When researchers in Uganda set up camera traps to observe African leopards and spotted hyenas in a national park last year, they ended up capturing much more than those specific species. Multiple camera traps placed near a cave known to host Egyptian fruit bats recorded various animals interacting with the bats. Notably, these bats are known to carry the Marburg virus, which poses a risk to human health and can cause severe fever. This captured footage provides crucial insights into how diseases can spread within ecosystems.
It’s established that bats can transfer viruses to humans directly, or through other animal species as intermediaries. The Ugandan team believes they might have captured the first evidence of such intermediate species in a known hotspot for Marburg virus, related to Ebola. “It is certainly the first in such a well-documented form,” remarked Gábor Kemenesi, a virologist from Hungary, who wasn’t part of the research.
The findings were published in the journal Current Biology after being shared in a preprint ten months earlier. The research team documented ten different species interacting with bats at Python Cave in Queen Elizabeth National Park. They witnessed blue monkeys reaching into the cave for bats, a crowned eagle battling a Nile monitor lizard over captured bats, and even a leopard seemingly upright, trying to snatch bats from the cave. This behavior might confirm that leopards hunt live bats for the first time. “It’s never been seen,” said study co-author Alexander Braczkowski, adding that leopards might consume dozens of bats in a single night.
Dangerous encounters
Even more surprising was that they recorded over 200 individuals—tourists, local wildlife trainees, and school children—approaching the cave during the four months the cameras were running. Alarmingly, only one tourist was seen wearing a mask despite the cave being marked with warnings about the Marburg virus, which currently has no known treatment or vaccine.
“I was quite shocked,” said Elke Mühlberger, a virologist from Boston University. Direct contact with caves has been a major factor in the transmission of the Marburg virus to humans. An analysis shared by Adam Hume, another virologist from Boston University, indicated that 43% of confirmed Marburg outbreaks since 1967 have involved cave visits, while 29% ruled out caves completely, leaving the origin of the rest uncertain.
Bats in Python Cave are directly connected to past outbreaks of Marburg. One outbreak in 2007 at Kitaka mine, located about 50 kilometers from the cave, was traced back to bats that roost in the cave. Two tourists who visited the site in 2007 and 2008 contracted the virus, with one of them dying. There are mixed reports on whether they entered the cave or simply looked in; the surviving individual recalled going in about three meters and observing for a significant time. Jonathan Towner, a viral ecologist from the CDC in Atlanta, speculated that they likely came into contact with bat waste as the creatures flew around.
