Concurrent occurrence of human and equine West Nile virus infections in Central Anatolia, Turkey: the first evidence for circulation of lineage 1 viruses.

BACKGROUND: West Nile fever is an important zoonotic infection caused by West Nile virus (WNV), a member of the Flaviviridae. Previous serological data from Turkey suggest widespread WNV circulation. This report includes cases of human and equine WNV infections occurring concurrently, and manifesting as central nervous system infections, in two neighboring provinces of Central Anatolia, Turkey. A partial phylogenetic analysis of the causative virus is given for the first time. METHODS: The cases were reported in February (horses) and March (human). Symptoms of the disease were similar in the two species, characterized by neurological manifestations suggesting meningoencephalitis. Real-time/nested PCRs and commercial immunoassays and a plaque reduction neutralization assay were employed for the detection of viral RNA and specific antibodies, respectively. RESULTS: WNV RNAs were detected in buffy coat (horses) and cerebrospinal fluid (human) samples. Partial nucleotide sequences of the E-gene coding region revealed that the strains are closely related to viruses of lineage 1, clade 1a. Accompanying equine serosurveillance demonstrated WNV-specific antibodies in 31.6% of the samples. CONCLUSIONS: This is the first report of acute WNV infections caused by lineage 1 strains from Turkey, in concordance with previous reports from some European and North African countries.

Molecular evidence indicates that Phlebotomus major sensu lato (Diptera: Psychodidae) is the vector species of the recently-identified sandfly fever Sicilian virus variant: sandfly fever turkey virus.

Sandfly fever turkey virus (SFTV) is a recently-discovered sandfly fever Sicilian virus (SFSV) variant (family Bunyaviridae, genus Phlebovirus), characterized during retrospective evaluation of febrile disease outbreaks in Turkey. In addition to causing sandfly fever, SFTV was observed to induce elevation of liver enzymes, and to cause thrombocytopenia in affected individuals. This study was conducted to identify vectors for phleboviruses including SFTV in Ankara province, Turkey, where evidence indicates ongoing circulation of SFTV, as well as Toscana virus. Sandfly sampling was performed in Ankara province in the vicinity or in animal housing facilities in 15 peri-domestic sites. Male sandflies were identified morphologically, whereas females were evaluated individually for Phlebovirus RNA via a nested-PCR assay with consensus primers. Selected individuals and PCR-positive sandflies were subjected to barcoding via cytochrome c oxidase sequence analyses. The source of blood meals in virus-infected sandflies was investigated using a multiplexed PCR targeting the mitochondrial cytochrome b gene of various vertebrates. A total of 667 sandflies were captured in 11 locations. Morphological identification of males (n=226) revealed Phlebotomus major sensu lato as the most abundant species (38.9%), followed by Phlebotomus sergenti (20.4%), Phlebotomus halepensis (17.7%), Phlebotomus papatasi (10.2%), Phlebotomus simici (3.98%), Larrousius spp. (3.53%), Phlebotomus tobbi (1.32%), Phlebotomus perfiliewi perfiliewi (1.32%), and others. Virus sequences were detected in 3 (3/441) sandflies, two of which were characterized as P. major s.l. via barcoding. The detected sequences in sandflies were identified as SFTV, and were identical or similar to sequences from patients from the same area and the prototype SFTV strain. Bovine and human blood meals were demonstrated in SFTV-infected sandflies. P. major s.l. has been identified as the vector species for SFTV. Bovidae need to be evaluated as probable amplifying hosts for SFTV.