What causes ebola virus

Overview

Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever, is a rare but severe and often fatal illness in humans. It is caused by the Ebola virus, a type of filovirus. The virus is native to tropical Africa and is thought to have originated in fruit bats, which are considered the natural reservoir for the virus.

How Ebola Virus Spreads

The transmission of the Ebola virus to humans typically occurs through direct contact with infected animals. This can happen when humans hunt, butcher, prepare, or consume infected bushmeat. Once the virus is introduced into the human population, it can spread from person to person through direct contact with the bodily fluids of an infected individual.

Animal-to-Human Transmission

The initial jump of the Ebola virus from animals to humans is known as a spillover event. Fruit bats are strongly suspected to be the natural hosts of the Ebola virus. Other animals, such as chimpanzees, gorillas, monkeys, and even forest antelope, can become infected by eating fruit contaminated by bat saliva or feces, or by direct contact with infected bats. When humans come into contact with the bodily fluids of these infected animals—whether through hunting, handling carcasses, or preparing bushmeat for consumption—they can contract the virus. This initial transmission is a critical step in the emergence of Ebola outbreaks.

Human-to-Human Transmission

Once an individual is infected with the Ebola virus, human-to-human transmission becomes the primary mode of spread. This occurs when there is direct or indirect contact with the bodily fluids of an infected person who is showing symptoms of the disease. Bodily fluids that can transmit the virus include:

• Blood
• Vomitus
• Urine
• Saliva
• Sweat
• Feces
• Breast milk
• Semen

Transmission can happen through:

• Direct Contact: Touching an infected person's skin (including burial rituals that involve touching the body) or mucous membranes (eyes, nose, mouth) with infected bodily fluids.
• Indirect Contact: Touching surfaces or objects (like contaminated clothing, bedding, or medical equipment) that have come into contact with infected bodily fluids and then touching your own eyes, nose, or mouth.

It is important to note that individuals are not contagious until they begin to show symptoms of EVD. However, once symptoms appear, they can transmit the virus. Even after recovery, some bodily fluids, particularly semen, can continue to carry the virus for a period, posing a risk of sexual transmission.

Factors Influencing Transmission

Several factors contribute to the spread of Ebola:

• Close Contact: The virus requires close contact with infected fluids to spread. Casual contact with an infected person is generally not sufficient for transmission.
• Healthcare Settings: Outbreaks have often been amplified in healthcare settings where infection control practices may be overwhelmed or inadequate, leading to nosocomial transmission (spread within a hospital or clinic).
• Cultural Practices: Certain cultural practices, such as traditional burial rites that involve washing and touching the body of the deceased, can facilitate transmission if proper precautions are not taken.
• Lack of Awareness: Limited public awareness about how the virus spreads and how to prevent it can contribute to continued transmission.

What Ebola Virus Does NOT Spread Through

It is crucial to understand that Ebola virus is NOT spread through:

• Air (like the flu)
• Water
• Food (unless contaminated by infected bodily fluids during preparation)
• Mosquitoes or other insects

Understanding these transmission routes is vital for implementing effective prevention and control measures during outbreaks.