Epidemiology and Infection

Original Papers

Respiratory infection

Serosurveillance study on transmission of H5N1 virus during a 2006 avian influenza epidemic

M. CEYHANa1 c1, I. YILDIRIMa2, O. FERRARISa3, M. BOUSCAMBERT-DUCHAMPa3, E. FROBERTa3, N. UYARa4, H. TEZERa1, A. F. ONERa5, T. BUZGANa6, M. A. TORUNOGLUa6, B. OZKANa7, R. YILMAZa8, M. G. KURTOGLUa9, Y. LALELIa4, S. BADURa10 and B. LINAa3

a1 Hacettepe University, School of Medicine, Department of Pediatric Infectious Diseases, Ankara, Turkey

a2 Boston University, Schools of Medicine and Public Health, Departments of Pediatric Infectious Diseases and Epidemiology, Boston, MA, USA

a3 Centre National de Référence des Virus Influenza, Région Sud, Groupement Hospitalier Est, Hospices Civils de Lyon, & VirPath, CNRS FRE 3011, Université de Lyon, Lyon, France

a4 Duzen Laboratory Group, Ankara, Turkey

a5 Van 100. Yil University, School of Medicine, Department of Pediatrics, Van, Turkey

a6 Ministry of Health, General Directorate of Primary Health Care Services, Ankara, Turkey

a7 Ataturk University, School of Medicine, Department of Pediatrics, Erzurum, Turkey

a8 GOP University, Department of Pediatrics, Tokat, Turkey

a9 Directorate of Health, Van, Turkey

a10 Istanbul University, School of Medicine, Department of Microbiology, Istanbul, Turkey

SUMMARY

In 2006 an outbreak of avian influenza A(H5N1) in Turkey caused 12 human infections, including four deaths. We conducted a serological survey to determine the extent of subclinical infection caused by the outbreak. Single serum samples were collected from five individuals with avian influenza whose nasopharyngeal swabs tested positive for H5 RNA by polymerase chain reaction, 28 family contacts of the cases, 95 poultry cullers, 75 individuals known to have had contact with diseased chickens and 81 individuals living in the region with no known contact with infected chickens and/or patients. Paired serum samples were collected from 97 healthcare workers. All sera were tested for the presence of neutralizing antibodies by enzyme-linked immunoassay, haemagglutination inhibition and microneutralization assays. Only one serum sample, from a parent of an avian influenza patient, tested positive for H5N1 by microneutralization assay. This survey shows that there was minimal subclinical H5N1 infection among contacts of human cases and infected poultry in Turkey in 2006. Further, the low rate of subclinical infection following contact with diseased poultry gave further support to the reported low infectivity of the virus.

(Accepted December 16 2009)

(Online publication January 22 2010)

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