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The global pig production has undergone major changes over the past 30 years with larger farms, more intensified production as well as improved hygiene and biosecurity practices. To investigate whether these changes, along with expanded pig welfare, have had an impact on parasite occurrence, a cross-sectional study was conducted in Sweden on farms where the pigs are always loose-housed, floors are solid and bedding material is provided. A total of 1615 faecal samples were collected on 42 conventional indoor farms from a) post-weaning piglets (n = 337); b) growers (n = 345); c) fatteners (n = 308); d) dry sows (n = 277) and e) pre-partum sows (n = 348). Samples were analysed using centrifugal flotation with a saturated glucose-salt solution and a modified McMaster technique, with a lower detection limit of 50 eggs or oocysts per gram. Samples positive for strongyle-type eggs were cultured to third stage larvae for genus identification. Farms also responded to a questionnaire regarding biosecurity, hygienic measures, and other management routines. Risk factors for parasite occurrence were assessed using mixed-effects logistical regression to account for farm-level clustering of samples. Interestingly, the prevalence of Ascaris suum was reduced compared to a similar investigation in the 1980s. In the present study A. suum was detected only in 43 % of the herds, with the highest prevalence in pre-partum sows (37 %) followed by fatteners (25 %). Small sized farms were associated with higher odds of being positive, compared to large sized farms (OR = 159.1, P = 0.010). Oesophagostomum spp. were detected in 64 % of the herds and again mainly in pre-partum sows (63 %). Trichuris suis was detected in 10 % of the herds but only in <1% of the samples. Moreover, Cystoisospora suis and Eimeria spp. were detected on 60 % and 64 % the farms, with the highest prevalence in post-weaning piglets and sows, respectively. Anthelmintic drugs (ivermectin or fenbendazole) were commonly used and administered mainly to pre-partum sows on 93 % of the farms. Toltrazuril against neonatal coccidiosis was administered to piglets on 14 % of the farms. The use of antiparasitic drugs did not significantly affect parasite prevalence. Overall, it appears that the altered farming routines with focus on improved pig welfare have not solely resulted in a higher occurrence of parasites, most likely due to the adequate biosecurity and hygiene practices instituted. Thus, there seems to be no conflict between implementing measures to promote pig welfare and adequately control the more pathogenic and economically important parasites., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Internal parasites are common in pigs worldwide and may induce clinical disease or subclinical infections with negative effects such as poor weight gain and reduced welfare, which in turn affect productivity. Effective parasite control to reduce the negative impact of parasitic infections demands a combination of antiparasitic drugs as well as various hygiene and biosecurity practices. The aim of this study was to obtain information on current management practices and parasite control routines used on Swedish pig farms using an online questionnaire., Results: Antiparasitic drugs were used on 69% of the farms routinely and were mainly administered to sows just prior to farrowing. Less than 5% of the herds conducted faecal analysis for parasites. Batchwise, age segregated rearing was common and overall, it was practiced for piglets, growers, and fatteners on 88, 80 and 75% of the farms, respectively. Large and medium sized farms appeared to apply stricter hygiene and biosecurity measures to the growing pigs compared to small farms. Dry sows were mainly housed in groups on deep litter straw beds and cleaning, as well as disinfection, between each group was less common compared to what was practiced for growing pigs. Outdoor access was rare and only occurred on organic and small farms. Most of the farms, 54, 74 and 82% of small, medium, and large sized herds respectively, reported to have less than 5% white spot lesions, caused by migrating A. suum larvae, registered at slaughter., Conclusion: Several risk factors for parasite infections, such as bedding material, group housing and solid floors, are mandatory requirements by national law. However, it was evident from this study that although strategic hygiene and biosecurity practices appeared common, they were not practiced in all herds and less so for dry sows. Antiparasitic drugs were used frequently and mainly through routine prophylactic treatments without prior testing for parasites. A holistic approach is necessary when designing efficient parasite control programs, and it is essential that management factors and routine monitoring of parasites are given attention. This to achieve efficient parasite control and reduce the risk of unnecessary use of antiparasitic drugs.

Background: For the first time in Sweden, Angiostrongylus vasorum was detected on the island of Sydkoster in foxes and dogs in 2003. After sporadic detection of the parasite in foxes in southern Sweden, the first positive canine faecal sample on the mainland was found in 2011. Since then a total of 2882 faecal samples have been analysed with the Baermann test at the National Veterinary Institute (SVA) during the years 2011-2015; 20 of them being positive. Contemporaneously, of over 525 fox necropsies, only three were found to be infected. To gather a more accurate knowledge of A. vasorum occurrence in Sweden, a large scale seroepidemiological survey was performed and totally 3885 serum samples from dogs were tested for both the presence of circulating antigens and of specific antibodies to A. vasorum., Results: In total, 0.10% (n = 4, 95% Confidence Intervals, CI 0.03-0.26%) of the dogs were positive for both antigen and antibodies, whereas 0.51% (n = 20, CI 0.31-0.79%) of the tested dogs were only antigen positive and 0.88% (n = 34, CI 0.61-1.22%) only positive for specific antibodies. Seropositive animals, as well as the majority of A. vasorum-positive faecal samples tested during the same period, were spread over central and southern Sweden. Annual prevalence of positive faecal dog samples and of necropsied A. vasorum positive foxes (coming from southern Sweden) varied from 0.3 to 0.9% (overall: 0.7%, CI 0.4-1.1%) and 0.0 to 1.4% (overall: 0.3%, CI 0.1-0.9%), respectively., Conclusions: The findings confirmed that A. vasorum has become established in various geographical areas of central and southern Sweden. Veterinarians and dog owners should be aware of the potential risks of infection in large areas of the country, since canine angiostrongylosis may be a fatal disease if left untreated.

Background: This study was performed in order to gather recent epidemiological data on feline endoparasites in Swedish cats. Faecal samples from 205 outdoor cats were collected by their owners and submitted to the National Veterinary Institute for analysis. The study population was comprised of cats with access to an outdoor environment and with no history of anthelmintic treatment within the last 3 months. Intestinal parasites were detected with a centrifugal flotation technique and Baermann larval sedimentation was performed to detect metastrongylid lungworms. Eggs, larvae and oocysts were identified morphologically by microscopic examination. The following information was collected from cat owners: breed, sex, age, anthelminthic medication last used, observation of cestode proglottids and residential address., Results: Endoparasites were detected in 25% of samples. Eggs of Toxocara cati were found in 21% of samples, followed by taeniid eggs (4%), oocysts of Cystoisospora felis/C. rivolta and capillarid eggs (both 1%). One cat tested positive for Toxoplasma gondii-like oocysts. Larvae of Aelurostrongylus abstrusus were detected in one cat, which is the first published observation of this parasite in Sweden., Conclusions: The occurrence of intestinal parasites is rather high in outdoor cats in Sweden, which could indicate the need for more intensive deworming routines in the population. Clinical practitioners should be aware of the possible occurence of A. abstrusus in Swedish cats when considering potential causes of respiratory problems in cats in the future.

Background: In the last few years stud farms have experienced increasing problems with Parascaris equorum infections in foals despite intensive deworming programs. This has led to the question as to whether the anthelmintic drugs used against this parasite are failing. This study aimed to investigate the efficacy of ivermectin, fenbendazole and pyrantel on the faecal output of ascarid eggs of foals., Methods: A Faecal Egg Count Reduction Test (FECRT) was performed on nine large studs in Sweden. Anthelmintic drugs were given orally and faecal samples were examined for ascarid eggs on the day of deworming and 14 days later. Faecal Egg Count Reductions (FECRs) were calculated on arithmetic means of transformed individual FECRs and on arithmetic means of individual FECRs., Results: Seventy-nine (48%) out of a total of 165 foals sampled were positive for P. equorum eggs before deworming and 66 of these met the criteria for being used in the efficacy assessment. It was shown that there was no, or very low activity of ivermectin on the output of ascarid eggs in the majority of the foals, whereas for fenbendazole and pyrantel it was >90%., Conclusion: Ivermectin resistance was shown in 5 out of 6 farms. Therefore, ivermectin should not be the drug of choice in the control of P. equorum infections in foals. According to the results of this study, fenbendazole or pyrantel are still effective and should be used against this parasite.

Background: Virtually all horses are infected with helminth parasites. For some decades, the control of parasites of Swedish horses has been based on routine treatments with anthelmintics, often several times per year. Since anthelmintic resistance is becoming an increasing problem it is essential to develop more sustainable control strategies, which are adapted to different types of horse management. The aim of this study was to obtain information on practices used by Swedish horse owners for the control of endoparasites., Methods: A questionnaire with 26 questions about management practices and parasite control routines was posted to 627 randomly selected horse establishments covering most types of horse management in Sweden., Results: The response rate was good in all categories of respondents (66-78%). A total of 444 questionnaires were used in the analyses. It was found that virtually all horses had access to grazing areas, usually permanent. Generally, pasture hygiene was infrequently practiced. Thirty-six percent of the respondents clipped or chain harrowed their pastures, whereas weekly removal of faeces from the grazing areas was performed by 6% of the respondents, and mixed or rotational grazing with other livestock by 10%. The number of anthelmintic treatments per year varied from 1-8 with an average of 3.2. Thirty-eight percent considered late autumn (Oct-Dec) to be the most important time for deworming. This finding, and an increased use of macrocyclic lactones in the autumn, suggests a concern about bot flies, Gasterophilus intestinalis. Only 1% of the respondents stated that faecal egg counts (FEC) were performed on a regular basis. The relatively high cost of FEC analyses compared to purchase of anthelmintics was thought to contribute to the preference of deworming without a previous FEC. From the study it was evident that all categories of horse owners took advice mainly from veterinarians., Conclusion: The results show that routines for endoparasite control can be improved in many horse establishments. To increase the knowledge of equine endoparasite control and follow the recommendations for how to reduce the spread of anthelmintic resistance, a closer collaboration between parasitologists and veterinary practitioners is desirable.

The objective of the study was to investigate different aspects on the efficacy of three anthelmintics on cyathostomin nematodes of Swedish horses. A faecal egg count reduction (FECR) test was performed on 26 farms. Horses were treated orally with recommended doses of ivermectin, pyrantel pamoate or fenbendazole. Faecal samples were collected on the day of deworming and 7, 14 and 21 days later. No resistance was shown against ivermectin; the FECR was constantly >99%. The effect of pyrantel was assessed as equivocal in 6 farms 14 days after treatment; the mean FECR was 99%. As many as 72% of the fenbendazole-treated groups met the criteria for resistance; the mean FECR was 86%, ranging from 56% to 100%. A re-investigation of two farms where pyrantel resistance had been suspected clearly revealed unsatisfactory efficacy of pyrantel on one of these farms; the FECR varied from 72% to 89%. Twenty-six of the horses previously dosed with pyrantel or fenbendazole, and which still excreted >/=150 eggs per gram of faeces 14 days after treatment, were dewormed with ivermectin and fenbendazole or pyrantel in order to eliminate the remaining cyathostomins. A total of 13 cyathostomin species were identified from horses that initially received fenbendazole and seven species were identified from pyrantel-treated individuals. The egg reappearance period (ERP) following treatment with ivermectin and pyrantel was investigated on two farms. The shortest ERP after ivermectin treatment was 8 weeks and after pyrantel was 5 weeks. We conclude that no substantial reversion to benzimidazole susceptibility had taken place, although these drugs have scarcely been used (<5%) in horses for the last 10 years. Pyrantel-resistant populations of cyathostomins are present on Swedish horse farms, but the overall efficacy of pyrantel is still acceptable.

The aim of this study was to investigate the suitability of a larval development assay (LDA) for the determination of anthelmintic resistance in cyathostomin nematode populations of the horse. In addition, comparison of results between geographic regions, types of horse establishment, and the use of anthelmintics in Sweden, was established. Seventy horse herds from different parts of Sweden were sampled, and strongyle eggs from the faeces of 54 of those were investigated by an LDA (DrenchRite). The following anthelmintics were tested: thiabendazole (TBZ), levamisole (LEV), ivermectin monosaccharide (IVM-MS), ivermectin aglycone (IVM-AG) and pyrantel (PYR). The LC50 values for TBZ and LEV were generally lower than those previously reported in other LDA studies on horse nematodes. This could be related to the infrequent use of these compounds for the past 20 years in Sweden. In this study, there was a great variation within and between assay plates that could not be explained. Still the LC50 values differed significantly between the regions for all anthelmintics, except for pyrantel. The highest LC50s were observed in parasite populations from the south of Sweden. There were no significant differences between riding schools and studs. Limitations of this technique exist, namely the lack of established cut-off values for susceptible and resistant populations and interpretation problems related to multi-species infections. Although there are advantages with LDA such as the possibility of testing several compounds simultaneously without interference with the deworming programmes on the farms, we conclude that LDA currently is not a reliable alternative to the faecal egg count reduction test (FECRT).

The egg output and humoral antibody response to scolex antigens of the equine tapeworm Anoplocephala perfoliata were monitored in naturally infected foals by an egg flotation/centrifugation method and an indirect enzyme-linked immunosorbent assay (ELISA). The study was performed on a stud farm in south-western Sweden between May 1994 and April 1995. Sequential blood and faecal samples were taken from 21 foals during their first summer on pasture and until tapeworm eggs were detected. Results were expressed separately for 10 and 11 foals born before and after the end of April 1994, respectively. Increased levels of antibodies were noticed from October and onwards in both groups whereas tapeworm eggs were detected in the faeces of all foals about 4 months later. The antibody response was similar in both groups but it was more pronounced in foals born before April 1994. All foals were treated in March 1995 with an oral paste formulation of pyrantel pamoate at a dose rate of 38 mg/kg bodyweight. Most animals responded to the anthelmintic treatment and one month later, tapeworm eggs were only detected in one out of the 18 foals examined one month after treatment. Thus, the treatment reduced the number of A. perfoliata egg positive horses by 94%. A concomitant decline in antibody levels was also observed. Western immunoblot analysis of sequential individual serum samples showed that at least 10 different scolex antigens in the molecular weight range 10-200 kDa were recognised. Banding intensities, especially of the 10 kDa, 45 kDa and 66 kDa proteins were different in the sequential sera taken during the course of infection.