"Just because the risk of hantavirus is low does not mean it should be minimised"

The doctor in Molecular Biosciences, one of the most authoritative voices on the subject, recalls that «it is not a new or unknown virus, as cases and outbreaks associated with hantavirus have been known for decades in different parts of the world» and stresses that the great media and public repercussion of the outbreak is due to Spain's direct participation in health management and the «greater social and media sensitivity to any infectious outbreak» that exists after the coronavirus pandemic.

-What exactly is hantavirus and how does it spread?

-Hantavirus is not a single virus, but a group of viruses with rodents as the main reservoir. Typically, people become infected by inhaling particles contaminated with urine, faeces or saliva from infected rodents, for example when cleaning enclosed spaces where mice have been present. However, this particular outbreak involves the Andes virus, a type of hantavirus that can also be transmitted from person to person, although this is rare and usually requires close and prolonged contact.

- What are the possible health consequences and what symptoms should alert the population?

-Hantaviruses can cause severe illness and death in humans. In the case of the Andes virus, it can cause what is known as hantavirus cardiopulmonary syndrome. At first it may look like a flu infection, resulting in fever, muscle pain, fatigue and abdominal discomfort. However, over the course of a few days it can rapidly worsen to severe, even life-threatening, conditions.

- In the case of the cruise, how can contagion occur in an apparently controlled environment?

-It is true that a cruise ship is a very controlled space. However, it is also a closed space where many people live together for days or weeks at a time, sharing cabins, dining rooms and other common areas. On a cruise ship like this, there may be several hypotheses. The first is that someone was infected before boarding or during a stopover in an area where the virus circulates, through contact with rodents or with environments contaminated by their excrement. Then, since it is the Andes virus, there could have been some contagion between people in very close and prolonged cohabitation conditions, such as cabins or shared spaces. The other possibility would be the presence of infected rodents on the ship.

- What type of health and logistical operation is usually activated for disembarkation and the management of possible victims?

-Diagnostic tests would be expected to be carried out in conjunction with a medical assessment of persons on board to identify suspected cases and close contacts. Persons with symptoms or suspected infection would be kept in isolation, either on the ship itself or in hospital if required. Close contacts could be quarantined or under active surveillance during the incubation period. For all other passengers, measures would depend on their level of exposure and what the health authorities indicate.

-Is there a real risk for the population in Spain or is this a very localised episode?

-For the general population in Spain, the risk is low, as this is a very localised episode and probably due to exposure in an area where the virus circulates naturally. However, the fact that the risk is low does not mean that it should be minimised. It is a virus that can cause serious illness and, in the case of the Andes virus, can be transmitted from person to person. It is therefore important to maintain close vigilance to cut off any possible chain of transmission.

- After the covid experience, many fear another health crisis: could hantavirus cause a pandemic or should we see it in a different context?

-It is important to see it in another context. COVID-19 was caused by a new respiratory virus, with very efficient human-to-human transmission via the respiratory route. In contrast, the Andes virus was identified decades ago, is a known virus and does not transmit that easily. Person-to-person transmission can occur in some cases, but it usually requires close and prolonged contact. Therefore, with what we currently know, it does not have the same pandemic potential as other respiratory viruses. That said, it is important to keep in mind that there is no such thing as zero risk, as viruses are constantly evolving and it is therefore important to maintain good epidemiological and virological surveillance, especially when it comes to viruses that can cause severe disease.

- What can a person do in their daily life to reduce the risk of infection, even if it is a rare virus?

-In Spain, the risk in everyday life is very low, but there are simple measures that can be taken to reduce it even further. The most important is to avoid direct contact with rodents, their nests or droppings, especially when cleaning enclosed spaces that have not been used for a long time. In such cases, it is advisable to ventilate well before entering or cleaning. Another general hygiene recommendation, although not specific to hantavirus, is to avoid drinking directly from cans or containers that may have been stored in unhygienic places or places where animals are present.