2019 年 70 巻 2 号 p. 41-52
The main vectors of the Chagas disease in the Central America were Triatoma dimidiata, T. nitida and Rhodnius prolixus. The former two species inhabited cracks and crevice on the mud walls, especially closed to beds, while R. prolixus lived only inside thatched roofs, especially above beds. The parasitic rate of the protozoa, Tripanosoma cruzi, was 20% or higher in the vector and human during investigation periods (1994–1999) in Guatemala. The vectors distributed over 21 departments (=prefectures) out of 22 in Guatemala; however, the vectors could not be collected over 1600 m above sea level. In the nine departments located in the south-west region, the infestation indexes were high. T. cruzi was found serologically positive in the blood of the domestic or wild animals such as chickens, dogs, cats, opossums and cows; whereas, most in human blood. The number of persons at risk were estimated approximately 330,000 according to the vector infestation index, natural infection of T. cruzi, risk houses in each department in 1994 National CENSUS in Guatemala. The vectors were highly susceptible to pyrethroid insecticides. The nine departments were selected for vector control project from 2000 in Guatemala. After spraying pyrethroid insecticides, R. prolixus was dramatically reduced and could not be recovered again. T. dimidiata required more than two time treatments to the walls. The vector control program established in Guatemala has spread to El Salvador, Honduras and Nicaragua in the Central America from 2003. R. prolixus has been eliminated from the Central America by 2009, while T. dimidiata remained in some area after insecticide spraying.
