Resumo

PALOMINO S, Miriam et al. Evaluación del efecto residual del Temephos en larvas de Aedes aegypti en Lima, Perú. Rev. perú. med. exp. salud publica [online]. 2006, vol.23, n.3, pp.158-162. ISSN 1726-4634.

Temephos has been used as the only control strategy for Aedes aegypti in Lima for the past few years instead it is probably the only larvicidal agent currently being used in Peru. Objective: Assess the residual efficacy of temephos for the control of Ae. aegypti in field and laboratory conditions in Lima, Peru. Materials and methods: Eight low concrete tanks (LCT), containers, which are predominantly infested with Ae. aegypti in the San Juan de Lurigancho district, located North of the Lima sub-urban area. The number of larvae was determined with a hand net; all larvae were returned to the LCT after the tally. LCTs were treated with temephos, at a dose of 1 ppm on day zero (0). Mortality of wild larvae was evaluated at 24, 48 and 72 hours post treatment, and a periodic follow-up was conducted every 7 days for up to 14 weeks. At time 0 and on a weekly basis, 500 mL of water was collected from each treated tank and sent to a laboratory for bioassays (exposure of 25 larvae for 24 to 48 hours and subsequent record of mortality). Results: All the LCTs were infected (median of 43.5 larvae). Mortality at 24 hours in the LCTs was 99.7% and there appeared to be no further increase in mosquito larvae after the initial dose of Temephos in LCTs until week 14. However, evidence of 11% weekly decrease in mortality starting on week 7. Mortality at week 14 was inversely associated to the frequency of water changes in the LCTs (p<0,05). Conclusions: Temephos is efficient for the control of Ae. aegypti in field conditions in Lima for up to 14 weeks. This type of study should be conducted on a routine basis to monitor effectiveness of temephos.

Palavras-chave : Aedes aegypti; Vector control; Insecticide resistance; Peru.

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