Entries by Scott McPherson (423)
H7N2 avian influenza also a threat to "go pandemic"
Scott McPherson
in influenza and infectious diseases
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While the world watches the spread of Qinghai H5N1 across Asia, Europe, and Africa, the threat of other subtypes of influenza also exists. And veteran influenza researchers and other interested parties have mentioned time and again that other strains of influenza are just as apt to gain pandemic status.TORONTO, June 19 (UPI) -- While the threat of a bird flu pandemic continues to hang over the world, authorities in the United Kingdom now believe a second strain of avian flu -- previously considered of little human risk -- does indeed pose a real danger to people.
"When you have to hospitalize someone for respiratory illness in the U.K., where hospital beds are hard to allocate, then the person has a serious illness," said Jonathan Nguyen-Van-Tam, a senior lecturer at Public Health Laboratory Services in London.
"In this outbreak, we had four people who tested positive for H7 influenza strain, and three of them were hospitalized," he told United Press International. "One person was a candidate for intensive care before he finally came around.
"I think we need to reconsider the H7 strain on the basis of this outbreak," Nguyen-Van-Tam said in reporting how British authorities dealt with the disease encountered on small farms in Wales in the spring of this year.
He presented the report in a special late-breaker session at the Options for the Control of Influenza VI conference in Toronto, attended by more than 1,400 healthcare professionals.
Worldwide, the H5N1 strain of avian influenza, the so-called bird flu, has infected 313 humans and killed 191 of them. The H5N1 disease, seen sporadically since 1996 in Southeast Asia, Europe and Africa, does infect human beings with a strain that is not easy to combat, but so far, its ability to effectively spread from human to human has not occurred. However, health authorities worldwide are nervously watching for that possibility.
But while experts prepare for that grim possibility, a lesser-known relative of the H5N1 virus may be emerging as an equally formidable threat, based on what health authorities encountered recently on a handful of tiny chicken farms in Wales and northern England.
Authorities were alerted to an outbreak there at a smallholding -- a small farm often considered to be inefficient for profitable farming -- where 30 to 40 hens were kept. The farmer had purchased 10 new hens from a trader at the Chelford Market in England.
When the new hens began dying between May 1 and May 17, health authorities from both countries descended on the farm, testing the sick birds and determining that the birds had H7N2 disease.
Health officials also found illness in the farmer's wife and the farmer, a neighbor/visitor and her partner. Only the neighbor's partner tested positive for H7. The partner was not hospitalized but was treated with oseltamivir, sold as Roche's Tamiflu.
Tracking sales at the live poultry market through primitive sales records, Nguyen-Van-Tam said the health agency was led to another smallholding -- so small that the birds were being raised inside the home.
Ducklings purchased around May 7 began getting ill and dying on May 10. By May 15, the pregnant resident and a male resident were hospitalized with influenza-like illnesses and both later tested positive for H7 disease.
With two such cases on record, authorities tried to find the dealer who sold the sick animals but had problems finding him on his farm on the Llyn Peninsula in Wales. That was because, Nguyen-Van-Tam said, the farmer had been hospitalized for five days with an influenza-like illness. He also tested positive for H7 disease.
Authorities then discovered another outbreak among hens purchased at Chelford May 7 at another smallholding in St. Helens in northwest England. The surviving birds tested positive for H7. However, the resident who had an influenza-like illness and his 3-year-old grandson who developed a fever both tested negative for H7.
Over the course of the investigation, people who had contacts with the birds or with the patients were treated with oseltamivir. Eventually that amounted to 369 individuals, 31 of whom had contacts with the birds.
Nguyen-Van-Tam said 23 people developed some form of influenza-like symptoms during the course of the investigation and cleanup. Fourteen of those individuals had secondary contact, but none showed immediate exposure to H7 virus.
Blood testing to further determine if there was spread of the disease is under way. Nguyen-Van-Tam said the investigation was even more difficult because the outbreaks occurred during the seasonal influenza outbreak, making it difficult to determine with sophisticated testing if the patients were infected by the seasonal bug or by avian flu.
"This was a challenging incident," Nguyen-Van-Tam said, "complicated in terms of time and space. No evidence of person-to-person transmission has been found, but serology tests are awaited."
Nguyen-Van-Tam also reported on efforts to contain an H5N1 outbreak in February on a turkey farm in Suffolk, England.
That outbreak was contained in three days, during which authorities slaughtered 160,000 turkeys and treated 482 people who worked on the large poultry farm or were from public health offices engaged in capturing the turkeys and euthanizing them.
The people exposed to the birds were treated with oseltamivir, but no human cases of H5N1 occurred in that incident.
Bird flu clusters on the increase
Scott McPherson
in influenza and infectious diseases
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This story appeared yesterday in the South China Morning Post. The story serves as confirmation of what we already knew; namely, that many cluster cases of H5N1 have indeed been documented by the WHO. Also, at least 20 per cent of the cases are believed to have involved limited human-to-human transmission, with the transmissibility ending with the third generation of transmission. This also means, in large part, that H2H transmission ended with the last death -- the virus died with the last death. The exception to this was the Sumatra cluster of May, 2006, where a male survived (photo at left) after spending nearly a full season in hospital and being continually pumped with Tamiflu. He still suffers brain damage, as the virus went after his brain as well as his lungs (a classic sign of a severe strain of influenza and hallmark of the 1918 virus).
I want to point out that FluTrackers.com and other Websites were accurately predicting and documenting this dramatic upswing in cluster cases all along. The collaboration contained within FluTrackers and other influenza-related Websites is hereby validated with this WHO report. Nice work, gang!
Mary Ann Benitez
South China Morning Post
Jun 18, 2007
The World Health Organisation is investigating clusters of bird flu cases which have been occurring increasingly since late 2005, a visiting WHO official said.
Forty-two clusters involving 111 people have been identified, with a mortality rate of 65 per cent. Ten out of 12 countries with human cases of bird flu have had at least one cluster.
The WHO concluded that limited human-to-human transmission could not be ruled out in 20 per cent of the clusters.
"We have to rule out human transmission. For that reason, clustering is very important for us in terms of catching a possible pandemic at the early stage," said Nikki Shindo, medical officer with the WHO's global influenza programme in Geneva.
She said sporadic cases of bird flu were expected, given that there were ongoing poultry outbreaks. So far, those clusters investigated have not progressed beyond the third generation of victims.
Takeshi Kasai, regional adviser in communicable diseases surveillance and response at the WHO western Pacific regional headquarters, said the latest assessment was that the risk for a pandemic remained the same as it had been since 2003.
The WHO officials were interviewed on the fringes of a closed-door workshop on outbreak communications, which ended on Friday.
The WHO has tried to determine why clusters of cases occurred.
"There are several hypotheses. One of them is that the infected family member has a genetic characteristic to get the disease more easily than the others. The other hypothesis is perhaps they had a heavier exposure than anybody else," Dr Shindo said.
There could also be some environmental factors at play, she said.
Ninety-two per cent of the cases involved blood relatives and 89 per cent were aged under 40. The index cases involved contact with sick or dying poultry. Many clusters had seen parent-to-child or sibling-to-sibling infections, but spouses infecting each other had not been seen.
Clusters involve two or more people who are epidemiologically linked. The largest cluster found, involving eight people, was in North Sumatra in May last year.
Today's Dilbert
Scott McPherson
in Information technology, influenza and infectious diseases
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OK, let's take a shot at this blogging thing.
Scott McPherson
in run of the mill stuff.....
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Despite my concerns that blogging is an essentially ego-driven process, I will take the plunge.
Why? because I, too, have an opinion on a dazzling array of topics. But I will never, ever render an opinion on anything I decide I am unqualified to discuss.
My opinions will cover several areas of speciality, including pandemic preparedness (yes, another "bird flu" blog, but this one is well-qualified!), popular culture, politics, information technology, and college football.
God help you all.
Scott
Worldview, June 14, 2007
Scott McPherson
in influenza and infectious diseases
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Events in both Egypt and Indonesia are troubling, and the situation in Wales continues to remind us that a pandemic needn't start in Guangdong, China.
In case you missed it, two young patients in the southern Nile region have been diagnosed with H5N1, and one has died. The death, a 10-year old girl, we the first death in the southern Nile region. This is significant, because previous H5N1 cases from that region were considered mild. That, in turn, led experts to believe the virus had mutated/recombined into a less lethal strain. In the meantime, the central and northern Nile delta continued to produce extremely lethal H5N1 cases, despite some focused response from the Egyptian government.
In Indonesia, meanwhile, we continue to get wildly mixed signals. Government authorities continually produce 40-point headlines, while the WHO comes in behind them and says, in effect, "Move along, nothing to see here, move along."
For example, an official disclosed recently that chickens were testing positive for H5N1 antibodies without exhibiting symptoms of the disease. That is remarkable, since the "symptoms" of H5N1 in poultry resemble Ebola in humans. Another official reported a few weeks ago that the H5N1 virus had significantly mutated and was becoming easier for humans to catch, due to changes in the receptor binding domain (hemagglutinin, or the "H" in influenza A). Think of those Velcro dart games with the ping pong ball. Hemagglutinin is the amino acid that allows the virus to "stick" to the walls of a throat, nasal passage or lung.
Other revelations coming from Indonesian scientists and officials include the discovery of cats as a possible vector (transmitter) of the disease. Jakarta television news accounts graphically showed Army forces and public health professionals grabbing and swabbing the throats of housecats all over the sprawling city. Bet you didn't see that on your local news!
Finally, in Wales, the "low path" H7N2 aftermath continues to show up in news accounts. Human cases seem to have peaked, but remember this axiom: If unchecked, low path bird flu goes in; high path bird flu comes out. British authorities may have successfully beaten back any further spread of H7N2, but it serves as a cautionary tale that pandemics, like 1732 and 1918, can start in the New World and not just the Old World.