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Home > Global Health Matters Nov/Dec 2022 > Climate change accelerates Ebola outbreak frequency Print

Climate change accelerates Ebola outbreak frequency

November / December 2022 | Volume 21 Number 6

The image is an artist’s rendering based on electron micrography of an ebolavirus particle. One filament stands out against a cluster of an entangled bunch. Individually they look like twisted pieces of string colored orange and red. Image courtesy of NIAIDAn artist’s rendering based on electron micrography of filamentous ebolavirus particles. The frequency of Ebola outbreaks in Uganda has been increasing due to climate change and this is likely happening in other African nations as well, according to Dr. Sam Okware, director general of the Uganda National Health Research Organization. Central Africa has suffered 28 large Ebola outbreaks, and, since 2000, Uganda has experienced seven of these, including the most recent declared in September. Managing fear and rumors is crucial to an effective outbreak response, given the negative impacts of social media seen in some places, noted Okware, who spoke at a November 25 webinar sponsored by the African Forum for Research and Education in Health (AFREhealth), an interdisciplinary group seeking to improve the quality of health care in Africa.

Lieutenant Colonel Dr. Henry Kyobe Bosa, incident commander, provided a status update for the current outbreak of Sudan ebolavirus, for which there is no proven vaccine. Tallies for the ninth week include 141 total cases, 55 deaths, 79 recoveries, and 22 probable cases (where samples could not be taken). The highest recovery rate has been in Kampala, where 83% of infected people have survived the illness. Lowest recovery has been seen in Mubende and Kassanda, the epicenters of illness, where 73% of infected children under age 9 have died. The movement from rural epicenter to Uganda’s capital city was rapid, taking just two weeks and resulting in 10 independent clusters, Bosa noted. “Rural tools for contact tracing are ineffective in cities.” Developing better response tools for an urban setting is a priority.

This currrent outbreak has been a disease of children and women, signaling household transmission, noted Bosa. While the initial outbreak affected children, now there is mainly illness among young adults. “Since November 12, we haven’t had any new cases,” stated Bosa, adding that this is considered a real “remission” given surveillance systems are running well.

Dr. Jean-Jacques Muyembe TamFum, a member of the team that investigated the first known Ebola outbreak at Yambuku Mission in 1976, recounted lessons learned from past Zaire ebolavirus outbreaks in the Democratic Republic of Congo (DRC).  Of the 318 total infected patients, 280 died during the Yambuku outbreak, which lasted less than 11 weeks—an 88% case fatality rate (CFR). Muyembe, a microbiologist, recalls lacking even basic personal protective equipment, including gloves, so he carefully washed his hands with soap and water after handling patient samples. He credits this practice with his personal survival.

In 1995, the first outbreak after Yambuku occurred in Kikwit, also in DRC, recounted Muyembe who is now director of the country's National Institutes of Bio-Medical Research. Researchers recorded 317 total cases and 250 deaths there, a 78% CFR. Kikwit saw the first implementation of public health interventions, including case management, contact tracing, infection prevention and control. 

Eight patients were treated with blood from survivors, and, in a paper published in The Journal of Infectious Diseases, “we concluded that Ebola antibodies were protective,” said Muyembe. Yet this experiment “remained a mere anecdote for a long time” because the observational study lacked a control arm and had a small sample size, plus subsequent laboratory tests failed to show an immune response.

Still Muyembe believed in the protective qualities of antibodies, and, with help from other scientists, “the dream of my life is now a reality.” That dream is EBANGA, a therapy based on a single monoclonal antibody isolated from a human survivor of the outbreak in Kikwit. Today, EBANGA is used to treat children and adults who've been infected with Zaire ebolavirus.

Africa needs to develop more mobile and local laboratory capacity if it is to become more effective in rapidly addressing outbreaks of the deadly hemorrhagic fever in the future, concluded Muyembe. 

Dr. Francis G. Omaswa, webinar moderator and director of The African Center for Global Health and Social Transformation, suggested Africa needs to produce its own vaccines and therapeutics to protect vulnerable populations. The webinar, co-moderated by Dr. Jean B. Nachega, Professor of Medicine, Stellenbosch University, can be viewed on the AFREHealth website.

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Updated December 15, 2022

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