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Introduction
An outbreak of peritonitis in Finnish reindeer occurred in 2003. Severe peritonitis with large numbers of nematodes in the peritoneal cavity was a consistent finding at post-mortem examination (fig. 1). The location of the nematodes in reindeer, as well as their large size, was highly suggestive of Setaria sp. (Laaksonen et al. , 2006).Fig. 1
Four adult female worms of Setaria tundra on the surface of the liver of a reindeer with severe fibrinous perihepatitis.
The genus Setaria Viborg consists of nematodes commonly found in the peritoneal cavity of ungulates. They are long, slender and milk-white in colour. The posterior end of the male is spirally coiled. The mouth is surrounded by a cuticular ring and a peribuccal crown. The tail of the male usually bears four pairs of precloacal and four pairs of postcloacal papillae. Spicules are unequal and dissimilar with the longer (left) spicule being slender with or without a long sclerotized membrane. On the tail, near the tip, there is a pair of small ventrolateral appendages. Larvae, known as microfilariae, are transmitted by arthropods (Anderson, 2000).
Setaria spp. are usually well-adapted nematodes and thus considered harmless inhabitants of the abdominal cavity of ungulates (Urquhart et al. , 1996). However, earlier papers describe outbreaks of peritonitis and poor body condition associated with heavy Setaria sp. infection in reindeer in Scandinavia in 1973-1974 (Rehbinder et al. , 1975; Kummeneje, 1980). The presumed causative agent in these outbreaks was S. tundra . Nevertheless, the identification of these nematodes was based on the host and location in the host rather than on detailed morphological studies. Setaria yehi has been associated with chronic peritonitis in reindeer in Alaska (Dieterich & Luick, 1971). The aim of the present study is therefore to accurately identify the causative agent of peritonitis. A description of Setaria tundra associated with peritonitis in the reindeer Rangifer tarandus is provided.
Materials and methods
In January 2004, 10 female and 10 male specimens of Setaria sp. were collected from the abdomen of 8-month-old reindeer calves slaughtered in the Kuusamo slaughterhouse in the south-eastern part of the Finnish reindeer herding area (Laaksonen et al. , 2006). Samples were preserved in 70% alcohol, dehydrated in a series of alcohol and cleared in lactophenol. To enable...