Susceptibility Status of Aedes aegypti to Insecticides and Its Connections with Cases of Dengue Haemorrhagic Fever in Bogor City

Abstract

Nowadays, Dengue Haemorrhagic Fever is still one of the health problems in Indonesia, especially in Bogor City. Spraying insecticides with malathion are the most common activity to control Aedes aegypti as a Dengue vector. The objective of this study was to obtain data on susceptibility status of Ae. aegypti to malathion (organophosphate), bendiocarb (carbamate) and deltamethrin (pyrethroid) in Bogor City. The research was carried out by using the method of susceptibility test (WHO 1975) which contained malathion 0,8%, bendiocarb 0,1% and deltamethrin 0,025% impragnated paper. Ae. aegypti was collected by ovitrap from 12 endemic regions in Bogor City. The eggs were hached and reared in laboratory until F2 generations, then treated by those insecticides. The result showed that based on percentage of mortality, five isolates of Ae. aegypti (i.e. Lawang Gintung, Kebon Kelapa, Kebon Pedes, Kedung Waringin, and Tegal Gundil) were resistant against malathion (organophosphate); five isolates (i.e. Katulampa, Bondongan, Tegal Lega, Menteng, and Bantarjati) were tolerant; and two isolates (i.e. Baranangsiang and Cilendek Barat) were still susceptible. Otherwise, all strains of Ae. aegypti from 12 regions in Bogor City were resistant against bendiocarb (carbamate) and deltamethrin (pyrethroid). Meanwhile the result of RR50 value showed that eight isolates (i.e. Katulampa, Bondongan, Tegal Lega, Menteng, Bantarjati, Baranangsiang dan Cilendek Barat, Kebon Kelapa) were resistant against malathion; four isolates of Ae. aegypti (i.e. Lawang Gintung, Kebon Pedes, Kedung Waringin, and Tegal Gundil) ware not resistant (RR<10). Otherwise, all strains of Ae. aegypti from 12 regions in Bogor City were resistant against bendiocarb and deltamethrin (RR>10). The susceptibility status of 12 Ae. aegypti isolates in Bogor City were also performed in distribution by map. The study on dengue cases in Bogor City showed that the high insidence of dengue was related to the high frequency of using insecticides as one of the vector control method. Beside that the dengue cases in Bogor City during the years of 2008- 2012 were also related to the climate factors such as precipitation, temperature and humidity. The result analysis of correlation between dengue cases and precipitation for 5 years showed significant values (P<0,05) on seven areas (i.e. Baranangsiang, Kebon Kelapa, Cilendek Barat, Kebon Pedes, Bantarjati, Tegal Gundil, and Kedung Waringin). However, five areas showed no significant values (P>0,05) (i.e. Katulampa, Bondongan, Tegal Lega, Menteng and Lawang Gintung). Meanwhile, the relationship of dengue cases with average temperatures for five years showed no significant values in all area of Bogor City. Futhermore, the relationship of dengue cases with average humidity during the years of 2008-2012 showed significant values (P<0,05) in five areas (i.e. Baranangsiang, Kebon Kelapa, Cilendek Barat, Kebon Pedes, and Bantarjati), while the seven areas (i.e Katulampa, Bondongan, Tegal Lega, Cilendek Barat, Kebon Pedes, Lawang Gintung and Menteng) showed no significant values (P>0,05).