investigation
Australia on alert: World Health Organisation urges efforts to prevent bird flu strain with pandemic potential

The World Health Organisation has urged countries to lift efforts to counter a strain of bird flu that could spark another human pandemic. The particular strain of the H5N1 virus has infected people, but crucially, there are no confirmed cases of human-to-human spread so far. Infectious disease experts have warned that could change as the virus mutates. The WHO wants more surveillance efforts to get an early warning alarm that the virus has crossed that threshold. The hope is, it doesn’t. Australia remains the only part of the planet free from the worrying strain, known as Clade 2344b HPAI H5N1. It hasn’t been detected any in birds tested here. Michelle Wille, a senior research fellow at the University of Melbourne’s Centre for Pathogen Genomics is searching for signs of it here and closely monitoring the global situation. She has long said it’s a matter of “when, not if“ the virus gets here, most likely carried by long distance migratory birds. “It’s really inching a bit closer and closer all the time,” she told The Sunday Times. “This virus managed to cross the Pacific Ocean. It crossed the Atlantic Ocean. It went from South America to Antarctica. These are vast distances the virus has been spreading with wild birds. Australia to Asia is not that far, so I think it will arrive eventually.” “We are doing quite a lot of surveillance right now, really focused on these migratory birds, shore birds and sea birds. “We’re not alarmed, but we are concerned. And I think it’s really important that we continue to monitor the situation closely.” Since 2020, the virus has spread to a vast range of birds, wild animals, farm animals and marine mammals that have never been infected with bird flu before. It’s received a great deal of international media attention recently because of concerning developments in North America, including the infection of dairy cattle, with more than 400 herds affected in at least 14 US States. And there was the first known infected pig, on a backyard farm in Oregon. Professor Raina MacIntyre, head of the biosecurity program at the University of NSW’s Kirby Institute, said that was “a worrying development in the trajectory of this virus”. “Pigs are the ideal genetic mixing vessel to generate a human pandemic influenza strain, because they have receptors in their respiratory tracts which both avian and human flu viruses can bind to,” she wrote recently in The Conversation. “This means pigs can be infected with a bird flu virus and a human flu virus at the same time. These viruses can exchange genetic material to mutate and become easily transmissible in humans. “Interestingly, in the past pigs were less susceptible to H5N1 viruses . . . The infection of a pig is a warning. If the virus enters commercial piggeries, it would create a far greater level of risk of a pandemic, especially as the US goes into winter, when human seasonal flu starts to rise.” The 2009 influenza pandemic virus in humans originated from pigs, Dr Wille pointed out. “(But) I think (the issue) is bigger than pigs,” she said. “I think it’s really livestock contact with multiple viruses, and that the interface between humans and animals is quite big in livestock. “Humans are touching these animals and working with these animals every day. So, there is more chance for humans to be become infected from livestock relative to wildlife.” University of WA virologist Associate Professor Allison Imrie said it was now understood humans could be infected with H5N1 directly from birds, without pigs acting as a mixing vessel. “The ancestor of this virus is the one that emerged back in 1997 and killed a lot of people in Hong Kong and in that area, and then kind of disappeared for a while, and now it’s come back as a significant variant of the original one,” she said. “It’s kind of been bubbling away in the background and picked up a major gene that’s come back from birds. The virus we’re seeing now is a reassortant (mix) that’s kind of a distant progeny of the first H5N1 and one that emerged in the 1990s. So far, humans, mostly farm workers, who’ve been infected with clade 2344b of H5N1 have only experienced mild illness, compared with the very serious sickness caused by other H5N1 clades. However, an infected Canadian teenager is in a critical condition at a hospital in British Columbia. “It’s concerning that this teenager is quite sick, but it’s also not outside of a pattern of people getting really sick from these viruses,” Dr Wille said. Ian Barr, deputy director of the WHO’s Collaborating Centre for Reference and Research on Influenza, said the Australian Government was treating the risks seriously. “They’ve put aside $95 million for extra precautions and measures to try and mitigate or ameliorate the situation, and stockpiling vaccines and and antivirals for that matter,” he said. “If (antivirals) are used within the first few days of infection, they should be quite effective.” Melbourne-based Professor Barr agreed the 2344b clade of H5N1 appeared less aggressive. “Other types of H5 such as those which have been circulating in South East Asia in recent years, they can be quite deadly. So it just depends which H5 you run into.” WA’s Department of Primary Industries and Regional Development said it was working with Federal and other State Governments, as well as animal and industry groups “to prepare for the possible arrival of this strain and its potential impacts”. “DPIRD is working closely with WA poultry producers and industry to enhance biosecurity on poultry farms to minimise the interaction with wild birds. “The WA poultry industry is proactive in reporting any disease signs consistent with avian influenza to DPIRD to ensure early detection and rapid response.” Professor MacIntyre said surveillance was key to early detection of a possible pandemic. “This includes comprehensive testing and reporting of infections in birds and animals, alongside financial compensation and support measures for farmers to encourage timely reporting,” she wrote. “Early identification can prevent a pandemic. Any delay in identifying an emerging pandemic strain enables the virus to spread widely across international borders.” Australia’s only H5N1 detection was in a child who acquired the infection while travelling in India, and was hospitalised with illness in March. “This kind of delay can be costly . . . Only about five per cent of tests positive for influenza A are subtyped further in Australia and most countries,” she wrote. Prof Imrie said PathWest’s main laboratory in Nedlands looked for signs of H5N1 in local flu cases. “They test what is supplied to them by doctors who might see people presenting with flu-like symptoms. Dr Wille said the national surveillance program was extensive and supported by the public. The Federal Government had established a dedicated High Pathogenicity Avian Influenza Preparedness Taskforce, comprising representatives of key government departments to prepare for and coordinate response to any future outbreak. Maria Van Kerkhove, the WHO’s epidemic and pandemic preparedness and prevention director, this week said countries can be doing a lot more. “We need much stronger efforts in terms of reducing the risk of infection between animals to new species and to humans,” she added, notably through testing and proper protective equipment. Professor Van Kerkhove stressed the importance of preparing “for when or if we will be in a situation where we are in a flu pandemic.” “We’re not in that situation yet, but we do need more vigilance,” she said. Dr Wille urged bushwalkers and other members of the public who encountered dead birds to call a special hotline. “We need everyone’s help,” she said. “There’s a bunch of us working in the space, but Australia is a big country, and there are many people out there that can help us with this.” Unusual signs of disease or mass mortalities in domesticated birds, wild birds or other wildlife should be reported to the Emergency Animal Disease Hotline on 1800 675 888.

investigationAustralia on alert: World Health Organisation urges efforts to prevent bird flu strain with pandemic potential

investigation
Australia on alert: World Health Organisation urges efforts to prevent bird flu strain with pandemic potential