Echinococcus multilocularis in Svalbard, Norway: microsatellite genotyping to investigate the origin of a highly focal contamination.

Echinococcus multilocularis is a threatening cestode involved in the human alveolar echinococcosis. The parasite, mainly described in temperate regions of the Northern hemisphere was described for the first time in 1999 in the High Arctic Svalbard archipelago, Norway. The origin of this contamination could be due to an anthropogenic introduction from mainland Europe by domestic dogs or with the introduction of the sibling vole, perhaps from mainland Russia (St. Petersburg area), or with roaming Arctic foxes, known as the main definitive host of the parasite in Arctic regions. The genetic diversity of E. multilocularis in Svalbard was investigated here for the first time by genotyping using EmsB microsatellite and compared to other genotyped populations in the main worldwide endemic areas. We found low polymorphism amongst the 27 metacestode isolates from sibling voles trapped in the core of the distribution area of the vole on Svalbard. E. mutilocularis Arctic populations, using the Arctic fox as the definitive host, were genetically separated from European temperate populations that use the red fox, but closely related to St. Lawrence Island samples from Alaska. The result is inconsistent with the hypothesis of an anthropogenic introduction from mainland Europe, but can be seen as consistent with the hypothesis that Arctic foxes introduced E. multilocularis to Svalbard.

Patent Toxocara canis infections in previously exposed and in helminth-free dogs after infection with low numbers of embryonated eggs.

The outcome of Toxocara canis infections in the canine host depends on the migratory pathway of parasite larvae (somatic or tracheal) which is considered to be related to the host's age and its immune status. However, field studies attest high prevalences of patent T. canis infections in adult animals. The controlled induction of patent infections with low doses of embryonated eggs was investigated in 18 beagles in a 7-month study until their 16th life month. The animals were assigned to three groups, each consisting of three vertically infected dogs (with a short patent infection as pups before anthelmintic treatment) and three helminth-free dogs. At study days 10 and 40, the animals of groups 1 and 3 were given each 100 embryonated T. canis eggs. In each case, group 1 was treated 10 days post-infection with Milbemax, while dogs of group 3 remained untreated. Control group 2 was not experimentally infected but treated as group 1. Two weeks after first egg administration, a sharp increase of specific antibody reactions in ELISA and increased eosinophilic counts indicated larval invasion in all infected dogs. 42-56 days following first infection, patent infections were detected coproscopically in all animals of group 3, but in none of the uninfected dogs (group 2) or the infected and treated dogs (group 1). Following a 3-month observation period, all animals of the three groups were treated with piperazine citrate to eliminate intestinal infections and all were administered 100 embryonated eggs. Subsequently, patent infections developed in animals of all groups: in one of the infected and treated animals of group 1, in five of the so far not infected control group 2 and in four of the dogs with previous patent infections (group 3). Susceptibility to patent infections was not significantly altered in T. canis-free dogs compared to dogs with previous patent infection (vertically acquired or experimentally induced). However, dogs of group 1 treated with Milbemax after repeated egg administration developed a significantly increased resistance to patent infections as compared to control dogs (group 2). Observed prepatency periods were between 40 and 56 days and did not differ in the three groups. Even in urban areas, facing high infection pressure with Toxocara eggs maintained by a high dog and fox population, dogs of all ages are at risk to develop patent T. canis infections.

[Travel medicine of parasitic diseases in the dog]. / Reisemedizin parasitärer Erkrankungen des Hundes.

Companion animals are increasingly brought along by their owners to foreign countries. Thus, small animal travel medicine is becoming more important. The field includes both prophylaxis and metaphylaxis against various infectious diseases, as well as their diagnosis and treatment. Dogs returning from Southern Europe, but also from more tropical regions, may be infected with exotic pathogens. In addition, imported pedigree or working dogs, and especially stray dogs imported through welfare organisations, are at high risk. The present overview summarises the clinical and practical aspects of exotic parasitic diseases that may affect such dogs, and the risk of such diseases becoming autochthonously transmitted in Switzerland. Furthermore, the zoonotic potential of these infections will be considered.

PMWS: an emerging disease identified in archived porcine tissues.

Postweaning multisystemic wasting syndrome (PMWS) is a disease caused by porcine circovirus type 2 (PCV-2). The disease was present as early as 1986 in Spain, 1989 in Japan and 1993 in Thailand. In view of this, we considered it possible that the disease may also have been present in Switzerland prior to its first description in 2001. A retrospective investigation was performed on paraffin-embedded lymphoid organs and ileum from 496 pigs aged 5-13 weeks collected between 1976 and mid-2001. The sections were investigated immunohistochemically using a monoclonal antibody specific for PCV-2 capsid antigen encoded by ORF2. Virus antigen was detected in tissue samples of 39 pigs from 28 farms. The earliest positive sample originated from 1986. After 1989, positive pigs were found almost every year among the 20-40 cases investigated annually. These results indicate that PCV-2 has been present in Switzerland for some time, and at least since 1986.

[Autochthonous infections with Angiostrongylus vasorum in dogs in Switzerland and Germany]. / Autochthone Infektionen mit Angiostrongylus vasorum bei Hunden in der Schweiz und Deutschland.

Angiostrongylus vasorum is endemic in foxes an other carnivores in the South and south East of France, Denmark and Great Britain. The reddish nematode is present in the Arteria pulmonalis and the right side of the heart and causes respiratory and cardiovascular symptoms. From 1999 to 2004, A. vasorum was diagnosed in 5 dogs from northern Switzerland, in 1 dog from southern Germany and in 3 dogs from south Ticino. Clinical signs in the affected dogs varied and ranged from cough, tachypnoea and dyspnoea to neurological symptoms in 2 of the dogs. Four dogs died and in 3 of the 4 dogs adults and larvae were found after digestion of formalin-fixed tissue. Diagnosis in the other 5 dogs was achieved by detecting the larvae coproscopically. Based on anamnestic data, these 9 dogs are probably autochthonous cases.

Porcine circovirus as a possible cause of postweaning wasting in pigs in Switzerland.

Postweaning wasting is a major worldwide problem in pig production, particularly with respect to the disease termed postweaning multisystemic wasting syndrome (PMWS). In addition to wasting, PMWS symptoms include respiratory distress, diarrhoea, pallor and occasional cases of jaundice. The causative agent is porcine circovirus type 2 (PCV-2). The objective of the present study was to determine the significance of PMWS and similar conditions in Switzerland. A total of 72 weaned piglets from 26 farms showing wasting were examined for the presence of PCV-2 by immunohistochemical and histological analysis and 57 piglets from 21 farms were examined serologically. Possible causes for wasting other than PCV-2 were investigated by macroscopic, histological and bacteriological methods. PCV-2 antigen was identified immunohistochemically in the lymphatic organs in 11 of these 72 piglets. However, only 4 animals showed histological changes typical of PMWS. PCV-2 antibodies were found in 70% of the piglets. Piglets with wasting syndrome not associated with PCV-2 infection suffered from conditions including porcine proliferative enteropathy, gastric ulcers, polyserositis and polyarthritis. The most frequent condition was chronic enteritis not associated to circovirus infection. The results from the serological analyses indicate a wide distribution of PCV-2 in the Swiss pig population. However, confirmed cases of PMWS were rare in the investigated piglets.