| an ecotype of neorickettsia risticii causing potomac horse fever in canada. | neorickettsia (formerly ehrlichia) risticii is an obligatory intracellular bacterium of digenetic trematodes. when a horse accidentally ingests aquatic insects containing encysted trematodes infected with n. risticii, the bacterium is transmitted from trematodes to horse cells and causes an acute and often fatal disease called potomac horse fever (phf). since the discovery of n. risticii in the united states in 1984, using immunofluorescence and pcr assays, phf has been increasingly recognized t ... | 2016 | 27474720 |