Eimeria phocae (Apicomplexa: Eimerirdae) in harbour seals Phoca vitulina from Sable Island, Canada

Eimeria phocae infections were detected in eight 5 to 10 mo old harbour seals Phoca vitulina housed in the Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada.All seals occupying the facility had been captured on Sable Island, an emergent sand bar lying in the Northwest Atlantic 160 km east of mainland Nova Scotia.Oocysts sporulated in thin layer culture or faeces incubated in air but not when suspended in standing or aerated seawater.Sporulation time varied from 50 h at 2OoC to 1300 h at O.Z°C.Most infections were asymptomatic but clinical signs that included lethargy, loss of appetite and hemorrhagic diarrhea developed in 2 underweight males.Subsequent necropsy of one of these seals revealed endogenous stages of the parasite and associated pathology in the proximal 3 m of small intestine.Giant meronts 80-128 X 64-85 pm were found in colonies of 800 to 1200, which formed macroscopic nodules 900-1520 X 750-1050 pm extending from submucosa to intestinal lumen.Macro-and microgamonts were confined to lamina propria of villi.Areas of intestine with high gamont densities were marked by haemorrhaging, polyrnorphonuclear leukocyte infiltration (mainly eosinophils), shortening and thickening of villi and necrosis and shedding of epithelium and lamina propria.