A Virginia Tech disease ecologist said the outbreak of Andean hantavirus on the international cruise ship MV Hondius highlights how little scientists still know about the virus quietly circulating in wild rodent populations before infecting humans.
Most hantaviruses infect humans through animal-to-human transmission, but the Andean strain can spread from person to person, highlighting global vulnerabilities in interconnected travel networks.
Viruses with the ability to infect multiple species and spread silently between people require serious attention before an outbreak spreads. Most of our research on zoonotic viruses remains reactive, studying viruses after they have spilled into humans rather than understanding in advance how they circulate in wild animals. ”
Luis Escobar, disease ecologist at Virginia Tech
Most hantaviruses that infect humans originate from animal-to-human transmission, but the Andes strain has the potential to spread between humans, highlighting global vulnerabilities in interconnected travel networks.
Escobar explained the unique biology of the virus and why current public health models often fail to predict ramifications.
How are Andean hantaviruses different from European and Asian variants?
Our study revealed that European and Asian hantaviruses tend to maintain closer relationships with their original rodent hosts. However, the Americas variant shows greater ecological plasticity, meaning the rodent can transmit the virus to a wider range of species. This biological flexibility is a major warning sign for the emergence of disease. However, the ecological and evolutionary mechanisms behind these differences remain unclear, and further research is needed to understand how hantaviruses circulate in wildlife before spilling over to humans and causing outbreaks.
Why do official case numbers underestimate the true scale of the outbreak?
In addition to severe symptoms, hantaviruses can cause asymptomatic or mild infections, but the potential role of silent infection in disease spread is unclear. Because hospitalization data captures only the most severe cases, the true scale of outbreaks is often underestimated.
Understanding the true scale of an outbreak is critical as it directly impacts public health decisions such as containment strategies, surveillance, and risk assessments.
Why are hantaviruses compared to diseases such as COVID-19 and bird flu?
Like these respiratory viruses, hantaviruses can cause an exaggerated inflammatory response. In severe cases, the immune system essentially goes into overdrive, causing the lungs to fill with fluid even if the lung tissue is not extensively destroyed.
Do you know if the virus associated with the cruise ship outbreak is circulating elsewhere in North America?
Genetic sequences associated with clusters of Andean hantaviruses found in Chile and Argentina have not been published. All we know at this point is that this outbreak is linked to a hantavirus that can cause a pulmonary syndrome.
Are concerns about hantavirus overblown?
As with the COVID-19 pandemic, history has shown that underestimating a virus in its early stages can lead to a delayed response. The US National Academy of Medicine warns that the world remains poorly prepared for new pandemics. With environmental change and increased human movement, we should expect more outbreaks associated with wildlife-borne pathogens, not fewer.
Does Andean hantavirus really have pandemic potential?
Yes, for several reasons:
● Can be transmitted from person to person
● There is an incubation period and silent infection may occur.
● There is currently no vaccine available.
● Treatment is primarily supportive or palliative
However, not all infected individuals transmit the virus (high levels of viremia may be required for the virus to spread), and hantavirus outbreaks have been successfully contained when local epidemiologists have the resources and authority to intervene.
What is the mortality rate?
This is significantly higher than the coronavirus disease (COVID-19). In parts of southern Chile, the mortality rate for hospitalized patients could approach 60%. This high mortality rate makes rapid containment and international cooperation essential.
This means rapid containment is essential. The earlier an outbreak is identified and controlled, the better for global public health.
Is there evidence that the virus has mutated and become more spreadable?
We have seen no evidence that changes in the virus are involved in transmission. In fact, human behavior appears to be more important in promoting infection. Researchers need more baseline data on hantaviruses in wild rodents to determine whether new outbreaks are being caused by virus evolution, environmental changes, or increased human exposure.
