Culex tritaeniorhynchus

Until recently, the resistance of mosquitoes to pyrethroids has not been taken as a serious issue. In Japan, C. p. pallens and Aedes albopictus (Skuse) are the main species living around houses. Although mosquito coils have utilized natural pyrethrins as insecticidal ingredients for about 50 years and then allethrin for about 50 years, there has been no report on resistance development. The reason for this is considered to be the short active time of 4-5 months per year for C. p. pallens. Yasutomi et al. [50] reported in 1989 the presence of pyrethroid-resistant Culex tritaeniorhynchus in Okinawa, but Japanese encephalitis transmitted by C. tritaeniorhynchus decreased markedly after 1992 and disappeared. 

Yasutomi K, Takahashi M (1989) Insecticidal resistance of Culex tritaeniorhynchus in Chinen, Okinawa Prefecture, with special reference to the mechanism of pyrethroid-resistance. Jpn JSanitZool 40 315-321... 

Viral infections are yellow and dengue fevers, caused by flaviviruses transmitted by Aedes aegypti, and Japanese encephalitis, also caused by a flavivirus, which is spread by Culex tritaeniorhynchus All these are controlled by vaccine administration. 

Singh, S.P., P. Sharma and L.K. Vats Light-Dependent Toxicity of the Extract of Plant Tagetes erecta and Alpha-Terthienyl Toward Larvae of Mosquito Culex tritaeniorhynchus. Toxic. Environ. Chem. 16, 81 (1987). 

Esterasss. Esterases are a major mechanism of resistance to organophosphates and in certain cases may also contribute resistance toward carbamates and certain pyrethroids. The role of esterases in resistance in mosquitoes and aphids has been the subject of especially fruitful research during the past few years. In collaborative studies between our laboratory and French laboratories in Montpellier, Antibes and Pau, several electrophoretic forms of esterases A and B have been identified in mosquitoes (Figure 5). Esterases Ai, A2, A4, Bi, B2, and B4 are found in the Culex pipiens complex, i.e. C. pipiens and C. quinquefasciatus. Two other forms, esterases A3 and B3, are present in C. tarsalis, and still others (not yet named) in Aedes aegypti and Ae. nigromaculis from California, C. tritaeniorhynchus from Japan (22) and various Culex species from Mexico. 

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