Hantavirus declared Thailand’s 14th dangerous communicable disease
Thailand’s disease board has approved hantavirus as a dangerous communicable disease, requiring reports within three hours.
Thailand’s National Communicable Disease Committee has approved the designation of hantavirus disease as the country’s 14th dangerous communicable disease, saying that although transmission is difficult, the disease is highly dangerous.
The committee has required cases to be reported within three hours, with an investigation to begin within 12 hours of detection. Authorities also stressed that Thailand has not found a strain capable of human-to-human transmission.
Dr Somrerk Chungsaman, Permanent Secretary for Public Health, said on Friday that the National Communicable Disease Committee had resolved to approve adding hantavirus disease as Thailand’s 14th dangerous communicable disease.
He said the decision was made because the disease can be severe, can spread through respiratory droplets, and some types can be transmitted from person to person. It is also a matter of global concern.
The designation covers both Hantavirus Pulmonary Syndrome (HPS) and Hemorrhagic Fever with Renal Syndrome (HFRS).
Dr Somrerk said the announcement specifies the name and key symptoms as follows:
(14) Hantavirus Disease may cause fever, chills, headache, muscle pain and fatigue. It may also involve gastrointestinal symptoms such as stomach pain, nausea, vomiting or diarrhoea.
In severe cases, patients may develop coughing, breathing difficulties, pneumonia, fluid in the lungs, shock, low blood pressure, bleeding from different parts of the body, acute kidney failure, respiratory failure and may die.
The disease surveillance definitions for hantavirus disease are:
- Patient under investigation (PUI): A person who meets the clinical criteria and has a risk history.
- Probable case: A PUI with an epidemiological link to a confirmed patient.
- Confirmed case: A PUI who tests positive under specific laboratory criteria, including detection of hantavirus genetic material by RT-PCR, detection of hantavirus antigen through immunohistochemistry, or antibody testing showing IgM antibodies or at least a fourfold rise in IgG antibodies specific to hantavirus.
The clinical criteria for hantavirus disease apply to a person with a fever above 38°C and at least one of the following symptoms: chills, muscle pain, headache, stomach pain, nausea, vomiting or diarrhoea.
The patient must also have at least one abnormal finding, divided into either haemorrhagic fever with renal syndrome (HFRS) — including abnormal bleeding, low blood pressure or acute kidney failure — or hantavirus pulmonary syndrome (HPS).
“When a patient meets the criteria for disease investigation, the case must be reported within three hours, and an investigation must begin within 12 hours of a suspected case being found at every level,” Dr Somrerk said.
“High-risk contacts will be subject to 42 days of quarantine from the date of contact with a probable or confirmed patient. If symptoms develop, they must be treated as suspected patients who require isolation and testing.”
Dr Montien Kanasawadse, Director-General of the Department of Disease Control (DDC), said the main reason for the resolution approving hantavirus disease as a dangerous communicable disease was the severity of the illness and its high fatality rate.
He said the designation would help establish clearer control measures, particularly legal powers under the Communicable Diseases Act 2015 to quarantine suspected cases, conduct surveillance and enforce reporting requirements. Legal action can be taken if high-risk groups fail to comply with the measures.
Regarding the current situation, nearly 1,000 travellers from high-risk countries have been monitored, but none have shown any abnormal symptoms. Thailand has also never detected the same hantavirus strain as the one found on the cruise ship.
“The Andes strain of hantavirus involved in the cruise ship outbreak has not mutated in a way that makes transmission easier. Thailand currently faces a low risk, and people should not panic. However, monitoring travellers with fever remains a necessary preventive measure,” Dr Montien said.
He further explained that the Andes strain, which is found in South America, is currently the only strain reported to be capable of human-to-human transmission. On average, however, its transmission rate is only around one person to one person.
The large number of infections found on the cruise ship was a “super-spreader” case, involving close contact in an enclosed space over a long period, such as between married couples or close companions who spent the whole day together.
Compared with Covid-19, the Andes virus is far more difficult to spread. Covid-19 can spread widely within a short time, from one person to 10 people, while the Andes strain requires genuinely close contact. Therefore, ordinary conversation in an open, well-ventilated area carries a very low risk.
“The key reason it must be declared a dangerous communicable disease is not because it spreads easily, but because of the severity of the illness if infection occurs, including its fatality rate. This is to ensure officials are ready to respond in a timely manner,” he said.
Thailand had previously designated Covid-19 as the 14th dangerous communicable disease. However, after Covid-19 became a seasonal epidemic disease, it was removed from the list of dangerous communicable diseases.
Thailand now has 14 dangerous communicable diseases, comprising:
- Plague
- Smallpox
- Yellow fever
- Severe acute respiratory syndrome, or SARS
- Ebola virus disease
- Middle East respiratory syndrome, or MERS
- Marburg virus disease
- Hendra virus disease
- Nipah virus disease
- Lassa fever
- Crimean-Congo haemorrhagic fever
- West Nile encephalitis
- Multidrug-resistant tuberculosis
- Hantavirus disease
