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H7N9, China: Guangzhou Zengcheng detected H7 virus in chicken samples (Ifeng, May 15 2013)

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  • H7N9, China: Guangzhou Zengcheng detected H7 virus in chicken samples (Ifeng, May 15 2013)

    [Source: Ifeng, full text in Chinese: (LINK). Automatic translation.]
    H7N9, China: Guangzhou Zengcheng detected H7 virus in chicken samples

    2013 05 15, 2011 23:22 Source: China News


    China news agency, Guangzhou, May 15 - (Cheng Jingwei Zhang Branch), Guangzhou City, 15, the agricultural sector poultry samples collected from the increase in the city Licheng R & F market on a poultry sales stalls detect abnormality was found, was sent to Guangdong Province, the agricultural sector. The re-examination found a chicken samples detected suspected H7 subtype avian influenza virus (in accordance with the procedure needed to serve the country the poultry influenza reference laboratory-confirmed).

    The night of the Guangzhou city by the prevention and control of human infection of H7N9 avian influenza Leading Group Office informed that the poultry sales stalls practitioners do not have clinical symptoms, yet found infection.

    In accordance with the deployment of the Guangzhou Municipal Bureau of Agriculture to carry out emergency prevention and control work in conjunction with the Guangzhou Municipal Health Bureau, Zengcheng municipal government quickly organized the implementation of the emergency temporary blockade, Zengcheng Licheng R & F market closed, thoroughly disinfected involved in poultry culling and victims processing, the market of poultry stalls practitioners and close contacts to carry out a seven-day health monitoring.

    After receiving the report, Zengcheng City, Guangzhou launched four emergency response for epidemic prevention and control, the emergency temporary control the Licheng R & F market, closed to control the market poultry transported strictly limited venue all animals transferred to tune out; mobilization of emergency epidemic prevention materials disinfectants, protective equipment and emergency call from the animal disease prevention and control of emergency material storage processing materials, and the implementation of a comprehensive cleaning and disinfection of the market.

    At the same time, the Guangzhou strengthen quarantine and monitoring of the city's major wholesale poultry market, strict implementation of the Wholesale Poultry Market regularly closed system, increase market cleansing and disinfection frequency. (End)
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  • #2
    Re: H7N9, China: Guangzhou Zengcheng detected H7 virus in chicken samples (Ifeng, May 15 2013)

    Published Date: 2013-05-17 11:25:01
    Subject: PRO/AH/EDR> Avian influenza (63): China, zoonotic LPAI H7N9, animal, update
    Archive Number: 20130517.1719324

    AVIAN INFLUENZA (63): CHINA, ZOONOTIC LPAI H7N9, ANIMAL, UPDATE
    ************************************************** *************
    A ProMED-mail post
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    In this update:

    [1] Control measures, export halt, Guangdong
    [2] Link between exposure to poultry and human infection (paper)

    ******
    [1] Control measures, export halt, Guangdong
    Date: Fri 17 May 2013
    Source: South China Morning Post, HK [edited]



    Exports from a Guangzhou poultry farm have been suspended after the bird flu virus was found in a nearby market.

    The Centre for Food Safety said it learned from the Guangdong Entry-Exit Inspection and Quarantine Bureau that an H7 subtype of the virus was found in a poultry sample taken from a market stall in Zengcheng on Wed [15 May 2013].

    Poultry from the registered farm, located within a 13-km radius of the market, tested negative for the virus. But the Guangzhou health authorities temporarily suspended exports of the farm's live poultry and other products -- including frozen poultry and eggs -- to Hong Kong [A confirmation of the term "frozen" will be appreciated. -Mod.AS].

    Currently, all live poultry from the mainland have to come from registered farms and pass the test for bird flu before being exported. Since 11 Apr 2013, samples of the mainland's live poultry also undergo H7 tests at the Man Kam To Animal Inspection Station when they enter Hong Kong. None of the samples so far have tested positive for the virus.

    If the sample collected from the market in Licheng town, Zengcheng tests positive for H7N9, it would be the 2nd discovery of the fatal strain of bird flu in Guangdong.

    Last month [April 2013], one sample out of 130 collected from poultry in a wholesale market in the province's Dongguan city -- about 90 km from Hong Kong -- tested positive for the H7 subtype of the virus. But no human infection of the virus has so far been found in Guangdong province.

    Former government veterinary officer Howard Wong Kai-hay said all live poultry from the mainland should be banned for 21 days to give time for tests on other registered farms.

    [Byline: Danny Mok]

    --
    Communicated by:
    ProMED-mail Rapporteur Dan Silver

    ******
    [2] Link between exposure to poultry and human infection (paper)
    Date: Thu 16 May 2013
    Source: Eurosurveillance, Volume 18, Issue 20, article 2 - rapid communications [summarised, edited]
    We analysed the association between influenza A(H7N9) confirmed cases and exposure to poultry in Huzhou city, China. All cases (n=12) had a history of direct exposure to poultry or live poultry markets. We detected A(H7N9)-positive poultry samples from each site that was epidemiologically associated with cases. None of the cases' close contacts tested positive. After closure of the markets, no new cases were identified, suggesting an epidemiological link between poultry exposure and A(H7N9) virus infection. .



    Epidemiological link between exposure to poultry and all influenza A(H7N9) confirmed cases in Huzhou city, China, March to May 2013. J Han, M Jin, P Zhang, J Liu, L Wang, D Wen, X Wu, G Liu, Y Zou, X Lv, X Dong, B Shao, S Gu, D Zhou, Q Leng, C Zhang, K Lan.

    1. Summary
    -----------
    We analysed the association between influenza A(H7N9) confirmed cases and exposure to poultry in Huzhou city, China. All cases (n=12) had a history of direct exposure to poultry or live poultry markets. We detected A(H7N9)-positive poultry samples from each site that was epidemiologically associated with cases. None of the cases' close contacts tested positive. After closure of the markets, no new cases were identified, suggesting an epidemiological link between poultry exposure and A(H7N9) virus infection.

    2. All cases had a history of exposure to poultry before symptom onset.
    ---------------------------------------
    Nine of the 12 cases had visited nearby live poultry markets at least once (range: 1-10 times) during the 10 days before symptom onset [Table 1; see at the original paper at source URL]. Of these 9 cases, 4 (Cases 4, 5, 6, and 8) had had direct contact with live poultry during this time. Although 3 patients had not visited poultry markets, they all had a history of direct contact with live poultry during the 10 days before symptom onset. Case 7 was exposed to live poultry as part of a government campaign to cull poultry at live poultry markets. Case 9 and her neighbour had purchased 12 chickens from a chicken vendor and had raised them in the same courtyard for about 20 days. Case 9 killed her 7 chickens when she found that one of them had become ill. For Case 11, her husband purchased 4 live chickens from a market on 8 Apr 2013 and raised them at home. On 10 Apr 2013, because the chickens developed an acute illness, the patient gave them antibiotics.

    3. Influenza A(H7N9) viral RNA was detected in all poultry markets visited by cases.
    ---------------------------------------
    In total, 9 live poultry markets were epidemiologically associated with the patients [Table 1, Figure 1; see in the original paper at source URL]. Therefore, we collected poultry faeces, waste and sewage from these markets to test for the presence of A(H7N9) viral RNA. We also collected throat and anal swabs and faeces from the chickens raised by the neighbour of Case 9 and chicken faeces from the house of Case 11. Of the 135 samples obtained, 38 samples were positive. Of particular note, A(H7N9) viral RNA was detected in samples from all 9 markets as well as those from the courtyard of Case 9 and the house of Case 11.

    In addition, we expanded our surveillance to 7 other nearby live poultry markets that the cases had not visited. Of 75 samples tested, 23 were positive for A(H7N9) viral RNA.

    We also collected throat swabs from the close contacts (n=339) of the 12 patients. Among 339 samples, none tested positive for A(H7N9) viral RNA, indicating no human-to-human transmission of the virus.

    4. Discussion
    -----------
    Previous studies have suggested that several mutations in the HA might be involved in the acquisition of the ability of the A(H7N9) virus to infect humans, and genetic evidence indicates that poultry is the reservoir of the virus. However, preliminary observations that not all patients have had a history of exposure to poultry raise the controversial issue of the source and transmission route of the A(H7N9) virus.

    Our results provide epidemiological evidence to support the hypothesis that A(H7N9) virus-infected poultry are a transmission source. A total of 139 live poultry markets (including those tested) in the 5 districts or counties in Huzhou city were closed sequentially, from 11-21 Apr 2013 [Table 2; see in the original paper at source URL]. As of 15 May 2013, no new cases have been identified in Huzhou city (p less than 0.01). Although based on small case numbers, our findings support the view that poultry are a crucial transmission source and also indicate that closing live poultry markets in affected areas is an effective strategy to stop the outbreak.

    With respect to the absence of reported poultry exposures in some patients (n=18) in a previous study, we can suggest 2 possible explanations arising from our findings:
    (i) some patients may have forgotten some details of their exposure history by the time the epidemiological investigation was carried out; or
    (ii) some patients may have been unable to provide timely and reliable information due to their serious clinical conditions.

    It may, therefore, be possible that patients with no documented exposure may have in fact been exposed to poultry.

    We tested 339 throat swabs from the cases' close contacts, but none tested positive for the A(H7N9) viral RNA, suggesting that these patients did not spread the virus to their close contacts. Although throat swabs may not be as often positive as deep sputum samples, we did not collect sputum samples from these close contacts because they had no obvious symptoms. Most patients (n=9) were aged 50 years or older, consistent with the nationwide data (78/107). Distinct from the nationwide data, however, 2/3rds (8/12) of the cases in Huzhou city were female (nationwide data: 32/106). This could possibly be due to the fact that in Huzhou city, housewives are mainly responsible for buying food, such as meat or vegetables, in local markets. It should also be borne in mind that most of the cases (n=10) had chronic underlying conditions. Whether an individual's health status is associated with susceptibility to A(H7N9) virus infection remains to be proved.

    Although an earlier study found that some live poultry markets tested positive, only a few poultry vendors (n=4) were found to be infected with the virus. Why most vendors remained infection-free despite extremely frequent exposure to infected poultry is also unclear. Whether there is some pre-existing cross-reactive immunity which enhances the susceptibility of patients to A(H7N9) virus infection or prevents poultry vendors from infection needs to be determined.

    --
    Communicated by:
    ProMED-mail
    <promed@promedmail.org>

    [The above detailed observations from Huzhou city, Zhejiang province (map at http://tinyurl.com/bq75fo7) add supportive circumstantial evidence to the role attributed to poultry as a source of human A/H7N9 infection in Eastern China, while underlining the significance of the poultry's history of movement into/through live poultry markets. The origin and epidemiology of the virus on the markets, including hypothetical involvement of migratory birds and/or other animals, remain to be clarified, as well as the reported, enigmatic absence of infection in poultry vendors. - Mod.AS

    A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1zaU, http://healthmap.org/r/1zaU.]

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    .................................................a rn/msp/mpp

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