Susceptibility of European jackdaws (Corvus monedula) to experimental infection with lineage 1 and 2 West Nile viruses

Abstract

Mass bird mortality has been observed in North America after the introduction of West Nile virus (WNV), most notably massive die-offs of American crows (Corvus brachyrhynchos). In contrast, WNV epidemic activity in Europe has been characterized by very low incidences of bird mortality. As the general susceptibility of European corvids to strains of WNV remains in question, European jackdaws (Corvus monedula) were inoculated with WNV strains circulating currently in Greece (Greece-10), Italy (FIN and Ita09) and Hungary (578/10), as well as a North American (NY99) genotype with a demonstrated corvid virulence phenotype. Infection with all strains except WNV-FIN resulted in mortality. Viraemia was observed for birds inoculated with all strains and virus was detected in a series of organs upon necropsy. These results suggested that jackdaws could potentially function as a sentinel for following WNV transmission in Europe; however, elicited viraemia levels might be too low to allow for efficient transmission of virus to mosquitoes.

West Nile Virus Infections in (European) Birds

“…In our laboratory, we have also shown that jackdaws can be productively infected and succumb to WNV infection. Although approximately 50% of this bird species is susceptible to lethal infection, jackdaws could function as sentinel to follow WNV activity in Europe [5]. Nevertheless, these experiments clearly showed that not all WNV strains that circulate in Europe can cause lethal infection in these birds [4,5].…”

“…Although approximately 50% of this bird species is susceptible to lethal infection, jackdaws could function as sentinel to follow WNV activity in Europe [5]. Nevertheless, these experiments clearly showed that not all WNV strains that circulate in Europe can cause lethal infection in these birds [4,5]. Characterization of European WNV strains in mice has revealed little differences in virulence between the different strains [6].…”

The role of Culex pipiens mosquitoes in transmission of West Nile virus in Europe

“…Thus far, two laboratory studies investigated the susceptibility of two bird species in The Netherlands. Both the carrion crow (Corvus corone) and European jackdaw (Corvus monedula) were found to be susceptible to WNV (Lim et al 2015, Lim et al 2014. Although it was questionable whether viraemia of European jackdaws was sufficient to support transmission (Lim et al 2014), viraemia of carrion crows could support transmission (Lim et al 2015).…”

“…Both the carrion crow (Corvus corone) and European jackdaw (Corvus monedula) were found to be susceptible to WNV (Lim et al 2015, Lim et al 2014. Although it was questionable whether viraemia of European jackdaws was sufficient to support transmission (Lim et al 2014), viraemia of carrion crows could support transmission (Lim et al 2015). These laboratory findings are supported by field studies carried out in northern Europe, which reported serological evidence of WNV in sentinel chickens, resident birds, and migratory birds in the United Kingdom (Buckley et al 2006, Buckley et al 2003, and in migratory birds in Germany (Linke et al 2007).…”

“…Despite the presence of susceptible bird hosts (Lim et al 2015, Lim et al 2014, and high abundance of one of the main mosquito vectors, Cx. pipiens, during summer (Hesson et al 2013, Rudolf et al 2013, Weitzel et al 2011, WNV outbreaks have not yet occurred in northern Europe.…”