Molecular characterization of the re-emerging West Nile virus in avian species and equids in Israel, 2018, and pathological description of the disease

Parasites & Vectors

Avishai Lublin¹  Yigal Farnoushi¹  Asaf Berkowitz¹  Nir Edery²  Shelly Hahn²  Oran Erster³  Gili Schvartz⁴  Amir Steinman⁵ 

[1] Division of Avian diseases, Kimron Veterinary Institute, Bet Dagan, Israel;Division of Pathology, Kimron Veterinary Institute, Bet Dagan, Israel;Division of Virology, Kimron Veterinary Institute, Bet Dagan, Israel;Central Virology Laboratory, Israel Ministry of Health, Sheba Medical Center, Ramat Gan, Israel;Division of Virology, Kimron Veterinary Institute, Bet Dagan, Israel;Koret School of Veterinary Medicine, The Robert H. Smith, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 7610001, Rehovot, Israel;Koret School of Veterinary Medicine, The Robert H. Smith, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 7610001, Rehovot, Israel;

关键词: West-nile virus;    Avian species;    Equids;    Histopathology;    Phylogenetic analysis;   

DOI  :  10.1186/s13071-020-04399-2

来源: Springer

【 摘 要 】

BackgroundIn this report we describe the molecular and pathological characteristics of West Nile virus (WNV) infection that occurred during the summer and fall of 2018 in avian species and equines. WNV is reported in Israel since the 1950s, with occasional outbreaks leading to significant morbidity and mortality in birds, high infection in horses and humans, and sporadic fatalities in humans.MethodsAnimal and avian carcasses in a suitable condition were examined by post-mortem analysis. Tissue samples were examined for WNV by RT-qPCR and the viral load was quantified. Samples with sufficient material quality were further analyzed by Endpoint PCR and sequencing, which was used for phylogenetic analysis. Tissue samples from positive animals were used for culturing the virus in Vero and C6/36 cells.ResultsWNV RNA was detected in one yellow-legged gull (Larus michahellis), two long-eared owls (Asio otus), two domesticated geese (Anser anser), one pheasant (Phasianus colchicus), four hooded crows (Corvus cornix), three horses and one donkey. Pathological and histopathological findings were characteristic of viral infection. Molecular analysis and viral load quantification showed varying degrees of infection, ranging between 70–1.4 × 106 target copies per sample. Phylogenetic analysis of a 906-bp genomic segment showed that all samples belonged to Lineage 1 clade 1a, with the following partition: five samples from 2018 and one sample detected in 2016 were of Cluster 2 Eastern European, two of Cluster 2 Mediterranean and four of Cluster 4. Four of the positive samples was successfully propagated in C6/36 and Vero cell lines for further work.ConclusionsWNV is constantly circulating in wild and domesticated birds and animals in Israel, necessitating constant surveillance in birds and equines. At least three WNV strains were circulating in the suspected birds and animals examined. Quantitative analysis showed that the viral load varies significantly between different organs and tissues of the infected animals.

【 授权许可】

CC BY