Two Outbreaks Are Active Simultaneously. One Began on a Cruise Ship Crossing the South Atlantic. The Other Is Spreading Across Eastern Democratic Republic of the Congo and Has Now Reached Uganda.

This week CliniScope Weekly departs from its standard single-paper review format to cover two concurrent active public health emergencies that together represent the most significant infectious disease moment since the COVID-19 pandemic. The Andes hantavirus outbreak linked to the cruise ship MV Hondius and the Bundibugyo Ebola virus outbreak in the Democratic Republic of the Congo are biologically distinct, geographically remote, and epidemiologically unrelated. But in the same week they are both dominating public health response infrastructure, straining international coordination mechanisms, and raising fundamental questions about pandemic preparedness, WHO capacity, and the consequences of chronic underinvestment in outbreak surveillance. Covering one without the other would be an incomplete picture.

On May 2, 2026, WHO was notified of a cluster of severe acute respiratory illness among passengers and crew of a cruise ship in the Atlantic Ocean. The cruise ship MV Hondius departed from Ushuaia, Argentina on April 1, 2026 and traveled across the South Atlantic Ocean, stopping at several remote locations including Antarctica, South Georgia Island, Tristan da Cunha, Saint Helena, and Ascension Island. It carried 147 people from 23 different countries. On May 6, WHO confirmed the causative agent as Andes virus. As of May 8, eight cases had been reported including six confirmed and two suspected, with three deaths.

Illness onset ranged from April 6 to at least April 28, after the ship had departed Ushuaia. On April 24, 26 cruise passengers from 13 nationalities disembarked on St Helena Island and flew back before the outbreak was declared, creating multiple potential exposure threads across international air travel networks.

Andes virus is the only hantavirus documented to spread from person to person. Transmission typically requires close prolonged contact with a symptomatic person including direct physical contact, prolonged time in close or enclosed spaces, and exposure to infected saliva, respiratory secretions, or other body fluids. Among patients who develop severe respiratory symptoms, the case fatality rate has been estimated at approximately 38%.

No specific treatment is recommended for hantavirus infection. Early supportive care is critical even before diagnosis is confirmed. In severe cases, extracorporeal membrane oxygenation (ECMO) can significantly improve survival to approximately 80% if started early. Symptoms usually appear within 4 to 42 days after exposure. Early symptoms including fever, fatigue, and muscle aches can be easily confused with influenza. Late symptoms appearing approximately 4 to 10 days after the initial phase include coughing, shortness of breath, and chest tightness.

On May 5, 2026, WHO received an alert regarding an unknown illness with high mortality in Mongbwalu Health Zone, Ituri Province, DRC, including four health workers who died within four days. The first known suspected case, a health worker, reported onset of symptoms including fever, hemorrhaging, vomiting, and intense malaise on April 24, 2026, and died at a medical centre in Bunia.

On May 15, 2026, the Ministry of Health of the DRC confirmed an outbreak of Ebola disease in Ituri Province. Laboratory analysis conducted by the National Institute of Biomedical Research confirmed the cause as Bundibugyo virus infection. As of May 16, a total of 246 suspected cases and 80 deaths had been reported.

As of May 22, 2026, 836 suspected cases and at least 186 deaths had been reported across the DRC and Uganda. Cases have been confirmed in Ituri Province, North Kivu Province, the capital city of Kinshasa, and the Ugandan capital Kampala. On May 16, 2026, the WHO Director-General declared the outbreak a Public Health Emergency of International Concern (PHEIC).

This is a critically important distinction from prior DRC outbreaks. The Bundibugyo virus has an estimated case fatality rate between 25% and 50%. There is no approved vaccine or medicine for Bundibugyo virus. Experimental vaccines have been tested on macaques. Experts have discussed the possibility of using the vaccine approved for Zaire ebolavirus, Ervebo, for Bundibugyo patients, but animal studies suggest it may be only partially effective against this strain with concerns around both effectiveness and safety.

For the hantavirus outbreak, the CDC recommends that clinicians include hantavirus pulmonary syndrome (HPS) in the differential diagnosis for any ill person with compatible symptoms who has had direct physical contact or spent time in close or enclosed spaces with a symptomatic person with confirmed or suspected Andes virus infection within the 42 days before symptom onset. In healthcare settings, for patients with suspected or confirmed Andes virus infection, CDC recommends patient placement in an airborne infection isolation room and use of a gown, gloves, eye protection, and an N95 or higher level respirator.

For the Ebola outbreak, the risk to individuals in the United States remains very low at this time. However clinicians should take a thorough travel history from any patient presenting with fever, hemorrhagic symptoms, vomiting, or intense malaise, particularly those with recent travel to eastern DRC or Uganda.

Two simultaneous active outbreaks of distinct viral hemorrhagic and pulmonary pathogens, a weakened WHO, no approved therapy for one of them, and a global contact tracing challenge already underway. This is not a worst case scenario, it is a reminder that the infrastructure for detecting and containing emerging infectious diseases is only as strong as the sustained political and financial commitment behind it. That commitment has been eroding. These outbreaks are the consequence.