Hantaviruses are a group of zoonotic viruses carried by rodents that can cause severe and sometimes fatal disease in humans. Infection typically occurs through contact with infected rodents or their excreta—urine, droppings, or saliva. While hantaviruses are found worldwide, the diseases they cause and their modes of transmission vary by region.
Disease Spectrum
In the Americas, hantaviruses are known to cause hantavirus cardiopulmonary syndrome (HCPS), a rapidly progressive respiratory illness with a case fatality rate as high as 50%. The Andes virus, found in South America, is notable for rare instances of human-to-human transmission among close contacts, primarily in Argentina and Chile.
In Europe and Asia, hantaviruses cause haemorrhagic fever with renal syndrome (HFRS), which primarily affects the kidneys and blood vessels. Human-to-human transmission has not been documented in these regions.
Viral Classification
Hantaviruses belong to the family Hantaviridae within the order Bunyavirales. Each virus is usually associated with a specific rodent reservoir, where it causes a long-term, asymptomatic infection. While many hantavirus species exist, only a few are known to cause disease in humans.
Burden of Disease
Globally, hantavirus infections are relatively rare but can be deadly. The case fatality rate is generally 1–15% in Europe and Asia, but up to 50% in the Americas. Each year, an estimated 10,000 to over 100,000 infections occur worldwide, with the highest burden in Asia and Europe.
- East Asia, especially China and the Republic of Korea, reports thousands of HFRS cases annually, though incidence has declined in recent decades.
- Europe sees several thousand cases each year, mainly in northern and central regions where the Puumala virus circulates.
- In the Americas, HCPS is rarer, with hundreds of cases reported annually. The United States has recorded fewer than 1,000 cases, while South American countries such as Argentina, Brazil, Chile, and Paraguay report small numbers each year. Despite the lower incidence, HCPS is a major public health concern due to its high fatality rate.
Transmission
Humans are infected primarily through inhalation of aerosolized particles from rodent excreta, but transmission can also occur through rodent bites or direct contact. High-risk activities include cleaning enclosed or poorly ventilated spaces, farming, forestry work, and sleeping in rodent-infested areas.
Human-to-human transmission is rare and has only been documented for the Andes virus, typically among household members or intimate partners during the early phase of illness.
Symptoms and Clinical Presentation
After an incubation period of one to eight weeks, symptoms often begin with fever, headache, muscle aches, and gastrointestinal complaints such as abdominal pain, nausea, or vomiting.
- HCPS rapidly progresses to cough, shortness of breath, pulmonary edema, and shock.
- HFRS may lead to low blood pressure, bleeding disorders, and kidney failure.
Diagnosis
Early diagnosis is challenging because symptoms overlap with other illnesses like influenza, COVID-19, dengue, or sepsis. A detailed patient history—especially regarding rodent exposure, occupation, travel, or contact with known cases—is crucial.
Laboratory confirmation is achieved through serological tests (IgM antibodies or rising IgG titers) and molecular methods such as RT-PCR during the acute phase. Due to the biohazard risk, samples must be handled under maximum biological containment and transported using triple packaging.
Treatment
There is no specific antiviral treatment or vaccine for hantavirus infection. Management is supportive, focusing on close clinical monitoring and treatment of respiratory, cardiac, and renal complications. Early access to intensive care improves outcomes, especially for HCPS patients.
Prevention and Control
Prevention centers on reducing contact with rodents:
- Keep homes and workplaces clean.
- Seal entry points for rodents.
- Store food securely.
- Use damp cleaning methods in rodent-contaminated areas (avoid dry sweeping or vacuuming).
- Practice good hand hygiene.
During outbreaks, early case identification, isolation, and contact tracing are essential. In healthcare settings, standard and transmission-based precautions should be used, with airborne precautions for aerosol-generating procedures.
WHO Response
The World Health Organization (WHO) supports countries in surveillance, laboratory capacity, risk communication, and outbreak response. WHO also promotes One Health approaches, recognizing the interconnectedness of human health, rodent reservoirs, and the environment. The organization regularly updates guidance on diagnosis, case management, infection prevention, and contact tracing to reflect emerging evidence.
Source: WHO
