How do ebola outbreaks start

Reston virus can cause disease in nonhuman primates and pigs, but there have not been cases in people. Bombali virus was first identified in bats in , and experts do not know yet if it causes disease in either animals or people. Ebola virus was first discovered in near the Ebola River in what is now the Democratic Republic of Congo. Since then, the virus has been infecting people from time to time, leading to outbreaks in several African countries. Scientists do not know where Ebola virus comes from.

Based on similar viruses, they believe EVD is animal-borne, with bats or nonhuman primates being the most likely source. Infected animals carrying the virus can transmit it to other animals, like apes, monkeys, duikers and humans. The virus first spreads to people through direct contact with the blood, body fluids and tissues of animals. Ebola virus then spreads to other people through direct contact with body fluids of a person who is sick with or has died from EVD. This can occur when a person touches these infected body fluids or objects that are contaminated with them.

There is no cure for Ebola, but promising experimental medications are in development. Several investigational antiviral treatments are being provided to people with laboratory-confirmed Ebola and preliminary evidence has shown favorable results for two treatment options, REGN-EB3 or mAb Avoid traveling to areas where there is an Ebola outbreak.

If you do travel to such an area, avoid contact with people who are sick or have died of Ebola, particularly their bodily fluids or objects their fluids have touched. There have been many Ebola outbreaks since the first known outbreak in , all in sub-Saharan west, east and central Africa. By far the deadliest outbreak occurred in when more than 11, people died most in west African Guinea, Liberia and Sierra Leone.

Currently Ebola is not considered a threat outside of certain countries in sub-Saharan Africa. Very few people with Ebola have been outside of that area. During the outbreak, 11 people with Ebola were treated in the United States, nine of whom had contracted it in western Africa, most as health care workers. Two American nurses contracted the disease while treating the Liberian patient, but both recovered. In other words, only two people have ever been infected with Ebola while on American soil and neither died.

By comparison, CDC estimated 79, Americans died from influenza during the flu season. Several people with Ebola received treatment in the U.

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Ebola virus disease EVD is a severe disease caused by Ebola virus, a member of the filovirus family, which occurs in humans and other primates. Between and no cases or outbreaks were detected, however since that time outbreaks have been recognised with increasing frequency see table below. Over 28, cases were recorded. Several research workers became infected with the virus during these outbreaks, but did not become ill.

Investigations traced the source of all outbreaks caused by RESTV to one export facility in the Philippines, but how the facility was contaminated was not determined. A number of workers developed antibodies but none had had any symptoms. A 6th species of ebolavirus was discovered in bats in Sierra Leone in , and named Bombali ebolavirus.

It is not yet known if this species is pathogenic for humans. In Africa between and , outbreaks of EVD primarily occurred in remote villages close to tropical rainforests in Central and West Africa. In , Ebola outbreaks occurred for the first time in West Africa Guinea, Liberia and Sierra Leone , and in these countries there was intense transmission in urban areas. See information on current Ebola outbreaks. A total of 8 people developed antibodies but did not become ill.

Antibodies were detected in 6 workers on the farms, but none had clinical illness. Ebola is believed to be zoonotic, however, the natural reservoir is unknown, despite extensive investigations. Non-human primates have been a source of human infection, however, they are not thought to be the reservoir as they develop severe, fatal illness when infected.

High numbers of animal carcasses were noted in surrounding areas prior to outbreaks in Gabon and DRC , and recovered carcasses were infected with a variety of strains of Ebola virus suggesting they were not the reservoir but had been infected by more than one source. Harvesting of migrating fruit bats was thought to be the source of a large outbreak in the DRC in The first human case in an Ebola outbreak is acquired through contact with blood, secretions organs or other bodily fluids of an infected animal.

The first case in the West Africa outbreak was likely acquired via exposure to bats. The virus is then transmitted from person to person through direct contact with the blood, secretions, organs or other bodily fluids of infected persons.

People can also become infected through contact with objects, such as needles or soiled clothing, that have been contaminated with infected secretions.