Arrival of rabbit haemorrhagic disease virus 2 to northern Europe: Emergence and outbreaks in wild and domestic rabbits (Oryctolagus cuniculus) in Sweden.

Incursion of rabbit haemorrhagic disease virus (RHDV) into Sweden was documented in 1990 and it is now considered endemic in wild rabbit (Oryctolagus cuniculus) populations. Rabbit haemorrhagic disease virus 2 (RHDV2), a new, related lagovirus was first detected in France in 2010, and has spread rapidly throughout Europe and beyond. However, knowledge of RHDV2 in northern Europe is sporadic and incomplete, and in Sweden, routinely available diagnostic methods to detect rabbit haemorrhagic disease (RHD) do not distinguish between types of virus causing disease. Using RHDV2-specific RT-qPCR, sequencing of the VP60 gene and immunological virus typing of archived and prospective case material from the National Veterinary Institute's (SVA) wildlife disease surveillance programme and diagnostic pathology service, we describe the emergence of RHDV2 in Sweden in both wild and domestic rabbits. The earliest documented outbreak occurred on 22 May 2013, and from May 2013 to May 2016, 10 separate incidents of RHDV2 were documented from six different municipalities in the southern half of Sweden. Phylogenetic analysis of the VP60 gene shows clear clustering of Swedish isolates into three separate clusters within two different clades according to geographic location and time, suggesting viral evolution, multiple introduction events or both. Almost all cases of RHD examined by SVA from May 2013 to May 2016 were caused by RHDV2, suggesting that RHDV2 may be replacing RHDV as the predominant cause of RHD in Sweden.

Trichinella pseudospiralis foci in Sweden.

In Sweden, the prevalence of Trichinella infection in domestic pigs has greatly decreased since the 1970s, with no reports in the past 4 years. However, infected wild animals continue to be found. The objective of the present study was to identify the species of Trichinella present in animals of Sweden, so as to contribute to the knowledge on the distribution area and hosts useful for the prevention and control of this zoonosis. In the period 1985-2003, Trichinella larvae were detected in the muscles of 81/1800 (4.5%) red foxes (Vulpes vulpes), 1/6 (16.7%) arctic fox (Alopex lagopus), 1/7 (14.3%) wolf (Canis lupus), 10/200 (5.0%) lynxes (Lynx lynx), 4/8000 (0.05%) wild boars (Sus scrofa), and 27/66 x 10(6) (0.000041%) domestic pigs. All four Trichinella species previously found in Europe were detected (Trichinella spiralis, T. nativa, T. britovi and T. pseudospiralis). The non-encapsulated species T. pseudospiralis was detected in three wild boars from Holo (Stockholm area) and in one lynx from Froso (Ostersund area), suggesting that this species is widespread in Sweden. These findings are consistent with those of a study from Finland, both for the unexpected presence of T. pseudospiralis infection and the presence of the same four Trichinella species, suggesting that this epidemiological situation is present in the entire Scandinavian region. The widespread diffusion of T. pseudospiralis in the Scandinavian region is also important in terms of it potential impact on public health, given that human infection can occur and the difficulties to detect it by the trichinelloscopic examination.

Cerebral cysticercosis in a woodchuck (Marmota monax).

A juvenile woodchuck (Marmota monax) with vestibular signs was found in Woodbridge, Ontario (Canada) and later euthanized. At necropsy there was marked distortion of the right side of the skull, where a large, fluctuant, subcutaneous mass extended under the zygomatic arch and caudally from the right eye towards the right ear. The mass was multiloculated and contained a large number of tapeworm cysticerci, each about 1 to 2 mm in diameter. The third and lateral ventricles of the brain were dilated and contained large numbers of similar cysticerci. Based on the exogenous budding of cysts and the morphology of the scolex in each cyst, they were identified as cysticerci of Taenia crassiceps. This is the first report of cerebral cysticercosis in a woodchuck.

Seroprevalences of Toxoplasma gondii and Neospora caninum in Swedish red foxes (Vulpes vulpes).

The prevalences of antibodies to the protozoan parasites Toxoplasma gondii and Neospora caninum were investigated by the direct agglutination test (DAT) and ELISA, respectively, in 221 red foxes (Vulpes vulpes) from different parts of Sweden. A total of 84 (38%) of the analysed sera had antibodies to T. gondii, but none of the foxes had antibodies to N. caninum. The results indicate that T. gondii infection is fairly common in Swedish red foxes and that the infection is present in most parts of the country. They also show that N. caninum is not widespread as a latent infection among red foxes in Sweden.

Brachyspira spp. (Serpulina spp.) in birds: a review and results from a study of Swedish game birds.

Only limited data concerning the prevalence of intestinal spirochetes are available in game birds. This paper describes the prevalence and biochemical reactions of spirochetes isolated from 25 common partridges, 7 pheasants and 16 mallards originating from nine Swedish game-bird farms. The birds, which had been submitted for post-mortem examination due to various problems, showed a variety of underlying diseases. Additionally, fecal droppings from 22 common partridges, 20 pheasants and 20 mallards obtained at one of the farms were included in the study. Intestinal spirochetes were isolated from 85.4% of the game birds and from 71% of the fecal droppings. Seven biochemical types were identified. Seventeen per cent of all isolates were classified as Brachyspira pilosicoli and 3% as B. intermedia. One isolate showed strong beta-hemolysis and a positive indole reaction that is consistent with B. hyodysenteriae. In addition, three previously unknown biochemical types were found. Unclassified spirochetes in presumed mixed cultures were observed in 21% of all samples of fecal droppings. Histologic examination of spirochete-positive birds revealed numerous spirochetes in the lumen and crypts of the cecum, in some cases densely adhered by one end to the luminal surface. The significance of the findings is discussed.

Descriptive epidemiology of roe deer mortality in Sweden.

A retrospective epidemiologic study was conducted to examine causes of mortality of 985 wild roe deer (Capreolus capreolus) submitted to the National Veterinary Institute (SVA; Uppsala, Sweden) from January 1986 to December 1995. Age, sex, body condition, and geographic distribution as related to disease conditions are reported herein. The most common causes of mortality in roe deer were trauma (19%), winter starvation (18%), gastritis/enteritis (15%), bacterial infections (11%), parasitic infection (11%), systemic diseases (11%), neoplasia (2%), congenital disorders (1%), and miscellaneous causes (6%). Cause of death was not determined in 6% of the cases. The distribution of causes of death reported in this study differ from previous works in Sweden in that infectious and parasitic diseases were more common than winter starvation. The pathologic findings in studies like this do not necessarily represent what is occurring in the natural environment, but they do provide a good indication of distribution of diseases over time as well as age and sex structure in relation to disease conditions. Further research and more detailed studies are in progress to better understand specific mortality factors as well as etiologies of certain described diseases in roe deer in Sweden.