Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important public health concern and pigs have been implicated in human infections. Cross-sectional studies have demonstrated that MRSA can be commonly found in pigs internationally, but little is known about age-related changes in MRSA colonization. This study evaluated MRSA colonization in piglets in a longitudinal manner. Serial nasal swabs were collected from piglets born to 10 healthy sows. The prevalence of MRSA colonization on days 1, 3, 7, 14 and 21 was 1% (1/100), 6.2% (3/97), 8.5% (8/94), 4.4% (4/91) and 20% (18/91) respectively, with an overall pre-weaning prevalence of 34.5%. The prevalence on days 28, 42, 56 and 70 was 34% (31/91), 65% (57/88), 50% (44/88) and 42% (36/87) respectively, with an overall post-weaning prevalence of 85%. Eighty-four percent of piglets from negative sows and 100% of piglets from positive sows that survived at least until the time of weaning were colonized with MRSA at one or more times during the study. There was a significant association between sow and piglet colonization. The age of the piglet was significantly associated with the probability of colonization. No piglets or sows received antimicrobials during the study period. These results indicate that age must be considered when designing surveillance programmes and interpreting results of different studies on MRSA.

BackgroundThe spread of PRRSV among pig herds has been investigated experimentally, but few observational studies have investigated this subject. Because PRRSV is endemic and live modified vaccines are used in Ontario, the spatial and temporal distributions of 6 PRRSV genotypes were investigated in the province during the period from 2004–2007. The purpose was to find evidence of spread of PRRSV genotypes and determine if spread could be attributed to supplier or ownership connections between herds. Sequence information from PRRSV ORF5 and related source-herd demographic information were obtained from diagnostic submissions to the Animal Health Laboratory, University of Guelph.ResultsA spatial cluster that could not be attributed to supplier or ownership connections among herds in the cluster was detected for RFLP type 1-3-4. Because of genetic dissimilarity among members of the cluster, it was considered to be a result of past spread of the RFLP type. A spatio-temporal cluster detected for RFLP type 1-18-4 was attributed to a shared gilt supplier among the herds in the cluster. Significant spatio-temporal patterns detected for RFLP type 2-5-2, which is considered to be a vaccine-type virus were most likely due to grouping of herds in an ownership that used the corresponding vaccine. Clustering within herd-ownership was a risk factor for presence of five of the six genotypes investigated in the present study.ConclusionsAlthough the literature indicates that PRRSV can spread via aerosol between pig herds, the present study found no strong evidence of this occurring in Ontario. The evidence pointed toward transmission of PRRSV occurring in this population by common sources of animals or similarity of herd ownership, which is a proxy measure for other connections between herds. It is also apparent that the recognition and testing of these connections between herds is a necessary part of interpreting spatio-temporal patterns of PRRSV genotypes.

BackgroundThe aims of this study were to investigate the prevalence of Campylobacter species in Swedish dogs, to identify the species of the Campylobacter isolates and to genotype the C. jejuni isolates. Young and healthy dogs were targeted and the sampling was performed at 11 veterinary clinics throughout Sweden from October 2011 to October 2012. Faecal swab samples were collected and sent to the laboratory at the National Veterinary Institute (SVA) for isolation of Campylobacter, speciation and genotyping.ResultsCampylobacter spp. were isolated from 67 of the 180 sampled dogs which yields an overall prevalence of 37%. The most prevalent species of Campylobacter among the participating dogs was C. upsaliensis with 52 of the 67 identified isolates. A lower prevalence was observed for C. jejuni with seven identified isolates and one isolate was identified as C. helveticus. Multi-locus sequence typing (MLST) was carried out on the seven C. jejuni isolates and all sequence types that were found are also commonly found in humans. The dogs were divided into three age groups; 1) under 12 months, 2) 12 to 23 months and 3) 24 months and older. The highest prevalence was found in the two younger age groups. Dogs shedding C. jejuni were between 3–12 months of age while dogs shedding C. upsaliensis were found in all ages.ConclusionsThe present investigation finds that Campylobacter spp. known to cause campylobacteriosis in humans are present in Swedish dogs. The results suggest an age predisposition where dogs under 2 years of age are more likely to shed Campylobacter spp. than older dogs. The most commonly isolated species was C. upsaliensis followed by C. jejuni, which was only detected in dogs up to 12 months of age. All C. jejuni isolates identified in the present study were of the same MLST types that have previously been described both in humans and in animals. The awareness of the Campylobacter risk of healthy young dogs may be an important way to reduce the transmission from dogs to infants, young children and immunocompromised adults.

BackgroundThe systemic form of porcine circovirus associated disease (PCVAD), also known as postweaning multisystemic wasting syndrome (PMWS) was initially detected in the early 1990s. Starting in 2004, the Canadian swine industry experienced considerable losses due to PCVAD, concurrent with a shift in genotype of porcine circovirus type 2 (PCV2). Objectives of the current study were to explore spatial characteristics of self-reported PCVAD distribution in Ontario between 2004 and 2008, and to investigate the existence and nature of local spread.ResultsThe study included 278 swine herds from a large disease-monitoring project that included porcine reproductive and respiratory syndrome (PRRS) virus-positive herds identified by the diagnostic laboratory, and PRRS virus-negative herds directly from the target population. Herds were included if they had growing pigs present on-site and available geographical coordinates for the sampling site. Furthermore, herds were defined as PCVAD-positive if a producer reported an outbreak of circovirus associated disease, or as PCVAD-negative if no outbreak was noted. Spatial trend was investigated using generalized additive models and time to PCVAD outbreak in a herd using Cox's proportional hazard model; spatial and spatio-temporal clustering was explored using K-functions; and location of most likely spatial and spatio-temporal clusters was investigated using scan statistics. Over the study period, the risk of reporting a PCVAD-positive herd tended to be higher in the eastern part of the province after adjustment for herd PRRS status (P = 0.05). This was partly confirmed for spread (Partial P < 0.01). Local spread also appeared to exist, as suggested by the tentative (P = 0.06) existence of spatio-temporal clustering of PCVAD and detection of a spatio-temporal cluster (P = 0.04).ConclusionsIn Ontario, PCVAD has shown a general trend, spreading from east-to-west. We interpret the existence of spatio-temporal clustering as evidence of spatio-temporal aggregation of PCVAD-positive cases above expectations and, together with the existence of spatio-temporal and spatial clusters, as suggestive of apparent local spread of PCVAD. Clustering was detected at small spatial and temporal scales. Other patterns of spread could not be detected; however, survival rates in discrete Ontario zones, as well as a lack of a clear spatial pattern in the most likely spatio-temporal clusters, suggest other between-herd transmission mechanisms.

BackgroundCampylobacter jejuni is among the most frequent causes of bacterial gastroenteritis in Europe. Over 8,000 C. jejuni multilocus sequence typing sequence types (STs) have been described; ST-21 and ST-45 have been identified as the most frequent types in all human studies so far. In contrast to other STs, ST-22 has been associated with the Guillain–Barré syndrome and ST-677 was recently linked to severe systemic infections in Finland. We investigated risk factors associated with hospitalisation in individuals with C. jejuni infections acquired in Sweden.MethodsA total of 1,075 individuals with domestically acquired C. jejuni infection diagnosed between November 2011 and October 2012 in Sweden were included in this retrospective cohort study. Typing data for the isolates as well as clinical data including hospitalisation dates and diagnosis codes for individuals with C. jejuni infection were obtained. Factors associated with hospitalisation and length of hospitalisation were investigated by multivariable analysis.ResultsA total of 289 individuals were hospitalised due to C. jejuni infection (26.8%); those with co-morbidities were over 14 times more likely to become hospitalised than those without (odds ratio [OR]: 14.39, 95% confidence interval [CI]: 6.84–30.26). Those with underlying co-morbidities were also hospitalised longer than those without (4.22 days vs. 2.86 days), although this was not statistically significant. C. jejuni ST-257 (OR: 2.38; CI: 1.08–5.23), but not ST-22 or ST-677, was significantly associated with hospitalisation.ConclusionST-677 was not associated with increased hospitalisation or a longer hospital stay in our study whilst ST-257 was. However, individuals with C. jejuni infections were generally more frequently hospitalised than previously demonstrated; this requires further consideration including possible targeted interventions.