Table 1.

Biological characteristics of Neorickettsia species

Species	Vertebrate host	Invertebrate vector/hosta	In vivo‐infected mammalian cells	Diseases & symptoms	Geographic distribution
N. helminthoeca	Canidae	Digenetic trematode Nanophyetus salmincola in snails (Oxytrema silicula) and fish (salmonid)	Monocytes and Macrophages	Salmon Poisoning Disease (pyrexia, anorexia, ocular discharge, weight loss, lethargy and dehydration, > 90% mortality)	California, Washington, Oregon, Idaho, Canada, Brazil
N. risticii	Horse, Bat	Digenetic trematode Acanthatrium oregonense in snails (Elimia virginica) and aquatic insects (caddisflies, mayflies)	Monocytes, Macrophages, intestinal epithelial cells and mast cells	Potomac horse fever (fever, depression, anorexia, dehydration, watery diarrhoea, laminitis and/or abortion, ~9% fatality)	USA, Canada, Brazil, Uruguay
N. sennetsu	Human	Unknown trematodes in snails and grey mullet fish	Monocytes and Macrophages	Sennetsu neorickettsiosis (fever, fatigue, general malaise and lymphadenopathy)	Japan, South‐East Asia

a. Transmission mode: all Neorickettsia spp. are transstadially and vertically transmitted through generations of trematodes.