Role oflarvae in transstadial transmission and endemicity ofin chronically infected sheep.

Abstract

, transmitted byticks, is the causative agent of ovine babesiosis, a disease characterized by fever, anemia, hemoglobinuria, and high mortality in sheep. This study investigates whether sheep that survived babesiosis without treatment can serve as a source of infection for-free host-seekinglarvae in a later season. Three donor sheep were experimentally infected with, and after six months, persistence ofwas assessed through blood and tick transmission experiments. Blood from donor sheep was intravenously injected into three recipient sheep, while donor sheep were also infested with-freelarvae. Engorged nymphs molted to adults, and new recipient sheep were infested with these ticks. All recipient sheep were monitored forfor 100 days using microscopic, serological, and molecular approaches. The presence ofwas confirmed in the recipient sheep that received blood, leading to clinical infection in two. However, nowas detected in recipient sheep infested with ticks. These results suggest that sheep recovering frominfection do not serve as a source of infection forlarvae in subsequent seasons.