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 who has tested positive has been transferred to Germany (with six high risk contacts). One other 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.

A multi-country cluster of hantavirus disease has been reported aboard a Dutch-flagged cruise ship, the MV Hondius, which departed Ushuaia, Argentina, on 1 April 2026 and travelled across the South Atlantic, with stops including Antarctica, South Georgia, Saint Helena, and Ascension Island. As of 6 May 2026, the vessel is on its way to Canary Islands and carried 146 passengers and crew from 23 nationalities.

CASES:

• Onset: 6 – 1 May 2026
  
• Dx (lab confirmation in South Africa): 2 May (case 2)
  
• Symptoms: Fever, GI symptoms, rapid progression to pneumonia, ARDS, and shock.
  
• Total: 8 cases (5 laboratory-confirmed, 3 suspected)
  
• Current status: 3 fatalities; 1 critically ill in ICU; 4 with mild-to-moderate symptoms
  
  • 1 confirmed case hospitalized in Zurich (mild)
    
  • 2 confirmed cases hospitalized in Leyden (mild)
    
  • 1 confirmed case hospitalized in Johannesburg (critically ill)
    
  • 2 suspect cases in Düsseldorf and Leyden
    

KEY DETAILS:

• Two early confirmed cases had travelled in South America before boarding the cruise ship.
  
• Andes virus infection was confirmed by PCR at the HUG reference laboratory.
  
• Human-to-human transmission of Andes virus is possible, particularly after close and prolonged contact. The risk appears highest during the first days of symptoms.
  
• A coordinated international response is ongoing, involving the United Kingdom, the Netherlands, South Africa, Spain, and Cabo Verde.
  
• Passengers have been advised to maintain physical distancing and remain in cabin isolation.
  
• Additional cases among cruise ship passengers remain possible, given the long incubation period of hantavirus infection, which can extend up to 6–8 weeks. Monitoring should therefore continue for several weeks.                               
• WHO press conference, 07.05.2026; youtube

Bolivia is currently experiencing simultaneous outbreaks of dengue, chikungunya, Zika, yellow fever:

Dengue: As of 22 March 2026, Bolivia has reported 36’007 suspected dengue cases (incidence rate: 282/100’000 population) since the start of the year, a more than 3.5-fold increase compared with the same period in 2025. Serotypes DENV1 and DENV2 have been recorded. 

Chikungunya: Ongoing chikungunya outbreak with 23’145 suspected including 7’817 confirmed cases and seven deaths since the beginning of 2026.

Yellow fever: Four confirmed cases of yellow fever have been reported in Santa Cruz Department, Bolivia, including three fatalities, indicating an escalation of the outbreak first reported in Cordillera Province. Fifteen suspected cases remain under clinical observation throughout the department.

Zika: As of 28 March 2026, 1’168 Zika cases since the start of the year (same period in 2025: 130 cases).

Five cases of dengue fever have been confirmed in the Galápagos Islands, with two additional suspected cases under investigation on Santa Cruz Island.

Chikungunya virus continues to circulate in French Guiana, with 143 cases reported since January 2026, with 33 cases in week 16 2026, compared with 15 cases the previous week (all cases confirmed by RT-PCR). Most cases (80%) are reported in the western coastal area, which was declared in epidemic phase (highest level) on 23 April 2026.

The Maroni, Savanes, and Ile de Cayenne sectors are in a phase of sporadic transmission, whereas the Intérieur, Intérieur Est, and Oyapock sectors remain in a surveillance phase, with no cases identified to date.

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.