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Attention, chocolate lovers: You may not be able to help yourselves. Swiss and British scientists have linked the widespread love of chocolate to a chemical "signature" that may be programmed into our metabolic systems.
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Encephalitis

Overview, Causes, & Risk Factors

Encephalitis is an inflammation of the brain.

What is going on in the body?

Encephalitis is usually caused by a viral infection of the brain tissue. The infection can also be caused by bacteria, fungi, or parasites. These tiny organisms can enter the brain tissue by any of the following routes:

direct infection of the cells in the brain, often following a head injury

through the bloodstream after a bite from a tick or mosquito

through the respiratory or gastrointestinal tracts. They then travel through the bloodstream and invade the brain.

traveling up nerves to the brain. This happens with a dormant herpes infection or after a bite from an animal with rabies.

What are the causes and risks of the condition?

Most cases of encephalitis are caused by a viral infection of the brain tissue. Viruses that commonly cause encephalitis include the following:

adenovirus, which also causes respiratory infections

Borrelia burgdorferi, which also causes Borrelia burgdorferi.\ It is passed to humans through tick bites. ',CAPTION,'Lyme Disease');" onmouseout="return nd();">Lyme disease

Colorado tick virus, which also causes Colorado tick fever

cytomegalovirus, which also causes a common childhood infection with mild or vague symptoms

enteroviruses, a group of viruses that also cause poliomyelitis and upper respiratory infections

Epstein-Barr virus, which also causes mononucleosis

herpes simplex viruses, a group of viruses that also cause cold sores and genital herpes

La Crosse encephalitis virus

measles virus, which also causes measles

rubella virus, which also causes German measles

St. Louis encephalitis virus

varicella zoster viruses, which also cause shingles and chickenpox

Western and Eastern equine encephalitis virus

West Nile virus

Bacteria that can cause encephalitis include the following:

leptospirosis, which also causes a flu-like illness

mycobacteria, a group of bacteria that also cause tuberculosis

mycoplasma, which also cause pneumonia

rickettsia, a group of bacteria that also cause Rocky Mountain spotted fever

West Nile virus, which also causes a flu-like illness

Other less-common causes of encephalitis include the following:

drug reactions

infections with fungi, such as histoplasma and cryptococcus

infections with parasites such as those that cause malaria

vasculitis, which is an inflammation of the blood vessels that supply the brain

People at high risk for encephalitis include those whose age is very young or very old, and those who have compromised immune systems.

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