tetano
Editor, Senior Moderator
Published Date: 2013-05-28 11:54:22
Subject: PRO/AH/EDR> Avian influenza (66): China, zoonotic LPAI H7N9, animal, RFI
Archive Number: 20130528.1741410
AVIAN INFLUENZA (66): CHINA, ZOONOTIC LPAI H7N9, ANIMAL, REQUEST FOR INFORMATION
********************************************************************************
A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org
In this posting:
[1] Investigation illuminates role of chickens in open markets
[2] Guangdong: tracing market infection to a chicken farm
******
[1] Investigation illuminates role of chickens in open markets
Date: Wed 22 May 2013
Source: New England Journal of Medicine, correspondence [summ., edited]
http://www.nejm.org/doi/full/10.1056/NEJMc1306100
[ref: Bao CJ, Cui LB, Zhou MH, et al. Live-animal markets and influenza A (H7N9) virus infection. N Engl J Med. 2013 May 22. [Epub ahead of print] DOI: 10.1056/NEJMc1306100]
----------------------------------------------------------------------
A recent outbreak of a previously unrecognized novel reassortant avian influenza A (H7N9) virus in China had resulted in 131 documented cases and 36 deaths as of 16 May 2013. Although some patients had a history of contact with live poultry or visiting live-animal markets before the onset of illness, the source of infection remains unclear.
A 45 year old woman was admitted to a hospital on 23 Mar 2013, with a 5-day history of fever (temperature, 41.0 deg C [105.8 deg F]), cough, expectoration, malaise, and shortness of breath. Computed tomography of the chest that was performed 2 days before admission showed infection in the right lung. On 28 Mar 2013, a specimen of tracheal secretion from the patient was collected for laboratory testing. Epidemiologic investigation showed that the patient was otherwise healthy except for a positive assay for hepatitis B surface antigen. She had worked for several years in a live-animal market as the sole poultry butcher. Her stall was located in a corner of the market (fig in supplementary appendix at http://www.nejm.org/doi/suppl/10.1056/NEJMc1306100/suppl_file/nejmc1306100_appendix.pdf). Except for the definite exposure from her working environment, she had had no contact with other animals or febrile patients. All the live poultry she slaughtered came from a neighboring stall (fig in the supplementary appendix). The live poultry had been purchased from a secondary wholesale market, where poultry raised on various farms were congregated before being sold to live-animal markets.
Laboratory investigation by means of various methods -- including real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay, viral isolation, and full-genome sequencing -- confirmed that the patient was infected with the novel H7N9 virus. To trace the possible source of infection, investigators collected 5 environmental samples from the 2 stalls in the market and 13 samples from the secondary wholesale market on 29 Mar 2013. One poultry-cage specimen from the neighboring stall was positive for the novel H7N9 virus. Furthermore, mixed avian-influenza viral nucleic acids (such as, subtypes H3, H7, N8, and N9) were detected on subtype-specific real-time RT-PCR from one feces sample collected from the secondary wholesale market.
Two viral strains, one from the patient (Nanjing/1) and one from poultry-cage specimens obtained in the neighboring stall (Env/Nanjing), were successfully isolated (GenBank numbers, KC896771-KC896778 for the case specimen and KC896763-KC896770 for the environmental specimen). Genome comparison showed that the similarity in the nucleic acids found in the 2 isolates ranged from 98.9 to 100 per cent; this would translate into an amino acid similarity of 98.2 to 100 per cent. Both isolates had potentially functional amino acid sites related to mammal- or human-adapting substitution T189A and Q226L (H3 numbering) in the receptor-binding site of hemagglutinin.
The 2 isolates showed E rather than K at position 627 of BP2. However, Nanjing/1 showed K rather than Q at position 591 of PB2, which has been shown to cooperate with position 627 of PB2, and the combination of 591K-627E showed higher virulence than that of 591Q-627E in mice with H5N1 viruses (Table S1 in the supplementary appendix).
These findings suggest that the novel virus had been evolving and might, with a few amino acid mutations, adapt to humans. Phylogenic analyses showed the M genes of the 2 isolates formed a unique sublineage, as compared with other available human H7N9 strains derived from avian H9N2 viruses, among others. This indicated that the novel H7N9 virus had varied origins and potentially had ongoing reassortment within poultry.
These data indicate that the novel H7N9 virus was most likely transmitted from the secondary wholesale market to the retail live-animal market and then to the patient. These findings echo those of a recent study (ref 1), which showed that human infections with the novel H7N9 virus had an epidemiologic association with chickens from live-animal markets. It is important to better understand the evolution of influenza viruses among poultry and transmission in live-animal markets to help control human infection.
Reference
---------
1. Chen Y, Liang W, Yang S, et al. Human infections with the emerging avian influenza A H7N9 virus from wet market poultry: clinical analysis and characterisation of viral genome. Lancet. 2013 Apr 25. pii: S0140-6736(13)60903-4. doi: 10.1016/S0140-6736(13)60903-4. [Epub ahead of print]
[See item [1] in ProMED-mail posting 20130429.1679734. - Mod.AS]
--
communicated by:
ProMED-mail
<promed@promedmail.org>
[For the affiliations of the authors, references, figures (including phylogenetic tree of full-length matrix protein (M) gene of novel H7N9 virus) and a supplementary appendix, please refer to the original paper at the source URL above.
The role played by the circulation of the H7N9 virus in open markets, most probably primarily carried by chickens, has been discussed in several earlier ProMED-mail postings. This subject has also been addressed by OIE's recent expert mission to China. They stated, in their concluding report of 30 Apr 2013: "The experts believe that live bird markets may play a key role in human and animal infections with H7N9 and that, even if the overall level of infection is relatively low (having not been detected yet in poultry farms), live bird markets provide an environment for amplification and maintenance of the H7N9 virus. Collaboration between human health and animal health sectors is useful to better understand transmission to humans." China's adopted policy in relation to biosecurity in live markets, even their (temporary) closure, seems to be perfectly on target; see also item [2]. - Mod.AS]
******
[2] Guangdong: tracing market infection to a chicken farm
Date: Sat 18 May 2013
Source: Wen Wei Po newspaper (Hong Kong) [in Chinese, trans. Rapp.DS, edited]
http://paper.wenweipo.com/2013/05/18/HK1305180014.htm
Guangdong Inspection and Quarantine Bureau yesterday [17 May 2013] revealed the source of the 1st H7 avian influenza sample found in Guangzhou's Zengcheng. Initial investigation shows that the chicken in question originally came from Mr Wen's Chicken Farm in Qianguan Township of Yunan County in Yunfu City. At the moment no chickens remain in this farm. Agricultural agencies have conducted disinfection of this farm and tested bird samples from nearby farms. Also, because Zengcheng has 2 farms which supply Hong Kong, Guangdong Inspection and Quarantine Bureau has stepped up supervision and testing. Up to now, no suspected cases of H7N9 or other avian influenzas have been found. Supply to Hong Kong has not been affected.
Zengcheng has already killed all chickens from the same source. 82 people who had close contact with the chickens are now undergoing health monitoring for a week. At the moment all tests for virus are turning up negative and there are no cases of infection. Mr Wen's Chicken Farm employs "all in, all out" raising methods and has no chickens on site at the moment and no cases of human infection. On 17 May 2013, Guangzhou Agricultural Bureau inspected 362 poultry farms and took 100 live poultry samples. H7N9 virus was not detected. For the moment all live poultry markets in Guangzhou have temporarily suspended operations.
--
communicated by:
ProMED-mail rapporteur Dan Silver
[ProMED-mail posting 20130522.1730662 included the following RFI: "The Zengcheng City Government said that the origin of the positive chicken has been verified and may be announced on 16 May 2013. ProMED-mail is not aware of a published verification of the origin of the positive chicken. Such information, if available, would be appreciated."
The information above, published by a Hong Kong newspaper, provides the missing information.
China's thorough efforts to trace back sources of infection, as also apparent from the published scientific correspondence in item 1, are impressive.
Any available information on experimental infection trials with the new, zoonotic, Chinese H7N9 virus, involving avian species such as chickens, quails, turkeys, ducks, pigeons, and/or other members of the vertebrate class _Aves_, will be much appreciated. - Mod.AS]
See Also
Avian influenza, human (83): China, H7N9 transmissibility in ferrets & pigs 20130524.1735447
Avian influenza (65): China (GD) zoonotic LPAI H7N9, animal, LBM, conf, OIE, RFI 20130522.1730662
Avian influenza (63): China, zoonotic LPAI H7N9, animal, update 20130517.1719324
Avian influenza (61): China (GD) zoonotic LPAI H7N9, animal, live bird market, susp. 20130516.1718130
Avian influenza (59): China, zoonotic LPAI H7N9, animal, update 20130515.1716159
Avian influenza (58): China, zoonotic LPAI H7N9, animal, prevention 20130514.1712913
Avian influenza (53): China (GD), zoonotic LPAI H7N9, animal, OIE 20130506.1695677
Avian influenza (48): China, zoonotic LPAI H7N9, animal, OIE 20130430.1683206
Avian influenza (47): China zoonotic LPAI H7N9, animal 20130429.1679734
Avian influenza (44): (China) zoonotic LPAI H7N9, animal, OIE, RFI 20130424.1670149
Avian influenza (43): (China) zoonotic LPAI H7N9, animal update 20130422.1664423
Avian influenza (41): (China) zoonotic LPAI H7N9, animal, RFI 20130420.1659952
Avian influenza (40): (China) zoonotic LPAI H7N9, source sought 20130418.1655718
Avian influenza, human (51): H7N9 update 20130418.1655610
Avian influenza (38): China, zoonotic LPAI H7N9, wild pigeon, OIE 20130417.1652959
Avian influenza (37): China, zoonotic LPAI H7N9, animals, RFI 20130414.1645731
Avian influenza (33): China (JS, ZH) LPAI H7N9, live markets, RFI 20130410.1636843
Avian influenza (30): China, H7N9, multiple market closures 20130407.1629270
Avian influenza (29): China H7N9, FAO, biosecurity 20130407.1628375
Avian influenza (28): China (SH) H7N9, OIE, update 20130405.1624901
Avian influenza, human (16): China (SH, AH) H7N9 WHO 20130401.1614707
Avian influenza, human (14): China (Shanghai, Anhui) H7N9, fatal 20130331.1612370
.................................................sb/arn/mj/sh
http://beta.promedmail.org/direct.php?id=20130528.1741410
Subject: PRO/AH/EDR> Avian influenza (66): China, zoonotic LPAI H7N9, animal, RFI
Archive Number: 20130528.1741410
AVIAN INFLUENZA (66): CHINA, ZOONOTIC LPAI H7N9, ANIMAL, REQUEST FOR INFORMATION
********************************************************************************
A ProMED-mail post
http://www.promedmail.org
ProMED-mail is a program of the
International Society for Infectious Diseases
http://www.isid.org
In this posting:
[1] Investigation illuminates role of chickens in open markets
[2] Guangdong: tracing market infection to a chicken farm
******
[1] Investigation illuminates role of chickens in open markets
Date: Wed 22 May 2013
Source: New England Journal of Medicine, correspondence [summ., edited]
http://www.nejm.org/doi/full/10.1056/NEJMc1306100
[ref: Bao CJ, Cui LB, Zhou MH, et al. Live-animal markets and influenza A (H7N9) virus infection. N Engl J Med. 2013 May 22. [Epub ahead of print] DOI: 10.1056/NEJMc1306100]
----------------------------------------------------------------------
A recent outbreak of a previously unrecognized novel reassortant avian influenza A (H7N9) virus in China had resulted in 131 documented cases and 36 deaths as of 16 May 2013. Although some patients had a history of contact with live poultry or visiting live-animal markets before the onset of illness, the source of infection remains unclear.
A 45 year old woman was admitted to a hospital on 23 Mar 2013, with a 5-day history of fever (temperature, 41.0 deg C [105.8 deg F]), cough, expectoration, malaise, and shortness of breath. Computed tomography of the chest that was performed 2 days before admission showed infection in the right lung. On 28 Mar 2013, a specimen of tracheal secretion from the patient was collected for laboratory testing. Epidemiologic investigation showed that the patient was otherwise healthy except for a positive assay for hepatitis B surface antigen. She had worked for several years in a live-animal market as the sole poultry butcher. Her stall was located in a corner of the market (fig in supplementary appendix at http://www.nejm.org/doi/suppl/10.1056/NEJMc1306100/suppl_file/nejmc1306100_appendix.pdf). Except for the definite exposure from her working environment, she had had no contact with other animals or febrile patients. All the live poultry she slaughtered came from a neighboring stall (fig in the supplementary appendix). The live poultry had been purchased from a secondary wholesale market, where poultry raised on various farms were congregated before being sold to live-animal markets.
Laboratory investigation by means of various methods -- including real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay, viral isolation, and full-genome sequencing -- confirmed that the patient was infected with the novel H7N9 virus. To trace the possible source of infection, investigators collected 5 environmental samples from the 2 stalls in the market and 13 samples from the secondary wholesale market on 29 Mar 2013. One poultry-cage specimen from the neighboring stall was positive for the novel H7N9 virus. Furthermore, mixed avian-influenza viral nucleic acids (such as, subtypes H3, H7, N8, and N9) were detected on subtype-specific real-time RT-PCR from one feces sample collected from the secondary wholesale market.
Two viral strains, one from the patient (Nanjing/1) and one from poultry-cage specimens obtained in the neighboring stall (Env/Nanjing), were successfully isolated (GenBank numbers, KC896771-KC896778 for the case specimen and KC896763-KC896770 for the environmental specimen). Genome comparison showed that the similarity in the nucleic acids found in the 2 isolates ranged from 98.9 to 100 per cent; this would translate into an amino acid similarity of 98.2 to 100 per cent. Both isolates had potentially functional amino acid sites related to mammal- or human-adapting substitution T189A and Q226L (H3 numbering) in the receptor-binding site of hemagglutinin.
The 2 isolates showed E rather than K at position 627 of BP2. However, Nanjing/1 showed K rather than Q at position 591 of PB2, which has been shown to cooperate with position 627 of PB2, and the combination of 591K-627E showed higher virulence than that of 591Q-627E in mice with H5N1 viruses (Table S1 in the supplementary appendix).
These findings suggest that the novel virus had been evolving and might, with a few amino acid mutations, adapt to humans. Phylogenic analyses showed the M genes of the 2 isolates formed a unique sublineage, as compared with other available human H7N9 strains derived from avian H9N2 viruses, among others. This indicated that the novel H7N9 virus had varied origins and potentially had ongoing reassortment within poultry.
These data indicate that the novel H7N9 virus was most likely transmitted from the secondary wholesale market to the retail live-animal market and then to the patient. These findings echo those of a recent study (ref 1), which showed that human infections with the novel H7N9 virus had an epidemiologic association with chickens from live-animal markets. It is important to better understand the evolution of influenza viruses among poultry and transmission in live-animal markets to help control human infection.
Reference
---------
1. Chen Y, Liang W, Yang S, et al. Human infections with the emerging avian influenza A H7N9 virus from wet market poultry: clinical analysis and characterisation of viral genome. Lancet. 2013 Apr 25. pii: S0140-6736(13)60903-4. doi: 10.1016/S0140-6736(13)60903-4. [Epub ahead of print]
[See item [1] in ProMED-mail posting 20130429.1679734. - Mod.AS]
--
communicated by:
ProMED-mail
<promed@promedmail.org>
[For the affiliations of the authors, references, figures (including phylogenetic tree of full-length matrix protein (M) gene of novel H7N9 virus) and a supplementary appendix, please refer to the original paper at the source URL above.
The role played by the circulation of the H7N9 virus in open markets, most probably primarily carried by chickens, has been discussed in several earlier ProMED-mail postings. This subject has also been addressed by OIE's recent expert mission to China. They stated, in their concluding report of 30 Apr 2013: "The experts believe that live bird markets may play a key role in human and animal infections with H7N9 and that, even if the overall level of infection is relatively low (having not been detected yet in poultry farms), live bird markets provide an environment for amplification and maintenance of the H7N9 virus. Collaboration between human health and animal health sectors is useful to better understand transmission to humans." China's adopted policy in relation to biosecurity in live markets, even their (temporary) closure, seems to be perfectly on target; see also item [2]. - Mod.AS]
******
[2] Guangdong: tracing market infection to a chicken farm
Date: Sat 18 May 2013
Source: Wen Wei Po newspaper (Hong Kong) [in Chinese, trans. Rapp.DS, edited]
http://paper.wenweipo.com/2013/05/18/HK1305180014.htm
Guangdong Inspection and Quarantine Bureau yesterday [17 May 2013] revealed the source of the 1st H7 avian influenza sample found in Guangzhou's Zengcheng. Initial investigation shows that the chicken in question originally came from Mr Wen's Chicken Farm in Qianguan Township of Yunan County in Yunfu City. At the moment no chickens remain in this farm. Agricultural agencies have conducted disinfection of this farm and tested bird samples from nearby farms. Also, because Zengcheng has 2 farms which supply Hong Kong, Guangdong Inspection and Quarantine Bureau has stepped up supervision and testing. Up to now, no suspected cases of H7N9 or other avian influenzas have been found. Supply to Hong Kong has not been affected.
Zengcheng has already killed all chickens from the same source. 82 people who had close contact with the chickens are now undergoing health monitoring for a week. At the moment all tests for virus are turning up negative and there are no cases of infection. Mr Wen's Chicken Farm employs "all in, all out" raising methods and has no chickens on site at the moment and no cases of human infection. On 17 May 2013, Guangzhou Agricultural Bureau inspected 362 poultry farms and took 100 live poultry samples. H7N9 virus was not detected. For the moment all live poultry markets in Guangzhou have temporarily suspended operations.
--
communicated by:
ProMED-mail rapporteur Dan Silver
[ProMED-mail posting 20130522.1730662 included the following RFI: "The Zengcheng City Government said that the origin of the positive chicken has been verified and may be announced on 16 May 2013. ProMED-mail is not aware of a published verification of the origin of the positive chicken. Such information, if available, would be appreciated."
The information above, published by a Hong Kong newspaper, provides the missing information.
China's thorough efforts to trace back sources of infection, as also apparent from the published scientific correspondence in item 1, are impressive.
Any available information on experimental infection trials with the new, zoonotic, Chinese H7N9 virus, involving avian species such as chickens, quails, turkeys, ducks, pigeons, and/or other members of the vertebrate class _Aves_, will be much appreciated. - Mod.AS]
See Also
Avian influenza, human (83): China, H7N9 transmissibility in ferrets & pigs 20130524.1735447
Avian influenza (65): China (GD) zoonotic LPAI H7N9, animal, LBM, conf, OIE, RFI 20130522.1730662
Avian influenza (63): China, zoonotic LPAI H7N9, animal, update 20130517.1719324
Avian influenza (61): China (GD) zoonotic LPAI H7N9, animal, live bird market, susp. 20130516.1718130
Avian influenza (59): China, zoonotic LPAI H7N9, animal, update 20130515.1716159
Avian influenza (58): China, zoonotic LPAI H7N9, animal, prevention 20130514.1712913
Avian influenza (53): China (GD), zoonotic LPAI H7N9, animal, OIE 20130506.1695677
Avian influenza (48): China, zoonotic LPAI H7N9, animal, OIE 20130430.1683206
Avian influenza (47): China zoonotic LPAI H7N9, animal 20130429.1679734
Avian influenza (44): (China) zoonotic LPAI H7N9, animal, OIE, RFI 20130424.1670149
Avian influenza (43): (China) zoonotic LPAI H7N9, animal update 20130422.1664423
Avian influenza (41): (China) zoonotic LPAI H7N9, animal, RFI 20130420.1659952
Avian influenza (40): (China) zoonotic LPAI H7N9, source sought 20130418.1655718
Avian influenza, human (51): H7N9 update 20130418.1655610
Avian influenza (38): China, zoonotic LPAI H7N9, wild pigeon, OIE 20130417.1652959
Avian influenza (37): China, zoonotic LPAI H7N9, animals, RFI 20130414.1645731
Avian influenza (33): China (JS, ZH) LPAI H7N9, live markets, RFI 20130410.1636843
Avian influenza (30): China, H7N9, multiple market closures 20130407.1629270
Avian influenza (29): China H7N9, FAO, biosecurity 20130407.1628375
Avian influenza (28): China (SH) H7N9, OIE, update 20130405.1624901
Avian influenza, human (16): China (SH, AH) H7N9 WHO 20130401.1614707
Avian influenza, human (14): China (Shanghai, Anhui) H7N9, fatal 20130331.1612370
.................................................sb/arn/mj/sh
http://beta.promedmail.org/direct.php?id=20130528.1741410