Laboratory Transmission of Japanese Encephalitis and West Nile Viruses by Molestus Form of Culex pipiens (Diptera: Culicidae) Collected in Uzbekistan in 2004

• Published in: Journal of medical entomology 2006-03, Vol.43 (2), p.296-300
• Main Authors: Turell, M. J., Mores, C. N., Dohm, D. J., Komilov, N., Paragas, J., Lee, J. S., Shermuhemedova, D., Endy, T. P., Kodirov, A., Khodjaev, S.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; biting rates; Chickens; Culex - virology; Culex pipiens form molestus; dissemination rate; Encephalitis Virus, Japanese; Encephalitis, Japanese - transmission; Female; Fundamental and applied biological sciences. Psychology; hematophagy; infection rate; insect vectors; Insect Vectors - virology; Insecta; Invertebrates; Japanese encephalitis; Japanese encephalitis virus; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; mosquitoes; transmission; Uzbekistan; vector competence; VECTOR/PATHOGEN/HOST INTERACTION, TRANSMISSION; Vectors. Intermediate hosts; viremia; Viremia - blood; virus transmission; West Nile; West Nile Fever - transmission; West Nile virus
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/0022-2585%282006%29043%5B0296%3ALTOJEA%5D2.0.CO%3B2

We evaluated the molestus form of Culex pipiens pipiens (L.) (hereafter referred to as “molestus”) captured near Tashkent, Uzbekistan, for their ability to transmit Japanese encephalitis (family Flaviviridae, genus Flavivirus, JEV) and West Nile (family Flaviviridae, genus Flavivirus, WNV) viruses under laboratory conditions. These molestus were highly competent laboratory vectors of WNV, with infection and dissemination rates of 96 and 81%, respectively. Approximately 75% of female molestus that fed after development of a disseminated infection transmitted virus by bite. Therefore, ≈60% of those molestus taking a second bloodmeal between 16 and 25 d after an infectious bloodmeal would be expected to transmit WNV by bite. In contrast, these molestus were less efficient vectors of JEV, with infection and dissemination rates of 51 and 25%, respectively. In addition, only 33% of individuals with a disseminated infection transmitted JEV by bite, indicating a significant salivary gland barrier. Therefore, only ≈8% of orally exposed individuals would be expected to transmit JEV by bite if they took a second bloodmeal 16–25 d later. These data indicate that the molestus form of Cx. p. pipiens should be considered a potentially important vector of WNV in Uzbekistan and may become involved in the transmission of JEV, should this virus be introduced into Uzbekistan.