General Diseases

When to see a doctor

Seek medical attention if you:

1. Have been bitten by an animal
2. Are having trouble breathing
3. Have been coughing for more than a week
4. Have severe headache with fever
5. Experience a rash or swelling
6. Have unexplained or prolonged fever
7. Have sudden vision problems

Causes

Infectious diseases can be caused by:

Bacteria. These one-cell organisms are responsible for illnesses such as strep throat, urinary tract infections and tuberculosis.

Viruses. Even smaller than bacteria, viruses cause a multitude of diseases ranging from the common cold to AIDS.

Fungi. Many skin diseases, such as ringworm and athlete's foot, are caused by fungi. Other types of fungi can infect your lungs or nervous system.

Parasites. Malaria is caused by a tiny parasite that is transmitted by a mosquito bite. Other parasites may be transmitted to humans from animal feces.

Risk Factor

While anyone can catch infectious diseases, you may be more likely to get sick if your immune system isn't working properly. This may occur if:

1. You're taking steroids or other medications that suppress your immune system, such as anti-rejection drugs for a transplanted organ
2. You have HIV or AIDS
3. You have certain types of cancer or other disorders that affect your immune system

In addition, certain other medical conditions may predispose you to infection, including implanted medical devices, malnutrition and extremes of age, among others

Complications

Most infectious diseases have only minor complications. But some infections — such as pneumonia, AIDS and meningitis — can become life-threatening. A few types of infections have been linked to a long-term increased risk of cancer:

1. Human papillomavirus is linked to cervical cancer
2. Helicobacter pylori is linked to stomach cancer and peptic ulcers
3. Hepatitis B and C have been linked to liver cancer

In addition, some infectious diseases may become silent, only to appear again in the future — sometimes even decades later. For example, someone who's had chickenpox may develop shingles much later in life.

Prevention

Wash your hands. This is especially important before and after preparing food, before eating, and after using the toilet. And try not to touch your eyes, nose or mouth with your hands, as that's a common way germs enter the body.

Get vaccinated. Vaccination can drastically reduce your chances of contracting many diseases. Make sure to keep up to date on your recommended vaccinations, as well as your children's.

Stay home when ill. Don't go to work if you are vomiting, have diarrhea or have a fever. Don't send your child to school if he or she has these signs, either.

Prepare food safely. Keep counters and other kitchen surfaces clean when preparing meals. Cook foods to the proper temperature, using a food thermometer to check for doneness. For ground meats, that means at least 160 F (71 C); for poultry, 165 F (74 C); and for most other meats, at least 145 F (63 C).

Also promptly refrigerate leftovers — don't let cooked foods remain at room temperature for long periods of time.

Practice safe sex. Always use condoms if you or your partner has a history of sexually transmitted infections or high-risk behavior.

Don't share personal items. Use your own toothbrush, comb and razor. Avoid sharing drinking glasses or dining utensils.

Travel wisely. If you're traveling out of the country, talk to your doctor about any special vaccinations — such as yellow fever, cholera, hepatitis A or B, or typhoid fever — you may need.