Epidemiology and Infection

Nipah and other viruses

Spread of West Nile virus in Iran: a cross-sectional serosurvey in equines, 2008–2009

F. AHMADNEJADa1a2 c1, V. OTARODa3, M. H. FALLAHa4, S. LOWENSKIa5, R. SEDIGHI-MOGHADDAMa6, A. ZAVAREHa1, B. DURANDa5, S. LECOLLINETa5 and P. SABATIERa2

a1 Viral Vaccines Production Department, Pasteur Institute, Tehran, Iran

a2 TIMC-IMAG Team EPSP, VetAgroSup, Campus Vétérinaire de Lyon, France

a3 Directorate Investigation Control of Animal Diseases, Iran Veterinary Organization, Tehran, Iran

a4 Engineering Research Institute, Tehran, Iran

a5 ANSES Laboratoire de Santé Animale, ANSES , Maisons-Alfort, France

a6 Central Veterinary Laboratory, Iran Veterinary Organization, Tehran, Iran

SUMMARY

We report the first large-scale serosurvey for West Nile virus (WNV) conducted in the equine population in Iran. Blood samples were obtained in 2008–2009 from 1054 equines collected from 260 districts located in 27 provinces. The overall seroprevalence rate for WNV neutralizing antibodies was 23·7%. Marked geographical variations were observed as province-specific seroprevalence rates ranged from 1% to 88%, the highest values being observed in the southern and western parts of the country. The presence of IgM-positive animals (n=9) indicated a recent circulation of WNV in several provinces. Logistic modelling confirmed this result with a significant effect of age on seropositivity. This study revealed extensive circulation of WNV in Iran particularly in southwestern provinces where the virus probably circulates every year.

(Accepted January 25 2011)

(Online publication March 14 2011)

Correspondence:

c1 Author for correspondence: Miss F. Ahmadnejad, TIMC-IMAG Vet Agro Sup, 1 avenue Bourgelat, 69280 Marcy l'Etoile, Lyon, France. (Email: f_ahmadnejad@yahoo.com)

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