A Survey of Mosquito Species in Crane, McCamey, and Rankin, Texas, for West Nile Viru

In this study, the towns of Crane, McCamey, and Rankin, Texas, were surveyed to determine the mosquito species' populations and the West Nile Virus (WNV) infection rates among Culex tarsalis and Culex quinquefasciatus mosquitoes. A total of 2,096 mosquitoes were collected from 12 sites over a period of 19 weeks from the start of the month of August to the middle of December in 2016 when mosquitoes were no longer able to be collected at the predetermined collection sites. A total of 1,908 female mosquitoes were identified to species representing 6 genera and 16 species. The genus Culex was the dominant genus of mosquito collected. Culex tarsalis and Culex quinquefasciatus, which are competent vectors for WNV, were found to be the dominant mosquito species in the three towns. Mosquito density was found to be highest during September and October, and lowest during December as temperatures decreased. The abundance of female mosquitoes was over 91% in most of the collection sites. Similarly, the abundance of unfed female mosquitoes was over 90% in most of the collected mosquito species. Also, there was not a statistical significant difference in the numbers of mosquitoes per species collected among the three towns. Similarly, there was not a statistical significant difference in the numbers of mosquitoes per species collected between the 12 collection sites. Furthermore, a total of 199 mosquito pools were tested using the VectortestRTM WNV antigen assay and only 4 pools were positive for WNV. Of the four pools that were positive for WNV, three contained Culex tarsalis mosquitoes while the other pool contained only Culex quinquefasciatus mosquitoes. The overall minimum infection rate (MIR) for Culex tarsalis was determined to be 2.84 per 1,000 tested, while that for Culex quinquefasciatus was determined to be 2.16 per 1,000 tested. Finally, the vector index (VI) for both Culex tarsalis and Culex quinquefasciatus was found to be 0.097, implying that less than an average of one infected mosquito was collected per trap-night in the three towns during the sampling period. The study revealed the need for an integrated mosquito surveillance and control program to prevent the risk of mosquito-borne diseases, such as WNV, arising from areas like the parks and animal husbandry areas in the three towns of this study.