ClinQuiz: Equine parasites, answer 4A
4) A — Incorrect.
Many related rickettsial pathogens, such as those in the genera Ehrlichia and Anaplasma, are transmitted by ticks. However, Neorickettsia risticii is more closely related to Neorickettsia helminthoeca, the agent of salmon poisoning in dogs, and, like N. helminthoeca, N. risticii is transmitted to horses by the ingestion of infected trematodes rather than ticks. 14,15 Neorickettsia risticiiis specifically transmitted through accidental ingestion of flies that develop and live around rivers and streams and that harbor infected stages of the trematode vector. 15