Hantavirus explained: The hidden dangers of rodent exposure

 

RECENT reports of a hantavirus outbreak linked to a cruise ship have attracted global attention, particularly following several deaths and concerns involving a strain capable of limited human-to-human transmission.

However, health experts stress that hantavirus behaves very differently from highly transmissible viruses such as COVID-19. The World Health Organisation (WHO) has indicated that the outbreak does not represent the start of another pandemic, although the infection should still be taken seriously.

Depending on the strain involved, severe hantavirus infections can carry mortality rates of up to 30 to 40 per cent.

According to Dr Lee Kok Soon, Consultant Physician and Infectious Diseases Specialist at Sunway Medical Centre, Sunway City, hantavirus is not a new disease. It has long been recognised in parts of Asia, Europe and the Americas, where rodent-borne infections continue to be reported each year.

“It is natural for people to become concerned whenever an unfamiliar infectious disease appears in the headlines, especially after the COVID-19 pandemic. While awareness is important, it is equally important to understand how these infections spread and the level of risk involved,” he said.

Different strains, different health risks

Pic credit: AFP

Hantavirus is not a single virus but a family of viruses carried primarily by rodents. Different strains affect the body in different ways.

Some strains mainly affect the lungs and respiratory system, while others are associated with kidney complications, causing a condition known as haemorrhagic fever with renal syndrome (HFRS).

“In the Americas, certain hantavirus strains can cause Hantavirus Pulmonary Syndrome (HPS), a severe illness characterised by fluid accumulation in the lungs that can lead to breathing difficulties and respiratory failure,” Dr Lee explained.

“In Europe and Asia, some strains are more commonly linked to kidney-related complications and bleeding disorders.”

The recent outbreak attracted international attention because it involved the Andes virus, one of the few hantavirus strains known to be capable of limited human-to-human transmission.

Even so, its transmission characteristics are very different from those of COVID-19 and do not support the same level of widespread community spread.

The overlooked risk of rodent exposure

According to Dr Lee, most hantavirus infections occur following exposure to environments contaminated by infected rodents such as rats and mice.

The virus can spread when microscopic particles from rodent urine, saliva or droppings become airborne and are inhaled. In rare cases, transmission may also occur through rodent bites or scratches.

“Something as simple as sweeping or vacuuming a contaminated storeroom can release infectious particles into the air without people realising it,” he said.

For this reason, Dr Lee advises against dry sweeping rodent-infested areas such as abandoned buildings, dusty warehouses or long-neglected spaces.

Instead, contaminated surfaces should first be sprayed with disinfectant, left for several minutes, and then cleaned using a damp cloth.

He also recommends practical precautions such as wearing gloves and masks during cleaning, ensuring good ventilation and disposing of waste properly.

Symptoms can resemble common illnesses

One of the challenges in diagnosing hantavirus is that its early symptoms often resemble those of more common infections.

Patients may initially experience fever, muscle aches, fatigue, nausea, headaches or dizziness. These symptoms can easily be mistaken for influenza, dengue, leptospirosis or COVID-19.

“Exposure history is often an important clue, especially if the patient has recently spent time in rodent-infested or poorly ventilated environments,” Dr Lee noted.

Diagnosis typically relies on a combination of clinical assessment, laboratory investigations and imaging studies.

In severe respiratory cases, chest imaging may reveal fluid accumulation in the lungs, while blood tests may show abnormalities involving platelet counts, kidney function or liver function.

Definitive diagnosis is usually confirmed through specialised laboratory testing, including polymerase chain reaction (PCR) or antibody testing.

Early treatment remains crucial

(Image: Sunway Medical Centre)

Although there is currently no specific antiviral treatment for hantavirus infection, early medical attention can significantly improve outcomes.

The disease may progress rapidly once severe respiratory symptoms develop, and some patients may require oxygen therapy, intensive care support or dialysis, depending on the organs affected.

While Malaysia has not reported any hantavirus outbreaks, Dr Lee said the recent attention surrounding the virus serves as a useful reminder that rodent-borne diseases should not be overlooked.

He advises households to maintain clean living environments, store food properly and exercise caution when cleaning neglected spaces, particularly after floods, renovations or long periods of abandonment.

“Simple preventive measures and safe cleaning practices can significantly reduce the risk of exposure. If symptoms develop or worsen after possible rodent exposure, it is important to seek medical attention promptly,” he said.

For most Malaysians, hantavirus remains a low-risk infection. However, understanding how it spreads and taking sensible precautions can help prevent unnecessary exposure and reduce the likelihood of serious illness. ‒  Focus Malaysia