Trakya Bölgesi'nde Sivrisinek Flavivirüslerinin Tespiti ve Kısmi Genomik Karakterizasyonu

Abstract

Flavivirus genus of the family Flaviviridae includes mosquito-borne viruses with significant global health impact, such as West Nile, Dengue and Zika viruses. Moreover, certain flaviviruses only infect various mosquito species and complete their replication cycle without the involvement of vertebrate hosts. Arthropod surveillance provides information on regional vector-borne or non-pathogenic virus circulation, for understanding virus epidemiology and risk assessment. In this study, we carried out flavivirus screening in mosquitoes via generic PCR, in eastern Thrace region with previously documented West Nile and mosquito flavivirus activity. The detected strains were characterized via sequencing. A total of 1461 mosquitoes were collected from 38 localities in 3 provinces, during August-September, 2016. Morphological identification revealed Culex pipiens s.l. (54,4%) to be the most abundant species, followed by Anopheles maculipennis s.l. (25,6%), Aedes albopictus (6,1%), Aedes caspius (5,7%) and others. The individuals were pooled in a total of 104 specimens, according to species, sex and collection sites. Flavivirus screening provided positive results in 5.7% of the pools (6/104). A sequence with the highest nucleotide homology to the Anopheles flavivirus variant 1 was characterized in a pools with An. maculipennis mosquitoes, collected around Edirne province. Comparison of nucleotide and putative amino acid sequences revealed the strain as a candidate for a novel flavivirus. In five pools comprising Ur. unguiculata, Ae. caspius ve Cx. pipiens s.l. mosquitoes, another novel sequence, characterized previously in Ur. unguiculata species around Edirne province, was detected. In two Ur. unguiculata pools comprising male and female individuals, DNA forms of the particular flavivirus was identified. Although sequencing reads from these specimens were partial and fragmented, they were well-conserved and retained protein coding capacity. This is the first detection of RNA and DNA forms of a particular mosquito flavivirus in field-collected specimens, confirming the occurence of these forms during infections in nature.

Flavivirus genus of the family Flaviviridae includes mosquito-borne viruses with significant global health impact, such as West Nile, Dengue and Zika viruses. Moreover, certain flaviviruses only infect various mosquito species and complete their replication cycle without the involvement of vertebrate hosts. Arthropod surveillance provides information on regional vector-borne or non-pathogenic virus circulation, for understanding virus epidemiology and risk assessment. In this study, we carried out flavivirus screening in mosquitoes via generic PCR, in eastern Thrace region with previously documented West Nile and mosquito flavivirus activity. The detected strains were characterized via sequencing. A total of 1461 mosquitoes were collected from 38 localities in 3 provinces, during August-September, 2016. Morphological identification revealed Culex pipiens s.l. (54,4%) to be the most abundant species, followed by Anopheles maculipennis s.l. (25,6%), Aedes albopictus (6,1%), Aedes caspius (5,7%) and others. The individuals were pooled in a total of 104 specimens, according to species, sex and collection sites. Flavivirus screening provided positive results in 5.7% of the pools (6/104). A sequence with the highest nucleotide homology to the Anopheles flavivirus variant 1 was characterized in a pools with An. maculipennis mosquitoes, collected around Edirne province. Comparison of nucleotide and putative amino acid sequences revealed the strain as a candidate for a novel flavivirus. In five pools comprising Ur. unguiculata, Ae. caspius ve Cx. pipiens s.l. mosquitoes, another novel sequence, characterized previously in Ur. unguiculata species around Edirne province, was detected. In two Ur. unguiculata pools comprising male and female individuals, DNA forms of the particular flavivirus was identified. Although sequencing reads from these specimens were partial and fragmented, they were well-conserved and retained protein coding capacity. This is the first detection of RNA and DNA forms of a particular mosquito flavivirus in field-collected specimens, confirming the occurence of these forms during infections in nature.