Dengue (pronounced DENgee) fever is a painful, debilitating mosquito-borne disease caused by any one of four closely related dengue viruses. These viruses are related to the viruses that cause West Nile infection and yellow fever.
Each year, an estimated 100 million cases of dengue fever occur worldwide. Most of these are in tropical areas of the world, with the greatest risk occurring in:
The Indian subcontinent
The Pacific Islands
This can happen if you eat nerve
tissue (the brain and spinal cord) of cattle that were infected with mad cow
disease. Over time, vCJD destroys the brain and spinal cord.
is no evidence that people can get mad cow disease or vCJD from eating muscle
meat—which is used for ground beef, roasts, and steaks—or from consuming milk
or milk products.
People with vCJD cannot spread it to others
through casual contact.
People who have spent a lot of time (at least 3 months) in places where mad cow disease has been found are not
allowed to give blood in the United States or Canada.2, 1 This is to help prevent vCJD from
What causes mad cow disease and variant Creutzfeldt-Jakob disease (vCJD)?
Experts are not sure what causes mad cow disease
The leading theory is that the disease is caused by infectious
proteins called prions (say "PREE-ons"). In affected cows, these proteins are
found in the brain, spinal cord, and small intestine. There is no proof that
prions are found in muscle meat (such as steak) or in milk.
cow is slaughtered, parts of it are used for human food and other parts are
used in animal feed. If an infected cow is slaughtered and its nerve tissue is
used in cattle feed, other cows can become infected.
get vCJD if they eat the brain or spinal cord tissue of infected cattle.
How common are mad cow disease and vCJD?
case of vCJD was reported in 1996. Since then, there have been a few cases of
vCJD reported in the world. Most of the cases have been in countries that are
part of the United Kingdom (England, Scotland, Wales, and Northern
In December 2003, mad cow disease was discovered in one
cow in the United States. Before this cow was found to have the disease, the
cow was slaughtered and its muscle meat was sent to be sold in grocery stores.
But its organs and nerve tissue were not used for human food. Although mad cow
disease cannot be spread through muscle meat, the United States Department of
Agriculture (USDA) quickly traced the meat and removed it from grocery stores.
Since 2004, only three more cows
in the United States have been found to have mad cow disease. The most recent case of BSE was found in April 2012 in a cow in California.