On 5 May 2026, WHO was alerted of a cluster of unknown febrile illnesses with a high mortality rate in Mongbwalu and Rwampara Health Zones, Ituri Province. Following investigation by rapid response teams, the cause was confirmed to be Bundibugyo virus disease (BVD) due to Bundibugyo virus (Orthoebolavirus bundibugyoense) -  a species of Ebola virus - on 15 May with 8/13 positive samples from Rwampara.

On 15 May 2026, the DRC declared its 17th Ebola outbreak, affecting Rwampara, Mongbwalu, and Bunia Health Zones. Uganda subsequently confirmed two imported cases. On 16 May 2026, WHO declared the outbreak a Public Health Emergency of International Concern (PHEIC).

As of 20 May 2026 (WHO press releaset):

• More than 600 suspected cases (>500 in DRC, 12 in Uganda) and 139 suspected deaths (131 in DRC, 1 in Uganda. Most suspected cases were reported in Mongbwalu (302 cases, 74 deaths) and Rwampara (136 cases, 74 deaths), Ituri Province.
  
  
• 35 confirmed cases (33 in DRC, 2 in Uganda), including 5 deaths (4 in DRC, 1 in Uganda), corresponding to a CFR of 14.3% (5/35). In DRC, confirmed cases were reported in four health zones in Ituri Province — Rwampara (19), Bunia (6), Nyankunde (4), and Mongbwalu (1) — and three health zones in North Kivu: Butembo (1), Goma (1), and Katwa (1).
  

WHO expects those numbers to keep increasing, given the amount of time the virus was circulating before the outbreak was detected.

Further cases:

• The US citizen that has tested positive has been transferred to Germany (with six high risk contacts). One contact will be transferred to Czechia.
  
• South Sudan is investigating a suspected Bundibugyo virus disease case in West Equatoria State after a preliminary positive result in a patient from South Yambio County.
  
• Information regarding transmission chains and affected population groups is currently limited, partly due to the complex context of ongoing insecurity and humanitarian challenges in the affected areas.
  
• Genomes from DRC and Uganda have been published and preliminary analysis shows distinct
  sequences from the previous outbreaks (Virological Ebolavirus/Bundibugyo ebolavirus, 18 May 2026).

Authorities are concerned about the risk of further spread due to population high mobility, insecurity, and the proximity of affected areas to Uganda and South Sudan through a porous border.

The D.R. Congo has experienced several Ebola outbreaks in recent years. The most recent outbreak, in the Kasai provinces (species Orthoebolavirus zairense), was declared over in December 2025. In Ituri Province specifically, Ebola disease due to Ebola virus (Orthoebolavirus zairense) was last documented during the 2018-2020 outbreak. Bundibugyo virus was first reported in 2007 in Bundibugyo district in Uganda during an outbreak. The most recent outbreak due to Bundibugyo virus was in 2012 in DRC.

The US CDC has updated the areas at risk for chikungunya on 16 April 2026 (Cuba no longer outbreak country). In addition, the Swiss Expert Committee for Travel Medicine assessed the risk for Mauritius, Argentina and French Guinea, (red = changes compared to last update 10 March2026):

Chikungunya is showing a strong increase, with 1’415 cases recorded since the beginning of the year, with a daily average of 50-40 infections. Currently, 148 cases are active.

The current outbreak represents a resurgence of chikungunya transmission in Mauritius following the 2025 epidemic. 

Argentina: A sharp rise in chikungunya activity has been reported since February. Around 750 new locally acquired cases have been confirmed, with more than 5’500 suspected cases nationwide through week 14, marking a significant increase above average levels. Most cases are concentrated in the northwestern provinces of Salta, Tucumán, and Jujuy.

French Guiana: Since the first case of chikungunya was detected in late January 2026, 85 locally acquired cases have been reported (+20 cases within the past four weeks).

Suriname: Between 1 January and mid-March, 2’579 chikungunya virus disease cases have been reported of which 1’354 were confirmed. Since January 2026, one EU Member State also observed a marked increase in detections of chikungunya virus among returning travelers from Suriname and Paramaribo in particular.

As of 28 March 2026, Bolivia has reported 1’168 Zika cases since the start of the year, a sharp increase compared with 130 cases in the same period in 2025. This figure is already approaching the total of 1’224 cases recorded for the whole year 2025.

The Western Australia Department of Health has issued a clinical alert after reporting 34 cases this year, with 29 cases concentrated in the Kimberley region. Both cutaneous and respiratory infections have been identified, with respiratory cases marking the first in over 50 years.

France reported a total of 11 travel associated ZIKV cases linked to Indonesia between July 2025 and March 2026, including four cases detected in early 2026. Most cases were associated with travel to Bali and neighboring islands. All cases were laboratory confirmed, and Asian lineage was identified in sequenced samples.

Despite high and increasing travel volumes from Indonesia to the EU/EEA since 2022, no corresponding increase in imported ZIKV cases has been observed by other EU/EEA countries.