FACTORS LIMITING THE DOMESTIC DENSITY OF TRIATOMA-INFESTANS IN NORTHWEST ARGENTINA - A LONGITUDINAL-STUDY

Reported are the environmental and demographic risk factors associated with the domestic infestation and density of Triatoma infestans in th ree heavily infested rural villages in Santiago del Estero Province, A rgentina. In a one-factor unadjusted analysis, the number of T. infest ans captured per person-hour was associated significantly and negative ly with the use of domestic insecticides by householders, type of that ch used in the roofs and the age of the house; and positively with the following: degree of cracking of the indoor walls and presence of hen s nesting indoors. in one model, using multiple linear regression and a backward stepwise elimination procedure, most of the variation in th e overall abundance of T, infestans was explained by insecticide use a nd the presence of hens nesting indoors in another model using the sam e procedure it was explained by insecticide use, bug density in 1988 a nd previous spraying with deltamethrin in 1985. Variations in bug dens ity per capture stratum (household goods, beds, walls and roof) were e xplained by the bug density in other strata and by one or two of the f ollowing risk factors: hens nesting indoors, type of roof, presence of cracks in the walls and number of people living in the house. Bug den sity might be locally controlled by the availability of refuges in the roofs and walls, by the presence of hens nesting indoors and by the u se of domestic insecticides. Certain local materials, such as a grass known as simbol, could be successfully used in rural housing improveme nt programmes aimed at reducing the availability of refuges for insect s in the roof.