20 August 2010
By M Ramya
"We wanted to create an awareness of the seriousness of the situation caused by breeding of mosquitoes," said M Parthiban, founder chairman of LIFO. He said the three cities were chosen because the organisation had entomological labs in both Patna and Chennai, and that Mumbai was chosen because Parthiban spent several years of his life there and was interested in finding out the situation there.
An exercise to collect the mosquito population density in two areas that were vulnerable to mosquito breeding in each of the three cities was conducted last week. The results showed that the two houses, termed mosquito catching stations, in Anna Nagar and Saidapet were frequented by an average of 178 mosquitoes, whereas in Mulund West and Vadala in Mumbai, the two houses selected saw 18 mosquitoes on an average, and residents of the two houses in Lohanipur and Kaushal Nagar in Patna counted 29 mosquitoes on an average.
"We chose houses in slums around areas where water was stagnant, and middle–class and upper–class people live in airconditioned homes that are sealed. So they are not really affected by the mosquitoes," Parthiban said.
During the period, Chennai saw a high incidence of the filaria–causing Culex and nuisance–creating Armigeres mosquitoes which do not cause diseases. Patna also saw Culex and Armigeres mosquitoes, whereas Mumbai saw Culex as well as the malaria–causing Anopheles and dengue–causing Aedes mosquitoes. The data was collected using both the ‘Pyrethrum spray total catch collection method’ and the ‘suction tube method’. The maximum number of mosquitoes captured using either method was noted.
Entomologists, however, not convinced about both methods being used simultaneously. "While the Pyrethrum spray method is used to get the number of mosquitoes within a dwelling, the suction method is used to gauge mosquito density in an open area. The two methods cannot be merged to get a single data, as the outcomes are different in each method," said S Sridharan, chief entomologist in the state.
LIFO is making efforts to rope in colleges and universities to sustain the observations, and also to involve the community.