Understanding and preventing hantavirus: Expert insights

Editor's Note: The recent hantavirus infection event on an international cruise ship has drawn widespread concern. To help the public understand the virus and avoid unnecessary fear, this article presents insights from Prof. Li Tongzeng, chief physician at the Department of Infectious Diseases, Beijing You'an Hospital, Capital Medical University. He addresses the most pressing questions about hantavirus transmission, clinical presentation and preventive measures, offering authoritative and practical health guidance.

The recent outbreak of hantavirus (Andes virus strain) on the Atlantic cruise ship MV Hondius led to multiple confirmed cases and deaths, drawing global attention. Hantavirus is not new, but its insidious nature and the high pathogenicity of some strains can easily cause panic. Fortunately, hantavirus is preventable and controllable, provided we avoid common misconceptions and adopt science-based countermeasures. This allows us to take the risk seriously without panicking.

1. The Andes virus is the only hantavirus capable of human-to-human transmission – and only under very limited conditions

Among all hantavirus strains, the Andes virus (ANDV) is currently the only one confirmed to be capable of human-to-human transmission. It was the cause of the recent cruise ship outbreak. However, there is no need for excessive alarms since its transmissibility among humans is low and fundamentally different from that of influenza.

First, human-to-human transmission typically requires close and prolonged contact – for example, among family members, caregivers, cabin mates on a ship, or health care workers providing direct, sustained care to an infected person. This virus does not spread through casual, brief contact such as simply passing by someone. Even under these conditions, transmission is limited. According to the World Health Organization (WHO) and experts, human-to-human transmission of ANDV typically occurs during the early symptomatic phase and only among very close contacts. Ordinary social distancing (over one meter) and brief encounters carry no risk of infection.

Second, transmission is extremely weak. The ANDV strain has never caused a large-scale human-to-human outbreak. The secondary spread on the cruise ship was a rare exception, made possible by the enclosed environment and prolonged close contact. This does not indicate that the virus has gained the ability to spread widely among humans.

2. Early symptoms mimic a cold, but severe cases progress fast – watch for these red flags

The clinical features of different hantavirus strains vary mainly in which organs they target, but early symptoms such as sudden high fever, headache, fatigue, muscle aches, nausea, vomiting and loss of appetite are nearly indistinguishable from the common cold or flu. That is a key reason for delayed treatment. The incubation period ranges from one to eight weeks (up to six weeks for the ANDV), with no apparent symptoms during this time.

Hantavirus primarily damages vascular endothelial cells. Anyone experiencing the following symptoms, especially if they have a history of rodent exposure or travel to endemic areas, should seek immediate medical care and inform the doctor of their exposure history: sudden high fever (≥38°C / 100.4°F) accompanied by headache, lowerback pain and eye pain (the "three pains"); flushing of the face, neck and upper chest, or fine petechiae (small red or purple spots); chest tightness, shortness of breath and difficulty breathing; edema (swelling) and markedly decreased urine output; and persistent vomiting, confusion and drop in blood pressure.

3. High-risk groups and high-risk behaviors: Who and what to watch out for

The risk of hantavirus infection is directly linked to contact with rodents or environments contaminated by them. Based on clinical cases and epidemiological investigations, the following are clearly identified high-risk groups and behaviors.

High-risk groups include:

1) people who work outdoors for long periods or in areas with frequent rodent activity;  

2) travelers to endemic areas; and

3) immunocompromised individuals, especially the elderly, who, due to weaker respiratory and physical barriers, are more vulnerable to infection, have longer recovery times and are more prone to exacerbation of underlying diseases.

High-risk behaviors include:

1) cleaning old houses, storage rooms or woodsheds without wearing a mask or gloves, and dry sweeping or dry wiping;  

2) hiking or camping in areas where you may brush against grass or leaf litter, entering long-unused cabins or shacks, or spending extended time in rodent-prone areas;  

3) eating unsealed food that may have been contaminated by rodents, eating wild fruits or vegetables outdoors without thorough washing, or drinking untreated water; and  

4) failing to clean up properly or promptly after finding signs of rodents in the home.

The cruise ship outbreak and common clinical questions reveal five myths about hantavirus. Debunking these is key to effective prevention.

Myth 1: You only get infected if you touch a rodent or get bitten.  

Fact: Even without touching a rodent or ever seeing one, people can become infected by inhaling virus-laden dust while cleaning rodent-contaminated environments.

Myth 2: Hantavirus spreads easily among people.  

Fact: Widespread human transmission does not occur. Only ANDV has shown limited human-to-human transmission, and that requires prolonged, close contact. Ordinary social contact poses an extremely low risk.

Myth 3: All hantavirus infections have a high fatality rate.  

Fact: Fatality depends on the virus strain and timing of treatment. The greatest danger is not the virus itself, but mistaking early symptoms for a common cold and delaying medical care, thereby delaying treatment.

Myth 4: The hemorrhagic fever vaccine used in China protects against all hantavirus strains.  

Fact: It does not cross-protect against ANDV (typically found in the Americas). Travelers to endemic areas in South America cannot rely on existing vaccines and must focus on strict personal protective measures.

Myth 5: Hantavirus exists only in the wild or remote areas.  

Fact: Climate change is expanding the range of rodent hosts, bringing infection risk into everyday environments – not just rural or wilderness settings.

(Cover: VCG)