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I Vågsholm

Publications and source records attributed to I Vågsholm.

At least 19 recordsLinked to original sources
PubMed2006

Feed-borne outbreak of Salmonella cubana in Swedish pig farms: risk factors and factors affecting the restriction period in infected farms.

In 2003, a feed-borne outbreak of Salmonella Cubana occurred in Sweden as a result of contamination in a feed plant. Salmonella Cubana was detected in 49 out of 77 pig farms having received possibly contaminated feed. In this study, potential risk factors for farms being salmonella positive were examined, and a survival analysis was performed to investigate risk factors affecting the restriction period for salmonella positive farms. The median restriction time for all 49 farms was 17 weeks. An increased risk for farms being salmonella infected (positive in feed and/or faeces) was seen for fattening farms and farms feeding soy. The survival analysis showed that herds with a low level of infection and farms with a high hygiene level had shorter restriction times. This study is unique as it investigates a real outbreak of feed-borne salmonella, where the source of infection was reliably identified, the period of exposure could be defined and data were collected from all exposed farms.

Animal Feed↗
PubMed2006

Postchill campylobacter prevalence on broiler carcasses in relation to slaughter group colonization level and chilling system.

Data from an ongoing national surveillance program of Campylobacter prevalence in broiler slaughter groups were related to results from a 1-year baseline study of broiler carcasses postchill. The goals were to establish the relation between Campylobacter prevalence in slaughter groups and on carcasses and to determine the effect of various chilling systems on Campylobacter prevalence. Pooled cloacal and neck skin samples from the surveillance program were analyzed after enrichment. Carcass rinse samples from the baseline study were analyzed after enrichment and by direct plating. Data from both studies were available for 614 carcasses. Direct-plating analyses indicated that the percentages of carcasses positive for Campylobacter jejuni and other Campylobacter spp. in slaughter groups with negative cloacal samples were 2 and 10%, respectively, whereas enrichment analyses indicated prevalences of 2% in both cases. Campylobacter prevalence in slaughter groups with a high degree of intestinal colonization (more than half of the pooled cloacal samples positive) was significantly higher than in slaughter groups with a low degree of colonization (76 to 85% and 30 to 50%, respectively, depending on Campylobacter spp. and analytical method). The prevalence of Campylobacter-positive carcasses postchill was at the same level as the prevalence of carcasses that originated from slaughter groups with positive neck skin samples at four of the six slaughterhouses. Only at one slaughterhouse, with an air-chilling system, was the postchill prevalence (13%) lower than that expected from slaughter group data (23%). The postchill prevalence (43%) was higher than that expected from slaughter group data (33%) at one slaughterhouse with immersion chilling.

Abattoirs↗
PubMed2005

Risk factors for hazard of release from salmonella-control restriction on Swedish cattle farms from 1993 to 2002.

In Sweden, only a few cattle farms are infected with salmonella each year and this can be attributed to the Swedish salmonella control programme. All findings of salmonella in animals, feed and food of animal origin are notifiable and restrictions are always put on infected herds until they have been cleaned up from the infection. However, there has been concern about increasing costs for clean-up of salmonella-infected farms as well as increasing length of the restriction periods. Our aim was to investigate potential risk factors associated with the length of restriction periods on Swedish cattle farms between 1993 and late 2002. All 112 cattle farms that were notified to the Swedish Board of Agriculture as infected with salmonella during the study period, were included in this longitudinal and retrospective study. The putative risk factors were analysed using the proportional-hazards model. There was a lower hazard for release from salmonella control restrictions after the European Union (EU) accession in 1995, and/or change of testing from one to two negative herd tests for release of restrictions (hazard ratio (HR)=0.56, 95% confidence interval (CI)=0.38, 0.84), for every additional number of 100 cows (HR=0.83; CI=0.7, 0.97), if rodents and/or wild birds were abundant (HR=0.5, CI=0.27, 0.98) and if there was more than one farm site in the company (HR=0.47, CI=0.28, 0.81).

Animal Feed↗
PubMed2005

Prevalence of verotoxin-producing Escherichia coli (VTEC) 0157 in Swedish dairy herds.

A prevalence study of verotoxin-producing Escherichia coli O157 (VTEC O157) was performed in 371 randomly selected dairy herds distributed throughout Sweden. Faecal and manure samples were collected and analysed by immunomagnetic separation and culturing. Data were recorded for each herd regarding herd size, age of sampled animals and whether, in addition to cattle, the farm kept other animals. VTEC O157 was isolated from 33 (8.9%) of the 371 investigated herds. The prevalence was higher (23.3%) in Halland county than in the rest of Sweden (P > 0.01). Halland was also the county in Sweden that during the study period had the highest incidence of human VTEC O157 cases. VTEC O157 was not detected on any farm in northern Sweden. Identified risk factors, in the multivariate analyses, for herds being VTEC O157 positive were herd size, geographical localization, presence of pigs on the farm and median age of sampled animals.

Animals↗
PubMed2005

Transmission of Campylobacter spp. to chickens during transport to slaughter.

AIMS: To determine the prevalence of Campylobacter-contaminated transport crates and to determine whether contaminated crates represent a risk for contamination of chickens during transport to slaughter. METHODS AND RESULTS: Samples were collected from cleaned transport crates before they were dispatched to the farms. Chicken groups were sampled within 24 h before transport to slaughter and at the slaughterhouse. Campylobacter spp. were isolated from 69 of 122 (57%) sampled batches of transport crates. Twenty-six slaughter groups, negative at farm level, were transported in batches of crates from which Campylobacter spp. had been isolated. In 11 (42%) of these 26 slaughter groups, Campylobacter spp. were found in samples taken at slaughter. The corresponding figure for at-farm-negative slaughter groups transported in negative crates was four (15%) testing positive at slaughterhouse of 27 slaughter groups [relative risk (RR) = 2.9, 95% CI 1.1-7.3]. In four of 11 slaughter groups, genetic subtyping by pulsed-field gel electrophoresis was able to support the hypothesis of contamination from crates to chickens during transport to slaughter. CONCLUSIONS: Despite washing and disinfection, crates were frequently contaminated with Campylobacter and it could have contaminated chickens during transport to slaughter. SIGNIFICANCE AND IMPACT OF THE STUDY: Campylobacter-positive crates are a risk factor for chickens testing campylobacter-positive at slaughter.

Abattoirs↗
PubMed2004

Surveillance programme for Campylobacter species in Swedish broilers, July 2001 to June 2002.

A total of 20,599 samples from 4133 slaughter groups representing about 71 million broilers slaughtered between July 1,2001 and June 30, 2002 were tested for Campylobacter species. From each slaughter group, 40 cloacal samples and 10 samples of neck skin were taken from the carcases on the slaughter line and the samples were pooled, 10 to a pool. Campylobacter species were detected in cloacal samples from 17 per cent of the slaughter groups and in neck skin samples from 22 per cent of the groups, and the monthly prevalence figures ranged from 6 to 32 per cent. In most of the infected groups all four pooled cloacal samples were positive, but 18 per cent of the infected groups had only one or two positive samples. More than 90 per cent of the Campylobacter-positive slaughter groups were delivered by half the producers, and one in four of the producers delivered no Campylobacter-positive slaughter groups.

Abattoirs↗
PubMed2003

Survey of Campylobacter species, VTEC O157 and Salmonella species in Swedish wildlife.

Samples collected from 791 wild animals (Canada geese, roe deer, hares, moose, wild boar and gulls) shot during hunting were examined for verocytotoxin-producing Escherichia coli (VTEC) O157, and thermophilic Campylobacter and Salmonella species. With the exception of one positive isolate from a wild boar, VTEC O157 was not isolated from any of the animals. Salmonella species were isolated only from the gulls, of which 4 per cent were estimated to be positive. Thermophilic Campylobacter species were commonly isolated from all the species except deer.

Animals↗
PubMed2002

Bulk milk testing for antibody seroprevalences to BVDV and BHV-1 in a rural region of Peru.

Bulk milk from 60 herds of dairy cattle in a rural region in the central highlands of Peru was tested for antibodies to bovine viral-diarrhoea virus (BVDV) and bovine herpesvirus type 1 (BHV-1). None of the herds had been vaccinated against BVDV or BHV-1. Commercially available indirect ELISA-kits were used for antibody detection. True prevalences of BVDV and BHV-1 antibody-positive herds were 96 and 51%, respectively. A relatively low proportion of strongly positive herds suggests, however, a low prevalence of active BVDV infection. BVDV optical densities (ODs) in bulk milk increased with herd size--indicating a higher within-herd prevalence in the larger herds (probably, in part a consequence of a higher rate of animal movement into these herds). For BHV-1, this pattern was not found; a relatively high proportion of the herds was free from BHV-1 infection in each size category. This could indicate a low rate of reactivation of latent BHV-1 infection.

Animals↗
PubMed2002

Animal- and herd-level risk factors for leptospiral seropositivity among sows in the Mekong delta, Vietnam.

In 1998, a total of 424 sows had sera collected in the Mekong delta in Vietnam. Of these, 283 sows were from 151 small-scale family farms in 19 villages, and 141 from seven large-scale state farms. The sera were subjected to the microscopic agglutination test (MAT) for antibodies to 13 Leptospira serovars. The overall leptospiral seroprevalence for titres > or =1:100 and > or =1:400, was 73 and 29%, respectively, and was higher (P=0.001) at small- than at large-scale farms. The highest seroprevalence was recorded for Leptospira interrogans serovar (sv) bratislava (52%). At small-scale farms, higher prevalences were found to serovars L. interrogans sv icterohaemorrhagiae (P=0.04) and L. interrogans sv pomona (P=0.02). Epidemiological information (at the individual-animal and herd-levels) was collected with a questionnaire. The data were analysed using logistic multiple regression. At the animal-level, sows seropositive for L. interrogans sv australis and sv autumnalis had less direct contact with sows in neighbouring pens (odds ratio (OR)=0.3 and 0.4, respectively) and sows seronegative for L. interrogans sv bratislava were of lower age (OR=0.1 for seropositivity). Also, sows seropositive for L. interrogans sv icterohaemorrhagiae had higher odds (OR=5.8) if they had not been born on the farm (had been introduced to it as gilts). Herds seropositive for sv javanica showed association with farms not taking measures to control the local rodent population (OR=7.8). Serovar pomona was also linked to the use of artificial insemination (AI), as opposed to natural-breeding services (OR=11.2). These results indicate that housing and management could affect the seroprevalence of Leptospira infection in pigs.

Age Factors↗
PubMed2001

Persistence of verocytotoxin-producing Escherichia coli O157:H7 in calves kept on pasture and in calves kept indoors during the summer months in a Swedish dairy herd.

In 1997, a Swedish dairy farm was implicated in a human case of verocytotoxigenic Escherichia coli (VTEC) infection. The bacterium was found in a faecal sample from the human case and in faecal samples from cattle on the farm. Subtyping with pulsed field gel electrophoresis (PFGE) showed that the isolates were identical. The farm was further studied to assess the occurrence and the epidemiology of the agent at the farm level. The objective of this part of the study presented here was to examine the persistence of VTEC O157:H7 in calves that were kept on pasture and indoors, respectively, during the summer. Twelve calves in the herd, with one positive faecal sample each of VTEC O157:H7 in April 1999, were followed by faecal sampling during the summer months. Six calves were kept indoors and six were kept on pasture. Faecal samples from each calf were collected once a month on five occasions from April to September. Bacterial examination was performed with immunomagnetic separation (IMS) and cultivation on CT-SMAC. PCR was used to test for the presence of genes encoding for verocytotoxin (VT), intimin (eaeA), enterohemorrhagic E. coli-hemolysin (EHEC-Hly) and the flagellar antigen H7. PFGE was used for genotyping the isolates. The faecal samples from the calves kept on pasture were negative during the whole period. It is possible that the faecal samples had bacterial counts lower than the detection limits for our procedure, or that the faecal samples were free from the bacteria at the time of sampling. This suggests that calves on pasture may be less exposed to the bacteria or that they clear themselves. In the pen group, there were between one and six culture positive individuals per sampling occasion. One of the calves that was housed indoors was positive in faecal culture on four consecutive samplings.

Animals↗
PubMed2001

Cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. and demographic, clinical and tick-exposure factors in Swedish horses.

A cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. in Swedish horses was conducted to evaluate associations with demographic, clinical and tick-exposure factors. From September 1997-1998, blood samples from 2018 horses were collected from the animals presented to veterinary clinics affiliated with the Swedish Horserace Totalizator Board (regardless of the primary cause for consultation). Standardized questionnaires with information both from owners and attending veterinarians accompanied each blood sample. The apparent seroprevalences to B. burgdorferi s. l. and granulocytic Ehrlichia spp. were 16.8 and 16.7%, respectively. The northern region had the lowest seroprevalences. Four logistic models were developed (controlling for demographic variables). In the disease model of seropositivity to B. burgdorferi s. l., age, breed, geographic region, the serologic titer to granulocytic Ehrlichia spp., season and the diagnosis coffin-joint arthritis were significant. In the tick-exposure model of B. burgdorferi s. l., pasture access the previous year and gender were significant. Age, racing activity, geographic region, season and the serologic titer to B. burgdorferi s. l. were associated with positivity to granulocytic Ehrlichia spp. In the tick-exposure model of granulocytic Ehrlichia spp., pasture access was a risk factor. An interaction between racing activity and geographic region showed that the risk of positive serologic reactions to Ehrlichia spp. was increased in the horse population in the south and middle of Sweden, but only among horses not used for racing. Except for the positive association between coffin-joint arthritis and serologic reactions to B. burgdorferi s. l., there were no significant associations in the multivariable models between non-specific or specific clinical sign or disease with seropositivity to either of these agents.

Animals↗
PubMed2000

Herd-based monitoring for tuberculosis in extensive swedish deer herds by culling and meat inspection rather than by intradermal tuberculin testing.

The effect of random slaughter and meat inspection as a tool to detect or eradicate tuberculosis in large, extensive deer herds in Sweden was evaluated. A computer spreadsheet model based on the Reed-Frost method was developed. Numbers of new infections and of infected deer slaughtered as well as probability of detecting tuberculosis or slaughtering all infected deer in a herd, were simulated. The model predicted that, given a 20% annual slaughter and that disease was introduced with one infected deer, the infection would be detected or eliminated in most herds (90%) after 15 years.

Abattoirs↗
PubMed1999

Incidence of diarrhea among calves after strict closure and eradication of bovine viral diarrhea virus infection in a dairy herd.

OBJECTIVE: To determine whether strict closure of a dairy herd and eradication of bovine viral diarrhea virus (BVDV) infection would decrease incidence of diarrhea in calves during the first 31 days after birth, whether specific risk factors were associated with incidence of diarrhea in calves, and whether diarrhea was associated with weight gain of the calves. DESIGN: 2-year cohort study. ANIMALS: 448 calves. PROCEDURE: Calves were monitored from birth to 31 days of age. Fecal samples were tested for rotavirus, blood samples were tested for BVDV and antibodies to BVDV, and serum samples were tested for IgG concentration. Risk factors were evaluated by means of survival analysis. RESULTS: Incidence of diarrhea in calves decreased significantly after strict closure of the herd and eradication of BVDV infection. Risk factors for diarrhea in calves interacted in a multifactorial way. Rotavirus infection and low serum IgG concentration increased the risk that calves would develop diarrhea. Calves that developed diarrhea gained significantly less weight than calves that did not develop diarrhea. CLINICAL IMPLICATIONS: To control diarrhea among calves in a dairy herd, emphasis should be on maintaining a strictly closed herd free from BVDV infection. However, other measures, such as measures to prevent rotavirus infection and to ensure that calves receive an appropriate amount of colostrum after birth, should also be taken.

Animal Husbandry↗
PubMed1998

A Reed-Frost model of the spread of tuberculosis within seven Swedish extensive farmed fallow deer herds.

The within-herd transmission of tuberculosis, after introduction of infection, was evaluated in seven Swedish herds of farmed fallow deer. The evaluation was based on a subset of data obtained from a previous epidemiological investigation, comprising 13 tuberculosis-infected deer herds, with the purpose of tracing the source of infection. A computer spreadsheet model based on the Reed-Frost method was developed to estimate the number of new infections. For each herd, a k-value (the number of effective contacts made by an individual during a time period) was estimated through fitting the model to the observed incidence in each herd. We concluded that, despite the relatively short observation periods and uncertain tuberculosis incidence estimates for the observed herds, the k's obtained could be used to quantify the estimated spread of tuberculosis in extensive deer herds in Sweden.

Animals↗
PubMed1991

Economic analysis of vaccination applied to ovine listeriosis.

An economic model for determining whether vaccination against a disease would be beneficial financially on individual farms is proposed; it is based on four pieces of information: the costs of a disease case including its treatment, the cost of vaccinating each animal including veterinary fees, the expected incidence of the disease, and the efficacy of the vaccine. The model was applied to ovine listeriosis, which is a serious disease problem in Norway. Vaccination appeared to be beneficial for the average sheep flock of 100 ewes which might expect two or more cases of listeriosis per year. Furthermore, the model suggests the ratio of the price of a single vaccination to the cost of a disease case can be used to plan more efficient vaccine field trials.

Animals↗