|Johnson, L - ROCKY MTN ELK FOUNDATION|
Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 21, 2001
Publication Date: N/A
Interpretive Summary: Entry into the U.S. of horses infected with the tick transmitted causative agents (Babesia equi and Babesia caballi) of equine babesiosis concerns the nation's horse industry, as was seen during the 1996 Summer Olympic Games in Atlanta. In assessing the risk, we showed for the first time that two North American tick species can experimentally transmit B. equi to horses, and thus could spread the agent among horses in the field, given the opportunity.
Technical Abstract: The experimental vector competence for Babesia equi of 5 laboratory-reared, North American ixodid tick species known to infest equids in nature was evaluated by delayed transfer of male ticks from infected to susceptible equids or by infesting the latter animals with adult ticks previously fed as larvae and nymphs (or as lymphs only) on infected equids. After feeding for 5,6,or 13 days on acquisition hosts, ticks were removed and kept off the host for 6, 12, or 27 days. Transmission to susceptible ponies by Dermacentor variabilis males, and to susceptible burros by Boophilus microplus adults, was demonstrated by blood smear and serology. Tick species failing to transmit B. equi were Amblyomma americanum, Dermacentor andersoni, and D. occidentalis. The results indicated that male D. variabilis and adult B. microplus may be competent natural vectors of B.equi, given the opportunity.