistant), and other bloodborne pathogens. Injection drug use also conveys a risk of endovascular infections with skin and environmental flora, such as staphylococci, streptococci, Candida, and some gram-negative rods. Certain drugs, such as black-tar heroin, may be contaminated with anaerobic bacteria that can cause life- and limb-threatening anaerobic infections if injected. Finally, drug addiction may predispose patients to commercial sex work or trading of sex for drugs, which may increase their risk of acquiring sexually transmitted infections that are not injection related per se. Assess each patient's readiness to change his or her practices, and refer to drug treatment programs as appropriate. If the patient continues to use needles, discuss ways to avoid sharing needles and other drug equipment, refer to a needle exchange program so that syringes and needles are not reused, and teach proper cleaning of injection equipment. Specific recommendations about injection and other drug use can be found in the chapter Preventing HIV Transmission/Prevention with Positives. All injection drug users should be immunized against hepatitis A and hepatitis B if they are not already immune. Environmental and Occupational ExposuresNo specific measures are recommended to prevent exposure to Pneumocystis jiroveci pneumonia (PCP), Mycobacterium avium complex, Streptococcus pneumoniae, Haemophilus influenzae, Candida spp, or Cryptococcus neoformans. Contact with Infected PopulationsCertain activities or types of employment may increase the risk of exposure to tuberculosis. These include volunteer work or employment in health care facilities, correctional institutions, shelters for the homeless, and other settings identified as high-risk by local health authorities. The patient, along with the health care provider, should decide whether to continue such activities while taking into account the patient's specific duties in the workplace, the prevalence of tuberculosis in the community, and the degree to which precautions are taken in the workplace to prevent the transmission of tuberculosis. These decisions will affect the frequency with which the patient should be screened for tuberculosis. Child-care providers and parents of children in child-care facilities have an increased risk of acquiring CMV infection, cryptosporidiosis, and other infections (eg, hepatitis A and giardiasis) from children. Although the prevalence of CMV is high (50-70%) in the general adult population in the United States, it is higher (90%) in injection drug users, hemophiliacs, and men who have sex with men (MSM). Any HIV-infected child-care provider without an elevated risk of CMV (ie, no history of injection drug use, hemophilia, or sex with MSM) should be tested for CMV antibody. CMV-negative individuals can reduce the risk of acquiring infection by good hygienic practices, such as hand washing after contact with feces (eg, during diaper changing), urine, and saliva. Any CMV-negative person with HIV who needs a transfusion should receive blood that is CMV negative or leukocyte reduced. HIV-infected children and adults who are susceptible to varicella-zoster virus (VZV) (ie, those with no history of chickenpox or shingles) should avoid exposure to persons with chickenpox or shingles. Household contacts, especially children, should be vaccinated against VZV if they are HIV negative and have no history of chickenpox so that they will not transmit VZV to their HIV-infected contact. If a susceptible HIV-infected person is in close contact with someone with chickenpox or shingles, varicella-zoster immune globulin (VZIG) should be administered as soon as possible (ideally within 48 hours, but at least within 96 hours) after the exposure. Anti-varicella titers can be performed after exposure if the HIV-infected person's VZV immunity status is unknown. The U.S. Centers for Disease Control and Prevention (CDC) no longer supports the alternative approach of giving acyclovir, 800 mg orally 5 times a day for 3 weeks instead of VZIG, because no data exist to
support the efficacy of this approach. Contact with AnimalsOccupations involving contact with animals (eg, veterinary work and employment in pet stores, farms, or slaughterhouses) may pose a risk of cryptosporidiosis, toxoplasmosis, salmonellosis, campylobacteriosis, and Bartonella infection. However, the available data are insufficient to justify a recommendation against work in such settings. Contact with young farm animals, especially animals with diarrhea, should be avoided to reduce the risk of cryptosporidiosis. Soil ExposureGlove use and hand washing after gardening or other contact with soil may reduce the risk of cryptosporidiosis and toxoplasmosis. In histoplasmosis-endemic areas, patients should avoid activities known to be associated with increased risk, such as stirring up dust when working with surface soil; cleaning chicken coops; disturbing soil beneath bird-roosting sites; cleaning, remodeling, or demolishing old buildings; and exploring caves. In coccidioidomycosis-endemic areas, patients should consider avoiding activities associated with increased risk, such as extensive exposure to disturbed native soil (eg, at excavation sites, on farms, or in dust storms). Pet-Related ExposuresHealth care providers should inform HIV-infected persons of the potential risks posed by pet ownership. However, they should be sensitive to the possible benefits of pet ownership and should not routinely advise persons with HIV to part with their pets. They should advise their patients about the following. GeneralVeterinary care should be sought when a pet develops a diarrheal illness. If possible, HIV-infected persons should avoid contact with animals that have diarrhea. A fecal sample should be obtained from an animal with diarrhea and examined for Cryptosporidium, Salmonella, and Campylobacter. When obtaining a new pet, HIV-infected persons should avoid animals younger than 1 year, especially those with diarrhea. Because the hygienic and sanitary conditions in pet breeding facilities, pet stores, and animal shelters are highly variable, patients should exercise caution when obtaining a pet from these sources. Stray animals should be avoided. Animals less than 6 months of age, especially those with diarrhea, should be examined by a veterinarian for Cryptosporidium, Salmonella, and Campylobacter before contact with the patient. Patients should wash their hands after handling pets (especially before eating) and avoid contact with pet feces to reduce the risk of cryptosporidiosis, salmonellosis, and campylobacteriosis. CatsPatients should consider the potential risks of cat ownership such as the risk of toxoplasmosis, Bartonella infection, and enteric infections. Those who elect to obtain a cat should adopt or purchase an animal that is more than 1 year of age and in good health to reduce the risk of cryptosporidiosis, Bartonella infection, salmonellosis, and campylobacteriosis. Litter boxes should be cleaned daily, preferably by an HIV-negative, nonpregnant person; if the HIV-infected patient performs this task, he or she should wash hands thoroughly afterward to reduce the risk of toxoplasmosis. Also to reduce the risk of toxoplasmosis, cats should be kept indoors, should not be allowed to hunt, and should not be fed raw or undercooked meat. Flea control will help reduce the risk of Bartonella infection. Although declawing generally is not advised, patients should avoid activities that may result in cat scratches or bites to reduce the risk of Bartonella infection. Patients should wash the sites of cat scratches or bites promptly and should not allow cats to lick the open cuts or wounds. Testing of cats for toxoplasmosis or Bartonella infection is not recommended. BirdsScreening of healthy birds for C neoformans, M avium, or Histoplasma capsulatum is not recommended. Areas contaminated with bird droppings should be avoided if possible, and soil beneath bird-roosting sites should not be disturbed. Contact with chicks and ducklings has been associated with salmonellosis. OtherContact with reptiles (such as snakes, lizards, iguanas, and turtles) should be avoided to reduce the risk of salmonellosis. Gloves should be used while cleaning aquariums to reduce the risk of infection with Mycobacterium marinum. Contact with exotic pets, such as nonhuman primates, should be avoided. Food- and Water-Related ExposuresRaw or undercooked eggs (including foods that may contain raw eggs, such as some preparations of hollandaise sauce, Caesar and certain other salad dressings, homemade mayonnaises, eggnog, uncooked cake batter, and cookie dough); raw or undercooked poultry, meat, or seafood, especially raw shellfish; unpasteurized dairy products; unpasteurized fruit juice; and raw seed sprouts (alfalfa, mung bean sprouts) may contain enteric pathogens such as Salmonella, pathogenic strains of Escherichia coli, and parasites including Cryptosporidium. Poultry and meat are safest if the internal temperature is verified with a meat thermometer to be at least 180°F (poultry) or 165°F (red meat). If a thermometer is not available, meats should be cooked until no traces of pink remain; however, color changes do not always correlate with internal temperature. Fruits and vegetables should be washed thoroughly, or cooked, before being eaten. Cross-contamination of foods should be avoided. Uncooked meats should not be allowed to come into contact with other foods. Hands, cutting boards, counters, and knives and other utensils should be washed thoroughly after contact with uncooked foods. Although listeriosis is uncommon in the United States, it is a serious disease that occurs more frequently among immunocompromised persons, including those with HIV disease. Persons at increased risk of listeriosis may elect to do the following: - Avoid soft cheeses (eg, feta, brie, camembert, blue-veined, and Mexican-style cheeses such as queso fresco). Hard cheeses, processed cheeses, cream cheese, cottage cheese, and yogurt generally are safe from listeriosis.
- Cook leftover foods or ready-to-eat foods, such as hot dogs, until they are steaming hot before eating.
- Avoid foods from delicatessen counters, such as prepared meats, salads, and cheeses, or heat these foods until steaming before eating. Canned or shelf-stable pate and meat spreads need not be avoided.
- Avoid raw or unpasteurized milk or milk products, including goat's milk, or foods containing unpasteurized milk or milk products.
Patients should not drink water directly from lakes or rivers because of the risk of cryptosporidiosis and giardiasis. Even accidental ingestion of lake, river, or ocean water while swimming, rafting, boating, skiing, or engaging in other types of recreational activity carries this risk. During outbreaks or other situations in which a community "boil water" advisory is issued, patients should boil water for 1 minute to eliminate the risk of cryptosporidiosis. Use of submicron personal-use water filters (home or office types) or bottled water may reduce the risk. Not all bottled water can be considered free of oocysts, however. Water is considered safe if it been distilled, filtered with an "absolute" 1-micron or submicron filter, or filtered by reverse osmosis. Current data are inadequate to recommend that all HIV-infected persons boil or otherwise avoid drinking tap water in non-outbreak settings. Persons who wish to take independent action to reduce the risk of water-borne cryptosporidiosis may choose to take precautions similar to those recommended during outbreaks. Such decisions are best made in conjunction with the health care provider. Persons who opt for personal-use filters or bottled water should be aware of complexities involved in selecting the appropriate products, the lack of enforceable standards for the destruction or removal of oocysts, the cost of the products, and the difficulty of using these products consistently (eg, for toothbrushing, eating out, and travelling). Patients taking precautions to avoid cryptosporidiosis in drinking water should be advised that ice made from tap water can be a source of infection. In addition, fountain beverages served in restaurants, bars, theaters, and other public places may 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 (eg, 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 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 labeled as being
pasteurized should be considered safe. Other pasteurized beverages and beers also are considered safe to drink. No data are available concerning the survival of Cryptosporidium oocysts in wine. Travel-Related ExposuresTravel, particularly to developing countries, may carry significant risks for HIV-infected persons, especially for patients who are severely immunosuppressed, in terms of exposure to opportunistic pathogens. There is little medical evidence to support recommending against travel to developing countries, however, as long as precautions are taken. Consultation with health care providers and/or experts in travel medicine will help patients plan itineraries. During travel to developing countries, HIV-infected persons are at much higher risk of food-borne and water-borne infections than they are in the United States. Foods and beverages may be contaminated, especially raw fruits and vegetables, raw or undercooked seafood or meat, tap water, ice made with tap water, unpasteurized milk and dairy products, and items purchased from street vendors. Items that generally are safe include steaming-hot foods, fruits that are peeled by the traveler, bottled (especially carbonated) beverages, hot coffee or tea, beer, wine, and water brought to a rolling boil for 1 minute. Treatment of water with iodine or chlorine may not be as effective as boiling but can be used, perhaps in conjunction with filtration, when boiling water is not practical. Water-borne infections may result from swallowing water during recreational activity. To reduce the risk of cryptosporidiosis and giardiasis, patients should avoid swallowing water during swimming and other recreational activities and should not swim in water that may be contaminated (eg, with sewage, animal waste, or human waste). Antimicrobial prophylaxis for traveler's diarrhea is not recommended routinely for HIV-infected persons traveling to developing countries. Such preventive therapy can have adverse effects and can promote the emergence of drug-resistant organisms. Nonetheless, several studies (none involving an HIV-infected population) have shown that prophylaxis can reduce the risk of diarrhea among travelers. Under selected circumstances (eg, when the risk of infection is very high and the period of travel is brief), the provider and patient may weigh the potential risks and benefits and decide that antibiotic prophylaxis is warranted. When prophylaxis is offered, fluoroquinolones such as ciprofloxacin (500 mg daily) can be considered, although fluoroquinolones should not be used for pregnant women or children. Taking 1 double-strength tablet daily of trimethoprim-sulfamethoxazole (TMP-SMX) has been effective, but resistance to this drug is now common in tropical areas. Persons already taking TMP-SMX for prophylaxis against PCP may gain some protection against traveler's diarrhea. For HIV-infected persons who are not already taking TMP-SMX, the provider should use caution when prescribing this agent for prophylaxis of diarrhea because of the high rate of adverse reactions and the possible need for the agent for other purposes (eg, PCP prophylaxis) in the future. All HIV-infected travelers to developing countries should carry with them a sufficient supply of an antimicrobial agent to be taken empirically should significant diarrhea develop. One appropriate regimen is 500 mg of ciprofloxacin twice daily for 3-7 days. Alternative antibiotics (eg, TMP-SMX) should be considered as empirical therapy for use by pregnant women. Travelers should consult a physician if their diarrhea is severe and does not respond to empirical therapy, if their stools contain blood, if fever is accompanied by shaking chills, or if dehydration develops. Antiperistaltic agents such as diphenoxylate and loperamide are used to treat diarrhea; however, they should not be used by patients with high fever or with blood in the stool, and their use should be discontinued if symptoms persist beyond 48 hours. Travelers should be advised about other preventive measures appropriate for anticipated exposures, such as chemoprophylaxis for malaria, protection against arthropod vectors, treatment with immune globulin, and vaccination. They should avoid direct contact of the skin with soil and sand (eg, by wearing shoes and protective clothing and using towels on beaches) in areas where fecal contamination is likely. In general, live-virus vaccines should be avoided. An exception is measles vaccine, which is recommended for nonimmune persons, although not recommended for those who are severely immunocompromised. Immune globulin should be considered for measles-susceptible, severely immunocompromised persons traveling to measles-endemic regions. Inactivated (killed) poliovirus vaccine should be used instead of oral (live) poliovirus vaccine. Persons at risk for exposure to typhoid fever should be given inactivated parenteral typhoid vaccine instead of the live attenuated oral preparation. Yellow fever vaccine is a live-virus vaccine with uncertain safety and efficacy in HIV-infected persons. Travelers with HIV infection who are unvaccinated and for whom travel is necessary should be advised of the risk, instructed in methods for avoiding the bites of vector mosquitoes, and provided with a vaccination waiver letter. Travelers with asymptomatic HIV infection who cannot avoid
potential exposure to yellow fever should be offered the choice of vaccination after disclosure of its limitations. In general, killed and recombinant vaccines (eg, diphtheria-tetanus, rabies, hepatitis B, hepatitis A, Japanese encephalitis) should be used for HIV-infected persons just as they would be for HIV-uninfected persons anticipating travel. Preparation for travel should include a review and update of routine vaccinations, including diphtheria-tetanus. The currently available cholera vaccine is not recommended for persons following the usual tourist itinerary, even if that includes travel to countries that have reported cases of cholera. All patients traveling to other countries should be evaluated for both routine and destination-specific immunizations and prophylaxes. Travelers should be told about other area-specific risks and instructed about how to reduce those risks. Geographically focal infections that pose a high risk to HIV-infected persons include visceral leishmaniasis (a protozoan infection transmitted by the sandfly) and several fungal infections (eg, Penicillium marneffei infection, coccidioidomycosis, and histoplasmosis). Many tropical and developing areas have high rates of tuberculosis, which is a particular risk for HIV-infected persons. For further information about health precautions for travelers, including vaccination information, check the CDC Web page at: http://www.cdc.gov/travel/index.htm. The "Special Needs Traveler" section contains a link for HIV-infected travelers. Select the "Travelers' Health" option for regional travel documents and outbreak information. Those without Internet access can call the CDC, toll free, at 1-877-FYI-TRIP or 888-232-3299. References |
