Diphtheria — Comprehensive overview covers symptoms of this infection that's preventable with a vaccine.


Sexually transmitted diseases

Strep throat

Strep throat is a bacterial throat infection. It typically causes a very sore throat and is treated with antibiotics.

Swimmer's ear

Swimmer's ear, an infection in the outer ear, is usually caused by bacteria and is more common in ears exposed to water for long periods.


Toxoplasmosis is an infection caused by a parasite. It doesn't make most people ill, but infants and people with HIV/AIDS are at risk of complications.


Tooth abscess

Tooth abscess — Comprehensive overview covers symptoms, causes, treatment of this painful tooth condition.

Risk factors


More than 39 million people are living with HIV — the virus that causes AIDS. Millions more are likely to become infected in the next decade.

Hodgkin's lymphoma


Mononucleosis — also called kissing disease because it can be spread by kissing — causes fatigue, fever and swollen lymph glands.


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


Runny nose

Runny nose: What's causing your sniffles?

Tests and diagnosis

Complete blood count

A complete blood count can be used to evaluate your overall health, detect a wide range of disorders, or monitor a medical condition or treatment.

Needle biopsy

Find out what to expect during a needle biopsy.

Jan. 02, 2014

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