Sarcoptic mange in the wild boar, Sus scrofa, in Sweden

Sarcoptic mange caused by Sarcoptes scabiei has been present in the Swedish red fox (Vulpes vulpes) population since the 1970s. The disease has been described in other Swedish wildlife species, but not in the wild boar, Sus scrofa, until 2009. Single cases of sarcoptic mange have been diagnosed the last years in the expanding population of wild boar. This study aims to describe the histopathological lesions found on mangy wild boar and compare, by molecular methods, mites from wild boar cases with mites from mangy red foxes, raccoon dogs, and domestic pigs. Mangy wild boar with focal alopecia and clinical signs of pruritis were reported or submitted from various areas in southern Sweden to the National Veterinary Institute, Uppsala. The examined skin samples of wild boar infected with S. scabiei showed limited gross skin lesions, except for cases with severe exudative dermatitis. Histopathology of the affected wild boar skin samples showed an eosinophilic dermatitis with a variable hyperkeratosis and often low number of mites present. To study the relationship of S. scabiei mites isolated from different host species, a population genetics investigation was performed based on microsatellite markers. In total, 225 individual mites from eight individuals of four different host species; red fox (48 mites), wild boar (80 mites), domestic pig (48 mites) and raccoon dog (43 mites), were included in the study. In the phylogenetic analysis, all mites isolated from wild boar clustered together even though they originate from different geographical regions in Sweden. Mites from each individual host showed high similarity. The results indicate that wild boar mites differ from mites both from the red fox, raccoon dog, and domestic pig

Comparison of Multiple-Locus Variable-Number Tandem Repeat Analysis Profiles of Enteropathogenic Yersinia spp. Obtained from Humans, Domestic Pigs, Wild Boars, Rodents, Pork and Dog Food

The enteropathogenic Yersinia genus is commonly detected in wildlife including wild boars. Difficulties in its cultivation may hamper subsequent epidemiological studies and outbreak investigations. Multiple-locus variable-number tandem repeat analysis (MLVA) of Yersinia (Y.) enterocolitica and Y. pseudotuberculosis has proven useful in source attribution and epidemiological studies but has hitherto relied on the analysis of isolates. In the present study, MLVA profiles generated from 254 isolates of Y. enterocolitica indicated similarities between human, pig and rodent isolates. Further, MLVA analyses of 13 Y. pseudotuberculosis pure-cultured isolates were compared to MLVA analyses performed directly on the 14 PCR-positive enrichment broths from which the isolates originated, which showed matching MLVA profiles. This indicates that MLVA analysis performed directly on enrichment broths could be a useful method for molecular epidemiological investigations. In addition, 10 out of 32 samples of wild boar minced meat obtained from private hunters and from approved wild-game-handling establishments were PCR-positive for the presence of Y. enterocolitica and may indicate a risk for public health

Iron status in piglets at three days of age and at weaning and possible seasonal effects on the blood haemoglobin levels in a Swedish outdoor pig-producing farm

Background Piglets are born with limited stores of iron, and with an increasing number of live-born piglets, there may be a risk that the sows cannot provide enough iron to their offspring. The iron content in soil may not meet the demands of today's piglet, born and reared in an outdoor setting. The study aimed to describe the blood haemoglobin (Hb) levels in pigs reared outdoors and to determine whether piglets have higher Hb levels at weaning when an iron supplement is administered intramuscularly at three days of age, as compared to pigs not given an iron supplement. The seasonal variation in Hb-levels was also to be investigated. The Hb concentration was analysed with a HemoCue 201 + Hb photometer. Results In total 56 litters (399 piglets) were included in the study and sampled at three days of age, while 378 piglets were sampled at weaning. The mean Hb level at three days of age was 91 g/L (48-154 g/L). In total 47% of the piglets had Hb levels < 90 g/L at three days of age. The mean Hb level at weaning was 127 g/L (76-176 g/L), with a lower level (122 g/L) in the group given the iron supplement than in the group not given an iron supplement (132 g/L). Only 1% of the piglets had Hb levels lower than 90 g/L at weaning. Results indicative of a seasonal effect on Hb levels at three days of age was demonstrated. Piglets born in spring had significantly lower Hb levels, and piglets born in autumn had significantly higher Hb levels. No seasonal effect could be demonstrated for Hb levels at day 33. Conclusions The results indicate that the natural uptake from the environment was sufficient, but that there was a seasonal effect on the Hb levels at three days of age. This indicates that there might be a need for different routines regarding iron supplementation in outdoor reared piglets depending on the climate and season

Enteropathogenic Yersinia spp. and Salmonella spp. in Swedish wild boars

Wild boars are reported as carriers of several zoonotic agents. The aims of this thesis was to investigate the presence of the foodborne enteropathogens Salmonella spp., Yersinia (Y.) spp. and E. coli O157:H7 in Swedish wild boars, the influence of potential risk factors presumably associated with their occurrence, the presence of Yersinia spp. and Salmonella spp. in minced meat, and to establish a method for molecular epidemiological studies (MLVA). The thesis includes studies on lymphatic tissue and faeces from 178 wild boars and 32 samples of wild-boar minced meat. MLVA was evaluated on 254 isolates of Y. enterocolitica from several sources. Further, the wild boar populations were characterized with respect to four factors that possibly may be associated with the presence of enteropathogens in the wild boar. A PCR-based protocol for the detection of enteropathogenic Yersinia spp. and Salmonella spp. was developed and evaluated. The protocol offered the possibility to obtain molecular epidemiological data of Yersinia spp. by MLVA on enrichment broths. In total, 91 (51.1%) of the sampled wild boars carried the enteropathogens investigated and 46, 37 and 32 animals were PCR-positive for the presence of Y. enterocolitica, Y. pseudotuberculosis, and Salmonella spp., respectively. The subsequent cultivation yielded a total of 28 isolates of Salmonella spp., 10 isolates of Y. enterocolitica and 13 isolates of Y. pseudotuberculosis. None of the investigated risk factors were associated with the presence of these enteropathogens. However, a strong association between high levels of artificial feeding and high population densities was seen and the practice of leaving slaughter waste out in nature was found to be common among the hunters. In the new protocol, a positive selection for motile bacteria was used and seemed favourable in the detection of Y. enterocolitica and Salmonella spp. but not in the detection of Y. pseudotuberculosis. Further, MLVA performed directly on the enrichment broth seemed promising. MLVA on the isolates demonstrated a close resemblance between two human isolates and those obtained from domestic pigs whereas one rodent isolate was identical to that from pigs in the same farm. In conclusion, human enteropathogens are present in a majority of the Swedish wild boars which may be of concern for the public health. The findings warrants further surveillance on the enteropathogens present and the new protocol presented within this thesis may be useful to obtain molecular epidemiological data for future reference in e.g. outbreak investigations

Evidence of Anaplasma phagocytophilum infection in an island population of Scandinavian moose (Alces alces) in the South-eastern Sweden

In the second half of the 1990's the moose population on the island Öland declined drastically and the hunters decided to completely stop hunting for moose for a number of years. When the hunting commenced the hunters found the slaughter weights to be lower than expected and the number of calves were also low. The hunters then contacted the Swedish National Veterinary Institute who then initiated a project which this report is a part of. Samples from a total of 40 moose was collected, 32 out of 33 sampled moose were positive for antibodies against Anaplasma phagocytophilum and 4 out of 36 samples were positive by PCR for Ananplasma phagocytophilum. Out of these three were calves and one was a female yearling. Reported slaughter weights for calves were low and the number of observed calves per adult female were half compared to the mainland. This survey indicates that infection with Anaplasma phagocytophilum constitutes a contributing cause for the low number of observed calves in the moose population on the island of Öland.Under senare delen av 90-talet minskade älgstammen på Öland drastiskt och jägarna valde då gemensamt att helt avstå jakt under ett antal år. När jakten återupptogs upplevde jägarna att kalvarna var få till antalet och hade låga slaktvikter. De kontaktade då SVA som inledde ett projekt med omfattande provtagning. Detta arbete är en del av detta projekt. Prover från totalt 40 älgar samlades in, 32 av 33 provtagna älgar visade på antikroppar mot Anaplasma phagocytophilum medan 4 av 36 provtagna var PCRpositiva för Anaplasma phagocytophilum. Av dessa var tre kalvar och en var en kviga. De slaktvikter som rapporterades in för kalv visade på låga siffror och antalet observerade kalvar per vuxet hondjur var hälften av vad som observerats på fastlandet. Denna undersökning pekar på att infektion med kan vara en bidragande orsak till det låga antalet observerade kalvar hos älgpopulationen på Öland

Prevalence and genomic characteristics of zoonotic gastro-intestinal pathogens and ESBL/pAmpC producing Enterobacteriaceae among Swedish corvid birds

Introduction: Wild birds pose a potential threat to animal and human health by spreading infectious diseases. In the present study, we studied the occurrence of bacterial zoonotic pathogens as well as enterobacteria with transferrable antimicrobial resistance genes among Swedish corvids. Materials and methods: Intestines from 66 jackdaws, crows, rooks and magpies from the vicinity of livestock farms at 14 locations in 7 counties were analysed by direct culture or PCR screening followed by culture. Isolates were investigated by whole-genome sequencing. Results and discussion: Campylobacter jejuni were detected in 82% and Yersinia in 3% of the birds. ESBL-producing E. coli were found in one sample (2%) and carried blaCTX-M-55. No Enterobacteriaceae with transferable carbapenem resistance were identified. No Salmonella or E. coli O157:H7 were found, but PCR analysis for enterohaemorrhagic E. coli virulence genes revealed 35% positive samples for intimin, 9% for verotoxin 1 and 17% for verotoxin 2. C. jejuni isolates from corvids were compared to previously published isolates from Swedish sources by multi-locus sequence typing based on genome sequences. All corvid C. jejuni isolates formed a cluster, intermingled with human and chicken isolates. Our results indicate that C. jejuni is ubiquitous among Swedish corvid birds, with sporadic transmission to poultry and humans

Inclusion of silage in diets to fattening pigs: effect on gastric ulcers and skin lesions

Limited access to high-quality feed protein for pigs has made it necessary to evaluate new protein sources that both promote sustainable pig production and meet the nutritional requirements of pigs. Providing pigs with roughage has positive effects on their behaviour and gut health. However, roughage is seldom given as a part of the pigs’ diet and often has a long straw length. Knowledge is lacking on the effect of feeding silage with smaller particle size and as a part of the pigs' diet on pig behaviour and welfare. This study evaluated the influence of feeding fattening pigs silage with different particle sizes on aggressive encounters, measured as the number of skin lesions, and on the occurrence of gastric lesions and ulcers. In total, 128 Swedish Yorkshire × Hampshire pigs were fed either a commercial control feed without silage (Pellet-C), or silage mixed with commercial feed, either in a pellet (Pellet-S) or in a total mixed ration (TMR) with chopped (TMR-Ch) or intensively treated silage (TMR-Ex). Skin lesions were assessed twice in the study according to the Welfare Quality® protocol. The first assessment was performed when the pigs were 105 days old and the second assessment at 132 days of age. Gastric lesions were examined in both the pars oesophagea and the pars glandularis region of the stomach. Stomachs were collected after slaughter, and gastric lesions were scored based on established scoring criteria. There was a treatment × assessment interaction on the number of skin lesions on the ear (P = 0.049). Apart from this interaction, no other effect of treatment on the number of skin lesions could be observed between the treatments or the assessment occasions. Treatment had a clear effect on the occurrence of gastric lesions and pigs fed the fresh silage (TMR-Ch and TMR-Ex) had a lower occurrence of gastric lesions and ulcers compared to the pelleted treatments (Pellet-C and Pellet-S) (P = 0.001). This study could not show any clear reduction effect of dietary silage inclusion on skin lesions. However, feeding silage in TMR significantly reduced the occurrence of stomach ulcers

Distribution of enteropathogenic Yersinia spp. and Salmonella spp. in the Swedish wild boar population, and assessment of risk factors that may affect their prevalence

Abstract Background Pure Eurasian wild boars and/or hybrids with domestic pigs are present in the wild on most continents. These wild pigs have been demonstrated to carry a large number of zoonotic and epizootic pathogens such as Salmonella spp., Yersinia enterocolitica and Y. pseudotuberculosis. Wild boar populations throughout Europe are growing and more and more wild boar meat is being consumed, the majority within the homes of hunters without having passed a veterinary inspection. The aim of this study was to investigate if factors such as population density, level of artificial feeding, time since establishment of a given population, and the handling of animal by-products from slaughtered animals could influence the presence of these pathogens in the wild boar. Results In total, 90 wild boars from 30 different populations in Sweden were sampled and analysed using a protocol combining pre-cultivation and PCR-detection. The results showed that 27% of the sampled wild boars were positive for Salmonella spp., 31% were positive for Y. enterocolitica and 22% were positive for Y. pseudotuberculosis. In 80% of the sampled populations, at least one wild boar was positive for one of these enteropathogens and in total, 60% of the animals carried at least one of the investigated enteropathogens. The presumptive risk factors were analysed using a case–control approach, however, no significant associations were found. Conclusion Human enteropathogens are commonly carried by wild boars, mainly in the tonsils, and can thus constitute a risk for contamination of the carcass and meat during slaughter. Based on the present results, the effect of reducing population densities and number of artificial feeding places might be limited

Prevalence of human pathogenic Yersinia enterocolitica in Swedish pig farms

Abstract Background Pigs are the most important reservoir for human pathogenic Yersinia enterocolitica. We investigated the herd prevalence of human pathogenic Y. enterocolitica in Swedish pig farms by analysing pen faecal samples using a cold enrichment of 1 week and thereafter subsequent plating onto chromogenic selective media (CAY agar). Results Pathogenic Y. enterocolitica was found in 32 (30.5%) of the 105 sampled farms with finisher pigs. Bioserotype 4/O:3 was identified at all but one farm, where 2/O:9 was identified. Pen-prevalence within the positive herds varied from 1/4 to 4/4 pens. The calculated intra-class correlation coefficient ICC (0.89) from a model with a random effect for grouping within herd indicated a very high degree of clustering by herd. None of the explored risk factors, including herd size, herd type, pig flow, feed type, access to outdoors, evidence of birds and rodents in the herd, usage of straw, number of pigs in sampled pen and age of pigs in pen were significantly associated with Y. enterocolitica status of the pen. The use of high pressure washing with cold water was significantly associated with Y. enterocolitica in the pen (OR = 84.77, 4.05–1772). Two culture methods were assessed for detection of Y. enterocolitica, one of which included the use of a chromogenic agar (CAY agar) intended for detection of human pathogenic Y. enterocolitica. The chromogenic media was found equal or superior to traditional methods and was used in this study. The isolates obtained were characterised by biotyping, serotyping, mass spectrometry (MALDI-TOF) and PCR. Characterisation by MALDI-TOF gave identical results to that of conventional bioserotyping. All porcine isolates were positive for the ail and inv genes by PCR, indicating that the isolates were most likely pathogenic to humans. Conclusions Human pathogenic Y. enterocolitica was found in nearly one-third of the Swedish pig farms with finisher pigs. The use of high pressure washing with cold water was associated with the presence of Y. enterocolitica in the pen. A modified culturing method using a chromogenic agar was efficient for detection of pathogenic Y. enterocolitica in pig faeces. The use of masspectrometry for identification and subtyping was in agreement with conventional biotyping and serotyping methods