Observing Animal and Human interactions around a Marburg Virus-infected Bat colony.

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.

 Multi-species predation and scavenging at a Marburg Virus Bat reservoir. The distribution of detections per species across 368 trap nights at Python Cave recorded using  6 remote, solar-powered camera traps. Blue indicates predation and scavenging events, whereas  orange represents detections where cave exploration, entry, exit, or resting was observed. Atukwatse et al. (2026).

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. 

A collage of hunting and foraging by a variety of species. Insets show confirmed prey contact and feeding events. (i) An African Leopard, Panthera pardus, with its Bat prey emerging from the cave interior. (ii) A Crowned Eagle, Stephanoaetus coronatus, with its Bat prey. (iii) A Blue Monkey, Cercopithecus mitis, holding a Bat in its left hand. (iv) A Melanistic Genet, Genetta victoriae, with Bat prey. (v) A Nile Monitor, Varanus niloticus, approaching and then consuming a fallen Bat. (vi) An interspecific interaction (likely a fight) between a Crowned Eagle and a Nile Monitor over two Bats captured by the Eagle. (vii) An African Civet, Civettictis civetta, scavenging on Bat remains. (viii) A Palm-nut Vulture, Gypohierax angolensis, scavenging a Bat carcass. (ix) A group of Olive Baboons, Papio anubis, at the cave mouth, possibly foraging on Bat guano. Atukwatse et al. (2026).

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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Outbreak of Bundibugyo Virus in eastern Democratic Republic of Congo suspected of killing more than 220 people.

More than 220 people are thought to have died, and more than 900 people to have been infected, in an outbreak of Bundibugyo Virus in the Eastern Democratic Republic of Congo, according to a press release issued by the United Nations on 25 May 2025. Bundibugyo Virus, properly Bundibugyo ebolavirus, is a member of the Ebola Virus Family, Filoviridae, which causes an Ebola-like hemorrhagic fever, and is often referred to simply as 'Ebola'.

The World Health Organization was first notified of the outbreak on 5 May 2026, as an unknown illness with a high mortality rate which had already claimed the lives of four health workers in the Mongbwalu Health Zone of Ituri Province, Democratic Republic of Congo. The identity of the disease as Bundibugyo Virus was determined from samples sent to the Institut national de recherche biomédicale in Kinshasa on 15 May. 

By this time the Virus had spread to the Rwampara and Bunia health zones, also in Ituri Province, with 246 reported cases and 80 fatalities. Health workers began investigating clusters of deaths with compatible symptoms in the community. A case was also confirmed in Uganda, after an elderly man from Democratic Republic of Congo was admitted to a private hospital with severe symptoms and subsequently died. This patient was subsequently confirmed as having been infected with Bundibugyo Virus by the Central Emergency Surveillance and Response Support Laboratory at Wandegeya. His remains were subsequently returned to the Democratic Republic of Congo. A second case was reported in Uganda on 16 May, this time a Ugandan national who had recently returned from Democratic Republic of Congo. This patient is being treated in Uganda; no transmission of the Virus in Uganda has been reported. 

Health Zones affected by Bundibugyo Virus Disease in Democratic Republic of Congo, as of 16 May 2026. World Health Organization.

By 21 May the outbreak had spread to North Kivu and South Kivu provinces, with 746 suspected cases and 176 deaths thought to have been caused by Bundibugyo Virus, although only 85 cases, including ten fatalities have been confirmed by laboratory analysis. No further cases had been reported in Uganda, but an American national who had been working as a surgeon in Democratic Republic of Congo was confirmed as having the Virus and airlifted to Germany for treatment.

Risk mapping of Health Zones in Democratic Republic of Congo as of 21 May 2026. World Health Organization.

Bundibugyo Virus was first described in 2008 following an outbreak in Bundibugyo District Uganda. Only one subsequent outbreak has been reported prior to 2026, in Province Orientale, Democratic Republic of Congo, in 2012. Thus, although the Virus is closely related to Ebola, and produces a similar disease, there has been no specific treatment developed for it, and no vaccine to prevent its spread. This has made it difficult to implement an effective treatment and containment program against a disease with a 30% fatality rate.

Ituri Province is located in the northeast of Democratic Republic of Congo, with borders with Uganda and South Sudan. It has a large, if generally informal, mining sector, which attracts workers from neighbouring provinces and countries. The infrastructure of Ituri Province is generally weak, with healthcare services largely dependent on support by aid programs run by western countries, particularly the United States. These programs have been cut heavily by the current US administration, further weakening healthcare provision.

To make matters worse, a long running conflict in the province has seen an upsurge in violence since December 2025, with fighting between the Convention for the Popular Revolution and the Armed Forces of the Democratic Republic of Congo leading to at least 40 people being killed and around 100 000 being displaced. The Convention for the Popular Revolution is one of several rebel groups active in the region, and has been accused by the Congolese Government of forcibly recruiting child soldiers and being a front for the Ugandan and/or Rwandan governments to exploit the regions mineral wealth. Nevertheless, the Convention for the Popular Revolution has sometimes worked alongside the Armed Forces of the Democratic Republic of Congo and Ugandan Army to fight against other groups, notably the Allied Democratic Forces, a group thought to be allied to Islamic State.

Unloading supplies for the isolation and treatment tents at the Bunia Referral Hospital, Ituri Province, Democratic Republic of the Congo, May 2026. World Health Organization.

All of this has made it extremely difficult to implement effective track-and-trace and treatment programs to contain the Bundibugyo Virus outbreak. To complicate things further, a disinformation campaign appears to have been circulating on social media, adding to the distrust of outsiders and officialdom in general which is prevalent in the local population, something that has led to attacks on healthcare workers and facilities. Local people have reportedly set fire to two treatment centres in which patients were being treated in isolation, following a dispute over a safe burials program implemented to prevent the spread of the disease. This involves the burial of the deceased by healthcare workers with a minimal number of people present, and goes against local customs of large funerals and ritually washing the dead by relatives. 

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The Bahamas ends mother-to-child transmission of HIV.

The Bahamas has been recognised as having eliminated the mother-to-child transmission of HIV, according to a press release issued by the World Health Organization on 22 April 2026. The has been achieved through the establishment of a comprehensive universal healthcare system, and the implementation of an Elimination of Mother-To-Child Transmission program, which aims to eliminate the mother-to-child transmission of three diseases, HIV, Syphilis, Hepatitis B. Under the terms of this program, all expectant mothers are offered screening for these diseases, as well as treatments to prevent transmission to the child. The program has also included making available pre-exposure prophylaxis treatments for HIV, which prevent people becoming infected following an initial exposure, reducing the prevalence of HIV in the population. The Bahamas becomes the twelfth country in the Americas Region to have eliminated mother-to-child transmission of HIV.

The national flag of the Bahamas. St Kitts & Nevis Observer.

Human Immunodeficiency Virus, or HIV, is a form of Lentivirus which causes infections in Humans, spread through sexual intercourse or exchange of blood. Notably, the Virus infects the cells of the Human immune system, where it is hard for that immune system to attack, and eventually leads to a breakdown of the immune system known as AIDS (Acquired Immune Deficiency Syndrome), during which the body becomes vulnerable to a wide range of infections, including many by micro-organisms which are not usually pathogenic. 

Untreated, HIV invariably leads to AIDS, and AIDS is invariably fatal, but, as with Syphilis, HIV infections can go through long phases of dormancy, leaving infected people unaware that they have the disease. Neither an effective vaccine nor a cure for HIV has yet been developed, however, it is possible to suppress the infection with a combination of anti-viral drugs, allowing patients to lead relatively normal lives, as long as their supply of antivirals is not interrupted. Children born to mothers with HIV are not automatically infected, as the Virus is usually unable to cross the placenta, but there is a high chance of infection during birth if the mother is not receiving treatment.

Scanning electron microscope image of an HIV virion. Hockley et al. (1988). 

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Monkey Pox outbreak in Democratic Republic of Congo officially declared to have ended.

An outbreak of Monkey Pox in the Democratic Republic of Congo which has been raging since 2023 has officially been declared to have ended by the Ministry of Public Health. During the course of the epidemic, 161 000 people are thought to have been infected with the disease in the Democratic Republic of Congo, with 37 000 cases confirmed by laboratory testing. A total of 2286 deaths have been attributed to the disease within the country, although only 127 of these were confirmed by laboratory testing. At the height of the epidemic the disease spilled over into several neighbouring, and internationally connected, countries, causing the World Heath Organization to declare a global emergency.

A patient with Monkey Pox waiting at the Kamituga General Hospital in South Kivu Province, Democratic Republic of Congo, in September 2004. Moses Sawasawa/AP.

Monkeypox (or Mpox) is caused by a double-stranded DNA virus of the genus Orthopoxvirus, which is the same genus as the Viruses which cause Smallpox and Cow Pox. It causes a Chickenpox-like disease, with a distinctive rash with large blisters or sores on all parts of the body, as well as a fever, headaches, muscle and back aches, joint pain, chills, exhaustion, and swollen glands. Most patients recover within a few weeks, however it can cause more dangerous secondary symptoms, including pneumonia, sepsis, encephalitis, and blindness. Older and younger patients are particularly at risk, as are patients who have weakened immune systems or are pregnant. The disease typically has a case fatality ratio of about 1%.

Monkeypox is a zoonotic disease, with a wild reserve of the Virus found in several species of Primates and Rodents. Outbreaks usually start with an Animal-to-Human infection, although Humans at the blistering stage of the disease are capable of spreading it to other Humans. The Virus was first detected in Crab-eating Macaques, Macaca fascicularis, in a laboratory in Denmark in 1958, an outbreak which gave the disease its name (it is now thought to be more prevalent in Rodents than Primates). The first known Human infection with Monkeypox was reported from the Democratic Republic of Congo in 1970.

Monkeypox Virus size and structure in comparison to HIV, SARS-COV-2 and Poliovirus. Membranes and membrane-bound proteins are in purple, capsids are in dark blue, and genomes and nucleoid-associated proteins are in turquoise. PDB-101.

There are two main clades of Monkeypox, Clade I, which is predominantly found in Central Africa, and Clade II, which is predominantly found in West Africa. However, in May 2022 a cluster of cases was found in London, England, which is thought to have been brought to the country by a patient from Nigeria. These infections were caused by a new strain, which was apparently transmitted from Human-to-Human more readily than previously encountered variants, and was given the identifier Clade IIb (because it was a new clade derived from Clade II, which subsequently became referred to as Clade IIa. Notably, the spread of this strain has been linked to sexual activity. Clade IIb subsequently spread to 121 countries over the next two years, infecting more than 99 500 people and causing over 200 deaths.

In September 2023, another new and apparently more virulent variant, later named Clade Ib, was identified in the mining town of Kamituga in South Kivu Province, Democratic Republic of Congo. This spread from Human-to-Human more readily than previously known forms of the disease, and had a case fatality ratio of 3-4%, making it much deadlier than previously encountered variants. Unlike Clade IIb, Clade Ib appeared to spread largely among children, with 70% of reported cases and 85% of reported deaths being under the age of 15, although it has been suggested that this is in part because the disease has spread through several large refugee camps, where large numbers of children are also suffering from malnutrition, as well as other infectious diseases such as Cholera and Measles. 

Clade Ib has subsequently been reported in 25 countries, although in most cases this has been single patients who developed symptoms of the disease after returning from travel to Central Africa. However, in neighbouring countries such as Burundi, Rwanda, and the Central African Republic, as well as Indonesia and the Philippines, the clade has begun to spread locally, leading to public health campaigns to contain it.

Fortunately, because Monkeypox is closely related to Smallpox, vaccines against that disease have been shown to be effective against its spread. Because the last recorded case of Smallpox was in 1977, and the disease was declared officially globally eradicated in 1980, few countries maintain a stock of the vaccine, and active vaccination programs against Smallpox have not been carried out for decades. However, the technology to produce these vaccines still exists, and manufacturers in the United States, Spain, and Denmark have been distributing the vaccines since 2024.

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More than 100 dead in outbreak of Measles in Bangladesh.

More than 100 people have died of suspected Measles in an outbreak of the disease in Bangladesh. Cases started appearing in mid-March 2026, since when more than 7500 suspected cases have been reported, with more than 4600 people hospitalised, almost all of whom are young children, with about one third of those affected being under nine months old. Over 900 cases have been laboratory-confirmed, including 16 of those who lost their lives.

A patient being treated for Measles at the Dhaka Medical College in Bangladesh. Drik Picture Library/Getty Images.

Measles is a human disease caused by a Virus in the Paramyxovirus family. The Virus infects the respiratory tract, then spreads throughout the body. It can lead to major epidemics with significant morbidity and mortality, especially among vulnerable people. Among young and malnourished children, pregnant women, and immunocompromised individuals, including those with HIV, cancer or treated with immunosuppressives, Measles can cause serious complications, including severe diarrhoea, blindness, encephalitis, pneumonia, and death.

Thin-section transmission electron micrograph revealing the ultrastructural appearance of a single Viron, of the Measles Virus. The measles Virus is a Paramyxovirus, of the genus Morbillivirus. It is 100-200 nm in diameter, with a core of single-stranded RNA, and is closely related to the Rinderpest and Canine Distemper Viruses. Two membrane envelope proteins are important in pathogenesis. They are the F (fusion) protein, which is responsible for fusion of virus and host cell membranes, viral penetration, and hemolysis, and the H (hemagglutinin) protein, which is responsible for adsorption of virus to cells. Centers for Disease Control and Prevention/Wikimedia Commons.

Transmission is primarily person-to-person by airborne respiratory droplets that disperse rapidly when an infected person coughs or sneezes. Transmission can also occur through direct contact with infected secretions. Transmission from asymptomatic exposed immune persons has not been demonstrated. The Virus remains contagious in the air or on contaminated surfaces for up to two hours. A patient is infectious from four days before the start of the rash to four days after its appearance. There is no specific antiviral treatment for Measles, but most people recover within 2-3 weeks.

An effective and safe vaccine is available for prevention and control. The Measles-containing-vaccine first-dose is given at the age of nine months, while the Measles-containing-vaccine second dose is given at the age of 15 months. A 95% population coverage of Measles-containing-vaccine first-dose and Measles-containing-vaccine second dose is required to stop measles circulation.

In areas with low vaccination coverage, epidemics typically occur every two to three years and usually last between two and three months. However, their duration varies according to population size, crowding, and the population’s immunity status.

The Measles outbreak in Bangladesh this year is thought to have been linked to the recent political instability in the country, as well as the Covid-19 pandemic. Bangladesh typically runs a major Measles vaccination campaign every four years. However, the 2020 campaign is thought to have been disrupted by the diverting of staff and resources to deal with the impacts of the Covid-19 pandemic, and the 2024 campaign was cancelled amid the political turmoil which led to the removal of the country's president, Sheikh Hasina, and the installation of an interim government under the economist Muhammad Yunus, which made repairing the country's economic and political systems a priority.

Following elections in February 2026, a new government was sworn in, led by Tarique Rahman of the Bangladesh National Party. This new government has launched a major new Measles vaccination campaign in response to the epidemic, beginning with 30 identified hotspots in 20 of the country's 64 districts, targeting 1.2 million children between the ages of six months and five years who have not received the vaccination. 

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