What It Means When a Disease Is Endemic

Humanitarian aid volunteer talking to villagers about malaria prevention

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An endemic disease is a disease that is always present in a certain population or region. One of the most talked-about endemic diseases is malaria. The CDC estimates that around half the world's population live in areas where they are at risk of Malaria infection. It is endemic in large parts of Africa as well as some areas of South America.

How Endemic Differs From Epidemic

Endemic diseases are often confused with epidemics. However, an epidemic refers to an outbreak of a disease. An epidemic occurs when a disease is spreading through one or more populations. In contrast, the endemic disease is one that is constantly present in a group or geographic area. Pandemics are worldwide epidemics. Under certain circumstances, an epidemic can lead to a disease becoming endemic.


Endemic diseases are not always present at high levels. They can be relatively rare. The defining feature of a regional endemic disease is that it can always be found in the population that lives there.

Malaria as an Example

Malaria is endemic in many areas of Africa. Malaria is such a fixture in certain parts of Africa that a protective mutation—sickle cell trait—has become common in local populations. The sickle cell gene makes people less susceptible to malaria. However, it works best when people have one copy of the gene. When they have two, it can cause significant health problems.

Endemic STDs

In certain areas of the world, there are several STDs that could be considered endemic. For example, HIV is considered to be endemic in many parts of Africa. At this point, and for the conceivable future, eradication is unlikely. That's true even as improving treatment is starting to bring the HIV epidemic under control.

Hepatitis B (HBV) is also endemic throughout the world. Although HBV is not always a sexually transmitted disease, it can be sexually transmitted. Fortunately, there is a vaccine available to prevent hepatitis B transmission. If a person is planning on traveling to an area where hepatitis is endemic, vaccination is usually recommended. Vaccination against hepatitis is also part of the standard childhood immunization schedule in the United States.

Syphilis used to be endemic around the world. Fortunately, effective treatments have gone a long way in reducing the number of people infected by this disease. Unfortunately, partially due to spread through oral sex, syphilis has recently been on the rise. It's unlikely that it will become endemic again. at least in the U.S. However, it can still lead to significant problems—particularly for newborns. Syphilis is also still considered to be endemic in certain parts of Africa. A related disease, known as Yaws, is also endemic in some areas of the tropics. Yaws is mostly found in children, and it is not sexually transmitted. However, it's caused by a close relative of the bacterium that causes syphilis. The bacteria that causes Yaws is known as T. pallidum sp. Pertenue. The one that causes syphilis is Treponema pallidum sp. pallidum.

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