"The Bionomics and Vector Competence of Anopheles albimanus and Anopheles vestitipennis in Southern Belize, Central America"
UNIFORMED SERVICES UNIV OF THE HEALTH SCIENCES BETHESDA MD F EDWARD HEBERT SCHOOL OF MEDICINE
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During an 18 month study period 1997-1998 in the Toledo District, southern Belize, a series of studies were undertaken to evaluate the vector competence of the Anopheles mosquitoes. At both Golden Stream and Rancho, the population densities of An. vestitipennis showed positive correlation with human cases of P. vivax and tested positive for P. vivax 210 MFIR of 0.01 and MFIR of 0.0004, respectively. Population densities of An. darlingi from Golden Stream showed a negative correlation with high numbers of malaria cases but also tested positive for P. vivax 210 MFIR of 0.001. Population abundance of An. albimanus from Rancho showed a negative correlation with malaria transmission and was not found naturally infected with malaria parasites. The feeding preference study showed An. vestitipennis to prefer feeding on human blood while An. albimanus showed a strong tendency for feeding on cattle and non-human hosts. Human landing collections showed An. albimanus exhibited a bimodal biting pattern with an OI ratio of 10.1. Anopheles vestitipennis, however, exhibited a high level of biting activity throughout the night and a strong endophagic behavior OI ratio of 10.9. Post spray, deltamethrin functioned primarily as an irritant, causing premature exiting behavior. DDT exerted a powerful repellency effect resulting in a 97 post-spray reduction of An. vestitipennis females entering the hut. Results from the comparative susceptibility study showed An. darlingi maintains a high salivary gland infection rate 41.0 with P. falciparum NF-54. Anopheles vestitipennis had a low salivary gland infection rate of 9.3 with moderate numbers of sporozoites i.e. 85.7 containing 50-250 sporozoites. Anopheles albimanus was the least susceptible to salivary gland infection Golden Stream, 0.0 and Buena Vista, 2.2. Although the rate of infection for An. vestitipennis low, its strong endophagic and anthropophagic behaviors augment its overall vector potential.
- Medicine and Medical Research