In-depth

Back pain

Bird flu (avian influenza)

Brucellosis

Brucellosis is an infectious disease that spreads from animals to people, mainly via unpasteurized dairy products. Travelers should take special care to avoid infection.

Cancer

Celiac disease

Celiac disease is an immune reaction to gluten, a protein found in certain foods. As a result, the body is unable to absorb some important nutrients.

Chronic fatigue syndrome

Cold sore

Cyclospora infection

Dengue fever

Dermatomyositis

Ebola virus and Marburg virus

Ehlers-Danlos syndrome

Ehrlichiosis

Encephalitis

Encephalitis is inflammation of the brain usually caused by a viral infection. Severe cases can cause brain damage, even death.

Endocarditis

Generalized anxiety disorder

Genital herpes

Hangovers

Hantavirus pulmonary syndrome

Hantavirus pulmonary syndrome is initiated by a rodent-carried virus that infects the lung tissues, bringing on flu-like symptoms, respiratory problems and even death.

Hemophilia

Hepatitis A

Hepatitis C

Histoplasmosis

HIV/AIDS

Hypercalcemia

Hypoparathyroidism

Influenza (flu)

Jet lag disorder

Legionnaires' disease

Legionnaires' disease, a severe form of pneumonia, is caused by bacteria that can live in water in air conditioning systems, showers and spas.

Listeria infection

Most people exposed to listeria don't become ill. But for those at risk of a listeria infection — a foodborne illness — the consequences can be severe.

Mixed connective tissue disease

Myofascial pain syndrome

Polio

One of the most feared diseases of the 20th century, polio has been eradicated from the developed world but remains a threat in less developed nations.

Polymyositis

Porphyria

Porphyria is a group of inherited disorders that result from buildup of natural chemicals call porphyrins, which can cause nervous system and skin problems.

Post-polio syndrome

Premenstrual syndrome (PMS)

Pulmonary fibrosis

Pulmonary fibrosis results from scar tissue that forms in your lungs. This affects your ability to breathe and obtain enough oxygen.

Salmonella infection

Salmonella infection will cause only diarrhea and stomach pain in some people, but for infants and immunocompromised people, this bacterial illness can cause life-threatening complications.

Severe acute respiratory syndrome (SARS)

Severe acute respiratory syndrome (SARS) has sickened people worldwide. Although effective treatments aren't yet available, common-sense precautions may help you avoid infection.

Staph infections

Syphilis

Syphilis, a sexually transmitted infection, first appears as painless sores on your genitals, rectum or mouth. Early diagnosis is important.

Toxic shock syndrome

Trichinosis

Vasculitis

Yellow fever

March 19, 2016