Variation in clinical and parasitological traits in Pietrain and Meishan pigs infected with Sarcocystis miescheriana

Future prophylaxis needs new concepts, including natural disease resistance of hosts against infectious agents. Genomic approaches to detect and improve disease resistance in farm animals and the molecular mechanisms involved in host-parasite interactions depend to a high degree on the trait differences between founder breeds, i.e. on the animal model. The present study evaluates differences in susceptibility/resistance against Sarcocystis miescheriana in the European Pietrain (PI) and the Chinese Meishan (ME) pig breeds, based on 25 individuals, infected orally with 5x10(4) sporocysts of S. miescheriana. Significant differences appeared in clinical, serological, haematological and parasitological findings. The major discriminating period post infection (p.i.) was between days 42 and 45. Severity of signs was negatively correlated with specific immunoglobulin titres during the first 3 weeks p.i. and positively with the load of bradyzoites in muscle tissues of the pigs. Loads of bradyzoites in muscle tissues were 20 times higher in PI than in ME. Sarcocystis-specific differences between the two breeds were in the range of 1-2 standard deviations. The study lays the foundation for further experiments to analyse chromosomal regions, candidate genes, and thus the molecular basis of Sarcocystis susceptibility/resistance as a model for host-parasite interaction in protozoan infectious disease.     

An analysis of the performance characteristics of serological tests for the diagnosis of Neospora caninum infection in cattle

AIMS: To analyse the performance characteristics (sensitivity/specificity) of two enzyme-linked immunosorbent assays (ELISA) against the indirect fluorescent antibody test (IFAT). METHODS: A total of 1199 sera were tested in two ELISAs and the IFAT and results analysed utilising software that performed a receiver-operating characteristic (ROC) analysis. RESULTS: Sensitivity and specificity for the two ELISAs were calculated for a range of different cut-offs. Minimal misclassification was achieved at cut-offs that, in the case of the Central Animal Health Laboratory (CAHL)-ELISA were in line with previously published cut-off values. In the case of the IDEXX-ELISA lower cut-off values than suggested by the manufacturer were calculated. CONCLUSIONS: ROC-analysis resulted in optimised, as compared to the IFAT, cut-off thresholds for the CAHL and IDEXX-ELISA which can be further adjusted depending on the purpose of the investigation.     

Neospora caninum and Waddlia chondrophila strain 2032/99 in a septic stillborn calf

Characteristics of an intracellularly growing micro-organism isolated from an aborted bovine foetus are described. The organism replicated within cytoplasmic vacuoles, was resistant to penicillin and exhibited structural characteristics compatible with Waddlia chondrophila. An ELISA specific for Chlamydia spp., immunofluorescence tests using antibodies directed against Chlamydia spp. or Simkania negevensis, and PCR using Chlamydia-specific primers showed that the agent was distinct from Chlamydiae or S. negevensis. Determination of 16S and partial 23S ribosomal RNA gene sequences in combination with the PCR results and the morphological, antigenic and developmental characteristics provided evidence that the isolate 2032/99 can be classified as W. chondrophila or a closely related organism.     

Ataxia and disequilibrium in domestic ducks (Anas platyrhynchos f. dom.) with intracranial lipomas

Four birds in a flock of 125 purebred Crested ducks (Anas platyrhynchos f. dom.) had cerebellar signs of unknown etiology. They had radiographically evident perforations of various sizes in the parieto-occipital calvaria. Gross necropsy of euthanatized ducks revealed yellow intracranial masses in the brain of each. Histologically, these masses were intracranial lipomas consisting of univacuolated fatty tissue separated into lobules by strands of connective tissue. The masses had caused serious deformation of the rostral part of the cerebellum, leading to a nearly complete flattening of cerebellar folia, and were interpreted as the cause for the central nervous clinical signs observed. These intracranial lipomas were similar to those previously reported in other animals and humans.     

Effect of seasonal conditions on oestrus occurrence and postpartum period in Anatolian water buffaloes

Oestrus and calving records of Anatolian buffaloes were analyzed to investigate influence of climatic conditions on oestrus occurrence and postpartum period. Oestrus records showed a seasonal pattern concentrated between July and September which is the warmest period of the year. Likewise, more than half (52.7%) of the total calvings occurred between May and August. Month of calving significantly influenced the length of calving to first oestrus interval and open period (P < 0.01). The average length of open period was significantly shorter in autumn and summer calvers compared to those calved in spring and winter (P < 0.05) during long days. The humidity rate was negatively correlated with both calving to first oestrus interval and open period (P < 0.05). In conclusion, exposure to high environmental temperatures around 20 degrees C exerted no suppressive influence on ovarian activity in Anatolian buffaloes. Although humidity rate (P < 0.05) and ambient temperature (P < 0.01) was found to be correlated with the duration of postpartum period, day length might be the main factor regulating reproductive biorhythm and postpartum events in Anatolian buffalo cows.     

Prevention of intramammary infections in dairy cows by the use of a premilking teat dip method with a foaming iodophor dip agent

In this study we investigated the efficacy of premilking teat dipping with a foaming iodophor teat dip in a negative controlled field study. Incidence of new intramammary infections (IMI), incidence of clinical mastitis, influence on somatic cell count (SCC) and the characteristics of udder tissue and teats were used as parameters to evaluate clinical efficacy. Predipping was compared with a negative control using a split-udder experimental design. Right teats were predipped with a foaming disinfectant containing 0.27% iodine while left teats served as controls. The latter were conventionally cleaned with damp cloth towels and dried manually with disposable paper towels ("best cleaning practice"). All teats were dipped after milking with the same dip. There were no differences between treated and control quarters with respect to incidence of new IMI during the study period (treated quarters: 6.6% vs. untreated: 6.95%), incidence of clinical mastitis (30 cases in the treatment group vs. 39 cases in the control group) and geometric mean of SCC of quarter milk samples. Spectrum of detected pathogens was also comparable. Condition of udder tissue and teat ducts did not differ between treated and control quarters.     

Specificity of inhibition between Salmonella strains

A phenomenon of inhibition among Salmonella organisms colonizing the gut of young animals can be demonstrated which is important in connection with immunization using live Salmonella vaccines. For practical utilization of this inhibition phenomenon, research into its specificity is very important. In vitro broth culture and animal experiments have shown inhibition to be genus-specific, i.e. there is no inhibition between strains of different genera of Enterobacteriaceae in most cases. The strongest inhibition occurs between isogenic (identical genotype) strains (strain-specific inhibition). This applies to Salmonella and other genera of Enterobacteriaceae. There was a close correlation between the degree of the inhibitory effect and the genetic relatedness of the strains, as has been demonstrated in Salmonella strains of different epidemiological classification. The inhibitory capacity was most pronounced among closely related strains. Clonal strains of Salmonella Enteritidis phage type 4 fully inhibited caecal colonization by Salmonella Enteritidis phage type 4 strains in 65% of the combinations tested in chicks. In broth culture experiments, the share of combinations with complete inhibition was above 90%. A significant inhibitory competence of a selected strongly inhibitory Salmonella Enteritidis phage type 4 strain against the majority of Salmonella Enteritidis field isolates can be expected. However, Salmonella Enteritidis strains of all phase types showed almost no inhibitory competence against other Salmonella serotypes.     

Prognosis for presumed feline vaccine-associated sarcoma after excision: 61 cases (1986-1996)

OBJECTIVE: To evaluate time to first recurrence (TFR) and overall survival in cats with presumed vaccine-associated sarcomas (VAS) treated with excision. DESIGN: Retrospective study. ANIMALS: 61 cats with presumed VAS. PROCEDURE: Medical records of cats that received excision as the only initial treatment for presumed VAS were reviewed to evaluate prognosis. Overall survival curves and TFR were determined. RESULTS: Median TFR was 94 days. Median TFR for tumors treated with excision performed at a referral institution (274 days) was significantly longer than that for tumors excised by a referring veterinarian (66 days). Radical first excision yielded significantly longer median TFR (325 days) than did marginal first excision (79 days). Cats with tumors located on the limbs had longer median TFR (325 days) than cats with tumors located in other sites (66 days). Median overall survival time was 576 days. Significant differences in survival times between groups were not detected. Few cats (13.8%) receiving only surgical treatment had long-term (> 2 years) survival. CONCLUSIONS AND CLINICAL RELEVANCE: Radical first excision of presumed VAS is essential for extended TFR. Current recommendations for vaccination of the distal portions of the extremities are appropriate, because this practice permits radical excision of tumors (amputation) that develop at vaccination sites; however, surgery alone is seldom curative.     

The development of rabies in Switzerland--landscape determines the spread of a wildlife epidemic

The rabies epidemic that reached Switzerland in 1967 developed in response to landscape factors as long as no efficient control strategies were available. The landscape acted either as barrier to the spread of rabies, or it influenced the density of red foxes and thus the habitat of the epidemic. Following the first cases in the canton of Schaffhausen, the whole northwestern Switzerland was infected followed by the eastern Alps, large parts of the Plateau and the Jura mountains. In 1978, in the canton of Valais, the first campaigns of oral immunization of foxes against rabies started. The design of vaccination campaigns during the next two decades was always closely linked to landscape features. Thus, it was possible to free first the Alps and then the Plateau from rabies and finally, at the end of the 1990s, to eliminate it completely within the country. We describe the entire development of the epidemic within the period of 30 years from the first infection up to the last registered case and the final vaccination campaign.