Bird flu infected fewer humans in the second half of the year, prompting experts to point to a new enemy in the fight against a possible pandemic: complacency.
The lethal H5N1 strain of avian influenza was reported in people every two days in the H1. Since July, the number of cases has slowed to about one a week and scientists say the virus hasn't yet found a way to easily infect humans. Governments should continue to track and eradicate the disease, even as public perception shifts and a pandemic poses no immediate threat, said David Nabarro, the United Nations coordinator for avian and pandemic influenza. The flu spread in domestic poultry and wild birds across 38 countries in Asia, Africa and Europe since February, offering the virus more chances to mutate into a form dangerous for humans.
„You don't stop airport security screening because there have been no hijacks for two years,” Nabarro said in an interview from New York last week. „The danger of a pandemic is as profound now as it was a few years ago.” Since January, countries including the US and Japan have pledged about €1.9 billion ($2.5 billion) to fund efforts to monitor, manage and eradicate H5N1 and to prepare for a possible pandemic. Those efforts may have helped, according to Nabarro. „It would be nice to think that the enormous amount of work that's been put into this is having an impact,” he said. „I think it's a bit early to tell.”
The flu pandemic that struck in 1918 would probably kill about 62 million people nowadays, as many as died during World War II, the Lancet medical journal said last week. The H5N1 bird flu strain has killed 157 people since 2003, according to the World Health Organization. This year, 114 cases, including 79 deaths, were reported, with 88 of the new infections counted between January and June. While scientists agree on the need to track the virus and prepare for a pandemic, they are divided over whether the H5N1 strain is a likely trigger.
Some say governments and doctors should focus on being prepared for any pandemic - not just a bird flu one - and work to reduce the impact of seasonal flu, which contributes to the death of as many as 500,000 people each year. „One could make the argument more people die of hiccups” than of avian influenza, says Peter Palese, chair of Mount Sinai School of Medicine's department of microbiology in New York. „The virus hasn't really gone in a major way into humans. That is a very important fact, which makes it doubtful that H5N1 is really the next pandemic strain.”
It could take millions of years for H5N1 to mutate into a pandemic form, and panic over the virus is being fanned by „an avian flu bureaucracy” egging on governments to provide ever more money, US science writer Michael Fumento wrote in an article appearing in the December 25 edition of the Weekly Standard. Still, concern prompted some consumers to stockpile Roche Holding AG's Tamiflu antiviral drug and spurn chicken and duck meat in the past year. In France, Europe's largest poultry supplier, producers hurt by a slump in demand lost about 40% of their income in the Q1, according to the World Bank.
The reduction in reported infections and a decline in media coverage don't mean the virus is no longer continuing to circulate in many countries, according to virologist Ilaria Capua, whose laboratory in Padova, Italy, handles some of the avian flu screening for the World Organization for Animal Health. „At the beginning of the year there was a sort of race to show the world that even Africa had the problem, and African countries were very outspoken,” Capua said in a telephone interview on December 23. Some outbreaks were mistakenly diagnosed, hurting trade and tourism and making countries more reluctant to acknowledge the disease, she said.
In February, Nigeria became the first of eight countries in Africa to report outbreaks in poultry. Last week, the UN reported that H5N1 had been found in 17 of Nigeria's 36 states. „I am pretty confident that if it's widespread in some countries like Nigeria, then it is also widespread in other countries,” Capua said. More than 700 outbreaks of H5N1 among wild birds and domestic poultry were reported to the World Organization for Animal Health this year.
„We're in a situation of low incidence, but I'm sure we're going to see some peaks of infection in the future,” said Peter Roeder, an animal health officer with the UN's Food and Agriculture Organization, who helped Indonesia set up its bird surveillance. „How important they will be, how serious they will be it's not possible to say right now.”
The lethal strain of H5N1 was traced to a farmed goose in the southern Chinese province of Guangdong in 1996. It was found in South Korea in December 2003, before spreading across eastern Asia the following year and to Eastern Europe in 2005. „H5N1 viruses have been around for nearly a decade and it might be tempting to conclude that if they were going to proceed to form or contribute to a pandemic strain, they would have done so by now,” the influenza team at the European Centre for Disease Surveillance and Control said in a report last week. Still, the strain that sparked the 1918 pandemic „had been around for some years before it became part of a virus that could efficiently transmit between humans,” they said.
A pandemic can start when a novel A-type flu virus, to which almost no one has natural immunity, emerges and begins spreading. H5N1 has put the world closer to another pandemic than at any time since 1968, when the last of the 20th century's three major outbreaks occurred, according to the WHO. „Sooner or later there will be a highly lethal form of influenza and who knows when sooner or later is?” Kenneth Hill, a visiting professor at the Harvard Center for Population and Development Studies in Cambridge, Massachusetts, said in an interview last week. „I don't think we should be complacent.” (Bloomberg)