Affiliations: *National Institute of Health, Department of Medical Sciences,
Tiwanond Road, Nonthaburi 11000
Source: Bulletin of Department of Medical Sciences 1999; 41(3): 245-254
Language: Thai with English abstract
The present study was conducted to search for local strains of Bacillus thuringiensis with specific larvicidal activity against Aedes aegypti, vector of Dengue Haemorrhagic Fever. All 1,967 mud and soil samples from mosquito breeding habitats and surrounding areas of 35 provinces of Thailand were collected. It was found that 74 out of 4,429 isolates or 1.69% had potential in killing Ae. aegypti larvae. Among these, 16 isolates possessed LC50 values at the concentration lower than 103 spores/ml. All of mentioned isolates produced exotoxin but 8 isolates also exhibited endotoxin while none of them expressed beta exotoxin. The isolate N-PR 2502 from mud sample collecting in the drainage ditch of Tung-kwao District, Muang municipality, Phrae Province was proved to have the highest larvicidal activity.