Investigations and actions taken during 2011 due to the first finding of Echinococcus multilocularis in Sweden.

Echinococcus multilocularis is a parasite that can cause alveolar echinococcosis disease. After the first positive finding of E. multilocularis in Sweden in 2011, a consulting group with representatives from relevant authorities was summoned. In this group, all relevant information was shared, strategies for information dissemination and any actions to be taken due to the finding of E. multilocularis were discussed and decided. The present paper describes the actions taken during 2011 and the results thereof, including surveillance in animals, risk assessment for humans to become infected and recommendations given to the public. Further discussion about whether the parasite was introduced, and if so, how, as well as possible future development of the infection in animals and humans in Sweden and future actions are included.

First detection of Echinococcus multilocularis in Sweden, February to March 2011.

Surveillance for the fox tapeworm, Echinococcus multilocularis, has been carried out in Sweden since 2000, with about 300 red foxes analysed annually. We report the first finding of E. multilocularis in Sweden, in a fox shot in December 2010 in the south-west of the country. A second infected fox shot in the same location was detected in March 2011. This paper describes the national monitoring programme and the ongoing work to estimate the prevalence and spread of the infection.

ITS2 sequences of Dictyocaulus species from cattle, roe deer and moose in Sweden: molecular evidence for a new species.

Total DNA was isolated from adult lungworms of the genus Dictyocaulus, collected from cattle, moose (Alces alces) and roe deer (Capreolus capreolus) in Sweden. The second ribosomal internal transcribed spacer was amplified with PCR, and DNA sequences were determined from nine individual worms that all came from different hosts in order to avoid analysis of siblings. The sequence data obtained were aligned and compared with similar data derived from German lungworm isolates from cattle and fallow deer (Cervus dama). These analyses clearly showed that specimens of the cattle lungworm, Dictyocaulus viviparus, were almost identical irrespective of their geographical origin. However, when the second internal transcribed spacer sequence of D. viviparus was compared with that of lungworms from moose and roe deer, major differences were noticed. Although lungworms collected from these cervids had identical second internal transcribed spacer sequences, they proved to be genetically different from Dictyocaulus eckerti of German fallow deer, displaying a 66.5% similarity. In an evolutionary tree, inferred by maximum likelihood analysis, the Dictyocaulus species from cattle and wild cervids clustered as compared with Dictyocaulus filaria from sheep. The study has thus demonstrated that A. alces and C. capreolus in Sweden are parasitised with a Dictyocaulus species that is different from D. viviparus and D. eckerti, indicating that we are dealing with a new species in moose and roe deer.

Cervical laminectomy without fusion in patients with rheumatoid arthritis.

OBJECT: The authors performed a prospective study to determine whether cervical laminectomy without simultaneous fusion results in spinal instability. METHODS: Because of clinical and radiographic signs of cord compression, 15 patients with rheumatoid arthritis (including one with Bechterew's disease) and severe involvement of the cervical spine underwent decompressive laminectomy without fusion performed on one or more levels. Preoperative flexion-extension radiographs demonstrated dislocation but no signs of instability at the level of cord compression. Clinical and radiological reexamination were performed twice at a median of 15 months (6-24 months) and 43 months (28-72 months) postoperatively. One patient developed severe vertical translocation 28 months after undergoing a C-1 laminectomy, which led to sudden tetraplegia. She required reoperation in which posterior fusion was performed. No signs of additional instability at the operated levels were found in the remaining 14 patients. In three patients increased but stable dislocation was demonstrated. The results of clinical examination were favorable in most patients, with improvement of neurological symptoms and less pain. CONCLUSIONS: The authors conclude that decompressive laminectomy in which the facet joints are preserved can be performed in the rheumatoid arthritis-affected cervical spine in selected patients in whom signs of cord compression are demonstrated, but in whom radiographic and preoperative signs of instability are not. Performing a simultaneous fusion procedure does not always appear necessary. Vertical translocation must be detected early, and if present, a C-1 laminectomy should be followed by occipitocervical fusion.

Experimental infection of red foxes (Vulpes vulpes) with Sarcoptes scabiei var. vulpes.

Two of 3 red foxes became experimentally infected with Sarcoptes scabiei v. vulpes isolated from a naturally infected wild fox. The first clinical sign was seen after 10 days. After 30 days hairless patches were observed on the back of one of the foxes while general hair loss continued slowly. On the other fox the only macroscopical changes was tangling of the hair. The foxes died after 67 and 94 days, respectively. Both foxes were anaemic and in very poor condition. Scratching was seen in only 1 of the foxes.

Babesia motasi in sheep on the island of Gotland in Sweden.

Serological survey with an IFA-test showed that 58% (73/125) of the lambs and 88% (46/52) of the ewes on the island of Gotland (Sweden) has antibodies against Babesia motasi. It is likely that such a high incidence of the blood protozoan organisms plays an important part in causing the often observed anaemia in sheep on that island.

A field evaluation of anthelmintics in horses in Sweden.

A field evaluation of anthelmintics in 336 horses on 37 farms was conducted between February and May 1986 in Sweden. The herds, each comprising at least eight horses, had histories of grazing on permanent pastures and receiving regular treatments against parasites at least three times a year. Small strongyles were refractory to (pro)-benzimidazole drugs in all but one of 23 herds examined. There was an average reduction in egg output of approximately 60%, and approximately 30% of 205 horses examined were shedding less than 100 eggs g-1 7 days after treatment. There was great between-herd variation of both the faecal egg-count depression (6.4-90.4%) and drug efficacy (0.0-80.0%). The non-benzimidazole drugs under investigation were fully effective against mature small strongyles.

A field evaluation of treatment with febantel for the control of Toxocara canis in pups.

The faecal egg count depression (FECD) of febantel (Rintal vet. 100 mg tablets, Bayer AG, Veterinär-Bereich, Leverkusen), against Toxocara canis was tested in suckling pups treated at 2 weeks of age. The dose rate was 30 mg kg-1 body weight given orally, once every 12 h, three times. The effect of a further treatment of 6- and 12-week-old pups on excreted eggs was also evaluated. The FECD of 6-week-old pups was 100%. However, some of the 12- and 17-week-old pups had low eggs per gram (epg) values indicating that shorter intervals between the treatments should have been used in order to minimize the risk of spreading T. canis eggs. The control pups of the first treatment group were untreated litter mates. They were treated when 4 weeks old and then followed a similar regimen to the experimental animals. At 6 weeks of age, their FECD was 100%, but low epg values were observed among 12- and 17-week-old pups, similar to the test group.

Winter survival in Sweden of L(3)-stage larvae of the ostrich wireworm Libyostrongylus douglassii.

Libyostrongylus douglassii, a pathogenic trichostrongylid nematode of the ostrich, was recently identified as a potentially important parasite in ostriches on Swedish farms. This parasite is well adapted to the hot and dry climates of sub-Saharan Africa, the natural habitat of the ostrich. The influence of low temperatures in colder climates, such as in Sweden, on free-living stages of L. douglassii is however insufficiently known. In this study, parasite free ostrich faeces were mixed with infective L(3)-stage larvae of L. douglassii, which had been cultured from eggs obtained from two Swedish farms. Samples of the mixture were placed on a grass surface, and analyses for L(3)-stage larvae were performed at regular intervals. The results of the study showed that L(3)-stage larvae may remain alive during a period of at least 97 days on pasture during the winter season in Sweden, even when the temperature within the samples was repeatedly below -0.1 degrees C, and the air temperature varied between -19.6 and +14.9 degrees C. It was concluded that L(3)-stage larvae of L. douglassii probably have the ability to remain viable on pastures during winter in Sweden.

Observations on the use of ELISA for detection of Babesia bigemina specific antibodies.

An indirect enzyme-linked immunosorbent assay (ELISA) was evaluated to study the cause of the high level of background reactions which hinders the application of ELISA as a field diagnostic test for Babesia bigemina. Different blockers to improve the specificity of the ELISA were compared. THe use of soya milk (25%), gelatin (2.5%) and chicken serum (2%) did not significantly improve the specificity of the test. It was noted that the presence of fibrinogen contributed to the positive ELISA results more than the presence of B. bigemina specific antigen. This conclusion was confirmed by testing bovine fibrinogen as a host protein antigen in ELISA which strongly responded against B. bigemina positive control sera. It is suggested that application of ELISA for B. bigemina is still unreliable until a more purified Babesia-specific antigen or specific monoclonal antibodies are available.

Experimental infection of dogs with the nasal mite Pneumonyssoides caninum.

A successful experimental transmission of the canine nasal mite, Pneumonyssoides caninum, is described. Some 11 weeks after repeated systemic ivermectin treatment, four Beagles were inoculated via the right nostril with 20 P. caninum mites of different sexes and life stages, obtained at the necropsy of an infected dog. The inoculated dogs and a matching uninoculated control were observed for clinical signs for 14 weeks and then euthanised. Vague upper respiratory signs and a transient minor increase in the number of eosinophils in peripheral blood were recorded in the inoculated dogs. At necropsy 4-12 P. caninum mites were found in the nasal cavities and sinuses of the inoculated dogs, but none in the control. In three out of the four infected dogs mites were found in both the right and left nasal cavities and sinuses of the skull. Since in no case more mites than the number used for inoculation were detected it is not clear if the mites managed to reproduce in the dogs. Inflammatory lesions were seen most consistently in the olfactory mucosa, respiratory mucosa and tonsils, and growth of opportunistic bacteria was observed in the tonsils of the infected dogs. The inflammatory lesions seen in the olfactory mucosa may explain why dogs infected with P. caninum sometimes appear to suffer from impaired scenting ability.

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.

Intestinal parasites in swine in the Nordic countries: prevalence and geographical distribution.

In Denmark (DK), Finland (FIN), Iceland (I), Norway (N), and Sweden (S), 516 swine herds were randomly selected in 1986-1988. Individual faecal analyses (mean: 27.9 per herd) from eight age categories of swine showed that Ascaris suum, Oesophagostomum spp., Isospora suis, and Eimeria spp. were common, while Trichuris suis and Strongyloides ransomi-like eggs occurred sporadically. Large fatteners and gilts were most frequently infected with A. suum with maximum prevalences of 25-35% in DK, N and S, 13% in I and 5% in FIN. With the exception of the remarkably low A. suum prevalence rates in FIN, no clear national differences were observed. Oesophagostomum spp. were most prevalent in adult pigs in the southern regions (21-43% in DK and southern S), less common in the northern regions (4-17% adult pigs infected), and not recorded in I. I. suis was common in piglets in DK, I, and S (20-32%), while < 1% and 5% were infected in N and FIN, respectively. Eimeria spp. had the highest prevalences in adult pigs (max. 9%) without clear geographical differences. I. suis and Eimeria spp. were recorded for the first time in I, and I. suis for the first time in N.

Parafilaria bovicola (Tubangui 1934) in cattle: epizootiology-Vector studies and experimental transmission of Parafilaria bovicola to cattle.

Parafilaria bovicola (Tubangui 1934), a filarial nematode, causes cutaneous bleedings of live cattle and bruise-like lesions in the subcutaneous and IM surfaces of affected carcasses. To determine the vector(s) of this nematode under Swedish conditions, a field survey was conducted during the pasture season, May-September 1980. A total of 9,931 insects were collected from cattle and subsequently examined for infective 3rd stage Parafilaria larvae. From the fly species collected. Musca autumnalis (De Geer), Hydrotaea irritans (Fall), and Haematobia stimulans (Meig) were those most frequently identified. The 3rd-stage larvae were only found in M autumnalis, face fly. Overall infection rate in these flies was 3.5%, with peak prevalence of 30% in June. Most of the nematode larvae were recovered from heads of female flies. In experiments in insect-free stables, 5 calves were experimentally inoculated with infective 3rd-stage P bovicola larvae. Two calves inoculated by the intraconjunctival route (larvae were instilled inside the eyelid) became infected, whereas 3 calves injected subcutaneously did not. Signs of infection were not seen in 4 control calves. The median development period of P bovicola from infective 3rd-stage larvae to the development of bleeding points was 43 weeks (301 days) in 26 cattle with spontaneous parafilariasis.

Inverse age resistance to experimental Babesia divergens infection in cattle.

Two groups of calves, 1.5-2 and 7-11 months old respectively, and dairy cows were inoculated i.v. with 3 x 10(7) erythrocytes infected with Babesia divergens. High parasitaemia, fever and other clinical signs of babesiosis occurred among adult animals. A very low parasitaemia and a slightly increased body temperature but no other symptoms occurred in calves. these findings substantiate the conclusion that there exists an inverse age resistance against Babesia divergens. The kinetics of B. divergens IgG antibody formation were similar in all age groups. Consequently this antibody response was not the factor determining the development of the primary parasitaemia and thus the inverse age resistance phenomenon. However, age is not necessarily the only factor involved in the clinical expression of babesiosis. The kinetics of antibody formation was not associated with the intensity of the parasitaemia. In fact only about half the animals had a demonstrable parasitaemia although the antibody responses were similar in all age groups.

The effect of birdsfoot trefoil (Lotus corniculatus) and white clover (Trifolium repens) in mixed pasture swards on incoming and established nematode infections in young lambs.

Lotus corniculatus L., a leguminous plant containing condensed tannins, is now being evaluated in Sweden as a component of mixed pastures. This is because of its high nutritive value, palatability, modest requirement for water, calcium and phosphorous and particularly because it has the ability to survive harsh weather conditions that typify northern Scandinavia. This trial was undertaken to assess the possible parasitological benefits of using L. corniculatus when fed as a minor component in a mixed pasture sward to young sheep. This was compared with similar sheep that were fed pasture with a comparable legume content consisting of Trifolium repens L. Separate groups of lambs, maintained in pens and provided with fresh pasture cuts containing either L. corniculatus or T. repens each day, were trickle-dosed with infective larvae of mixed parasite species. For each pasture type, groups of 6 lambs had either established worm burdens only, received incoming infections only, or had the combination of both adult and incoming infections. Worm burdens were monitored by serial faecal egg counts and at the termination of the study, all animals were slaughtered for worm recovery, identification and enumeration. The results showed that there were no differential effects between L. corniculatus and T. repens on the different stages of development for a range of nematode parasite species recovered from these lambs. Several reasons may account for this: such as the low level of condensed tannins in the L. corniculatus variety tested, the minor proportion of this plant in the diet and/or the variety of L. corniculatus used in this trial which do not provide any benefits to controlling parasites of sheep.