Symptoms, contagiousness, transmission, isolation, contact cases, recorded cases: all these things to know about hantavirus

They are not yet well known to the general public. In 2020, the world discovered Covid-19, now it’s another virus that is occupying everyone’s minds: l’hantavirus. On May 2, 2026, the World Health Organization warned of an outbreak of hantavirus on board the Dutch cruise ship MV Hondius. The boat connected Ushuaïa, in Argentina, to Cape Verde.

Currently, the death toll from this epidemic stands at three deaths. This Tuesday, May 12, nine cases are confirmed by the World Health Organization. « To date, eleven cases have been reported, including three deaths. All cases involve passengers or crew members of the ship. Nine of the eleven cases have been confirmed as the Andes virus, and the other two are probable,” said WHO boss Tedros Adhanom Ghebreyesus in a press briefing.

Among the cruise passengers and crew members already evacuated and tested, an American and a French woman tested positive for hantavirus. Five French passengers were repatriated and placed in isolation at Bichat hospital. Among these cruise passengers, a woman tested positive for hantavirus. Currently, she is in intensive care in serious condition with “the most severe form of cardiopulmonary presentation”.

Let’s rewind history to understand the current situation. In the media, on social networks and in French discussions, a new term has appeared: hantaviruses. These zoonotic viruses circulate between rodents (mainly voles) but can also be transmitted to humans. In the case of the cruise ship, virus sequencing made it possible to define the exact strain that is circulating. According to the results, it would be the Andean strain. The main reservoir of this strain is a very small animal; the long-tailed pygmy rice field rat. Hantavirus is transmitted through their urine, feces and saliva. This strain from the Andes is the only one that can be transmitted from one person to another.

In the majority of cases, hantaviruses are transmitted from animals to humans by inhaling dust contaminated by the feces and urine of infected rodents. Human-to-human transmission of the Andes virus most likely occurs through inhalation of droplets or aerosols. The main route of transmission is respiratory, through droplets of saliva. Depending on the type of virus, infection manifests as fever, headache, muscle pain and gastrointestinal symptoms such as abdominal pain, nausea or vomiting. The illness can progress quickly to cough, shortness of breath, fluid buildup in the lungs, and shock.

For the moment, studies do not allow us to know whether it is possible to be asymptomatic and contagious. “Perception of symptoms varies considerably from person to person. Some may only have a slight headache, others may still be at the beginning of the infection,” explains Christine Rouzioux, virologist and member of the Academy of Medicine interviewed by Santé Magazine

Olivier le Polain, head of the WHO EAR (Epidemiology and Analysis for Response) unit, gave an information point on several social media platforms: “If we impose or recommend quarantine, it is because people are contagious from the very beginning of the disease. (…) It is therefore during the first days, or even from the first moments of the disease, that contagiousness is strongest. Due to this incubation period, we can expect to see new cases emerge in the coming days or even next week, and this is why we must remain vigilant and ensure that, as soon as the first signs and symptoms appear, those affected are identified, isolated and cared for.” On average, it takes two to three weeks of incubation but it can go up to six. Thus, other cases of hantavirus may be detected in the coming weeks.

Some wonder why the passengers were not left on the cruise ship for treatment. Bad idea responds Christine Rouzioux: “When the illness breaks out, everything can go very quickly and respiratory failure can quickly appear. On a boat, there is no resuscitation service for appropriate care.

To curb the spread of the virus, isolation rules have been tightened. Monday May 11, the government announced that the 22 contact cases who crossed paths with passengers on the cruise ship were going to be hospitalized. As a precautionary measure, they are all quarantined in a hospital. The WHO boss recommends that those evacuated from the ship “be actively monitored, in a designated quarantine center or at home, for 42 days from the last exposure, which is May 10, which brings us to June 21.”

In France, the National Academy of Medicine recommends complete confinement of all 27 people concerned for six weeks: this period being necessary to cover any incubation period. In Spain, the rule is also to impose a complete quarantine of 42 days on the fourteen Spanish passengers at the Gómez Ulla military hospital in Madrid. In other countries, the rules are more flexible. Indeed, Germany and the Netherlands allow “home quarantine” with self-monitoring (taking temperature, daily calls to regional health services, avoiding gatherings, etc.).

Faced with the health risk, France is asking “closer coordination” of health protocols implemented in the countries of the European Union to fight against hantavirus. The announcement was made on Tuesday May 12 by Sébastien Lecornu. “I asked the ministers to immediately strengthen cooperation with neighboring states and to push for closer coordination of the health protocols put in place within the European Union and the Schengen area,” in order to “break possible chains of transmission,” the Prime Minister wrote on X.

« Isolation for six weeks is essential because we see in previous epidemics in Argentina that there can be transmissions of cases well beyond a month,” confirms Christine Rouzioux. A study conducted by the New England of Journal looked at the contagiousness of the hantavirus: “People say you need close contact. In the study, there are close cases such as meals at the table with around ten people but not necessarily close contacts such as living together, sexual relations, etc. On the same table, three people were sick. Currently, we don’t really know the close or close contacts of these 22 people.”

According to the results of scientific studies, the lethality of hantavirus for the Andean strain, that is to say the number of deaths in relation to the number of infected, is of the order of 35 to 50%. “These figures must be considered in the health conditions in Argentina with the absence of intensive care, the distance of certain populations from hospitals, etc.,” adds the virologist. The WHO takes hantavirus seriously but considers the risk to global health to be low. To slow the number of cases, it is therefore fundamental to isolate patients as quickly as possible to interrupt the chain of transmission.

Currently, There is no specific treatment or vaccine against hantavirus. Depending on the symptoms and the patients, rapid treatment can improve the prognosis. For example, a patient who suffers from severe lung damage may be placed on respiratory assistance in an intensive care unit. “The management of hantavirus infections is primarily based on treatments for fever and pain, as well as close monitoring of the patient and respiratory assistance if necessary,” underlines the WHO. For the moment, scientific studies have not confirmed the effectiveness of vaccines against all hantaviruses.

A major concern now seems to appear in the minds of the French: should there be a similarity with Covid-19? “We are very far from the situation with the Covid-19 epidemic. We learned lessons from the pandemic, the French government quickly mobilized and responded with isolation measures. We have recovered the 22 people, we will try to follow them and be careful in order to cut the chain of transmission,” assures Christine Rouzioux. Before adding: “In the coming days, we should expect new positive cases.” For the virologist as for others, it is completely useless to rush to pharmacies looking for a protective mask.