Evaluating the impact of nitisinone at mosquito-lethal doses on Lutzomyia longipalpis

Abstract

Nitisinone, a systemic inhibitor of tyrosine catabolism, has recently emerged as a promising endectocide with demonstrated lethality against mosquitoes and tse-tse flies. To assess its efficacy against Lutzomyia longipalpis, an important vector of Leishmania infantum —the causative agent of zoonotic visceral leishmaniasis prevalent in the Mediterranean basin, Latin America, and parts of the Middle East—, we exposed sand flies to a concentration previously shown to be lethal to Anopheles mosquitoes (250 ng/mL). Survival was monitored over 14 days and showed no significant difference between treated and control groups, indicating a lack of insecticidal effect at this dose. These findings suggest that Lu. longipalpis exhibits tolerance to nitisinone, likely due to species-specific metabolic differences. Although nitisinone remains a promising tool for systemic vector control, its effectiveness against sand flies may require higher doses or alternative compounds.