Uganda used public health measures like screening, testing of temperatures, and isolation of suspected cases to contain the Ebola outbreak. While those measures were successful, scientists warn that another outbreak could occur. Credit: Wambi Michael/IPS

By Wambi Michael
KAMPALA & MUBENDE, Mar 10 2023 (IPS)

It is two months since the World Health Organization declared Uganda free of the most recent Sudan ebolavirus, which killed 55 people.

Uganda employed public health measures to end the outbreak. In the absence of vaccines and therapeutics, the threat of the next outbreak looms.

Scientists are yet to find answers to questions like who was the first person to be affected? Or the index case, what viral host reservoir did that patient get in contact with?

“We don’t have answers to those questions. And honestly, we are hoping that Uganda will provide us and the world with those answers,” says Emmy Bore, program director for the CDC’s Division of Global Health Protection in Uganda.

“In every Ebola outbreak we have responded to, in West Africa, in DRC, there have been attempts to trace the roots back to the very first person who got infected. When you figure out where that person went and what they ate, you can figure out how they managed to get the virus. In most outbreaks, we don’t,” she said.

With those questions answered, Lt Colonel Dr Kyobe Henry Bossa, who has been at the front lines against Ebola outbreaks and COVID-19, told IPS that it is urgent they track precisely the viral host reservoir before the next outbreak.

“We know that the reservoir lives in the jungle innocently. We suspect that the viral host reservoir is a bat circulating in the area, and the virus is maintained in nature,” said Kyobe.

Bats have long been the prime suspects for what scientists have termed as the “spillover” of novel pathogens to humans. They are believed to harbor diverse viruses more lethal to humans than any other mammals.

Ugandan Veterinarian and Epidemiologist Dr Monica Musenero Masanza is no stranger to fighting viruses like Ebola and Marburg in Uganda and West Africa. Musenero came to be commonly known as Dr Kornya—loosely translated as a female warrior for her fight against Ebola in Port Loko in northern Sierra Leone. She told IPS that Ebola is categorized among emerging or re-emerging diseases.

“And those diseases show up with a lot of drama. Ebola, when it shows up, there is a lot of drama. Now those emerging and re-emerging diseases are attracting a lot of attention. Unfortunately, because we don’t know much about them, there is usually little we can do about them in the immediate except control,” said Musenero.

According to Musenero, now that Uganda successfully ended the Sudan ebolavirus, efforts should be geared towards finding pathogen X otherwise, another outbreak is guaranteed. “It’s not a matter of if, but when. That is why we should get to the jungles to find the host reservoir,” she said.

On September 20, 2022, Uganda declared an Ebola disease outbreak caused by the Sudan ebolavirus species in the Mubende district.

It was the country’s first Sudan ebolavirus outbreak in a decade and its fifth of this kind of Ebola. There were 164 cases (142 confirmed and 22 probable), 55 confirmed deaths, and 87 recovered patients.

The outbreaks have over the years occurred in a very similar region, with the suspected viral host reservoir suspected to be a bat.

Dr Trevor Shoemaker, an epidemiologist in the Division of High-Consequence Pathogens and Pathology at the National Center for Emerging and Zoonotic Diseases at the Center for Disease Control (CDC), suspects that bats carrying the virus are circulating in that area.

“It is not unexpected that there would be an outbreak where we have seen previous outbreaks in the central region of Uganda,” said Shoemaker.

According to Shoemaker, during the course of testing for ebolavirus cases in the just-ended outbreak, three of the samples were negative for ebolavirus but tested positive for another viral hemorrhagic fever called Crimean Congo hemorrhagic fever.

“There are pathogens that we know about, and there are those we know. So we need to trace them before they spill over to humans,” said Shoemaker.

Scientists from the University of Bonn have in the past confirmed the presence of Crimean Congo viruses in African bats and therefore suggesting that bats could play a role in spreading the virus.

Others studies have linked Crimean Congo viruses to ticks. While bats have been suspected as reservoirs of the Sudan ebolavirus, no conclusive evidence exists.

The district of Mubende and Kasanda forested with indigenous trees. Some private plantation forests are also thriving. Late in the evening, different species of bats fly into the darkening sky.

Fortytwo-year-old Bright Ndawula is an Ebola survivor. He tells IPS that there are as more as ten types of bats that he knows of “Some are tiny, they live under the rooftops, some are big, and they live in trees. Health workers told us that bats carry Ebola, but we don’t know one,” said Ndawula who lost his wife and three family members to the virus.

So far, scientists have been able to identify only one species of African fruit bat (R. aegyptiacus) positive for Marburg virus infection. No evidence of the Marburg virus was identified in the other species of insect-eating or fruit bats tested.

A few kilometers out of Mubende town, IPS comes across farmers and loggers living on the edge of the forest, risking some of the infectious diseases that may spill over from bats to humans.

Dr Charles Drago Kato leads a surveillance team with USAID funded project named Strategies to Prevent Spillover, or STOP Spillover. It targets viral zoonotic diseases—infections that originate in animals before they “spill over” into humans. His teams have been to Districts like Mubende, Kibale, and parts of the Rwenzori Mountains, specifically researching bats and humans.

He told IPS that under the project, they are trying to trace pathogens in bats that may be dangerous when they cross over to humans.

IPS UN Bureau Report