Ebola May be Present in More Animals than Previously Thought

Ebola may be present in more animals than previously thought, according to researchers studying the virus. So far, it has been detected in chimpanzees, gorillas, fruit bats, monkeys, antelopes, porcupines, rodents, dogs, pigs and humans.

Humans and primates are particularly susceptible to the deadly disease, at least to certain strains. During the outbreak currently wreaking havoc in Guinea, Sierra Leone and Liberia, Ebola has killed 670 people thus far and infected more than 1,000.

"The close evolutionary relationship between humans, chimpanzees and gorillas makes their immune systems very similar," Peter Walsh, a primate expert at the University of Cambridge, told Discovery News.

According to the World Health Organization (WHO), humans contract Ebola - formerly known as Ebola haemorrhagic fever - via direct contact with the blood, body fluids and tissues of infected animals or people. During an outbreak like this most recent one, those at the highest risk of being infected are health workers, family members and others in close contact with sick people and deceased patients.

Eating or handling bush meats are also potential sources of Ebola, but experts are now focusing on fruit bats, which they believe harbor the illness. Ebola is fatal in up to 90 percent of humans who become infected, according to the WHO. Most of the infected bats appear to come from the following three species: Hypsignathus monstrosus, Epomops franqueti and Myonycteris torquata.

"In general, Ebola researchers think that the natural host of Ebola virus are fruit bats, and that the virus is transmitted to non-human primates and then to humans through the bush meat trade," Purdue University's David Sanders, one of the world's leading experts on zoonotic diseases, told Discovery News.

He added, "It is possible that there is direct transmission from fruit bats to humans."

In certain African cultures humans eat bat meat, but as for non-human primates, they might become infected by consuming the same fruit that bats eat.

Sanders and his team found that even the way Ebola infects human cells is nearly identical - both structurally and biochemically - to the way that similar viruses enter bird cells. This suggests that the proteins of the virus had a fairly recent ancestor.

"It is therefore possible that Ebola was at one time associated with a bird host and may even be so today," Sanders said, adding that the bird must be native to Central Africa, where Ebola was first discovered in 1976.