Risk factors for Salmonella seroconversion of fattening pigs in farrow-to-finish herds

We did a prospective observational 9-month long study to quantify risk factors of managerial and hygiene practices, and pig-health status for Salmonella seroconversion of fattening pigs reared in subclinically infected French farrow-to-finish farms. During the fattening phase, 2,649 pigs belonging to the same batch of contemporary pigs, from 89 conventional farrow-to-finish farms were individually followed and regularly blood sampled on a monthly basis. Farm recruitment was based on the farmer's willingness to cooperate. Pig status was assessed using an indirect ELISA test. Evolution of the serological status was studied by means of survival analysis. A Cox proportional-hazards model, taking into account the clustering of animals at the farm level, was used to examine the effects of explanatory variables on the time to Salmonella seroconversion of pigs. Applying group level antibiotic treatment to the pigs during the fattening period (Hazard Ratio (HR) = 2.4; 95% CI: 1.7, 3.4) was identified as a risk factor for Salmonella seroconversion, as the presence of residual Salmonella contamination in the fattening pen before placing the pigs into the pens (HR = 1.9; 95% CI: 1.2, 2.9). Porcine reproductive and respiratory syndrome virus (PRRSV) seropositivity during the fattening period also indicated an increased hazard for seroconversion (HR = 1.6; 95% CI: 1.1, 2.5). The batch size was identified as a risk factor for Salmonella seroconversion: the higher the number of pigs was in the fattening room followed, the higher was the risk (HR(+10 pigs) = 1.05 for a 10-pig increment; 95% CI: 1.03, 1.06). The biosecurity measures of wearing specific clothes before entering the facilities (HR = 0.5; 95% CI: 0.3, 0.9) and enclosing the pig farm facilities were protective (HR = 0.4; 95% CI: 0.2, 0.8).     

Influence of the estrous cycle on urodynamic and morphometric measurements of the lower portion of the urogenital tract in dogs

OBJECTIVES: To compare the values of the urodynamic parameters of the lower portion of the urinary tract and vaginourethral measurements obtained during the phases of the estrous cycle in dogs and determine possible functional or anatomic modifications of the lower portion of the urinary tract associated with those phases. ANIMALS: 7 adult female Beagles. PROCEDURE: Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed in each dog during proestrus; estrus; early, mid, and late diestrus; and early and late anestrus. The maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP), urethral functional and anatomic profile lengths (UFPL and UAPL, respectively), integrated pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. RESULTS: For all measurements, significant interindividual variation was detected. Integrated and threshold pressures, APL, and each morphometric value significantly increased from late anestrus to proestrus. Compared with other phases, MUP, MUCP, and integrated pressure values were significantly lower in estrus and early diestrus; UAPL and UFPL values were significantly lower in late diestrus. At each cycle phase in old dogs, MUP, MUCP, threshold pressure, and vaginal length and width were significantly lower (except in proestrus for vaginal measurements) and threshold volume and compliance values were significantly higher, compared with middle-aged dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Urodynamic and morphometric measurements of the lower portion of the urogenital tract are affected by the changes in hormonal balance that occur during the estrous cycle. In sexually intact female dogs, estrous phase determination is important for the interpretation of urodynamic data.     

Reliable ELISAs showing differences between resistant and susceptible lines in hens orally inoculated with Salmonella Enteritidis

Reliable ELISAs were investigated with the aim to select hen lines resistant to Salmonella Enteritidis and producing high levels of antibodies. In the first experiment, the relation between the humoral response and the bacteriological results was assessed on hens from the Y11 resistant line and the L2 susceptible line, orally inoculated with 10(8) CFU S. Enteritidis per animal. Anti-lipopolysaccharide (LPS) IgG titres were higher but the liver and spleen were less contaminated in hens from the Y11 line than in hens from the L2 line (p = 0.013, 0.031 and 0.026 respectively). In the second experiment, the hens were inoculated orally with 1.7 x 10(8) CFU S. Enteritidis per animal in order to select the ELISA methods showing the more significant differences. ELISAs were based on LPS, flagella, LPS from rough (LPS-R) and smooth strains (LPS-S) and detected IgG and IgM antibodies from sera and yolks. No between-line host response variation was observed in the yolk, with LPS-S and R antigens nor with anti-LPS IgM in the sera. Otherwise, significant differences were encountered between hen lines with the ELISAs performed on the sera detecting anti-LPS IgG, anti-flagella IgG or IgM (p = 0.017, 0.017 and p < 0.001 respectively). When comparing the kinetics of the selected ELISAs, the IgG antibodies against LPS detected between-line variations as early as 1 to 4 weeks pi, whereas with IgG against flagella, the differences were only detected at 1 and 2 weeks pi and with IgM against flagella, the differences were significant at 1, 2, 4 and 8 weeks pi. In conclusion, resistant hen lines producing higher levels of antibodies than the susceptible hen lines may be selected with these ELISAs.     

An unusual form of canine babesiosis

An Akita Inu, living in Belgium, was presented with unusual clinical manifestations of acute babesiosis that included neurological signs and pancytopenia. Diagnosis was made by identifying Babesia canis in the blood smear. Neurological signs resolved after treatment with imidocarb diproprionate. Normalization of hematological abnormalities was gradual over 5 months.     

Understanding and valuing conflicts in marine protected areas: The best way to develop innovations?

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Distribution of equine infectious anemia in horses in the north of Minas Gerais State, Brazil.

The paper examines the prevalence of equine infectious anemia (EIA) in horse populations in the northern part (comprising 89 cities) of Minas Gerais State, Brazil, from January 2002 to December 2004. Data on 8,981 agar gel immunodiffusion test results from the region were used as input for a statistical and autoregressive analysis model to construct a city-level map of the distribution of EIA prevalence. The following EIA prevalence (P) levels were found: 49 cities with 0 < P < or = 0.5%, 26 with 0.5% < P < or = 1.5%, 10 with 1.5% < P < or = 5%, and 4 with 5% < P < or = 25%.     

A mathematical model of the effects of chronic carriers on the within-herd spread of contagious bovine pleuropneumonia in an African mixed crop-livestock system

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease of cattle; CBPP is caused by Mycoplasma mycoides subsp. mycoides small colony. CBPP is a major cause for concern for African countries (because of mortality, animal-production losses and cost of control). The clinical form of the disease is the more infectious (contagion occurs essentially through coughing). However, chronic lung lesions with viable mycoplasmas can persist in recovering cattle. Animals presenting these lesions might have a time-delimitated infectious phase. Such carriers are suspected to generate field outbreaks (although this hypothesis remains debated). We investigated the potential quantitative effects of these chronic carriers on the within-herd CBPP spread. Data were collected during a longitudinal field herd survey in a mixed crop-livestock system in the Ethiopian highlands. Two stochastic Markov-chain models' outputs (seroconversion dynamics, basic reproduction ratio R0, cumulative clinical incidence and risk of herd infection) were compared given different hypotheses on the carrier infectiousness. The late seroconversions observed in the field data were fitted correctly only for the highest carrier infectiousness we considered (mean chronic duration of 1 year and carriers 50-times less infectious than clinical cases). Although sensitivities (in terms of disease impact in the herd) were in general negligible when the carrier infectiousness was low (e.g. when carriers were assumed to be 1000-times less infectious than clinical cases), they rapidly became important when the infectiousness increased.     

Impact of the Salmonella status of market-age pigs and the pre-slaughter process on Salmonella caecal contamination at slaughter

The aim of this study was to evaluate the impact of the pre-slaughter process on Salmonella caecal contamination of pigs at slaughter. An observational study was carried out in 2001 on 101 conventional farrow-to-finish pig farms. On each farm, one batch of contemporary pigs was followed from the end of the fattening period until slaughter. The Salmonella bacteriological status of the batches was assessed by environmental samples of faecal material. The serological Salmonella status was obtained on 30 individually identified market-age pigs using an indirect ELISA test. At the slaughterhouse, 25 g of caecal contents were taken from 10 of the identified pigs. Faecal and caecal material were analysed according to a classical bacteriological method. A questionnaire was designed to obtain information about the type of feeding during the fattening period (dry versus wet), the duration of fasting on the farm before leaving for the slaughterhouse, the duration of transport between the farm and the slaughterhouse, the holding time in lairage at the slaughterhouse and loading and unloading conditions on the farm and at the slaughterhouse. To assess the relationships between these factors and the Salmonella caecal status of the pigs and the batches, two logistic models were fitted at the individual and at the batch level, respectively. The first analysis was performed using a random effects logistic regression model. The second analysis was based on a cumulative logit model with a positive caecal rate classified into three classes as the outcome variable. The results showed that the Salmonella status of market-age pigs assessed on the farm either by serological or bacteriological examinations and the time spent in lairage before slaughtering played a crucial role on caecal contamination. In the light of these results, actions should be considered both on the farm and at the slaughterhouse to decrease the risk of Salmonella contamination of the caecal contents.     

Wild boar rooting in a northern coniferous forest – minor silviculture impact

European wild boar (Sus scrofa) is expanding northwards beyond its preferred habitat of broadleaved forests. We studied wild boar habitat use in a northern coniferous forest, and noted whether their rooting damaged roots, thereby influencing timber quality and forest regeneration (n = 562 rootings). Overall, the animals selected older spruce (Picea abies L.) forest of higher soil fertility with sparse field vegetation for rooting. During winter, they rooted more in pine (Pinus sylvestris L.) forest on lower soil fertility, possibly because the lichen cover can easily be removed even on frozen ground. Average size and depth of rootings were 6 ± 0.6 m² and 10 ± 0.2 cm, respectively. Rooting occurred on <1% of the area and caused negligible damage to roots of trees with commercial value. Because the wild boar mainly rooted in older forest, rootings will do little to improve germination of seeds by scarification of the top soil layer.     

Intramuscular Grade 1 fibrosarcoma: Magnetic resonance imaging findings in 2 dogs

Two adult neutered male dogs were presented for evaluation of firm, painless masses arising within muscle: an 8-year-old German wirehaired pointer dog with an accessory tricipital growth, and a 3-year-old German shepherd dog with a gracilis muscle growth. Magnetic resonance imaging (MRI) characteristics suggested malignant behavior, with a central fluid-like portion with a hyperenhancing lining, a nidus of disorganized tissue, and an extensive reactive zone, whereas histopathology was consistent with low-grade fibrosarcoma. This report describes histologically low-grade, yet biologically high-grade intramuscular fibrosarcoma, in which MRI provided detailed information on tumor behavior and assisted with biopsy and surgical planning.