Introduction of West Nile Virus in the Middle East by Migrating White Storks

Abstract

West Nile virus (WNV) was isolated in a flock of 1,200 migrating white storks that landed in Eilat, a town in southern Israel, on August 26, 1998. Strong, hot westerly winds had forced the storks to fly under considerable physical stress before reaching the agricultural land surrounding the town. Most of the flock were fledglings, <1 year old, which had hatched in Europe. Thirteen dead or dying storks were collected 2 days after arrival and submitted to the laboratory for examination. Four WNV isolates were obtained from their brains. Out of 11 storks tested six days after arrival, three had WNV-neutralizing antibodies. Comparative analysis of full-length genomic sequences of a stork isolate and a 1999 flamingo isolate from the USA showed 28 nucleotide (nt) (0.25%) and 10 amino acid (0.3%) changes. Sequence analysis of the envelope gene of the stork isolate showed almost complete identity with isolates from Israeli domestic geese in 1998 and 1999 and from a nonmigrating, white-eyed gull in 1999. Since these storks were migrating southwards for the first time and had not flown over Israel, we assume that they had become infected with WNV at some point along their route of migration in Europe.

Prevalence of West Nile Virus Neutralizing Antibodies in Wild Birds from the Camargue Area, Southern France

“…Formal evidence for introduction of WNV into the Camargue from Africa, or elsewhere, will require a search for acute infection by WNV during migration. This has been shown in Israel for White Storks (Ciconia ciconia) migrating south (Malkinson et al, 2002) and in Cyprus for a Barred Warbler (Sylvia nisoria) migrating north (Watson et al, 1972), but requires considerable time and effort. The present serologic study should help to identify species that are frequently exposed to flaviviruses and that, therefore, might be considered as privileged target species for viral isolation studies.…”

“…Blood samples were centrifuged and plasma kept frozen at 220 C prior to testing. Plasma samples were tested for neutralizing antibodies to WNV in a BLS3 laboratory using a microneutralization protocol, as described (Malkinson et al, 2002;Figuerola et al, 2007). Briefly, plasma samples were inactivated at 56 C for 30 min and serially diluted twofold from 1:20 to 1:640 in 96-well plates.…”

New haematological data in Cory's shearwater,Calonectris diomedea(Aves, Procellariiformes)

“…During these migrations, individuals may come in contact with a wide array of pollutants (e.g. Baker et al 2002) and pathogens, some of which can be transmitted on a very large scale (Malkinson et al 2002;Weimerskirch 2004), with *Correspondence: J. Bried, Departamento de Oceanografia e Pescas, Centro do IMAR da Universidade dos Açores, 9901-862 Horta, Açores, Portugal. Tel: +351 292207800.…”

IS-98-ST1 West Nile virus derived from an infectious cDNA clone retains neuroinvasiveness and neurovirulence properties of the original virus

“…Cells were maintained in CO 2 incubators (5% CO 2 ) at 37uC. The Israeli isolate IS-98-ST1 of WNV has been described elsewhere [20]. Briefly, IS-98-ST1 was isolated from the cerebellum of a stork in Israel in 1998 on Vero cells and the recovered virus was used to infect mosquito AP61 cells.…”

“…During the 1998 epidemic in Israel, WNV strain IS-98-ST1 was isolated from a stork with severe neurological symptoms [20]. IS-98-ST1 is suitable for the study of viral determinants of WNV virulence, as well as host factors involved in viral pathogenicity [21,22,23,24,25].…”