Corvid birds (Corvidae) act as definitive hosts for Sarcocystis ovalis in moose (Alces alces)

Abstract

Epidemiological data and a unique phylogenetic position had suggested that Sarcocystis ovalis in moose and red deer might use a definitive host other than canids, felids, or humans. Corvid birds and rats were therefore evaluated as potential definitive hosts for this species in a small pilot study. Four laboratory rats were each inoculated with 10 or 25 sarcocysts of S. ovalis isolated from moose, but no Sarcocystis oocysts were detected in their intestinal mucosa upon euthanasia 2 to 3 weeks later. At a site where large flocks of corvid birds (hooded crows, ravens and European magpies) fed on remnants of moose carcasses during the hunting period in October, fresh bird droppings were collected on the ground and examined microscopically and by molecular methods. By microscopy, a small number of typical Sarcocystis sporocysts, measuring 12.8 × 8.4 μm, were found in the faecal samples. These sporocysts were identified as belonging to S. ovalis by a polymerase chain reaction assay using specific primer pairs targeting the ssu rRNA gene, followed by sequence analysis. The intestinal contents of a crow and two magpies shot near the dumping site were also examined. Sarcocystis oocysts (16.1 × 12.4 μm) and free sporocysts (12.5 × 7.9 μm) were found in the intestinal mucosa/contents of one magpie (Pica pica). These oocysts/sporocysts were also found to belong to S. ovalis by the same molecular assay. This is the first report of corvid birds acting as definitive hosts for a species of Sarcocystis.

Morphological and molecular characterization and phylogenetic placement of Sarcocystis capreolicanis and Sarcocystis silva n. sp. from roe deer (Capreolus capreolus) in Norway

“…This unique placement reflects on the fact that all the three aforementioned species seem to be using corvid birds as definitive hosts, as has recently been proven for S. ovalis from moose (Gjerde and Dahlgren 2010). The transmission via the faeces of corvid birds may not to be very efficient as only two of nine roe deer examined in both studies have been found to be infected with S. oviformis.…”

Wet Grasslands as a Green Infrastructure for Ecological Sustainability: Wader Conservation in Southern Sweden as a Case Study

“…Likewise, the Icelandic Black-tailed Godwit (Limosa limosa islandica) population has rapidly increased through a believed improvement in climatic conditions and habitat leading to larger and better quality breeding and foraging areas [34]. However, it should also be noted that Iceland has only one mammal predator, the Arctic fox (Alopex lagopus) [107], and only one corvid species, the Raven [108].…”

Molecular identification of Sarcocystis halieti n. sp., Sarcocystis lari and Sarcocystis truncata in the intestine of a white-tailed sea eagle (Haliaeetus albicilla) in Norway

“…The latter hosts acquire a Sarcocystis infection through the accidental ingestion of oocysts/sporocysts in fecally contaminated feed or water, whereas definitive hosts get infected through ingestion of sarcocysts, mainly located in striated muscles, via predation or scavenging. Hence, mainly carnivorous animals (mammals, birds, reptiles), but also some omnivores, e.g., corvid birds ( Gjerde and Dahlgren, 2010 , Irie et al, 2017 ), act as definitive hosts, whereas herbivores, omnivores and carnivores may act as intermediate hosts.…”