Blood leukocyte response in hosts parasitized by the hematophagous arthropods Triatoma protracta and Lutzomyia longipalpis.

The kinetics of peripheral blood basophil and eosinophil responses in guinea pigs to multiple infestation by nymphal and adult Triatoma protracta (vessel feeder) and adult Lutzomyia longipalpis (pool feeder) were examined. Hosts exhibited significant blood basophil and eosinophil responses to feeding by both arthropods. Basophilia was slow to develop and mild in intensity following primary Triatoma infestation but exhibited immediate anamnestic-type responses to secondary infestation, with marked but delayed-type responses to tertiary infestation. Basophilia developed quickly in guinea pigs infested with Lutzomyia, and this response remained fairly consistent throughout the three infestation periods. Eosinophils did not respond to primary Triatoma infestation but exhibited marked immediate responses to both secondary and tertiary infestations. Lutzomyia-infested hosts exhibited marked eosinophilia in response to all infestations. Eosinophil levels returned to control levels 10 days post-tertiary infestation in Triatoma hosts, whereas Lutzomyia hosts exhibited normal eosinophil levels within 3-4 days after peak response. This study demonstrates that hosts respond to fast-feeding hematophagous arthropods with a peripheral blood basophilia and eosinophilia, as reported for slow-feeding (ticks) hematophagous arthropods. The difference in feeding strategy, whether vessel or pool feeder, appears to be reflected by differences in host blood leukocyte kinetics in response to parasitization by specific arthropods.