TWO VIRUSES, ONE HEALTH CHALLENGE
At the heart of the infectious threats that still weigh heavily on Africa and, consequently, on global health, two viral diseases occupy a special place: Ebola virus disease and Mpox. Long considered rare illnesses confined to certain forested areas, they have emerged over the decades as major public health challenges, capable of triggering health, social, and economic crises of international proportions.
Ebola embodies the violence of emerging hemorrhagic fevers: a disease that is often brutal, highly lethal, and puts the most fragile health systems to the test. Despite the remarkable progress made in recent years—effective vaccines, monoclonal antibodies, and better-structured response strategies—the virus continues to reappear, as recently demonstrated by the 16th outbreak declared in the Democratic Republic of Congo.
Mpox, for its part, illustrates another facet of emerging diseases: that of a virus long neglected, now undergoing a major epidemiological mutation. Once primarily transmitted from animals to humans, Ebola has adapted to more efficient human-to-human transmission, with the emergence of more contagious and potentially more severe variants, particularly in Central Africa. Its resurgence, combined with insufficient vaccination coverage, has led the World Health Organization to issue its highest level of alert.
These two diseases, different in their nature and clinical presentation, nevertheless share common challenges: fragile health systems, unequal access to vaccines and treatments, and the crucial importance of epidemiological surveillance and community adherence to preventive measures. Understanding them, comparing them, and analyzing the responses implemented allows us not only to better grasp current crises but also to strengthen preparedness for future epidemics.
This report offers a comparative perspective on Ebola and Mpox, two viruses emblematic of the new balances—and imbalances—in global health.
EBOLA VIRUS DISEASE: SYMPTOMS, TREATMENT, PREVENTION
The Ebola virus, known for its virulence and fulminant hemorrhagic fevers, fascinates as much as it worries. Discovered in 1976, it has left its mark on global health history through sometimes deadly epidemics. While significant progress has been made—particularly in vaccines and treatment—Ebola remains a persistent threat, regularly reappearing in certain regions of Africa. Understanding its evolution, its mode of transmission, and current scientific advances is essential for better anticipating future crises.
Source : www.pasteur.fr
The Ebola virus, responsible for intense fevers and severe hemorrhaging, remains a significant threat: its lethality can still vary greatly, depending on the epidemic, with rates ranging from 30% to over 80%. Three major viral species are particularly problematic: the Zaire virus (the most deadly), the Sudan virus, and the Bundibugyo virus.
Since its discovery in 1976 in the Democratic Republic of Congo (DRC) and Sudan, Ebola has caused numerous outbreaks in Central Africa. More recently, in 2025, the DRC again declared an outbreak in the Kasai province, due to the Zaire virus.
The World Health Organization (WHO), Congolese authorities, and other partners responded strongly: treatment centers were established, teams were trained, and a ring vaccination campaign (targeting exposed individuals and healthcare workers) was launched using the Ervebo vaccine. According to CDC experts, if no new cases appear, the epidemic could be declared over by early December 2025.
Meanwhile, medical research is progressing. A new human antibody, named MAB 3A6, isolated from an Ebola survivor, has shown very good efficacy in non-human primates at remarkably low doses—which could facilitate its production and reduce costs. Another major advance concerns prevention: in Uganda, a clinical trial was launched in February 2025 for a candidate vaccine against the Sudan virus, which causes an Ebola-like illness (“Sudan virus disease”). This is the first time that an efficacy trial of a vaccine against this strain has been conducted in an emergency situation.
On the longer-term prevention side, the Gavi Alliance announced in 2024 the launch of a preventive vaccination program against Ebola in resource-limited countries, allowing the vaccine to be administered to “high-risk” populations even in the absence of a current outbreak.
Causes and modes of transmission
Fruit bats are considered the most likely natural hosts of the Ebola virus. Although they do not develop the disease, they can transmit the virus to other rainforest animals, particularly primates, in whom it becomes pathogenic. Humans become infected primarily through handling these infected animals—by hunting, consuming bushmeat, or butchering them.
Once introduced into a human body, the virus spreads through human-to-human transmission. This occurs through direct contact with the blood, secretions, or any other bodily fluid of an infected person, or through indirect contact with contaminated surfaces. The risk of contagion is zero during the incubation period, moderate at the onset of symptoms, and then very high once the disease is fully established. Recovered patients are no longer contagious, although precautions remain necessary because the virus can persist in semen for several months.
Ebola epidemics are sustained by these secondary transmissions. They are facilitated when protective measures are insufficient, particularly during the care provided to patients. Traditional funeral rites, involving direct contact with the body of the deceased, also constitute a major factor in the spread.
To break the chain of transmission, strict preventative measures are essential: rigorous hand hygiene, isolation of the sick, protection of healthcare workers, and systematic use of personal protective equipment (gloves, masks, goggles, coveralls, boots, etc.). For several years now, two vaccines have been available. One of them has been used successfully for ring vaccinations, aimed at rapidly immunizing people exposed around a confirmed case in order to contain outbreaks.
Symptoms
Ebola virus disease manifests as a particularly severe acute viral infection. The first signs often go unnoticed because they resemble those of a simple flu-like syndrome: a sudden fever exceeding 38°C (100.4°F), extreme fatigue, muscle aches, headache, and a sore throat. But the progression is rapid. Within a few days, patients develop vomiting, severe diarrhea, skin rashes, and kidney and liver damage. In the most severe cases, internal or external bleeding can occur, making the disease even more difficult to control.
The incubation period—the time between infection and the appearance of the first symptoms—varies from 2 to 21 days, with an observed average of 5 to 12 days. Because the clinical manifestations can resemble those of other tropical diseases, only laboratory testing can confirm the diagnosis. These tests are performed under strict safety conditions to prevent any risk of contamination.
Epidemiology
The Ebola virus was first discovered in 1976, during two simultaneous epidemics: one in Sudan (284 cases, 151 deaths, or ~ 53% fatality rate), the other in the Democratic Republic of Congo (DRC) (formerly Zaire), in a village near the Ebola River, hence the name of the virus (318 cases, 280 deaths, or ~ 88%).
The virus belongs to the Filoviridae family, and more specifically to the Orthoebolavirus genus. Several species exist:Zaire ebolavirus (EBOV), Sudan virus(SUDV),Bundibugyo virus(BDBV),Tai Forest virus(TAFV), thatReston virus(RESTV). Among them, the Zaire, Sudan and Bundibugyo strains are those that have caused the most significant outbreaks in humans.
Some notable outbreaks:
1995 (DRC, Kikwit): approximately 315 cases, 254 deaths (~81%)
2000 (Uganda): 425 cases, 224 deaths (~53%)
2003 (Congo): several waves, including 143 cases for 128 deaths (~90%) in one of the phases.
2007 (DRC): 264 cases, 187 deaths (~71%) for the Zaire strain.
At that time, the cumulative number of deaths was around 1,590 according to the historical data you mention, which corresponds to the first decades of emergence.
In 2014, a major outbreak linked toZaire ebolavirusIt began in Guinea's forest region, then spread to Liberia and Sierra Leone, in urban areas. This epidemic (2014-2016) is the largest ever recorded, with more than 28,000 cases and approximately 11,000 deaths according to the WHO.
Since 2016, several other outbreaks have occurred:
Large-scale epidemics are occurring in the DRC (Kivu).
Re-emergences on several occasions in the DRC.
In Guinea, a more limited epidemic in 2021.
More recently, in 2025, a new epidemic was declared in the Kasai province (DRC), caused by theZaire ebolavirus.
Treatment and management
The management of Ebola patients is primarily based on intensive supportive care: rehydration, fever and pain management, maintenance of vital functions (blood pressure, oxygenation, etc.), and treatment of complications (hemorrhages, electrolyte imbalances, etc.). This care significantly improves the chances of survival.
Recently, more targeted treatments have become available:
Inmazeb® (REGN-EB3): a cocktail of three monoclonal antibodies (atoltivimab, maftivimab, odesivimab) developed by Regeneron. It targets the glycoprotein of theZaire ebolavirusto block the virus from entering cells. This treatment was tested in the PALM trial conducted in the DRC in 2018-2019, and showed a significant reduction in mortality compared to other experimental treatments.
Ebanga® (mAb114 / Ansuvivab): another monoclonal antibody directed against theZaire ebolavirusIt is also recommended by the WHO according to their poster on Ebola therapies.
These treatments are currently only approved for theZaire ebolavirusand not for all Ebola species. Furthermore, access to these treatments remains a challenge: according to MSF, although these antibodies are recommended by the WHO, they are not always registered in endemic countries, which limits their local availability.
Prevention
Controlling epidemics relies not only on treatments, but also on a range of interventions:
Vaccination: Several vaccines are available or in development. (For example, Ervebo is a vaccine againstZaire ebolavirus.)
Hygiene and prevention measures: case monitoring, contact tracing, isolation, safe management of burials, community awareness.
Strengthening laboratory capacity to quickly detect cases.
Social mobilization: inform at-risk populations, reduce exposure behaviors (e.g., contact with wildlife, carcasses, etc.).
Assessment and outlook
The average mortality rate of Ebola disease is about 50%, but depending on the outbreak, it has varied from 25% to 90%.
The most serious epidemic to date remains that of 2014–2016 in West Africa (Guinea, Sierra Leone, Liberia).
Thanks to therapeutic advances (monoclonal antibodies) and vaccination, the prognosis for patients is improving, but it remains crucial to guarantee equitable access to these treatments in at-risk areas.
Research efforts continue, particularly on vaccines or treatments for other Ebola species (such as the Sudan virus, for which there is not yet a widely approved vaccine).
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