Getting to Know Hantavirus: What It Is

Hantavirus: Symptoms, Transmission, and Risk in Thailand

Situation Update (July 2026): On July 2, 2026, the World Health Organization declared an end to the Andes strain hantavirus outbreak linked to a cruise ship, with a total of 13 cases reported. The situation has returned to normal, and the risk to the general public is very low.

What is Hantavirus?

Hantavirus is an RNA virus in the Hantaviridae family, with rats and rodents as its primary reservoir hosts. Humans usually contract the infection by inhaling dust or secretions from rodents, such as urine, feces, or saliva contaminated in the environment.

The name "Hanta" comes from the Hantan River in South Korea, where the virus was discovered after the Korean War. This virus has been known in the medical field for several decades and is one of the conditions doctors must differentiate from dengue fever, especially in cases involving kidney failure, as well as leptospirosis due to their many similar symptoms.

Hantavirus is divided into 2 syndromes.

Hantavirus disease is found worldwide and can be divided into 2 groups based on symptoms.

1. Hemorrhagic Fever with Renal Syndrome – HFRS is mostly found in Asia and Europe.

2. Hantavirus Pulmonary Syndrome – HPS is found in the Americas, particularly South America.

How is Hantavirus transmitted?

• Inhaling dust contaminated with rodent secretions, which is the primary transmission route.
• Direct contact with rodent excrement
• Rat bite (rare)

Generally, Hantavirus does not spread from person to person, except for the Andes strain in South America, which is the only strain with confirmed reports of human-to-human transmission. This occurs rarely and is usually associated with prolonged close contact with a symptomatic patient.

Symptoms of Hantavirus disease

General Symptoms

• High fever
• Muscle pain
• Headache
• Nausea, vomiting

Symptoms in severe cases

• Kidney failure
• Bleeding similar to dengue fever
• Pulmonary edema
• Respiratory failure

For the Andes strain that causes HPS, symptoms usually appear about 4–42 days after infection, and the mortality rate in severe cases is as high as approximately 20–40%.

Has Hantavirus been found in Thailand?

Thailand has found evidence of Hantavirus and antibodies against the virus in both rodents and humans. The virus or its genetic material has been detected in several species of rodents, particularly rats such as bandicoot rats, and antibodies have also been found in certain groups of people, especially those who come into contact with rodents or work in agriculture.

However, Hantavirus disease in Thailand is considered very rare, and the strain found is different from the one causing severe outbreaks abroad. Furthermore, it has been present in Thailand for over 40–50 years. Therefore, the risk for Thai people is extremely low and not a cause for concern.

How to prevent Hantavirus

Although the risk in Thailand is low, overall prevention of rodent-borne diseases remains an important concern.

• Eliminate food sources and habitats for rats in and around the home. Keep food containers and trash cans tightly closed.
• Seal holes or entry points where rodents can enter the house.
• When cleaning areas with rodent droppings, wear gloves and a mask. Spray disinfectant thoroughly before wiping instead of sweeping or vacuuming to prevent dust from spreading.
• Open windows for ventilation before entering to clean rooms or storage sheds that have been closed for a long time.
• Agricultural workers or those who regularly come into contact with rodents should wear protective gear and wash their hands after work.

You should see a doctor if you have a high fever along with muscle pain and shortness of breath, especially if you have a history of contact with rats or have recently returned from an outbreak area. Always inform the doctor of your travel and contact history.

Frequently Asked Questions about Hantavirus

Can Hantavirus be transmitted from person to person? Generally, no. Only the Andes strain in South America has reported human-to-human transmission, which is rare and requires prolonged close contact.

Should Thai people be worried? The risk is at a very low level. The strain found in Thailand is a different strain from the one causing severe outbreaks, and it has been present in the country for decades.

Is there a vaccine available? Currently, there is no widely used vaccine. Prevention therefore focuses on controlling rodents and avoiding contact with rodent excretions.

How does it differ from leptospirosis? They are caused by different pathogens. Leptospirosis is caused by bacteria, while Hantavirus is caused by a virus. However, their initial symptoms are very similar, so laboratory testing is required for diagnosis.

Source: Prof. Dr. Yong Poovorawan, specialist in pediatric hepatology, gastroenterology, and virology, Bangpakok 9 International Hospital

Note: This article is intended for disseminating health knowledge to the public based on information from external medical sources. Such references are not intended to imply that the contributing physicians are attending physicians or have a consultation schedule at Piyavate Hospital.