Hantaan virus

HTNV · HFRS

Overview

Hantaan virus is the prototype hantavirus and the cause of the classical, severe form of hemorrhagic fever with renal syndrome (HFRS) in East Asia. It was first isolated by Lee Ho-Wang and colleagues from striped field mice (Apodemus agrarius) trapped near the Hantan River in South Korea, after the virus had caused thousands of cases of unexplained hemorrhagic fever among UN troops during the Korean War. Hantaan virus produces the most severe HFRS clinical course of any Old World hantavirus, with prominent fever, hemorrhage, hypotension, and acute renal failure.

Discovery

Between 1951 and 1954, more than 3,000 United Nations troops serving in the Korean War developed an unexplained haemorrhagic fever with renal involvement that puzzled military physicians and the broader infectious-disease community for two decades. In 1976, Korean virologist Lee Ho-Wang and his team at Korea University identified antigen-positive material in the lungs of striped field mice trapped near the Hantan River, and successfully isolated the virus in cell culture in 1981. The discovery resolved a 25-year diagnostic mystery, gave the entire virus family its name, and provided the reference reagents that subsequently linked Puumala virus, Seoul virus, and the New World HPS-causing strains to a unified taxonomic group.

Rodent reservoir

The striped field mouse (Apodemus agrarius) is a small grain-feeding rodent abundant across the temperate agricultural plains of East Asia — northeastern China, the Korean peninsula, far-eastern Russia, and parts of Mongolia. It thrives in cultivated fields, grasslands, and the immediate periphery of farms and grain stores. Hantaan virus prevalence in field-mouse populations is heterogeneous but reaches 5–15% in endemic provinces. Human exposure peaks during late autumn and early winter, when post-harvest rodents seek shelter in farm buildings, and during spring planting, when fieldwork disturbs nesting sites.

Transmission

Hantaan virus is transmitted to humans almost exclusively through inhalation of aerosolized excreta from striped field mice in agricultural and rural settings. Rodent bites, contact with contaminated food, and exposure to nest material can also transmit infection. Person-to-person transmission has not been documented for Hantaan virus. The strong rural-occupational pattern — farmers, soldiers on exercise, forestry workers — distinguishes Hantaan from the predominantly urban Seoul virus.

Clinical course

Hantaan virus HFRS follows a classical five-phase clinical course over 2–4 weeks: a febrile phase (3–7 days of fever, headache, lumbar pain, facial flushing, conjunctival injection); a hypotensive phase (sudden onset of shock, often lasting hours to two days); an oliguric phase (acute renal failure, hyperkalaemia, haemorrhagic manifestations); a polyuric phase (recovery of urine output, often dramatic); and a convalescent phase lasting weeks to months. Severe disease can involve disseminated intravascular coagulation, pulmonary oedema, and central-nervous-system involvement.

Diagnosis

Diagnosis is by serology — IgM and IgG against Hantaan virus antigens by ELISA — supplemented by RT-PCR on blood or tissue at reference labs. The five-phase clinical course is highly characteristic in endemic regions. Laboratory findings shift across phases: early thrombocytopenia and leukocytosis with atypical lymphocytes, evolving to marked elevation of creatinine, BUN, and liver enzymes during the oliguric phase, with proteinuria, haematuria, and disseminated intravascular coagulation parameters in severe disease.

Treatment & prognosis

Treatment is supportive: ICU-level monitoring during the hypotensive and oliguric phases, careful fluid and electrolyte management, vasopressors for shock, and haemodialysis for acute renal failure. Intravenous ribavirin has been used in China and elsewhere in East Asia for severe Hantaan virus HFRS and is associated with reduced mortality when given early in the febrile phase, particularly within the first four days of illness. Case-fatality is approximately 5–15% overall and is strongly tied to access to dialysis and intensive-care support.

Prevention

Two licensed inactivated Hantaan virus vaccines — Hantavax (Republic of Korea) and analogous bivalent products in China — are used for high-risk populations including agricultural workers, soldiers, and laboratory staff. Beyond vaccination, prevention emphasises rodent control around farm buildings and grain stores, exclusion of mice from human dwellings, and protective measures during harvest and post-harvest cleanup. Hantaan virus vaccines are not licensed for use in Europe or North America.

Tracked countries

Live risk index and news for countries where Hantaan virus is documented or surveilled.

Notable outbreaks

1. 1951–1954
   Korean War theatre

   More than 3,000 UN troops developed unexplained hemorrhagic fever; the responsible virus was not isolated until 1976.

2. 1980s
   China

   Annual reported HFRS case counts exceeded 100,000 at the peak; aggressive vaccination and rodent-control programmes have since reduced this to approximately 10,000 cases per year.

3. Annual
   Northeastern China (Heilongjiang, Liaoning, Jilin)

   China continues to report tens of thousands of HFRS cases annually, with Hantaan virus the dominant strain in rural agricultural provinces.

References & primary sources

• Korea Disease Control and Prevention Agency (KDCA)
• Chinese Center for Disease Control and Prevention
• WHO — Hantavirus
• Lee HW et al. 1978 — Isolation of the etiologic agent of Korean hemorrhagic fever

Other hantavirus strains