Hantavirus scare: What is Andes strain, the only type capable of human-to-human infection?

The Andes strain hantavirus has drawn global attention because it is the only known hantavirus capable of confirmed human-to-human transmission. Unlike most hantaviruses, which spread to humans through infected rodents, the Andes virus has caused limited outbreaks among close contacts in parts of South America, especially Argentina and Chile. 

Scientists say the virus remains rare, but its unusual transmission pattern makes it one of the most closely monitored hantavirus strains. 

What is Andes strain hantavirus? 

The Andes virus (ANDV) is a member of the hantavirus family and is linked to Hantavirus Pulmonary Syndrome (HPS), a severe respiratory illness that can become life-threatening. 

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The virus is mainly carried by the long-tailed pygmy rice rat found in Argentina and Chile. Most people become infected after inhaling virus particles from rodent urine, saliva, or droppings. 

What makes the Andes strain unique is its ability to spread between humans under certain conditions — something not seen in most other hantaviruses. 

Why is it the only hantavirus that spreads between humans? 

Researchers are still studying why Andes virus behaves differently, but evidence suggests it can remain in high concentrations in an infected person’s respiratory secretions during the early stage of illness. 

Most hantaviruses found in North America, Europe, and Asia do not transmit between people. Andes virus, however, has been linked to infections among family members, caregivers, and intimate partners who had prolonged close contact with patients. 

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Studies from outbreaks in Argentina indicate the virus may possess unique biological traits that allow limited person-to-person spread. 

However, experts stress that Andes virus does not spread as easily as COVID-19 or influenza. 

How does Andes virus transmit? 

Human-to-human transmission is believed to occur through close exposure to bodily fluids or respiratory secretions of an infected person, particularly before severe lung symptoms develop. 

Possible transmission routes include: 

• Prolonged close contact 
• Exposure to saliva or respiratory droplets 
• Caring for infected patients without protection 
• Intimate contact, including kissing 

There is no evidence of widespread airborne transmission or casual spread through brief contact. 

Why health experts are monitoring the Andes strain 

The Andes strain is closely monitored because human transmission increases the risk of localized outbreaks. Still, experts say the virus has not shown signs of spreading efficiently across communities. 

Most infections continue to be linked to rodent exposure in rural or forested areas. 

Scientists are also tracking whether future mutations could alter how the virus behaves or spreads. 

What are the symptoms of Andes hantavirus? 

Symptoms usually appear within one to six weeks of exposure and initially resemble the flu. Common symptoms include: Fever, muscle aches, fatigue, headache and nausea or vomiting 

In severe cases, patients may develop coughing, breathing difficulty, and fluid buildup in the lungs. 

Is Andes hantavirus a global threat? 

Andes hantavirus can be dangerous because it may cause severe respiratory disease with a high fatality rate. However, health experts do not currently consider it a major global pandemic threat. 

Human-to-human transmission remains rare and usually requires prolonged close contact. Most cases are still linked to infected rodents rather than community spread.