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- Age transition: mortality from hantavirus in adolescents aged 15-19 reaches 50%
Age transition: mortality from hantavirus in adolescents aged 15-19 reaches 50%
Brazilian scientists have found that the mortality rate from hantavirus infection among adolescents aged 15-19 reaches 50%, which is the highest rate among all age groups. Experts suggest that this may be due to an excessively strong immune reaction of the young body, so it is important to consult a doctor in time for infection. Rospotrebnadzor emphasizes that the "Andes" strain detected in cruise ship passengers is not found either in Europe or in Asia. Therefore, the probability of the spread of this particular variant of the virus in Russia is estimated as extremely low. At the same time, the WHO expects new cases of infection, since the disease has a long incubation period. Bookmakers estimate that the risk of a virus outbreak turning into a pandemic is 10%.
The most vulnerable group of patients
A group of scientists from Brazil, which has the highest number of cases of hantavirus infection in Latin America, analyzed data on the spread of the virus over ten years. The study showed that the highest mortality rate is observed among adolescents aged 15 to 19 years: about 50% of cases of infection end in death. This indicator is lowest in patients over 65 years of age — about 11%.
According to experts, increased mortality among young people may be associated with a stronger immune response of the body. With age, the activity of the immune system decreases, which is probably reflected in the statistics.
— Such results can be explained by the fact that young people had close contact with rodent-infested land. For example, during a football game or agricultural work. In addition, they develop a stronger immune response, which is common in hemorrhagic fevers. The infection was probably diagnosed too late. In case of infection, timely medical care and control of inflammation are extremely important," immunologist Mikhail Bolkov commented on the study.
In total, scientists analyzed 177 cases of infection. 89.7% of patients required hospitalization, and the average mortality rate for all age groups was 33.3%. The first pronounced symptoms of the disease appeared on average 3.5 days after going to the doctor, and recovery occurred after about eight days. The most common clinical manifestations of infection were fever, headache, and muscle pain.
The World Health Organization reported an outbreak of hantavirus infection in the open sea on May 4. The MV Hondius, carrying 146 people from 23 countries, left Ushuaia on April 1. The route included a visit to Antarctica, the southern Atlantic Ocean and the completion of the trip to Cape Verde. At the end of the first week of sailing, symptoms of fever appeared in a Dutch citizen. He died on April 11 right on board the ship. Later, his wife died in a hospital in Johannesburg, and then the third passenger of the liner.
In total, 11 people became infected. The authorities of Cape Verde did not allow the ship to dock, after which the liner headed towards the Canary Islands. After arriving, passengers began to return to their home countries.
On May 13, it became known that the Ambition cruise ship, with over 1,700 people on board, was quarantined in Bordeaux, France. The cause was the death of a passenger and cases of illness suspected to be related to norovirus.
New cases of infection
According to Tedros Adhanom Ghebreyesus, Director General of the World Health Organization (WHO), nine of the 11 cases of hantavirus infection have now been confirmed, and two more are considered probable.
— Over the past week, these figures have hardly changed due to the efforts of several governments and partner organizations. Since May 2, when WHO first received information about the group of cases, no new deaths have been registered," he said.
Given the long incubation period of the infection, new cases may be identified in the coming weeks. Each country where the cruise ship passengers were taken is responsible for monitoring their health status. According to him, WHO continues to receive reports of suspected infections from different countries, and the organization checks each of them together with national health authorities.
Against the background of the situation, one of the largest American forecasting and betting platforms has begun accepting bets on whether the outbreak of hantavirus on the ship will develop into a pandemic. Users have already bet about $700 thousand on this outcome. Currently, the service estimates the probability of such a scenario at about 10%. According to the rules, participants who choose the "yes" option will be able to receive winnings if the WHO officially characterizes the cases of hantavirus as a pandemic by the end of the year.
According to Rospotrebnadzor, a meeting was held at the agency the day before, including on the infection situation. The experts paid special attention to the case on a cruise ship related to the Andes variant. They noted that this strain is not found in Europe and Asia, but is distributed mainly in the countries of the New World — South, Central and North America. The natural reservoir is a dwarf rice hamster native to Argentina and Chile. The climatic conditions of Russia are unacceptable for him, which significantly reduces the risk of his appearance on the territory of the country, the department stressed.
At the same time, other variants of hantaviruses that cause hemorrhagic fever with renal syndrome (HFRS) are common in our country. The ministry stressed that no HFRS outbreaks have been recorded since the beginning of the year: the epidemiological situation remains stable and controlled, and the reported cases are isolated and sporadic.
Studies of the clinical features of infection in children and adolescents show that the course of the disease can vary depending on age, Andrey Isaev, General Director of the Scientific Center for Molecular Genetic Research at DNCOM, told Izvestia.
According to him, the Euro-Asian hantaviruses that occur on the territory of the Russian Federation — Puumala, Hantaan, Dobrava-Belgrade and others — are characterized primarily by a pronounced renal syndrome. In adolescents, it usually manifests itself more clearly.
At the same time, the specialist stressed that it is not necessary to mix the Russian hantaviruses and "Andes", which is currently being discussed in connection with the outbreak on the cruise ship.
— Hantavirus cardiopulmonary syndrome often begins as a common viral infection: fever, weakness, body aches, cough. But after 24-48 hours, the condition can deteriorate dramatically with the development of respiratory failure, acute respiratory distress syndrome and shock. This clinical picture is typical primarily for American viruses, including Andes," he said.
As the expert explained, early diagnosis is complicated by the fact that the initial symptoms are easily mistaken for acute respiratory viral infections. In case of suspicion, it is important to take into account the epidemiological history, including trips to endemic regions and possible contact with rodents.
For early detection of infection, PCR diagnostics is used to detect fragments of viral RNA in the blood. However, there are no mass commercial test systems for the Andes strain yet, so diagnostics are available only in a limited number of laboratories. Serological methods are also used to confirm the diagnosis, such as the determination of IgM and IgG antibodies to hantaviruses.
As Andrey Isaev noted, Rospotrebnadzor has not reported a single case of infection in the territory of the Russian Federation to date. In our conditions, such a virus can only be imported — for example, after contact with people who arrived from endemic regions of South America.
Переведено сервисом «Яндекс Переводчик»
