Information about the Hantavirus Outbreak
Published: 2026-05-08
Hantaviruses are zoonotic viruses that occasionally infect in humans. Hantaviruses primarily infect rodents. Transmission to humans is rare, but usually occurs through the inhalation of aerosolised particles from rodent urine, droppings, or saliva. Transmission through rodent bites or contact with contaminated materials can also occur. Human-to-human transmission is extremely rare, but has been documented with the Andes virus in South America. Infections in humans can lead to severe disease e.g., Pulmonary Syndrome (HPS) or Hemorrhagic Fever with Renal Syndrome (HFRS), which can be fatal. For more general information about hantaviruses, please see; World Health Organization (WHO), the European Centre for Disease Prevention and Control (ECDC), and Folkhälsomyndigheten.
The Andes virus (often abbreviated as ANDV) is one of the most clinically significant hantaviruses. It is primarily found in South America and is responsible for severe Hantavirus Pulmonary Syndrome (HPS) cases. Unlike most other hantaviruses, Andes virus has demonstrated limited human-to-human transmission, particularly among close contacts, such as household members or healthcare workers. It is associated with higher case fatality rates compared to many other hantaviruses, making it a key focus of surveillance and research during outbreaks.
In 2025–2026, increased hantavirus activity has been reported in several countries in the Americas, particularly in the Southern Cone region. The Pan American Health Organization (PAHO/WHO) reported hundreds of confirmed HPS cases and elevated mortality rates in countries including Argentina, Bolivia, Chile, Paraguay, Brazil, and Uruguay. In May 2026, international attention increased following an outbreak linked to the expedition cruise ship MV Hondius, where multiple suspected and confirmed Andes virus infections were identified among passengers and crew. Several deaths and severe cases were reported, and health authorities in Europe, South America, and North America initiated contact tracing and monitoring measures. WHO stated that the overall global public health risk remains low, although the Andes strain is notable because limited human-to-human transmission has been observed during close contact. More information about this particular outbreak is available from WHO, ECDC, and Folkhälsomyndigheten.
In Europe, including Sweden, hantavirus infections are mainly associated with the Puumala virus, which causes a milder form of Hemorrhagic Fever with Renal Syndrome (HFRS), known as nephropathia epidemica. Cases occur sporadically and are often linked to exposure to rodent habitats, particularly in forested or rural regions. The overall public health risk remains low, although seasonal increases in cases may occur depending on rodent population dynamics and environmental conditions. No cases of Andes virus have been detected in Sweden. Surveillance systems across Europe continue to monitor infections and emerging risks. For more information on surveillance and data for hantavirus, check the ECDC.
The Swedish Pathogens Portal continues to monitor and investigate research resources linked to emergent diseases, like hantavirus. If an outbreak does occur in Sweden, the portal will provide more resources.