Host Landing And Diel Activity of Potent Vectors of Bluetongue Disease, Culicoides Oxystoma and Culicoides Peregrinus

Abstract Background The spread of bluetongue virus depends on the vectorial ability of Culicoides affecting the susceptible host. Animal farms in West Bengal have reported prevalence of potent vectors of BTV (C. oxystoma, C. peregrinus and C. fulvus). Besides, high seroprevalence of BTV was also reported from this cattle dense region. Henceforth host-seeking activity of two important potent vectors, C. oxystoma and C. peregrinus on cattle were studied in two farm sites of West Bengal, India.Methods The study was done in 2018-19 comprising of total 297 hours of collection over 27 nights. A comparison was made between the catches obtained by mouth aspirator and light trap. Hourly collections of Culicoides were done directly from cattle (oral aspirator) as well as light trap was operated in close vicinity of cattle at a different shed.Results A total of 11,462 Culicoides belonging to C. oxystoma, C. peregrinus and C. fulvus were collected in light trap and aspirator. In aspirator 4764 midges were collected whereas 6698 individuals were collected in light trap. The following species were aspirated: C. peregrinus and C. oxystoma; however the light trap catches consisted of C. fulvus, C. oxystoma and C. peregrinus. Light trap collection exhibited crepuscular activity whereas aspirator collection was maximum between 4.00 am and 5.00 am. Likewise maximum landing of midges was observed in neck and hump region of cattle.Conclusion It was observed that the preferred time of feeding of C. peregrinus and C. oxystoma on cattle were early morning hours though midges were ubiquitous from dusk to dawn. Surprisingly the preferential landing of the two vectors were mostly restricted to the neck and hump region of the cattle. The results obtained during the study warrants further insight into the factors influencing the landing site by the vectors which may be useful biological data in disease management and draw effective deterrent strategies.