The Domestic Reindeer (Rangifer Tarandus) From Northern Norway As Intermediate Host for Three Species of Sarcocystis

Abstract

Sections of skeletal and cardiac muscle of reindeer from northern Norway were examined for sarcocysts by light microscopy. In skeletal muscle 3 different types of cysts were demonstrated; thick-walled macroscopic cysts surrounded by a fibrillar layer (Type 1), thick-walled microscopic cysts (Type 2) and thin-walled microscopic cysts (Type 3). In cardiac muscle only thin-walled cysts of type 3 were found. The 3 different types of cysts are considered to be cysts of 3 different species of Sarcocystis infecting the reindeer.

Dogs and foxes fed muscular tissue from reindeer started shedding Sarcocystis sporocysts measuring 13.9×10.2 µm and 14.4×10.4 µm, respectively, after a prepatent period of 11–17 days. Dogs and foxes are considered to be definitive hosts for Sarcocystis sp. with type 3-cysts. The original descriptions of Sarcocystis grueneri are critically reviewed and found to be inadequate. By comparing the size, cyst wall morphology and location of the cysts in the present investigation with those of the original papers, it is found that Sarcocystis sp. with type 3-cysts in all likelihood is identical with Sarcocystis grueneri. The name Sarcocystis grueneri is retained and assigned to the Sarcocystis sp. with type 3-cysts in cardiac and skeletal muscle of reindeer.

The dog (Canis familiaris), the silver fox (Vulpes vulpes) and the blue fox (Alopex lagopus) are recorded as definitive hosts for Sarcocystis grueneri.

Sammendrag

Skjelett- og hjertemuskulatur av rein frå Finnmark vart undersøkt for sarcocyster. I lysmikroskopiske snitt av skjelettmuskulatur fann ein 3 ulike cystetypar som representerer cyster av 3 ulike Sarcocystisarter.

Type 1-cystene var tjukkveggja, makroskopisk synlege cyster med ein 10–12 μm tjukk cystevegg med radiære stripningar omgjeven av eit 4–5 μm tjukt PAS-positivt fibrillært lag. Type 2-cystene var tjukkveggja, små cyster med ein 7–9 μm tjukk vegg med radiære stripningar. Stripningane tettare enn hos type 1-cystene. Type 3-cystene var tunnveggja, små cyster med ein 1–2 μm tjukk cystevegg. I hjertemuskulatur fann ein berre type 3-cyster.

I 4 separate forsøk fekk 12 revar og 6 hundar fersk skjelett- og/ eller hjertemuskulatur med sarcocyster. Etter ein prepatentperiode på 11–17 dagar tok 11 revar og 4 hundar til med a skilja ut Sarcocystissporocyster av storleik 14.4×10.4 μm (rev) og 13.9×10.2 μm (hund). Det vert konkludert med at hund og rev er endevertar for den Sarcocystis-arta som har type 3-cyster i hjerte- og skjelettmuskulatur hos rein.

Ved kritisk gjennomgang av originalartiklane der namnet Sarcocystis grueneri vart introdusert, finn ein at cystene til denne arta er ufullstendig definert. Ein finn likevel gode haldepunkt for at Sarcocystis grueneri er identisk med Sarcocystis sp. med type 3-cyster. Namnet Sarcocystis grueneri vert difor nytta om denne arta hos rein med hund og rev som endevertar.