世界アウトブレイク観測所

Since the publication of the previous Disease Outbreak News on 23 October 2026, the Bundibugyo virus disease (BVD) outbreak has expanded geographically in the Democratic Republic of the Congo.

While some areas have seen a slight decline in cases, sustained, high-level transmission continues overall in the Democratic Republic of the Congo. As of 3 November 2026, a total of 10 668 confirmed cases, including 5198 deaths (crude case fatality ratio: 48.7%), have been reported across 67 health zones in eight provinces, with active transmission ongoing in 51 health zones. The high proportion of deaths occurring in communities, especially among young children, continues to highlight challenges in early case detection and timely access to appropriate care. Of the 512 deaths reported since 21 October, 335 occurred in communities and 177 in treatment centres.

Yellow fever transmission continues in the WHO African Region, with recent outbreak activity concentrated in parts of West Africa. Between 1 January and 12 October 2026, 67 confirmed cases, including 18 deaths, were recorded in nine countries in the Region: Burkina Faso, Cameroon, the Central African Republic, Côte d’Ivoire, Ghana, Guinea, Liberia, Nigeria and Togo. The most recent outbreak activity has been concentrated in Burkina Faso, Côte d’Ivoire, Ghana and Liberia, including in areas close to international borders.

Occupational and environmental exposures, including work in or near forested areas, mining activities, and other outdoor occupations, are important risk factors for yellow fever infection. Frequent cross-border population movement, the presence of competent mosquito vectors, and uneven vaccination coverage increase the risk of further transmission and geographic spread.

On 20 October 2026, the National IHR Focal Point (NFP) of France notified WHO regarding the first documented human infection with Shamonda virus (SHAV). The case was an immunocompromised older man from eastern France with no travel history during the preceding year. He developed severe neurological illness on 23 September 2026 and was diagnosed with severe encephalitis (brain inflammation). The patient died on 8 October 2026.

SHAV is recognized primarily as an animal-associated virus, like the closely related Schmallenberg virus circulating in Europe, with no previously documented human infections.

Between 1 January and 5 October 2026, the Kingdom of Saudi Arabia reported eight laboratory-confirmed cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection, including one death. Cases were detected across six locations: Al Jouf (1), Arar (1), Hafr Al-Batin (1), Riyadh (2), Tabuk (1) and Taif (2). No epidemiological links were identified between any of the cases.

All eight cases were symptomatic, most commonly presenting with fever (6/8), dyspnea (5/8), and cough (4/8). None were health and care workers. Infection was confirmed by RT-PCR testing. MERS is a zoonotic viral respiratory disease for which dromedary camels serve as the primary animal reservoir and two cases reported direct contact with camels while six reported no known camel exposure. Seven of eight cases had underlying comorbidities, recognized risk factors for severe MERS-CoV disease. The cases appear to represent sporadic infections related to zoonotic spillover rather than a single outbreak cluster.

On 2 October 2026, WHO became aware through media reports of the death of an employee of the Irkutsk Antiplague Research Institute (APRI) of Siberia and the Far East, the Russian Federation. According to these reports, the individual died on 2 October following hospitalization for severe pneumonia on 29 September, and pneumonic plague was suspected as the cause of death, following occupational exposure in laboratory settings.

Following requests for verification from WHO, the National Focal Point for the International Health Regulations (2005) (NFP) of the Russian Federation confirmed the death and informed WHO that no case of plague had been registered recently in Irkutsk Oblast, that preventive and control measures had been implemented in accordance with national sanitary legislation, and that the laboratory testing of contacts detected no high-threat pathogens. The authorities also reported that no biosecurity incidents had occurred in the laboratory, contrary to reports in the media, and that there were no further case of severe pneumonia linked to this case.

The Bundibugyo virus disease (BVD) outbreak in the Democratic Republic of the Congo remains active, with sustained transmission driving increases in reported cases and deaths. As of 15 July 2026, a cumulative total of 2124 confirmed cases, including 828 deaths, have been reported from the Democratic Republic of the Congo. On 13 July 2026, German authorities informed WHO of a laboratory-confirmed case of Ebola disease caused by Bundibugyo virus in a humanitarian worker from the United States of America who was medically evacuated from the Democratic Republic of the Congo. This is the second United States citizen to be treated in Germany, reflecting the ongoing international response efforts.

In Uganda no new cases have been reported since 21 June 2026. The most recent case was discharged from the treatment centre on 16 July after two negative tests results. The country has therefore begun the 42-day period of enhanced surveillance required before the end of the outbreak can be declared.