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Published Date: 2012-01-03 17:51:44
Subject: PRO/AH/EDR> Avian influenza, human (02): China (GD) H5N1
Archive Number: 20120103.0018

AVIAN INFLUENZA, HUMAN (02): CHINA (GUANGDONG) H5N1
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Date: Tue 3 Jan 2012
Source: The Standard [edited]
http://www.thestandard.com.hk/news_detail.asp?we_cat=11&art_id=118460&sid=34949960&con_type=1&d_str=20120103&fc=1

Bird flu fears spread last night [2 Jan 2012] after Shenzhen experts revealed the virus that killed a bus driver is similar to the one found in a dead migratory bird in Yuen Long last month [December 2011]. Health officials are racing to track down the source of the [mutant ?] H5N1 amid growing fears. The 39-year-old Shenzhen driver died on Saturday [31 Dec 2011] in the 1st reported case of bird flu in a human in 18 months in China.

Hong Kong has declared a "control zone" banning the import of live and frozen chickens and poultry products from inside a 13-kilometer [8 mi] radius of the driver's home in the Shaijing area of Baoan district. The ban will be effective until 21 Jan 2012 -- 2 days before Lunar New Year [celebration].

The Shenzhen Centre for Disease Control said initial genetic analysis shows the virus that killed the man is similar to that in the Yuen Long bird. However, the genes of the virus that killed him are not as close to the virus found in dead poultry in Hong Kong, the centre added. The virus found on the victim is H5N1 clade 2.3.2.1. The center said that although the mutated [?] virus is highly pathogenic, it cannot be spread from human to human so people do not need to panic.

Further analysis is under way to confirm whether [the bus driver] caught the virus through wild birds. There is no evidence that suggests this virus is more contagious or deadly," said centre officer Wu Chunli. "Natural mutations happen in all flu viruses."

The victim developed a fever on 21 Dec 2011 and was sent to hospital on 25 Dec 2011 with severe pneumonia. On Saturday [31 Dec 2011] he was confirmed to have H5N1. The center said earlier that Chen regularly visited the wetland at Waterlands Resort for morning exercise. About 120 people who had close contact with him have not developed any abnormal symptoms, health authorities said.

The Guangdong Department of Agriculture announced on Saturday that no epidemic of bird flu among poultry has been reported in the province. Hong Kong infectious diseases specialist Lo Wing-lok criticized the center's report as "confusing" and "nonsense." Lo said: "They cannot say that the virus is similar to that found in wild birds and say the man may have contracted the virus from wild birds. There is no evidence in the whole world that suggests people contract H5N1 through wild birds. It is always through poultry. Does that mean the virus simply fell from the sky?"

Lo said H5N1 clade 2.3.2.1. is found in many H5N1 cases and is not especially deadly. He said further analysis is needed to compare this virus with that found on a dead chicken in Cheung Sha Wan last month [December 2011]. But Lo stressed mutation does not mean it is more deadly because flu viruses always mutate naturally. He called on people to wash their hands after handling live chickens and to cook them thoroughly before consumption.

The government said on 20 Dec 2011 that Hong Kong would have no live chicken supplies for 21 days after a dead chicken at the Cheung Sha Wan poultry market was found to have H5N1. The government culled 19 451 birds at the market, including 15 569 chickens.

[Byline: Phila Siu]

-- Communicated by: ProMED-mail Rapporteur Mary Marshall

[This report does not add much clarification, apart from the information that the deceased Shenzhen driver had a habit of spending time at the wetland of the Waterlands Resort. However, Dr Lo Wing-lok's strictures regarding the use of the term 'mutant' are relevant.

Readers' attention is draw to an 'Original Paper' newly compiled by FluTrackers.com, entitled: "A Summary of Worldwide Human H5N1 Cases in 2011", that is fully sourced including charts, graphs, and maps, all or part of which may be freely reproduced (see http://www.flutrackers.com/forum/showthread.php?t=179069).

The Abstract reads: "In 2011, 59 human cases of H5N1 were reported from around the world, a 23 percent increase over 2010. 5 countries reported cases in 2011, Bangladesh, Cambodia, China, Egypt, and Indonesia. Almost half of the 59 cases (about 45 percent) were children under 10 years old. The fatality rate did not appreciably decline in 2011, about half of all the reported cases died. 4 small family clusters were noted during the year. The source of exposure for all of the cluster cases has been reported as exposure to sick and dying poultry. None of these clusters resulted in sustained human-to-human transmission. Based on an analysis of the 2011 data, the potential for a virulent H5N1 pandemic has not diminished."

The document begins: "The big H5N1 news of 2011 was the bioethical debate surrounding the publication of the details of genetic research by 2 groups of scientists who were able to create a laboratory strain of H5N1 that maintained its virulence and was easily transmissible [among ferrets] in aerosolized droplets. A few of the many media reports and commentaries are referenced in this FluTrackers report [http://www.flutrackers.com/forum/showthread.php?t=177126]. Equally as important, but without the accompanying media hype, is that there was a 23 percent increase in the number of worldwide H5N1 human cases over the number of cases in 2010. In 2011, at least 59 cases were recorded; in 2010 the total was only 48. The following summary of human cases from 2011 is generally organized according to the outlined presented last year in "A Summary of Human H5N1 Cases in 2010" (http://www.flutrackers.com/forum/showthread.php?t=157504).

Perhaps of greatest interest is the section on High H5N1 Infection Rates Among Small Children. "Since 2009, there has been an observable trend of an increasing number of H5N1 infections among very young children. This should not be surprising since H5N1 is a novel influenza virus, and young children are more susceptible to influenza viruses in general. What is surprising is the recovery rate (that is, low CFR) for this age group. As virulent as H5N1 is, many of the infected children survive. The children survive at a much higher rate than their infected adult counterparts. These children would not have time to build up cross-protective immunity, so the recovery process for these young people is worthy of further study. Also, most of these child infections do not occur in family clusters so questions arise about the exposure source for these children. What is the nature of contact between exposed poultry and these young children? Is there a mild asymptomatic strain of H5N1 circulating in some countries?" But perhaps there is greater resort to treatment with neuraminidase inhibitors in the case of young children?

The original diagrams in this paper provide an elegant and easily assimilable condensation of the information contained in the text. - Mod.CP]

[The HealthMap/ProMED-mail interactive map of Shenzhen can be found at http://healthmap.org/r/1B7i. - Mod.MPP]

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