NIAID, WCS Scientists Show Feasibility of Tracking Bats, Ebola With GPS Collars

NIAID Now | October 16, 2019

A hammer-headed bat with a GPS collar ready for release in the Republic of the Congo

Credit: Sarah H. Olson, WCS

GPS tracking devices placed on hammer-headed bats in the Republic of the Congo have given NIAID scientists and colleagues the first detailed look at the daily routines of these suspected Ebola virus reservoirs.

The work is important: No researcher has isolated live Ebola virus in any bat species—though antibodies against Ebola virus proteins and fragments of the Ebola virus genome have been found in the hammer-headed bat. Those findings make scientists believe that hammer-headed bats could maintain Ebola virus in nature.

Tracking bat movements in the northern Republic of the Congo, near the village of Libonga, allows researchers to better understand bat patterns, including how often and when they visit villages. Future work, in a collaboration involving NIAID and the Wildlife Conservation Society (WCS), will involve studying how bats respond to stresses across seasons. Scientists will analyze stress data with Ebola virus surveillance, movement, demographic, and environmental data to help understand when bats are most likely to shed virus and come in contact with people. The project is part of a larger study to learn whether environmental factors—such as the length of the rainy season or high temperatures during the dry season—affect the behavior of bats and other wildlife. Scientists hope the results can help detect or predict viral disease outbreaks.

Since 2011, a NIAID research group that studies the relationship between ecology and viruses has trapped, sampled, released and watched bats near Libonga. In coordination with scientists from WCS, in December 2017 the groups began a pilot project using radio collars to track 10 bats for just over one week. In April 2018, they started a second pilot project using solar-powered GPS trackers placed on 11 bats, four females and seven males. The group tracked one female bat for about one year.

PLOS One published the results of the two pilot projects on Oct. 1. The study highlights a “lek”—a collective mating site for bats—that the researchers discovered. They also learned that female bats fly much further from the lek than males for a total of about 10 kilometers each day. Males tend to stay within about 1 kilometer of the lek, visiting the site frequently but otherwise having little daily movement. The scientists concluded that females visit the lek exclusively for mating.

The scientists say the study information will improve GPS-based bat tracking, in terms of technology and data-gathering choices, but also knowing when and where to place staff in relation to a lek and daily roosting sites. Ultimately, they believe that protecting human health in the region is connected to learning more about the relationship between bats and viruses.

Listen to the sound of bats at a lek.

Reference: S. Olson et al. Lek-associated movement of a putative Ebolavirus reservoir, the hammer-headed fruit bat (Hypsignathus monstrosus), in northern Republic of Congo. PLOS One. DOI: 10.1371/journal.pone.0223139 (2019)

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