How to prevent infections

A few simple precautions can help you avoid getting sick with an infectious disease

Infections are caused by microscopic organisms known as pathogens—bacteria, viruses, fungi, or parasites—that enter the body, multiply, and interfere with normal functions. Infectious diseases are a leading cause of illness and death in the United States and around the world. For certain people--particularly those with underlying illnesses like heart disease or cancer, those who have serious injuries, or those who are taking medications that weaken the immune system—it's more difficult to avoid getting sick with an infection. Living in an affluent country like the United States, the threat we face from deadly viruses, bacteria, and parasites can seem remote, but these infectious microbes are ever present among us, according to Dr. Michael Klompas, writing in the Harvard Medical School Special Health Report Viruses and Disease. Dr. Klompas is an infectious disease specialist at Harvard-affiliated Brigham and Women's Hospital. However, for most healthy people, following a few basic principles can go a long way in helping to prevent infections.

Understanding how infections are transmitted can help you avoid getting sick

Not long ago, no one understood that infectious diseases were caused by tiny organisms that moved from person to person. Even now, although we know that microscopic living microbes cause disease, how they do so is not always obvious. But we do know that most microbes enter through openings in the body—our noses, mouths, ears, anuses, and genital passages. They can also be transmitted through our skin through insect or animal bites. The best way to prevent infections is to block pathogens from entering the body.

Good hygiene: the primary way to prevent infections

The first line of defense is to keep germs at bay by following good personal hygiene habits. Prevent infection before it begins and avoid spreading it to others with these easy measures.

• Wash your hands well. You probably wash your hands after using the bathroom, before preparing or eating food, and after gardening or other dirty tasks. You should also wash up after blowing your nose, coughing, or sneezing; feeding or stroking your pet; or visiting or caring for a sick person. Wet your hands thoroughly. Lather up with soap or cleanser, and rub it into the palms and backs of your hands and your wrists. Be sure to clean your fingertips, under your nails and between your fingers. Rinse under running water. Dry your hands and wrists thoroughly.
• Cover a cough. Cover your mouth and nose with a tissue when you sneeze or cough, then dispose of it. If no tissue is handy, cough or sneeze into your elbow rather than into your hands.
• Wash and bandage all cuts. Any serious cut or animal or human bite should be examined by a doctor.
• Do not pick at healing wounds or blemishes, or squeeze pimples.
• Don't share dishes, glasses, or eating utensils.
• Avoid direct contact with napkins, tissues, handkerchiefs, or similar items used by others.

Practice good food-safety techniques to avoid getting sick

Although most cases of food-borne infection are not dangerous, some can lead to serious medical conditions, including kidney failure and meningitis. You can prevent infections by food-borne pathogens in your household by preparing and storing foods safely. The following precautions will help kill microbes that are present in the food you buy and help you avoid introducing new microbes into your food at home:

• Rinse all meat, poultry, fish, fruits, and vegetables under running water before cooking or serving them.
• Wash your hands with soap and water before and after you handle raw meat.
• Separate raw foods and cooked foods. Don't use the same utensils or cutting boards with cooked meat that were used to prepare the raw meat without washing between uses.
• Cook foods thoroughly, using a meat thermometer to ensure that whole poultry is cooked to 180° F, roasts and steaks to 145° F, and ground meats to 160° F. Cook fish until it is opaque.
• Defrost foods only in the refrigerator or in the microwave.

Whether you are young or young at heart, getting vaccinated is an essential part of staying healthy. Many serious infections can be prevented by immunization. While vaccines may cause some common side effects, such as a temporarily sore arm or low fever, they are generally safe and effective.

Vaccinations are essential if you are to avoid getting sick

Consult your health care provider regarding your immunization status. In general:

• Children should receive the recommended childhood vaccinations.
• Adults should make sure their vaccinations are up to date.
• When traveling abroad, check with your health care provider about additional immunizations.
• Make sure your pet's vaccinations are up to date, too. In addition to protecting your pet, this will also protect you and your family.

Take travel precautions

If you are planning a trip, ask your doctor if you need any immunizations. Discuss your travel plans with your physician at least three months before you leave.

• If you are traveling to an area where insect-borne disease is present, take and use an insect repellent containing DEET. In many tropical regions, mosquitoes can carry malaria, dengue, yellow fever, Japanese encephalitis, or other serious infections.
• Get your shots before you leave the United States. Avoid getting any unnecessary shots, immunizations, or tattoos abroad. Needles and syringes (even the disposable ones) are reused in some parts of the world.
• Do not consume ice while traveling. Freezing does not kill all water-borne infectious microbes.
• Drink only bottled drinks—such as soft drinks or bottled water—that have secure caps. Be aware that some fruit juices may be made with impure local water.
• Boil all tap water before drinking or drink only bottled water; use bottled or boiled water to brush your teeth.
• Do not eat uncooked vegetables, including lettuce; do not eat fruit you haven't peeled yourself.
• Do not consume dairy products (milk may not be pasteurized).

How to prevent infections by sexual transmission

The only sure way to prevent sexually transmitted diseases is to not have sexual intercourse or other sexual contact. That's not an option for most people, so the next best choice is to follow these safer sex guidelines:

• Engage in sexual contact only with one partner who is having sex only with you.
• Both you and your partner should be tested for HIV and other sexually transmitted diseases.

If you do have sex with a new partner, make sure the partner is tested, and take the following precautions:

• For vaginal sex, use a latex or polyurethane condom or a female condom.
• For oral sex, use a latex or polyurethane male condom or a female condom.
• For anal sex, use a latex or polyurethane male condom.

Avoiding bug-borne pathogens

Both mosquitos and ticks are carriers of viruses and bacteria. And both have been associated with serious epidemics in the last decade.

While it's true that most mosquitoes in northern climates don't transmit disease, some do. Within one decade, West Nile virus has spread throughout the United States and parts of Canada. Several other forms of mosquito-borne encephalitis are also carried by mosquitoes in North America. Tropical diseases pose a threat if the mosquitoes that carry them hitch a ride in boats or expand their range northward from Central America.

Ticks are widespread and can transmit a variety of diseases, including Lyme disease and many others. They live in grassy and brushy areas and are most prevalent during wet seasons. A common hiding place is in wet leaves. They often infest animals, including field mice and deer. And they may be transported into your home by your pets.

The following can help prevent infections from bug bites:

• Use insect repellents approved by the Environmental Protection Agency, including those containing DEET, picaridin, or oil of lemon eucalyptus. If mosquitoes are biting you, reapply the repellent.
• Limit outdoor activity during peak mosquito hours of early morning and evening.
• Drain any standing water near your home to prevent mosquitoes from breeding.
• Check your neighborhood and pick up trash, discarded cans, bottles, and other containers that can contain enough water to allow mosquitoes to breed.
• If you plan to spend time in an area where ticks are common (even your back yard), wear light-colored clothing so ticks can be spotted and removed before they attach. When hiking on trails, stay in the center of the trail to avoid picking up ticks from bushes and brush. When you return, check your clothing and body for ticks. Check your pet before allowing it indoors.
• If a tick has attached itself to you or your pet, grasp it firmly with tweezers close to the tick's mouth and pull steadily. Cleanse the area of the tick bite thoroughly with antiseptic. Watch the area closely for a couple of weeks for signs of rash or swelling.

Using animal-control to prevent infections

Controlling the population of mice or rats in and near your home can help you avoid pathogens spread by rodents and also help control the population of ticks that spread disease. Rodents can harbor a number of pathogens, including lymphocytic choriomeningitis virus, leptospirosis, plague, and hantavirus. Other wild animals can also transmit rabies and other infections. The following measures can help you avoid getting sick from diseases transmitted by animals:

• Keep food and garbage in covered, rodent-proof containers.
• Seal holes and cracks in your home to deter rodent access.
• Clear brush and junk away from the foundation of your home.
• Do not stir up dust in rodent-infested areas. Instead, wet-mop or sponge the area and treat with disinfectant.
• When outdoors, do not disturb rodent burrows or handle rodents.
• If your rodent problem is severe or persistent, consult a pest control expert.
• Stay clear of wild animals. Many wild animals, including raccoons, skunks, bats, foxes, and coyotes, can spread rabies to humans by biting. Keep your pets away from wild animals, too. Dogs, cats, or any other type of warm-blooded animal can pick up rabies from wild animals and pass rabies along to people.

– By Beverly Merz
Executive Editor, Harvard Women's Health Watch

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