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Volume 23, Number 2—February 2017

Seroprevalence and Transmission of Human Influenza A(H5N1) Virus before and after Virus Reassortment, Cambodia, 2006–2014

Sowath Ly, Paul F. Horwood, Malen Chan, Sareth Rith, Sopheak Sorn, Kunthea Oeung, Kunthy Nguon, Siam Chan, Phalla Y, Amy Parry, Reiko Tsuyuoka, Sovann Ly, Beat Richner, Denis Laurent, Sirenda Vong, Philippe Dussart, Philippe Buchy, and Arnaud TarantolaComments to Author 
Author affiliations: Institut Pasteur du Cambodge, Phnom Penh, Cambodia (S. Ly, P. Horwood, M. Chan, P. Y, S. Rith, S. Sorn, K. Oeung K. Nguon, S. Chan, S. Vong, P. Dussart,, P. Buchy, A. Tarantola); World Health Organization, Phnom Penh (A. Parry, R. Tsuyuoka); Ministry of Health, Phnom Penh (S. Ly); Kantha Bopha Children's Hospitals, Siem Reap and Phnom Penh, Cambodia (B. Richner, D. Laurent); GSK Vaccines R&D, Singapore (P. Buchy)

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Seroprevalence of influenza A(H5N1) virus in affected villages (excluding index cases), Cambodia, 2005–2014*

Reference Country, population type Year Clade Testing method Village population No. positive/no. tested % Positive (95% CI)†
(5) Cambodia, villagers 2005 1 MN, WB 1,146 0/351 0 (0–0.01)
(6) Cambodia villagers 2006 1 MN 1,192 7/674 1.0 (0–2.2)
(2) Cambodia villagers 2007 1.1.1 MN, HI 847 18/700 2.6 (0.2–4.1)
Unpub. data Cambodia, villagers 2009 1.1.1 MN, HI 927 10/622 1.6 (0.9–3.0)
Unpub. data Cambodia, villagers 2010 1.1.2 MN, HI 452 0/366 0 (0–0.01)
This study Cambodia, villagers 2014 1.1.2R‡ MN, HI 695 1/238 0.4 (0.1–3.0)
This study Cambodia, villagers 2014 1.1.2R‡ MN, HI 921 1/643 0.1 (0.0–1.1)
Cambodia, 2004–2010 studies 4,564 35/2,713 1.3 (0.9–1.8)
Cambodia, 2014 1,616 2/881 0.2 (0.1–0.9)
Cambodia, all studies 2004–2014 6180 37/3,594 1.0 (0.7–1.4)

*Positive results were determined by using World Health Organization criteria. HI, hemagglutination inhibition assay; MN, microneutralization assay; WB, Western blot.
†Poisson interval. An additional study conducted in 2008 in Cambodia focused on 394 soldiers (majority), support personnel, and their families in a confirmed H5N1 virus hotspot. No infections were found (prevalence 0%; 95% CI 0.0%–0.01%). The collective exposure was different from previous studies (soldiers had little or no exposure to poultry), so these data were not included in the table.
‡Clade 1.1.2 reassortant strain with internal and matrix genes originating from clade

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  1. Rith  S, Davis  CT, Duong  V, Sar  B, Horm  SV, Chin  S, et al. Identification of molecular markers associated with alteration of receptor-binding specificity in a novel genotype of highly pathogenic avian influenza A(H5N1) viruses detected in Cambodia in 2013. J Virol. 2014;88:13897909. DOIPubMedGoogle Scholar
  2. Cavailler  P, Chu  S, Ly  S, Garcia  JM. Ha do Q, Bergeri I, et al. Seroprevalence of anti-H5 antibody in rural Cambodia, 2007. J Clin Virol. 2010;48:123–6.
  3. Buchy  P, Vong  S, Chu  S, Garcia  JM, Hien  TT, Hien  VM, et al. Kinetics of neutralizing antibodies in patients naturally infected by H5N1 virus. PLoS One. 2010;5:e10864. DOIPubMedGoogle Scholar
  4. Trock  SC, Burke  SA, Cox  NJ. Development of framework for assessing influenza virus pandemic risk. Emerg Infect Dis. 2015;21:13728. DOIPubMedGoogle Scholar
  5. Vong  S, Coghlan  B, Mardy  S, Holl  D, Seng  H, Ly  S, et al. Low frequency of poultry-to-human H5NI virus transmission, southern Cambodia, 2005. Emerg Infect Dis. 2006;12:15427. DOIPubMedGoogle Scholar
  6. Wang  M, Di  B, Zhou  DH, Zheng  BJ, Jing  H, Lin  YP, et al. Food markets with live birds as source of avian influenza. Emerg Infect Dis. 2006;12:17735. DOIPubMedGoogle Scholar
  7. Wang  X, Fang  S, Lu  X, Xu  C, Cowling  BJ, Tang  X, et al. Seroprevalence to avian influenza A(H7N9) virus among poultry workers and the general population in southern China: a longitudinal study. Clin Infect Dis. 2014;59:e7683. DOIPubMedGoogle Scholar
  8. Wang  Y, Kong  WH, Zhu  HH, Luo  TY, Lin  XM, Yu  B, et al. [Investigation on the distribution of avian influenza virus in external environment and the level of H5N1 antibody in poultry-exposed population in Wuhan]. Zhonghua Yu Fang Yi Xue Za Zhi. 2011;45:10825.DOIPubMedGoogle Scholar
  9. Horm  SV, Sorn  S, Allal  L, Buchy  P. Influenza A(H5N1) virus surveillance at live poultry markets, Cambodia, 2011. Emerg Infect Dis. 2013;19:3058. DOIPubMedGoogle Scholar
  10. Horm  SV, Tarantola  A, Rith  S, Ly  S, Gambaretti  J, Duong  V, et al. Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections. Emerg Microbes Infect. 2016;5:e70. DOIPubMedGoogle Scholar
  11. Chea  N, Yi  SD, Rith  S, Seng  H, Ieng  V, Penh  C, et al. Two clustered cases of confirmed influenza A(H5N1) virus infection, Cambodia, 2011. Euro Surveill. 2014;19:20839. DOIPubMedGoogle Scholar
  12. Qin  Y, Horby  PW, Tsang  TK, Chen  E, Gao  L, Ou  J, et al. Differences in the Epidemiology of Human Cases of Avian Influenza A(H7N9) and A(H5N1) Viruses Infection. Clin Infect Dis. 2015;61:56371. DOIPubMedGoogle Scholar

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Page updated: January 17, 2017
Page reviewed: January 17, 2017
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