Cases Identified

As of 4 May, seven cases linked to hantavirus had been identified, including two laboratory-confirmed infections and five suspected cases. Three people have died, one patient remains in intensive care, and three others reported mild symptoms.

According to WHO, symptoms developed between 6 and 28 April and included fever, gastrointestinal illness, pneumonia, acute respiratory distress syndrome, and shock. Authorities are conducting laboratory testing, case isolation, medical evacuations, and contact tracing.

WHO said two confirmed cases had traveled in South America, including Argentina, before boarding the ship. One patient died aboard the vessel on 11 April after developing respiratory distress, while another died in South Africa after becoming ill during a flight from Saint Helena. A third confirmed patient was evacuated to South Africa and remains hospitalized in intensive care.

Old disease, emerging health scare

Hantavirus is not a new disease, despite renewed public attention following recent infection cases. The first major outbreak documented in Western medicine occurred during the Korean War in the 1950s, when thousands of United Nations soldiers developed what was then called Korean Hemorrhagic Fever, now known as Hemorrhagic Fever with Renal Syndrome (HFRS).

Although the disease was identified in the 1950s, the virus itself was not isolated until the late 1970s. It was later named the Hantaan virus after the Hantan River in South Korea, where investigations into the outbreak were concentrated.

According to the Centers for Disease Control and Prevention (CDC), hantaviruses infect people worldwide and spread mainly through contact with infected rodents such as rats and mice, particularly through urine, droppings, or saliva. Transmission through bites or scratches is possible but rare.

Hantaviruses cause two main illnesses. In the Western Hemisphere, including the US, they can lead to hantavirus pulmonary syndrome (HPS), a severe respiratory disease most commonly linked to the Sin Nombre virus in North America and the Andes virus in South America. In Europe and Asia, hantaviruses more commonly cause HFRS. The Seoul virus strain has also been detected globally, including in the US.

Symptoms to watch out for

Infection typically occurs in rural or rodent-infested areas and can cause symptoms ranging from fever and muscle pain to gastrointestinal illness, followed by sudden respiratory failure. Although uncommon worldwide, hantavirus infections can be fatal. Case fatality rates range from under 15% in Asia and Europe to as high as 50% in the Americas. There is no specific treatment or vaccine, but early intensive care improves survival.

Hantavirus infections are usually linked to exposure to infected rodents through urine, saliva, or droppings. Human-to-human transmission is rare, though limited spread has been documented in past outbreaks involving the Andes virus strain.

Transmission patterns in Asia

In Asia, hantavirus spread is linked to environmental changes that affect rodent populations and human contact with them. Cases usually rise twice a year, during spring and the colder autumn-winter months, when farming activities are more common. Farmers face higher risk due to inhalation of dust contaminated with rodent urine or droppings. Weather conditions such as temperature, rainfall, and humidity, along with urbanization and habitat changes, can also affect how the virus spreads.

Global response

WHO currently considers the global public health risk from the outbreak to be low. WHO pandemic preparedness and prevention director Maria Van Kerkhove said, “This is not COVID,” adding that the limited outbreak on the cruise ship does not signal the start of a COVID-like crisis or a pandemic.

The organization cautioned that additional hantavirus cases could still emerge and stressed the need for continued precautions. There are no vaccines and no known cure for the disease.

Despite the low global risk assessment, countries remain vigilant, with many in Asia adopting a cautious approach.

Indonesia, Thailand expand airport screening for hantavirus risk

Indonesia has tightened health screening and monitoring at Soekarno-Hatta International Airport for arrivals from the US, Argentina, Uruguay, and Panama amid concerns over potential hantavirus transmission.

Soekarno-Hatta International Airport Health Quarantine Centre head Naning Nugrahini said the enhanced measures target travelers from countries where hantavirus cases have been detected, according to Antara news agency on Tuesday. She said the list of countries may be updated if new cases emerge.

Screening measures include health declarations through the Satu Sehat app, thermal scanning, and a dedicated lane for infectious disease evaluation. A special ambulance service has also been prepared for transporting suspected infectious cases, she said.

Naning said preparedness steps were already in place at the airport as part of ongoing monitoring efforts.

Indonesian authorities urged travelers to remain vigilant, as hantavirus can spread through contact with rodent urine, saliva, and contaminated environments.

Similarly, Thailand has enhanced screening of passengers arriving from South America following global concern over hantavirus cases linked to an outbreak on the MV Hondius cruise ship.

On May 12, Thai health authorities announced stricter measures- mandatory screening for travelers who have visited 13 South American countries within the past six weeks according to the Department of Disease Control, despite no reported domestic cases so far. Deputy government spokeswoman Lalida Persvivatana said no cases of the deadly hantavirus have been detected in Thailand following a WHO alert on the cruise ship cases.

Passengers are required to submit detailed health declarations and report to disease control officers before immigration processing, said Dr Montien Kanasawadse, Director-General of the department.

Authorities have also ordered enhanced sanitation and vector control across all 74 international entry points, including cruise ships and transport vehicles.

Malaysia says no nationals on cruise; ups hantavirus monitoring

Malaysia has confirmed that no Malaysian citizens are among passengers or crew on the international cruise ship linked to a hantavirus outbreak, Health Minister Dr Dzulkefly Ahmad said.

He said the country is closely monitoring the situation despite no domestic involvement, according to his remarks on May 9. Dr Dzulkefly said authorities will continue tracking developments at both global and regional levels to maintain border preparedness and healthcare readiness.

He added that, following direct communication with Singaporean health authorities, two Singaporean crew members on board the vessel had tested negative for hantavirus.

On May 10, Dr Dzulkefly said Malaysia had increased health screenings at all international entry points, with particular focus on the maritime sector, to prevent hantavirus from entering the country. Authorities have boosted maritime monitoring and require health checks for all ships entering Malaysian waters, especially from high-risk areas.

Dr Dzulkefly said the situation remains under control and does not involve Malaysians, but surveillance efforts will continue as a precaution.

Along the same vein, the Penang Port Commission has ramped up precautionary health surveillance at the Swettenham Pier Cruise Terminal. While Malaysia has zero infection cases to date, Chairman Datuk Yeoh Soon Hin said the commission is bolstering ship sanitation checks and monitoring for rodent infestations to protect passengers, crew, and the local community.

He said the measures follow the International Health Regulations (IHR 2005) and are being carried out with the Health Ministry and other agencies. Health facilities at the terminal are on standby to handle suspected cases, while event-based surveillance has been intensified to detect unusual health incidents early.

Yeoh said cooperation with the Department of Veterinary Services and local authorities has also been expanded to improve vector control and environmental hygiene.

He advised passengers and crew to avoid contact with rodents or their droppings, use protective gear when cleaning contaminated areas, and seek medical care if symptoms such as fever, muscle aches, cough, or shortness of breath develop after possible exposure.

Philippines keeps an eagle eye on hantavirus, prepares broader response

Over in the Philippines, the Department of Health (DOH) said it is monitoring developments linked to a hantavirus outbreak and preparing laboratory and border response measures.

The Dutch ship includes 38 Filipino crew members. The Department of Migrant Workers earlier said all 38 crew members were not infected.

DOH spokesperson Undersecretary Albert Domingo said the country’s PCR machines, previously used during the pandemic, can be adapted for testing by updating primers. He added that three local institutions also have electron microscopes that can help identify the virus while confirmatory testing is underway.

The DOH is coordinating with the Bureau of Quarantine, which is working with international counterparts under the International Health Regulations.

Domingo said Filipino seafarers would undergo screening and be repatriated only after clearance under WHO-guided procedures.

Hantaviruses have also been found in wildlife in the Philippines, including a strain discovered in fruit bats in 2016 and named Quezon virus.