Viruses that cause avian influenza are capable of replicating at temperatures higher than a typical fever, according to a study in in vitro models and mice. ‘Fever-resistant replication could help explain why avian viruses and pandemic influenza viruses with avian PB1 cause more severe disease in humans,’ the authors write in the journal Science.
The North American strain of the H5N1 avian influenza virus has been shown to be capable of causing outbreaks in mammals such as cows, something not seen elsewhere in the world, including Europe. An international team has identified and tested two mutations in ferrets that may explain improved adaptation and greater virulence. According to the authors, who published the results in the journal Science Advances, the finding "highlights the urgent need for strengthened surveillance and targeted interventions.
Avian influenza has returned to Spain this summer. In addition to a few cases in wild birds, since 18 July there have been several outbreaks in poultry in different autonomous communities, causing the country to lose its disease-free status. To answer questions about the situation, its possible causes, evolution and consequences, SMC Spain organised an information session with researchers Inmaculada Casas, Ursula Höfle and Elisa Pérez Ramírez.
US Department of Health Secretary Robert Kennedy Jr's proposal to let bird flu spread in turkeys and chickens to identify surviving animals would be "dangerous and unethical", a group of scientists warns in a policy forum article published by Science. In addition to the suffering of infected animals, allowing a highly lethal, rapidly evolving and contagious virus to follow a natural course of infection "would prolong exposure for farmworkers, which could increase viral adaptation and transmission risks for poultry, other peridomestic animals, and humans," they warn.
A team in the US has tested the efficacy of baloxavir, an antiviral already on the market for treating common flu, against avian influenza in mice. The results, published in the journal Nature Microbiology, show that it is more effective than the currently recommended oseltamivir (Tamiflu) except when the infection is via the mouth, in which case it is equally effective. According to the authors, baloxavir ‘could be considered for the potential treatment of serious H5N1 virus infections in humans’.
A team of researchers from the USA has analyzed the B lymphocytes of seven healthy people in whom no exposure to H5 influenza viruses, such as the avian flu virus, had been documented. The results show that they present antibodies capable of recognizing this type of virus, which, according to the authors, could represent “a first line of defense” in the event of a pandemic. The results are published in the journal Science Immunology.
The H5N1 avian influenza virus can be transmitted between mammals, according to a study published in Nature. The research team isolated the virus from the milk of an infected cow in New Mexico (USA) and found that it spreads in mice and ferrets, reaching the mammary glands of both animals. In addition, the virus was also transmitted from infected lactating mice to their offspring. The European Centre for Disease Prevention and Control (ECDC) has issued a press release on Monday recommending increased surveillance for these viruses.
The World Health Organisation (WHO) has announced that a 59-year-old man infected with the H5N2 avian influenza virus died in Mexico on 24 April. This is the first confirmed human infection with the virus. The patient had multiple underlying medical conditions and had been bedridden for three weeks for other reasons before showing symptoms. The source of infection is unknown. The WHO assesses the risk to the general population as low.
An international group of scientists has studied epidemiological data since 2005 and more than 10,000 viral genomes to conclude that the epicentre of H5 avian influenza has shifted from Asia to parts of Africa and Europe. New lineages have emerged from these regions between 2020 and 2022, which evolved by genetic reassortment with low pathogenic viral variants as they spread. According to the authors, who publish their findings in the journal Nature, the increasing persistence of avian influenza in wild bird populations may be driving the evolution and spread of new strains.
According to a statement issued Monday by the World Health Organisation (WHO), Poland has reported that "unusual" cat deaths have been found in several areas of the country. Of the 47 samples tested (46 from cats and one from a caracal, another type of feline), 29 were positive for the avian influenza A(H5N1) virus. The surveillance period for all contacts has now ended and no contacts have shown symptoms. According to WHO, "sporadic A(H5N1) infections of cats have been reported previously, but this is the first report of a large number of infected cats in a large geographical area within a country".