AUTHOR=Ogola Edwin O. , Bastos Armanda D. S. , Slothouwer Inga , Getugi Caroline , Osalla Josephine , Omoga Dorcus C. A. , Ondifu Dickens O. , Sang Rosemary , Torto Baldwyn , Junglen Sandra , Tchouassi David P. 

TITLE=Viral diversity and blood-feeding patterns of Afrotropical Culicoides biting midges (Diptera: Ceratopogonidae)

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1325473

DOI=10.3389/fmicb.2023.1325473

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Culicoides</italic> biting midges (Diptera: Ceratopogonidae) are vectors of arboviral pathogens that primarily affect livestock represented by Schmallenberg virus (SBV), epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV). In Kenya, studies examining the bionomic features of <italic>Culicoides</italic> including species diversity, blood-feeding habits, and association with viruses are limited.</p></sec><sec><title>Methods</title><p>Adult <italic>Culicoides</italic> were surveyed using CDC light traps in two semi-arid ecologies, Baringo and Kajiado counties, in Kenya. Blood-fed specimens were analysed through polymerase chain reaction (PCR) and sequencing of cytochrome oxidase subunit 1 (<italic>cox1</italic>) barcoding region. <italic>Culicoides</italic> pools were screened for virus infection by generic RT-PCR and next-generation sequencing (NGS).</p></sec><sec><title>Results</title><p>Analysis of blood-fed specimens confirmed that midges had fed on cattle, goats, sheep, zebra, and birds. <italic>Cox1</italic> barcoding of the sampled specimens revealed the presence of known vectors of BTV and epizootic hemorrhagic disease virus (EHDV) including species in the Imicola group (<italic>Culicoides imicola</italic>) and Schultzei group (<italic>C. enderleni</italic>, <italic>C. kingi</italic>, and <italic>C. chultzei</italic>). <italic>Culicoides leucostictus</italic> and a cryptic species distantly related to the Imicola group were also identified. Screening of generated pools (11,006 individuals assigned to 333 pools) by generic RT-PCR revealed presence of seven phylogenetically distinct viruses grouping in the genera <italic>Goukovirus</italic>, <italic>Pacuvirus</italic> and <italic>Orthobunyavirus</italic>. The viruses showed an overall minimum infection rate (MIR) of 7.0% (66/333, 95% confidence interval (CI) 5.5-8.9). In addition, full coding sequences of two new iflaviruses, tentatively named Oloisinyai_1 and Oloisinyai_2, were generated by next-generation sequencing (NGS) from individual homogenate of <italic>Culicoides</italic> pool.</p></sec><sec><title>Conclusion</title><p>The results indicate a high genetic diversity of viruses in Kenyan biting midges. Further insights into host-vector-virus interactions as well as investigations on the potential clinical significance of the detected viruses are warranted.</p></sec>