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

Abstract

Background In 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. Methods Animal 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. Results WNV 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. Conclusions WNV 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.

West Nile Virus Lineage 1 in Italy: Newly Introduced or a Re-Occurrence of a Previously Circulating Strain?

“…Human and horse infections with Eastern WNV-L1 strains were also reported in Turkey in 2010 and following years [42,43]. In recent years, WNV-L1 circulation appeared to be limited to Northern African countries, the Iberian Peninsula, Cyprus, Turkey, Israel, and Serbia [36][37][38][39][44][45][46][47][48][49][50].…”

Point of care diagnostics and non-invasive sampling strategy: a review on major advances in veterinary diagnostics

“…Some of the examples include lumpy skin disease (LSD) (Tasioudi et al 2016;Sudhakar et al 2020), Rift Valley fever (RVF) (Gaudreault et al 2019;Lagare et al 2019), porcine reproductive and respiratory syndrome (PRRS) (Rajkhowa et al 2015;Zhang et al 2019), camel pox infections (Al-Zi'abi et al 2007Erster et al 2018) and equine coronavirus infections (Pusterla et al 2016;Nemoto et al 2019). Several other diseases of livestock that have re-emerged in the recent years due to the changing incidence of pathogens and patterns of diseases over time include blue tongue (BT) (Purse et al 2005;Sailleau et al 2017), African horse sickness (AHS) (Maclachlan and Guthrie 2010;Thompson et al 2012), West Nile fever (WNF) (Schvartz et al 2020) and anthrax (Kisaakye et al 2018;Stella et al 2020). Bearing in mind the recent patterns of evolving novel pathogens and emerging diseases such as influenza, Nipah, Middle East respiratory syndrome (MERS) and most recently coronavirus disease (COVID-19) in animals, constant awareness and pursuance of effective strategies for controlling infectious diseases and disease emergence thus remain crucial.…”

West Nile Virus in Common Wild Avian Species in Israel

“…In 2000, a major outbreak of WNV encephalitis was reported in hundreds of humans and dozens of horses in Israel [16,20,22]. Since then, minor outbreaks were reported sporadically, the most recent in 2018, where increased morbidity and mortality were observed in wild avian species concurrent with increased morbidity and mortality in humans [23,24]. Several cases were reported in horses, and four molecular isolations were identified [23].…”

“…Since then, minor outbreaks were reported sporadically, the most recent in 2018, where increased morbidity and mortality were observed in wild avian species concurrent with increased morbidity and mortality in humans [23,24]. Several cases were reported in horses, and four molecular isolations were identified [23]. All animal cases were phylogenetically identified as lineage 1, cluster 2 and 4.…”