Zoonotic infections, diseases which spread from an Animal host into a Human population, are a serious threat to public health, in some cases being the source of pandemics which kill millions of people around the globe, such as the Influenza and Covid Viruses and the medieval Plague outbreaks. Filoviruses, such as the Bundibugyo, Ebola, Marburg, and Sudan Viruses, can cause outbreaks of hemorrhagic fever which kill hundreds or even thousands of people in tropical Africa, after jumping from a natural host, usually a Fruit Bat. The Bats themselves seem to suffer little harm from infection with these Viruses, but Humans and other Animals often succumb very rapidly.
Since the nature of the wild host of these Viruses became apparent, public health campaigns in many countries have tried to minimise the extent to which people interact with Fruit Bats, but the often remote nature of the communities most at risk, combined with the ability of the Virus to jump from Bats into a variety of other hosts before infecting Humans, has limited the effectiveness of these, underlining the need to better understand the nature of interactions between Fruit Bats, Humans, and other Animals.
In a letter published in the journal Current Biology on 20 April 2026, Bosco Atukwatse, Orin Cornille, Johnson Muhereza, Winfred Nsabimana, and Yahaya Ssemakula of the Kyambura Lion Project of the Volcanoes Safaris Partnership Trust, Eric Enyel of the Uganda Wildlife Authority, Charlie Gould of the School of Biological Science at the University of Edinburgh, Arjun Gopalaswamy of Carnassials Global, and Alexander Braczkowski, also of the Kyambura Lion Project of the Volcanoes Safaris Partnership Trust, present the results of an study in which camera traps were deployed at Python Cave in the Queen Elizabeth National Park, the dwelling place of a colony of Egyptian Rousette Bats, Rousettus aegyptiacus, known to act as a reserve for Marburg Virus.
The camera traps were deployed as part of a carnivore-monitoring program in Queen Elizabeth National Park between 16 February and 23 June 2025, with a total of 8832 hours of filming producing evidence of at least 14 species of Animal visiting the size, including Carnivores, Primates, Raptors, and Reptiles. The most common visitors to the cave were Nile monitors, Varanus niloticus, (72 visits), Large Spotted Genets, Genetta tigrina, (69 visits), and Palm-nut Vultures, Gypohierax angolensis, (35 visits). The cave was visited twice by Olive Baboons, Papio anubis, and ten times by Blue Monkeys, Cercopithecus mitis, which were seen actively preying on Bats. African Fish Eagles, Icthyophaga vocifer, made 33 visits to the cave, Black Sparrowhawks, Astur melanoleucus, made 19 visits, Crowned Eagles, Stephanoaetus coronatus, made 17 visits, and Verreaux’s Eagle-owls, Bubo lacteus, made six visits. Seventeen Leopard visits were directly recorded, but parts of a cycle in which the same Leopard repeatedly entered the cave, captured Bats, and exited with them were recorded, leading the team to conclude at least 43 such hunts took place during the study time. A total of 63 incidents of hunting or scavenging Bats by different species were recorded, with a further 258 incidents of Animals entering the caves for less clear reasons.
More alarmingly, over the course of the study Atukwatse et al. also observed 214 individual Humans approaching the cave. These came in 22 different groups, including school groups, researchers, and tourists, many of whom came within meters of the cave entrance (a direct contradiction of park regulations), bypassing a designated observation platform 30 m from the entrance. Only one person, a tourist, was observed to wear a mask when approaching the cave.
Atukwatse et al. do not suggest that these observations represent evidence of Virus transmission, but rather a direct record of ecological interactions at a potential spillover site. This included direct predation of potentially-infected Bats during repeated visits to the cave, and provide direct evidence of the predator-guild targeting Bats in this setting.
Unlike other famous tropical Bat roosts within caves, such as Kitaka Mine in Uganda, Kitum Cave in Kenya, Goroumbwa Mine in Democratic Republic of Congo, or Macaregua Cave in Colombia, Python Cave lacks a vertical space separating the Bats from ground-based predators. Parts of the cave roof have collapsed, and the cave is partly filled with large volumes of guano, providing predators a way of directly reaching the Bats where they roost. This it turn provides an easy opportunity for any Virus present in the Bat community to spread to other wildlife within the cave. Atukwatse et al. observed instances of bats falling from the overcrowded roof of the cave, then having to crawl over the floor, presenting another tempting target for both terrestrial and airborne predators.
First ever large scale predation by at least 14 species on Egyptian Fruit Bats (a known Marburg Filovirus reservoir) in Python Cave Uganda. The trail cameras were placed at the cave as part of the Volcanoes Safaris Partnership Trust Kyambura Lion Project's long term Leopard and Hyena monitoring work in Queen Elizabeth National Park. Alex Braczkowski/YouTube.
The presence of piles of Bat bones and frequent and repeated visits to the caves by a variety of predators indicates that the site has become a prime feeding site for both predators and scavenges, and that to some extent the richness of the resource has led to a relaxation of normal inter-species hostilities, with, for example, Fish Eagles feeding alongside Vultures, Nile Monitors feeding alongside Pythons, and even a Genet and Python seen together. This implies a loss of territoriality and aggression only seen at the most abundant food sites, although on one occasion Atukwatse et al. did observe a Crowned Eagle and a Nile Monitor squabbling over a Bat.
These interactions are all the more remarkable in that they are occurring at a site with a frequent Human presence, something which many Animals avoid where possible. The Uganda Wildlife Authority has placed an observation platform about 30 m from the entrance to Python Cave, with the specific intention of limiting Human exposure to Marburg Virus-infected Bats, but despite this Atukwatse et al.'s camera traps recorded Tourists, students from a nearby wildlife training institute, and even school trips approaching the cave mouth without any form of protection. It is particularly concerning that this was happening during the Bat's birthing season, when they are known to shed the Virus at a higher rate. Atukwatse et al. recognise that Bat-viewing is a valuable contribution to the nation's ecotourism income, but nevertheless recommend that the Uganda Wildlife Authority imposes stricter regulation on the site, with mandates for protective gear, enforced distancing, and locally trained guides to serve as sentinels for biosurveillance and education.
It has generally been assumed that the spillover events which lead to outbreaks of Marburg Virus Disease, and other zoonotic infections, occur in locations effectively beyond the observation of science. Atukwatse et al.'s results refute this, providing an example of a site where Marburg-infected Bats are interacting with a variety of other Animals, which is also integrated into the local tourist industry. Some of the species observed, such as Blue Monkeys, have previously been associated with Marburg Virus, and are commonly hunted and consumed by Humans as bushmeat. The consumption of Bats by these Monkeys presents a new route by which Marburg Virus could make its way from the wild Bat reserve into Human populations. Atukwatse et al. recommend that serological surveys are carried out of both the predators seen frequenting Python Cave, and of park rangers who regularly enter the site, in order to assess potential exposure to Marburg or other Filoviruses. This, combined with enhanced surveillance of Python Cave and other similar sites, could enable the development of a new dataset to complement the genomic tools already being developed.
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