Concentration and prevalence of Escherichia coli O157 and Salmonella serotypes in sheep during slaughter at two Australian abattoirs

Objective This study aimed to determine the presence and concentration of Escherichia coli O157 and Salmonella spp. on fleece, faeces and carcases of sheep during slaughter. Procedure Faeces, fleece and pre-chill carcase samples were collected from 164 sheep slaughtered at two Australian abattoirs. The presence of E. coli O157 and Salmonella spp. were determined by use of automated immunomagnetic separation (AIMS) with enumeration by use of the ‘most probable number’ (MPN) method. Results Escherichia coli O157 was isolated from 5% of faeces, 3% of fleeces and 0.6% of pre-chill carcases. The mean log₁₀ count of E. coli O157 positive faecal samples was 2.32 MPN/g, but counts on fleeces and carcases were below the countable limit (−1 log₁₀ MPN/cm²). Salmonella spp. were isolated from 20% of faeces, 13% of fleeces and 1.3% of pre-chill carcases. The mean log₁₀ count of Salmonella spp. in faeces was 1.43 MPN/g and on fleece was −0.24 MPN/cm², but counts on carcases were below the countable limit (−1 log₁₀ MPN/cm²). Conclusion The prevalence and concentration of pathogens were low in the sheep tested in this study, indicating a low risk of human infection from products derived from these animals.     

Regulatory measures against Erwinia amylovora in Switzerland*

Switzerland joined the list of fireblight‐affected European countries in 1989. Vigorous and systematic steps were taken to limit the impact of the disease on fruit production and amenity plants. These efforts are codified in a Swiss law detailing prevention, eradication, control measures and issues of compensation. As with many Swiss legal directives, there is a defined coordination of federal and cantonal responsibilities and, in the case of fireblight, there is also an emphasis at all levels on personal responsibility of owners of susceptible objects (e.g. nurseries, orchards, host plants). Extension activities have been a key component in achieving compliance with disease management regulations and in obtained public support for control efforts. Agroscope FAW Wädenswil has taken a leading role in this respect through its website http://www.feuerbrand.ch .     

Factors associated with spread of pseudorabies virus among breeding swine in quarantined herds.

Knowledge of the factors that place susceptible gilts at highest risk of pseudorabies virus (PRV) infection in a quarantined herd is crucial to reduce spread of PRV within the herd. Cohorts of PRV seronegative gilts were monitored in 17 herds that were endemically infected with PRV to determine the location of breeding females at the time of infection with PRV and identify herd characteristics and management and housing factors that may influence spread of PRV in the breeding section of swine herds endemically infected with PRV. Blood samples were collected every 1 to 2 months for an average of 13.6 months. In addition, blood was collected from a representative sample of finishing pigs (greater than or equal to 20 weeks old) 3 times per year to determine their serologic PRV status. Incidence rates and relative risks of PRV infection were estimated for 4 areas of the breeding section: gestation barn, gilt pool, farrowing room, and breeding area. Overall, 28, 11, 8, and 2 females became infected with PRV in each of these areas, respectively. The greater number of females infected in the gestation barns, compared with the number of females infected in other locations, is probably a consequence of being at risk for a longer period rather than of a higher incidence rate. Herd size, common housing for gilts in the gilt pool and sows, and serologic pattern of PRV infection in finishing pigs were associated with the detection of spread of PRV in the breeding section of the 17 herds.(ABSTRACT TRUNCATED AT 250 WORDS)     

Detection of the fire blight biocontrol agent <Emphasis Type="Italic">Bacillus subtilis</Emphasis> BD170 (Biopro<Superscript>®</Superscript>) in a Swiss apple orchard

Fire blight, caused by Erwinia amylovora, is a major disease threat to apple, pear and other pome fruit worldwide. The disease is widespread in Europe and has recently become established in Switzerland. Antibiotics are the most effective controls used in North America but these are not permitted for agricultural use in most European countries. A newly registered biological control product Biopro^®, based on the antagonist Bacillus subtilis strain BD170, is being used as an alternative strategy for fire blight management. A specific molecular marker was developed for monitoring the spread of this agent on blossoms after Biopro^® spray application in a Swiss apple orchard throughout the bloom period for 2years. Direct spraying resulted in efficient primary colonisation of pistils in flowers that were open at the time of treatment. Subsequent bacterial dissemination (secondary colonisation) of flowers that were closed or at bud stage at the time of treatment was observed but was found to be dependent on the timing of treatments relative to bloom stage in the orchard. Foraging honeybees were shown to be disseminators of Biopro^®. We also report detection of the biocontrol agent in honey collected from hives where bees were exposed by placing Biopro^® at the entrance or in the hatching nest and from hives that were simply placed in sprayed orchards.     

Comparison of tissue stages of Hepatozoon americanum in the dog using immunohistochemical and routine histologic methods

American canine hepatozoonosis is caused by Hepatozoon americanum, a recently described species of apicomplexan protozoan parasite. An immunohistochemical procedure using a polyclonal antibody to sporozoites of H. americanum clearly identified asexual stages of H. americanum in canine striated muscle. The method also detects hepatozoa present in naturally infected coyotes and raccoons and reacts with certain other apicomplexans. Use of this immunohistochemical procedure confirms the canine intermediate host-parasite relationships that were presumptively established using conventional histopathologic methods.     

Bovine viral diarrhea virus type 2-induced meningoencephalitis in a heifer

The brain from a 15-month-old, black female Angus, with a 48-hour history of central nervous system disease, was submitted to the Oklahoma Animal Disease Diagnostic Laboratory. Microscopic findings consisted of acute, multifocal meningoencephalitis, with neuronal degeneration and necrosis and gliosis. Viral isolation yielded noncytopathic bovine viral diarrhea virus (BVDV). Virus genotyping classified the virus as BVDV type 2. Immunohistochemical labeling for BVDV antigens with BVD MAb 3.12F1 clone was prominent in the cytoplasm of neurons, glial cells, ependymal epithelium, perivascular macrophages and spindle cells, smooth muscle cells, and intravascular monocytes of the cerebrum and brain stem. Laboratory results support that tissue alterations occurred as a result of BVDV type 2 infection. In the absence of other clinical signs related to BVDV infection and using the microscopic and laboratory evidence presented, we propose that the BVDV type 2 isolated from this case may represent a neurovirulent strain of the virus. To the best of our knowledge, this is the first report of brain lesions and neuronal viral antigen localization in BVDV genotype 2 viral infection, acquired either congenitally or postnatally.