# How Ebola Works > In 2026 eastern Congo is fighting its largest Ebola outbreak on record, caused by the Bundibugyo virus, one with no approved vaccine. This film explains the fundamentals: how Ebola was found in 1976, what the thread-shaped virus is made of, how it slips into a cell using a cholesterol-carrying protein called NPC1, how it silences the body's alarm, why it spreads through contact with body fluids rather than through the air, and how contact tracing, safe burials and ring vaccination break the chain. Health information here is education, not medical advice. Interactive film: https://www.planetpast.com/stories/how-ebola-works/ Publisher: PlanetPast (https://www.planetpast.com/) · d => T('readPublished', l, { d: dateIn(d, l) }) 2026-10-17 · Biology, Society ## Prologue ### The thread and the ring *Viruses and epidemics* Why Ebola is so deadly, and what finally stops it. In the forests and towns of eastern Congo, health workers are fighting the largest Ebola outbreak the country has ever recorded. By early October 2026, the World Health Organization counted more than eight thousand seven hundred confirmed cases and more than four thousand two hundred deaths. It is caused by a rarer relative of the Ebola virus, the Bundibugyo virus, and there is no approved vaccine for it. Yet Ebola cannot travel through the air, and it cannot spread before its host feels sick. So why is it so hard to stop? ![The epicentre: forested hills on Congo’s border with Uganda. AI-generated still.](https://assets.planetpast.com/a/20/20ee48447174a474.jpg) - **8,728**: cases in Congo - **4,205**: deaths - **48%**: of confirmed cases died - first identified in Uganda, 2007 - no approved vaccine or specific treatment (WHO) - 7 of Congo’s 26 provinces affected Prologue · The news #### Congo’s largest Ebola outbreak Congo confirmed the outbreak in mid-May 2026. WHO’s Disease Outbreak News of 8 October 2026 reported 8,728 confirmed cases and 4,205 confirmed deaths in 64 health zones in seven provinces, with Ituri the most affected. WHO calls it the largest Ebola outbreak ever recorded in the country, whatever the virus species. According to CDC, Uganda, Kenya and France have reported a small number of linked cases. For comparison, the 2014–2016 West African epidemic, caused by a different species, killed 11,325 people. This film is education, not medical advice. Anyone who may have been exposed should contact local health authorities. How to use: pick a chapter or press ← →; drag to rotate. Many steps have buttons you can press. Sources: [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619); [Contagion Live: DRC outbreak passes 8,700 cases and 4,200 deaths (CDC figures to 6 Oct 2026)](https://www.contagionlive.com/view/ebola-update-drc-outbreak-passes-8-700-cases-and-4-200-deaths); [CDC: 2014–2016 Ebola outbreak in West Africa](https://www.cdc.gov/vhf/ebola/history/2014-2016-outbreak/index.html) ## Chapter I · The thread ### A river’s name *Chapter I · The thread* Two outbreaks in the same year, hundreds of kilometres apart. Ebola was first recognised in 1976, in two separate outbreaks. One began in Nzara, in what is now South Sudan, caused by a closely related virus now called the Sudan virus. The other began weeks later at a mission hospital in Yambuku, in what is now the Democratic Republic of the Congo. At Yambuku, three hundred and eighteen people fell ill and two hundred and eighty died. Investigators found that needles reused without proper sterilising had carried the virus from patient to patient. The new virus was named after the Ebola River, near the village. - first: Nzara, Sudan: 284 cases, 151 deaths - Aug–Nov: Yambuku, Zaire: 318 cases, 280 deaths - Nzara: Sudan virus - Yambuku: Ebola virus - **88%**: of those who fell ill died - **1 hospital**: needles rinsed in warm water between patients ![The virus took the name of a nearby river, not of the village. AI-generated still.](https://assets.planetpast.com/a/97/97d9ece9165b367d.jpg) Chapter I · The thread #### The first outbreaks WHO dates the first two outbreaks to 1976: Sudan virus disease in Nzara (now South Sudan) and Ebola virus disease in Yambuku (now the DRC), near the Ebola River. At Yambuku Mission Hospital, 318 people fell ill and 280 died. The investigation, which included the Belgian microbiologist Peter Piot, traced most early infections to vitamin injections given with needles that were rinsed in warm water rather than sterilised. The Sudan outbreak began a few weeks earlier and was caused by a different, related virus. Sources: [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease); [Wikipedia: 1976 Zaire Ebola virus outbreak](https://en.wikipedia.org/wiki/1976_Zaire_Ebola_virus_outbreak) ### Seven genes on a thread *Chapter I · The thread* The simplest machine that can kill a person. Under an electron microscope, Ebola looks like a thread, sometimes curled into a loop at one end. It belongs to the filoviruses, from the Latin word for thread. It is about eighty nanometres wide and roughly a thousand long. Inside is a single strand of RNA carrying just seven genes. On the outside, spikes made of one protein, the glycoprotein, stud the surface. They are the keys the virus uses to get into our cells. ![Coloured micrographs often show the “shepherd’s crook” curl. AI-generated illustration.](https://assets.planetpast.com/a/46/465eca95820d06fa.jpg) - **~80 nm**: wide: a thousandth of a hair - **~19,000**: letters of RNA - **7**: genes - GP: the surface spike - NP, VP30, VP35, L: copy the RNA - VP40, VP24: build the shell and bud out Chapter I · The thread #### What the virus is ViralZone describes the Ebola virion as filamentous, about 80 nm in diameter and around 970 nm long, enclosing a linear, negative-sense RNA genome of about 18–19 kilobases that encodes seven structural proteins: NP, VP35, VP40, GP, VP30, VP24 and the polymerase L. The glycoprotein GP forms the spikes used for attachment and entry. The 3D virus and cell are schematic models, not to scale. Sources: [ViralZone (SIB Swiss Institute of Bioinformatics): Ebola virus](https://viralzone.expasy.org/by_species/207) ### A family of viruses *Chapter I · The thread* “Ebola” is really several related viruses. Scientists now know six species of these viruses. Three have caused large human outbreaks: the original Ebola virus, the Sudan virus, and the Bundibugyo virus, first found in Uganda in 2007. They are close cousins, but different enough that a vaccine or drug built against one may not work against another. - Ebola virus: Ebola virus disease - Sudan virus: Sudan virus disease - Bundibugyo virus: Bundibugyo virus disease - Bundibugyo, Uganda 2007: ~30% - Bundibugyo, Congo 2012: ~50% - Bundibugyo, Congo 2026: 48% - Ebola virus, Yambuku 1976: 88% - Ebola River, Congo - Taï Forest, Côte d’Ivoire - Bundibugyo district, Uganda - Reston, Virginia, USA Chapter I · The thread #### Six orthoebolaviruses WHO lists six species in the genus Orthoebolavirus (family Filoviridae). Three cause large outbreaks: Ebola virus (EBOV), Sudan virus (SUDV) and Bundibugyo virus (BDBV). The approved vaccine Ervebo targets EBOV only. WHO gives case fatality of about 30% for the 2007 Bundibugyo outbreak in Uganda and about 50% for the 2012 one in Congo. Fatality varies with the virus, the care available and how quickly patients reach it. Sources: [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease); [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619); [Wikipedia: 1976 Zaire Ebola virus outbreak](https://en.wikipedia.org/wiki/1976_Zaire_Ebola_virus_outbreak) ## Chapter II · Breaking in ### Swallowed whole *Chapter II · Breaking in* The cell lets the virus in by mistake. A virus cannot do anything on its own. To make copies, it must get inside a living cell and hijack it. Ebola's spikes stick to molecules on the surface of a cell. The cell responds by doing something it does every day: it folds its membrane around the particle and gulps it into a bubble. This gulping is called macropinocytosis. The virus is now inside, but still trapped in the bubble. - raw materials to build copies - the cell’s protein factories - energy ![The membrane ruffles and closes around the particle. Schematic, AI-generated illustration.](https://assets.planetpast.com/a/b7/b78d0b55a62dc0d5.jpg) - **macro + pino + cytosis**: Greek for “big drinking by the cell” Chapter II · Breaking in #### Attachment and uptake According to ViralZone, the glycoprotein binds attachment factors on the cell surface (such as the lectins DC-SIGN and the receptor TIM-1, which recognises a lipid on the viral envelope). This triggers macropinocytosis, and the virion is carried into a large internal vesicle, the macropinosome. The 3D virus and cell are schematic models, not to scale. Sources: [ViralZone (SIB Swiss Institute of Bioinformatics): Ebola virus](https://viralzone.expasy.org/by_species/207) ### A lock inside the cell *Chapter II · Breaking in* The door Ebola needs is not on the outside. Inside the bubble, the cell's own enzymes trim the virus's spikes. That exposes a hidden tip, which fits a protein in the bubble's wall called NPC1. NPC1's everyday job is to move cholesterol. In 2011, two teams showed that Ebola cannot infect a cell without it. Cells lacking NPC1 resisted infection. Once the spike grips NPC1, the virus's envelope fuses with the bubble wall, and its RNA spills into the cell. Try removing NPC1 yourself. - cell enzymes (cathepsins) trim the spike - the trimmed spike binds NPC1 - membranes fuse; the RNA is released > If cells don’t make NPC1, they cannot be infected by Ebola virus. (ScienceDaily, on Carette et al. and Côté et al., Nature (2011)) - **cholesterol**: carried out of the bubble into the cell - **NPC1 partly missing**: most survived a lethal dose of Ebola Chapter II · Breaking in #### NPC1, the intracellular receptor Two papers in Nature in 2011 (Carette et al.; Côté et al.) showed that Niemann–Pick C1, a cholesterol transporter in the membranes of late endosomes, is essential for Ebola virus entry. Cells without NPC1 resisted infection, mice partly lacking it mostly survived a lethal challenge, and small molecules that block NPC1 inhibited infection. ViralZone summarises the sequence: cathepsins cleave GP inside the vesicle, the cleaved GP binds NPC1, and fusion releases the genome. These were laboratory results. No NPC1-blocking drug is an approved Ebola treatment. The 3D virus and cell are schematic models, not to scale. Sources: [ScienceDaily (2011): Ebola virus needs the cholesterol transporter NPC1 to infect cells (Carette et al. and Côté et al., Nature)](https://sciencedaily.com/releases/2011/08/110824192329.htm); [ViralZone (SIB Swiss Institute of Bioinformatics): Ebola virus](https://viralzone.expasy.org/by_species/207) ### The factory *Chapter II · Breaking in* Thousands of new threads bud from one cell. Now the virus's own enzyme reads its seven genes, and the cell's machinery builds viral proteins and fresh copies of the RNA. The new pieces gather under the cell's outer membrane and push out through it, wrapping themselves in a piece of it as they go. Each one buds off as a new thread, ready to infect the next cell. - L, the viral polymerase, reads the genes one by one - the cell’s ribosomes make the proteins - NP wraps each new RNA copy - VP40 lines the membrane from inside - the cell’s own ESCRT machinery pinches each bud off - the envelope is borrowed from the host - **cytoplasm**: Ebola copies itself outside the nucleus Chapter II · Breaking in #### Replication and budding Ebola replicates in the cytoplasm. The viral polymerase L transcribes the genes in sequence; once enough nucleoprotein is made, new genomes are copied and wrapped. The matrix protein VP40 brings the nucleocapsid to the plasma membrane, and new virions bud off using the host cell’s ESCRT complexes. The 3D virus and cell are schematic models, not to scale. Sources: [ViralZone (SIB Swiss Institute of Bioinformatics): Ebola virus](https://viralzone.expasy.org/by_species/207) ## Chapter III · In the body ### Cutting the alarm *Chapter III · In the body* Ebola attacks the very cells meant to raise the alarm. Many viruses must first get past the immune system. Ebola goes straight for it. Among its first targets are macrophages and dendritic cells, the sentries that normally sound the alarm. An infected cell usually releases interferon, a chemical alarm that tells neighbouring cells to shut their doors. Two Ebola proteins, VP35 and VP24, jam that signal. With the alarm silenced, the virus multiplies freely, and the infected sentries carry it through the body. Press the buttons to compare. ![Dendritic cells reach out with long arms to sample their surroundings. AI-generated illustration.](https://assets.planetpast.com/a/66/66f12e1e2ce99d40.jpg) - VP35: stops the cell from sensing viral RNA - VP24: stops the interferon message from reaching the nucleus - **type I interferon**: the defence Ebola suppresses most (review, 2015) - high levels of virus in the blood - infected sentries spread it to liver, spleen and other organs - the immune response comes late and out of balance Chapter III · In the body #### Immune evasion A 2015 review in Nature Reviews Microbiology describes filovirus disease as driven by potent suppression of the type I interferon response. Ebola VP35 blocks signalling through RIG-I-like receptors, the sensors that detect viral RNA, and VP24 blocks the nuclear import of the transcription factor STAT1, so interferon cannot switch on antiviral genes. Macrophages, monocytes and dendritic cells are major targets. Bray and Geisbert (2005) describe infected macrophages releasing inflammatory signals that contribute to leaky blood vessels and clotting problems. The 3D virus and cell are schematic models, not to scale. Sources: [Messaoudi, Amarasinghe & Basler (2015), Nature Reviews Microbiology: filovirus pathogenesis and immune evasion](https://www.nature.com/articles/nrmicro3524); [Bray & Geisbert (2005), Int. J. Biochem. Cell Biol.: the role of macrophages and dendritic cells in Ebola](https://researchexperts.utmb.edu/en/publications/ebola-virus-the-role-of-macrophages-and-dendritic-cells-in-the-pa/) ### From fever to shock *Chapter III · In the body* Why fluids and early care save lives. Symptoms appear between two and twenty-one days after infection. At first they look like many other illnesses: fever, aches, headache and weakness. After a few days, vomiting and diarrhoea can drain the body of fluid, and some patients bleed. An overwhelmed immune system and leaky blood vessels can lead to shock, a dangerous fall in blood pressure, and to organ failure. On average about half of patients have died in past outbreaks. But early supportive care, replacing fluids and treating symptoms, improves survival. - fever, intense headache - muscle and joint aches - weakness, sore throat - vomiting, diarrhoea, stomach pain - unexplained bleeding, in some patients - usually after 4–5 days of illness ![Each patient has a separate space, with fluids given through a drip. AI-generated still.](https://assets.planetpast.com/a/ed/ed515486eda52d00.jpg) - **~50%**: average - **25–90%**: range between outbreaks Chapter III · In the body #### The course of the disease CDC lists early “dry” symptoms (fever, aches, headache, weakness, sore throat) and later “wet” ones after four to five days of illness: vomiting, diarrhoea, abdominal pain and, in some patients, unexplained bleeding. WHO gives an average case fatality of about 50%, ranging from 25% to 90% in past outbreaks, and notes that early supportive care with rehydration and symptomatic treatment improves survival. For Ebola virus disease (not Bundibugyo), WHO recommends two monoclonal antibody treatments. This film is education, not medical advice. Anyone who may have been exposed should contact local health authorities. Sources: [CDC: signs and symptoms of Ebola disease](https://cdc.gov/ebola/signs-symptoms/index.html); [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease) ## Chapter IV · How it spreads ### Out of the forest *Chapter IV · How it spreads* Every outbreak starts with a jump from an animal. Between outbreaks, the virus survives somewhere in the wild. Fruit bats are thought to be its natural hosts, though this has not been fully proven. People can catch it by handling infected animals: bats, but also chimpanzees, gorillas, monkeys and forest antelope. One such jump from an animal can start a human chain. That is why outbreaks have mostly begun in or near the rainforests of central and west Africa. ![The suspected hosts belong to the family Pteropodidae, the fruit bats. AI-generated still.](https://assets.planetpast.com/a/34/34c4392879ad0660.jpg) - fruit bats - chimpanzees, gorillas, monkeys - forest antelope, porcupines - 1976: Yambuku and Nzara - 2007: Bundibugyo, Uganda - 2014–16: Guinea, Liberia, Sierra Leone - 2026: Ituri and beyond, Congo Chapter IV · How it spreads #### Animal hosts WHO: fruit bats of the Pteropodidae family are thought to be natural Ebola virus hosts. The virus is introduced into the human population through close contact with the blood, secretions, organs or other body fluids of infected animals such as fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines found ill or dead or in the rainforest. WHO’s Bundibugyo update calls the bat reservoir “suspected”. Map pins are approximate. Sources: [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease); [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619) ### Touch, not air *Chapter IV · How it spreads* Ebola spreads through body fluids, from the sick and the dead. Ebola does not spread through the air like flu or measles. It passes through direct contact with the blood or other body fluids of a sick person, through broken skin or the lining of the eyes, nose and mouth. People do not spread it before they have symptoms. That is good news. But the sicker a patient becomes, the more virus they carry, so the people most at risk are those who care for them: family members, and health workers without protection. And the virus remains in the body after death. Funerals where mourners wash or touch the body have spread it again and again. - blood, vomit, faeces and other body fluids - bedding, clothes or needles soiled with them - not through the air between people ![Handwashing stations stand at clinic and village entrances during outbreaks. AI-generated still.](https://assets.planetpast.com/a/ec/ec67da3555dcab61.jpg) - family members caring for the sick - health workers without protection - mourners who touch the body - **264 of 372**: reported deaths were in the community, not in a treatment centre Chapter IV · How it spreads #### Transmission WHO: human-to-human transmission is by direct contact, through broken skin or mucous membranes, with the blood or body fluids of a person who is sick with or has died from the disease, or with objects contaminated with these fluids. People cannot transmit the disease before symptoms appear, and remain infectious as long as their blood contains the virus. Health workers are frequently infected when infection control is lax, and burials that involve direct contact with the body can spread infection. WHO’s 8 October update reports that of 372 deaths since its previous update, 264 happened in the community rather than in treatment centres, which means more unprotected contact with patients and bodies. The outbreak simulation is a toy model to show the logic of transmission; it does not forecast any real outbreak. Sources: [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease); [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619) ### One number *Chapter IV · How it spreads* Above one, an outbreak grows. Below one, it dies out. Epidemiologists track one number: how many people, on average, each patient goes on to infect. They call it R. Early in the West African epidemic of 2014, R was estimated at between about 1.7 and 2. For a disease that kills so many, that may sound low. But any value above one means each new round of cases, the people infected by the round before, is bigger than the last. Push R below one, and the chain shrinks until it breaks. Try both. $$\text{cases}_{n+1} \approx R \times \text{cases}_{n}$$ - $R$: average new infections per case - $n$: round of cases - Guinea: 1.71 - Liberia: 1.83 - Sierra Leone: 2.02 - **× 58**: cases at R = 1.5 - **× 0.03**: cases at R = 0.7 - **R below 1**: and kept there until the last case Chapter IV · How it spreads #### The reproduction number The WHO Ebola Response Team (NEJM, September 2014) estimated the basic reproduction number as 1.71 in Guinea, 1.83 in Liberia and 2.02 in Sierra Leone, with a mean incubation period of 11.4 days. The 2014–2016 epidemic eventually caused 28,652 cases and 11,325 deaths (CDC). The “ten rounds” figures are simple arithmetic: 1.5¹⁰ ≈ 58 and 0.7¹⁰ ≈ 0.03. The outbreak simulation is a toy model to show the logic of transmission; it does not forecast any real outbreak. Sources: [WHO Ebola Response Team (2014), NEJM: the first 9 months of the West African epidemic](https://journalclub.wustl.edu/2014/09/23/ebola-virus-disease-in-west-africa-the-first-9-months-of-the-epidemic-and-forward-projections/); [CDC: 2014–2016 Ebola outbreak in West Africa](https://www.cdc.gov/vhf/ebola/history/2014-2016-outbreak/index.html) ## Chapter V · Breaking the chain ### Twenty-one days *Chapter V · Breaking the chain* Old-fashioned detective work still beats Ebola. Because Ebola only spreads from people who are already sick, the oldest tools still work. Teams list everyone a patient has touched and check on each of them for twenty-one days, the upper end of the incubation period. Anyone who develops a fever is isolated and cared for before they can infect others. And burial teams in protective suits help families bury their dead safely and with dignity. Every contact traced is a branch cut from the chain. Switch tracing on and watch R fall. - find and follow contacts for 21 days - isolate and treat the sick early - infection control in clinics - work with communities - **21 days**: the upper end of the incubation period (WHO: 2–21 days) ![Teams wear full protection; families can take part from a safe distance. AI-generated still.](https://assets.planetpast.com/a/2e/2e9b4cb8aafa1c2b.jpg) - **80.4%**: of contacts followed up - **85%**: the target Chapter V · Breaking the chain #### Tracing, isolation, safe burials WHO’s list of control measures: contact tracing (finding people exposed and monitoring them for 21 days), separating the sick from the healthy and isolating patients in treatment centres, safe and dignified burials, infection prevention and control in health facilities, surveillance and laboratory testing, and community engagement. In its 8 October 2026 update WHO reported contact follow-up at 80.4%, below the 85% target. The outbreak simulation is a toy model to show the logic of transmission; it does not forecast any real outbreak. Sources: [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease); [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619) ### The ring *Chapter V · Breaking the chain* Vaccinate the contacts, and the contacts of contacts. In 2015, in Guinea, a vaccine against the original Ebola virus was tested in a new way. Instead of vaccinating everyone, teams vaccinated a ring around each new case: the contacts, and the contacts of those contacts. Some rings were vaccinated at once, others three weeks later. Among those vaccinated at once, no one developed Ebola from ten days after vaccination. That vaccine, now called Ervebo, was approved in 2019. A ring of immunity around each case starves the virus of new people to infect. Switch the rings on and off and compare. ![A ring is a social circle, not a fixed distance: who visited, who cared, who lives nearby. AI-generated still.](https://assets.planetpast.com/a/0c/0cc1845c480188f8.jpg) - **0**: cases among 2,119 vaccinated at once - **16**: cases in the delayed rings - **100%**: estimated efficacy (statistical range 69–100%) - 2015: ring trial in Guinea - 2017: final results, The Lancet - Dec 2019: approved in the US (FDA) - one dose - protects against Ebola virus (Zaire) only - not approved for Sudan or Bundibugyo viruses Chapter V · Breaking the chain #### Ring vaccination In the Ebola ça Suffit! trial in Guinea and Sierra Leone, rings of contacts and contacts of contacts were randomised to immediate or 21-day-delayed vaccination with one dose of rVSV-ZEBOV. There were no cases with onset 10 or more days after randomisation among the 2,119 people vaccinated immediately, against 16 cases in the delayed clusters: an estimated efficacy of 100% (95% CI 68.9–100) (Henao-Restrepo et al., The Lancet, 2017). The vaccine, Ervebo, targets Ebola virus only (WHO). The US FDA approved Ervebo on 19 December 2019. The trial was open-label (participants knew whether they had been vaccinated), and the confidence interval is wide; the result has been borne out in later outbreaks where the vaccine was used. The outbreak simulation is a toy model to show the logic of transmission; it does not forecast any real outbreak. Sources: [Henao-Restrepo et al. (2017), The Lancet: final results of the Guinea ring vaccination trial (Ebola ça Suffit!)](https://scienceportal.msf.org/assets/efficacy-effectiveness-rvsv-vectored-vaccine-preventing-ebola-virus-disease-final-results-guinea-ring-vaccination-open-label-cluster-randomised-trial); [Drugs.com: Ervebo FDA approval history (approved 19 December 2019)](https://www.drugs.com/history/ervebo.html); [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease) ### No vaccine yet *Chapter V · Breaking the chain* Why Bundibugyo is harder to stop. Ervebo and the antibody treatments were built against the spike of the original Ebola virus. Bundibugyo's spike is different, so for this outbreak there is no approved vaccine or specific drug. Scientists are choosing the most promising candidate vaccines, and a treatment trial began in July 2026. Until results arrive, the chain must be broken the old way: tracing, isolation, care and safe burials. - Ebola virus: 2 vaccines, 2 antibody treatments - Sudan virus: none yet - Bundibugyo virus: none yet ![Sequencing virus samples shows how cases are linked, and whether the virus is changing. AI-generated still.](https://assets.planetpast.com/a/0f/0f94eec8fafa3676.jpg) - tracing and isolation - early supportive care - safe burials - community trust Chapter V · Breaking the chain #### Where things stand WHO’s 8 October 2026 update states that no approved vaccines or specific treatments exist for Bundibugyo virus disease, refers to a WHO review prioritising candidate vaccines, and notes that a clinical trial of treatments began enrolling patients in July 2026. It reports no results yet. The response relies on surveillance, testing, infection prevention, clinical care, community engagement and safe burials. This film is education, not medical advice. Anyone who may have been exposed should contact local health authorities. Sources: [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619); [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease) ## Epilogue ### The thread and the ring *Epilogue* A virus with seven genes, and a chain made of people. In Ituri, the outbreak is not over. Fifty years after Yambuku, the virus is still a thread of RNA with seven genes, which needs a lock inside our cells and silences our first alarm. But it can only travel by touch, from the sick and the dead to the people who care for them. That is its weakness. Every earlier outbreak has ended, and each ended the same way: by finding contacts and closing the ring. - 1976: first outbreaks: Yambuku and Nzara - 2007: Bundibugyo virus identified, Uganda - 2011: NPC1 found to be the lock Ebola needs - 2014–16: West Africa: 11,325 deaths - 2015: ring vaccination trial, Guinea - 2019: Ervebo approved - 2026: Bundibugyo outbreak, Congo ![All stills and illustrations in this film are AI-generated.](https://assets.planetpast.com/a/6c/6c4c71fa4563e7da.jpg) - find and follow every contact - isolate and care for the sick early - safe, dignified burials - a vaccine ring, where a vaccine exists Epilogue · Sources #### How Ebola works The biology in this film (the virus’s structure, NPC1-dependent entry, interferon suppression) and the epidemiology (contact transmission, no spread before symptoms, the 21-day window, ring vaccination) are well established and summarised by WHO, CDC and peer-reviewed reviews. Figures for the 2026 outbreak are WHO’s as of 6 October 2026 and will change. The 3D virus, cell and outbreak simulation are schematic teaching models, not to scale and not forecasts. Map pins are approximate. All stills are AI-generated. This film is education, not medical advice. Sources: [WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, Democratic Republic of the Congo (8 Oct 2026)](https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON619); [Contagion Live: DRC outbreak passes 8,700 cases and 4,200 deaths (CDC figures to 6 Oct 2026)](https://www.contagionlive.com/view/ebola-update-drc-outbreak-passes-8-700-cases-and-4-200-deaths); [WHO fact sheet: Ebola disease (2025)](https://www.who.int/news-room/fact-sheets/detail/ebola-disease); [Wikipedia: 1976 Zaire Ebola virus outbreak](https://en.wikipedia.org/wiki/1976_Zaire_Ebola_virus_outbreak); [ViralZone (SIB Swiss Institute of Bioinformatics): Ebola virus](https://viralzone.expasy.org/by_species/207); [ScienceDaily (2011): Ebola virus needs the cholesterol transporter NPC1 to infect cells (Carette et al. and Côté et al., Nature)](https://sciencedaily.com/releases/2011/08/110824192329.htm); [Messaoudi, Amarasinghe & Basler (2015), Nature Reviews Microbiology: filovirus pathogenesis and immune evasion](https://www.nature.com/articles/nrmicro3524); [Bray & Geisbert (2005), Int. J. Biochem. Cell Biol.: the role of macrophages and dendritic cells in Ebola](https://researchexperts.utmb.edu/en/publications/ebola-virus-the-role-of-macrophages-and-dendritic-cells-in-the-pa/); [CDC: signs and symptoms of Ebola disease](https://cdc.gov/ebola/signs-symptoms/index.html); [WHO Ebola Response Team (2014), NEJM: the first 9 months of the West African epidemic](https://journalclub.wustl.edu/2014/09/23/ebola-virus-disease-in-west-africa-the-first-9-months-of-the-epidemic-and-forward-projections/); [CDC: 2014–2016 Ebola outbreak in West Africa](https://www.cdc.gov/vhf/ebola/history/2014-2016-outbreak/index.html); [Drugs.com: Ervebo FDA approval history (approved 19 December 2019)](https://www.drugs.com/history/ervebo.html); [Henao-Restrepo et al. (2017), The Lancet: final results of the Guinea ring vaccination trial (Ebola ça Suffit!)](https://scienceportal.msf.org/assets/efficacy-effectiveness-rvsv-vectored-vaccine-preventing-ebola-virus-disease-final-results-guinea-ring-vaccination-open-label-cluster-randomised-trial)