Ebola Outbreak Investigations Include Bats as Potential EBOV Sources in West Africa

A major epidemiological investigation on the Ebola outbreak in West Africa led researchers to broaden the search for other possible sources of the virus. The study directed by the Robert Koch Institute in Berlin, Germany suggests that insectivorous bats may have transmitted Ebola virus to the villagers. Thus, instead of larger wildlife, these winged-mammals were identified as the potential source for this recent outbreak.

In April 2014, the research team embarked on a four-week field study in Guinea to determine the zoonotic origin of the epidemic that started from the small village of Meliandou. They have conducted wildlife surveys and observation of the inhabitants' exposure to bats, which is quite common in the area. Contact with bats occur when the villagers go hunting or when they consume the animal's meat. A number of bats in the area, including those from neighbouring villages, were captured for molecular analysis. Experimental data indicate that some of these bat species can withstand Ebola virus infection. The scientists also noted that other wild animals are unlikely the sources of this outbreak as there was no noticeable decline in wildlife population.

According to interviews with the locals, bat migrations of large numbers take place yearly in the region, and so hunting them down for food was widely practiced. These bats would normally be seen clinging to the roofs of homes or animal hides. Fruit bats are known to be natural reservoirs of Ebola virus, but consumption of their meat does not mean that humans would contract the infection instantly as the disease is not foodborne or airborne either. The World Health Organization states that humans contract the virus when they come in contact with body fluids, blood, and other secretions from infected animals that are sick or dead in the wilderness.

The villagers reported that children would also capture and roast bats over small fires. Some of the kids were frequently seen playing near a tree stump where a colony of Angolan free-tailed bats live. The 2-year-old toddler regarded as the index case for this outbreak lived nearby the hollow tree. The viral disease that spread from this small village to other parts of West Africa is so far the deadliest Ebola outbreak that took the lives of more than 8,100 people as of January 5, 2014.

A comprehensive report on the investigation of the West African Ebola outbreak is published in EMBO Molecular Medicine.

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