Emergence of West Nile Virus Lineage-2 in Resident Corvids in Istanbul, Turkey

Ozge Erdogan Bamac, Utku Y. Cizmecigil, Asli Mete, Aysun Yilmaz, Ozge Aydin, Hasan E. Tali, Besim H. Tali, Semaha G. Yilmaz, Aydin Gurel, Nuri Turan, Serhat Ozsoy, Ezgi Vatansever Celik, Jean Remy Sadeyen, Gleyder Roman-Sosa, Munir Iqbal, Juergen A. Richt, Huseyin Yilmaz

Research output: Contribution to journalArticlepeer-review


West Nile fever is a vector-borne viral disease affecting animals and humans causing significant health and economic problems globally. This study was aimed at investigating circulating West Nile virus (WNV) strains in free-ranging corvids in Istanbul, Turkey. Brain, liver, and kidney were collected from corvids (n = 34) between June 2019 and April 2020 and analyzed for the presence of WNV-specific RNA by quantitative RT-PCR. In addition, histopathologic and immunohistochemical examinations were also performed. Samples found to be positive by qRT-PCR were partially sequenced. WNV-specific RNA was detected in 8 of 34 corvids analyzed, which included 7 hooded crows (Corvus cornix) and 1 Eurasian magpie (Pica pica). Phylogenetic analysis based on partial WNV sequences from the 8 WNV-positive corvids identified in this study revealed that all sequences clustered within the WNV lineage-2; they were at least 97% homologues to WNV lineage-2 sequences from Slovakia, Italy, Czechia, Hungary, Senegal, Austria, Serbia, Greece, Bulgaria, and Germany. WNV sequences showed a divergence (87.94-94.46%) from sequences reported from Romania, Central African Republic, South Africa, Madagascar, Israel, and Cyprus, which clustered into a different clade of WNV lineage-2. Common histopathologic findings of WNV-positive corvids included lymphoplasmacytic hepatitis, myocarditis, and splenitis. The liver and heart were found to be the tissues most consistently positive for WNV-specific antigen by immunohistochemistry, followed by the kidney and brain. This study demonstrates for the first time the existence of WNV virus belonging to the genetic lineage-2 in resident corvids in Istanbul, Turkey. We hypothesize that the WNV strains circulating in Istanbul are possibly the result of a spillover event from Europe. Since WNV is a zoonotic pathogen transmitted by mosquito vectors, the emergence of WNV in Istanbul also poses a risk to humans and other susceptible animals in this densely populated city and needs to be addressed by animal and public health authorities.

Original languageEnglish (US)
Pages (from-to)892-899
Number of pages8
JournalVector-Borne and Zoonotic Diseases
Issue number11
StatePublished - Nov 2021
Externally publishedYes


  • corvids
  • histopathology
  • Istanbul
  • phylogeny
  • West Nile virus
  • WNV lineage-2

ASJC Scopus subject areas

  • Microbiology
  • Virology
  • Infectious Diseases


Dive into the research topics of 'Emergence of West Nile Virus Lineage-2 in Resident Corvids in Istanbul, Turkey'. Together they form a unique fingerprint.

Cite this