More than 199 countries and overseas territories have reported lab-confirmed cases of A(H1N1) influenza as of November 1, resulting in more than 6000 deaths, according to figures released Friday by the World Health Organization (WHO).
“As many countries have stopped counting individual cases, particularly of milder illness, the case count is likely to be significantly lower than the actual number of cases that have occurred,” said the WHO in its weekly update of the A(H1N1) influenza outbreak.
The pandemic is currently being driven by broad transmission throughout North America, coupled with an early start to winter flu season in Europe and parts of Asia, the U.N. health agency said.
“Intense and persistent influenza transmission continues to be reported in North America without evidence of a peak in activity,” the WHO said.
“Significantly more cases of pandemic H1N1 have been recorded in Mexico since September than were observed during the initial springtime epidemic,” the UN body said in its weekly update.
As of November 1, the official global death toll from A (H1N1) stood at 6,071, the WHO said. Of those, 4,399 deaths, or nearly three-quarters, occurred in the Americas region — an increase of 224 in just one week.
There are also signs of “increasing and active transmission” of pandemic flu virus across Northern and Eastern Europe, including Ukraine and Belarus and eastern Russia, the WHO said.
The pandemic is also gaining strength in Mongolia, Oman, Afghanistan and Japan, but is waning in tropical areas of Central and South America and parts of south Asia.
The WHO also called on Friday for stricter monitoring of farm workers and animals for influenza A viruses, following a string of recent cases in a wider range of animals than pigs.
Although these cases were isolated and did not impact how the A(H1N1) pandemic evolved in humans, recent findings may indicate broader potential for flu viruses to mix and mutate, the WHO said.
“While most influenza A viruses circulating in mammals preferentially infect a single species, cross-species transmission is known to occur,” said the WHO in a briefing note.
Pigs have historically acted as “mixing vessels” for different types of flu viruses, allowing them to mutate into new forms that could be transmitted to humans.
“These recent findings further suggest that influenza A viruses in animals and humans increasingly behave like a pool of genes circulating among multiple hosts, and that the potential exists for novel influenza viruses to be generated in animals other than swine,” said the WHO.
“This situation reinforces the need for close monitoring and close collaboration between public health and veterinary authorities,” it added.
“When influenza infections are detected in farmed animals, WHO recommends monitoring of farm workers for signs of respiratory illness, and testing for H1N1 infection should such signs appear.”
Currently, nations are only required to notify international authorities of avian influenza cases, although some nations have additional domestic rules that apply to other animals, such as pigs.
However, since the rules also require reporting of “any emerging disease” in animals to the World Animal Health Organization (OIE), “this would include infections with the pandemic H1N1 virus or other novel influenza viruses,” the WHO said.
The agency stressed that lab tests had not detected signs that the virus had mutated to a more virulent form.
“These isolated events have had no impact on the dynamics of the pandemic, which is spreading readily via human-to-human transmission,” it said.
The recent cases involving animals have included swine flu in pigs.
“As human infections become increasingly widespread, transmission of the virus from humans to swine is likely to occur with greater frequency,” the Geneva-based health agency added.
Other A(H1N1) infections have been reported in turkeys in Chile and Canada, and in domestic pets, including a cat in the United States. The UN health agency also noted the progress of highly virulent H5N1 bird flu in recent years.
Another case involved a “novel H3N2 influenza virus” recently found in mink in Denmark. The virus is a combination of human and swine genes that had not been previously identified in circulating flu viruses, the WHO said. However, testing of workers at the mink farms detected no spread to humans.
“However, the incident demonstrates the constantly evolving ecology of influenza viruses, the potential for surprising changes, and the need for constant vigilance, also in animals,” the WHO said.
The AFP news agency cited the Paris-based OIE as saying on Wednesday that there was no evidence that animals had played “any particular role in the epidemiology or the spread” of the pandemic virus.
“It does not come as a surprise that notifications of infection in new animals species are received; on the contrary it demonstrates animal disease surveillance is efficient and functioning to the benefit of all,” said OIE Director General Bernard Vallat in a statement.
As the pandemic continues to spread throughout the United States, many are having trouble gaining access to the swine flu vaccine.
A new telephone poll conducted by the Harvard School of Public Health found than just one-in-three adults who have attempted to get a swine flu vaccine have been able to do so. The figures held true even among those at heightened risk for severe complications and among parents who had tried to obtain the vaccine for their high-risk children.
The vaccine has been available in the U.S. for about a month, but supplies have been limited due to manufacturing delays.
At this point, the shots are only supposed to be given to those at high risk of complications.
The Harvard poll, which surveyed 1,000 adults last weekend, also showed that half of those who tried could not find information about where to obtain the swine flu vaccine.
Swine flu is widespread in 48 states, according to comments made Friday by officials with the Centers for Disease Control and Prevention (CDC). Many millions of Americans have been infected with the virus, though most suffered only mild illness. CDC officials said that 129 children have died from swine flu complications since April, when the virus was first identified.
The WHO’s full November 6 weekly update can be viewed at http://www.who.int/csr/don/2009_11_06/en/index.html.
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