West Nile virus infection in crocodiles - Letters - Letter to the Editor

Emerging Infectious Diseases, July, 2003 by Amir Steinman, Caroline Banet-Noach, Shlomit Tal, Ohad Levi, Lubov Simanov, Shimon Perk, Mertyn Malkinson, Nahum Shpigel

WNV has been endemic in Israel since the early 1950s (12). More recently, in the summer of 2000, an extensive outbreak occurred, affecting hundreds of people (11), dozens of horses (6), and several flocks of geese (5). However, no deaths of crocodiles were reported. This contrasts with the report from Florida (1), where WNV was isolated from dead alligators, and where hundreds of cases of sudden death had been reported in previous years; these deaths are now suspected to result, at least in part, from WNV disease.

The role of various reptile species in the epidemiology of other arboviruses such as western equine encephalitis, eastern equine encephalitis, and Venezuelan equine encephalitis is well documented (13-15). At present, the role of reptiles and amphibians in the life cycle and epidemiology of WNV is not known, and further research is necessary.

Acknowledgments

We thank Kubbi Ofer for assistance in the collection of serum samples from the crocodiles.

References

(1.) ProMED-mail. Florida: West Nile virus identified in alligators for the first time. ProMED-mail 2002; 14 Nov: 20021114.5797. Available from: URL: http://www.promedmail.org

(2.) Travis D, McNamara T, Glaser A, Campbell R. A national surveillance system for WNV in zoological institutions. Available from: URL: http://www.cdc.gov/ncidod/dvbid/westnile/conf/ppt/1a-travis.ppt

(3.) Nir Y, Lasowski Y, Avivi A, Goldwasser R. Survey for antibodies to arboviruses in the serum of various animals in Israel during 1965-1966. Am J Trop Med Hyg 1969;18:416-22.

(4.) Kostiukov MA, Gordeeva ZE, Bulychev VP, Nemova NV, Daniiarov OA. The lake frog (Rana ridibunda)--one of the food hosts of blood-sucking mosquitoes in Tadzhikistan--a reservoir of the West Nile fever virus. Med Parazitol (Mosk) 1985;3:49-50.

(5.) Malkinson M, Banet C, Weisman Y, Pokamunski S, King R, Drouet MT, et al. Introduction of West Nile virus in the Middle East by migrating white storks. Emerg Infect Dis 2002;8:392-7.

(6.) Steinman A, Banet C, Sutton GA, Yadin H, Hadar S, Brill A. Clinical description of equine West Nile encephalomyelitis during the outbreak of 2000 in Israel. Vet Rec 2002; 151:47-9.

(7.) Ianconescu M. Turkey meningoencephalitis: a general review. Avian Dis 1976;20:135-8.

(8.) Berthet FX, Zeller HG, Drouet MT, Rauzier J, Digoutte JP, Deubel V. Extensive nucleotide changes and deletions within the envelope glycoprotein gene of Euro-African West Nile viruses. J Gen Virol 1997;78:2293-7.

(9.) Savage HM, Ceianu C, Nicolescu G, Karabatsos N, Lanciotti RS, Vladimirescu A, et al. Entomologic and avian investigations of an epidemic of West Nile fever in Romania in 1996, with serologic and molecular characterization of a virus isolate from mosquitoes. Am J Trop Med Hyg 1999;61:600-11.

(10.) Ministry of the Environment, State of Israel. Available from: URL: http://www.sviva.gov.il

(11.) Weinberger M, Pitlik SD, Gandacu D, Lang R, Nassar F, Ben David D, et al. West Nile fever outbreak, Israel, 2000: epidemiologic aspects. Emerg Infect Dis 2001;7:686-91.