PubMed · 12365163
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Marianne Sloet van Oldruitenborgh-Oosterbaan. 2002-09-15. [Do animals have value?].. https://pubmed.ncbi.nlm.nih.gov/12365163/
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A total of 1,950 serum samples from dairy cattle in California, USA were tested for the presence of antibodies to Mycobacterium avium subspecies paratuberculosis (MAP) using a commercial enzyme-linked immunosorbent assay (ELISA) kit. The sampled animals came from 65 herds and were sampled to reflect the relative numbers and distribution of dairy herds within three geographic regions in the state. Using the manufacturers suggested cut-off for a positive test, 89 animals (4.6%) were positive. The seroprevalence was 6.9% in the northern region of the state, 3.7% in the central region and 5.2% in the southern region. Using the sensitivity and specificity claimed by the manufacturer of the ELISA kit, the true prevalence in California dairy cattle overall was calculated as 9.4% (99% CI, 7.7%, 11.1%) and the true prevalences for the northern, central and southern regions were 14.1% (99% CI, 9.6%, 18.65%), 7.5% (99% CI, 5.6%, 9.4%), and 10.6% (99% CI, 5.9%, 15.6%), respectively.
A longitudinal survey was conducted in France in a subclinically Salmonella-infected farrow-to-finish pig farm to describe the time-course of the serological response to Salmonella enterica in growing pigs. We used three batches of sows and their corresponding litters (n = 31 litters). Among these, 256 pigs randomly selected and individually identified were followed from the first week of age until slaughter. Serial individual blood samples were submitted to indirect Salmonella-ELISA testing. Salmonella shedding was investigated by bacteriological testing of faecal material regularly collected from the sows and pigs and by environment swabs taken from the pens. Caecal contamination was checked at the slaughterhouse. Information about litter composition (filiation), location of the pigs in post-weaning and fattening pens, sanitary events, sex and body weights was recorded. 11.6% of the pigs shed S. enterica; 52% of pigs seroconverted before slaughter. The age-related variation of the natural logarithm of calibrated optical densities (COD) of pigs was described with two linear mixed models. From 8 to 61 days of age, the decrease in COD with age was fitted with a model including random effects of the animal and the dam on the intercept and slope, a batch random effect on the intercept and an individual birth-weight fixed effect on the intercept. The dam random effect was explained by the parity of the sow, Salmonella shedding by the sow during the farrowing phase and the value of the optical density of colostrum collected at parturition. A second model fitting the increase in COD from 61 days of age until slaughter included the random effect on intercept of the batch and the random effects on slope and intercept of the animal, the dam and the pen in which the followed animals were located during the fattening phase and the environmental contamination as fixed effect. In this second model, no relation was found between individual slaughter-bacteriological results and increasing COD values. Considering seroconversion time between 61 days of age and slaughter, survival function were constructed using the Cox proportional-hazards model. Both methods suggested that seroconversions generally occurred during the last third of the fattening phase (from 140 days of age to slaughter), while shedding was observed during the first half of the fattening period. The fitted models suggest the existence of clusters (such as pen and litter of origin).
F18+ enterotoxigenic and verotoxigenic Escherichia coli (E. coli) are widespread and induce post-weaning diarrhoea and oedema disease, respectively. No commercial vaccine exists. Therefore, the F18 herd seroprevalence of 178 randomly selected pig-breeding farms in northern Belgium was evaluated by determining F18-specific IgG antibody titres in pooled sera of sows per breeding farm. This survey reported the first data concerning F18 herd seroprevalence and showed that F18+ E. coli seroprevalence was common in northern Belgium. Significantly more open pig-breeding farms were F18 seropositive (96.4%) compared to closed (88.8%). Furthermore, no clear association was determined between the F18 herd seroprevalence and the number of sows per breeding farm (rsp = 0.19), or with the number of fattening pigs per breeding farm (rsp = 0.17).