ObjectivesTo produce antisera to the 15 recognised reference strains of the Kielstein-Rapp-Gabrielson (KRG) serotyping scheme for Haemophilus parasuis, validate those sera and use them to serotype 46 Australian field isolates of H parasuis.Design Antisera were produced in rabbits and validated by cross-testing with the reference strains and re-testing 15 Australian field isolates of H parasuis that had been previously serotyped in the United States of America. The validated antisera were then used to determine the serovar of 46 Australian isolates. ResultsMonospecific antisera were produced for 14 of the 15 KRG serovars of H p a r a s u i s . Two Australian field isolates, confirmed previously as serovars 1 and 7, were used to produce monospecific antisera for serovars 1 and 7 respectively. The antiserum for serovar 4 gave a one-way cross reaction with the antigen of serovar 14. The typing antisera correctly typed all 15 H parasuis that had been previously typed by antisera produced overseas. The 46 field isolates were shown to belong to serovars 2 (two isolates), 4 (one isolate), 5 (18 isolates), 12 (two isolates) and 13 (four isolates). The remaining 19 isolates were non-typable.

Objective To validate a polymerase chain reaction (PCR) based method, Enterobacterial Repetitive Intergenic Consensus‐PCR (ERIC‐PCR), for the fingerprinting of Haemophilus parasuis strains and to use that method to differentiate isolates from apparently related outbreaks of Glässers disease on three pig farms. Design ERIC‐PCR was evaluated by comparing 15 different strains that represented all 15 recognised serovars in the Kielstein‐Rapp‐Gabrielson (KRG) scheme for serotyping H parasuis. Next, ERIC‐PCR was used to examine 14 Australian field isolates of H parasuis; 12 collected from three farms suffering apparently related outbreaks of Glässers disease and two from two other farms with no known connection. Results The 15 serovar reference strains all gave unique, reproducible ERIC‐PCR fingerprints. The 12 isolates from the three apparently related outbreaks all gave a single fingerprint, which was distinct from any seen in the 15 serovar reference strains and the two other Australian field isolates in the studied farms. The confirmation that all 12 isolates were the same strain allowed the development of a prevention and control program that has prevented the emergence of any further outbreaks of Glässer disease on the three farms. Conclusion ERIC‐PCR is a suitable technique for the differentiation of unrelated strains of H parasuis. The finding that the 12 field isolates of H parasuis all shared the same fingerprint is strong evidence that there was a common source of infection on all three farms. This study has shown, for the first time, that ERIC‐PCR is a suitable technique for the sub‐typing of H parasuis and useful for studying the epidemiology of outbreaks of Glässers disease.

Multiple sclerosis (MS) is the most prevalent inflammatory demyelinating disease of the central nervous system. Besides other pathophysiological mechanisms, mitochondrial injury is crucially involved in the development and progression of this disease. Mitochondria have been identified as targets for the peptide hormone melatonin. In the present study, we sought to evaluate the impact of oxidative stress on mitochondrial density and enzyme transcription during experimentally induced demyelination and the protective influence of melatonin. Adult male mice were fed with cuprizone for 5 weeks which caused severe demyelination of the corpus callosum (CC). Animals were simultaneously treated with melatonin by daily intra-peritoneal injections. Melatonin exposure reversed cuprizone-induced demyelination and axon protection. Transmission electron microscopy demonstrated significantly increased mitochondrial numbers and slightly increased mitochondrial size within CC axons after cuprizone exposure. Melatonin antagonized these effects and, in addition, induced the expression of subunits of the respiratory chain complex over normal control values reflecting a mechanism to compensate cuprizone-mediated down-regulation of these genes. Similarly, melatonin modulated gene expression of mitochondrial fusion and fission proteins. Biochemical analysis showed that oxidative stress induced by cuprizone was regulated by melatonin. The data implicate that melatonin abolishes destructive cuprizone effects in the CC by decreasing oxidative stress, restoring mitochondrial respiratory enzyme activity and fusion and fission processes as well as decreasing intra-axonal mitochondria accumulation.

Objective To characterise 18 isolates of Haemophilus paragallinarum isolated from chickens in Indonesia.Procedure The isolates were identified to species level by traditional phenotypic methods. Six of the isolates were also identified by a species-specific polymerase chain reaction. Fourteen of the isolates were examined for resistance to a panel of seven antimicrobial agents using a disc diffusion method. All 18 isolates were serotyped according to the Page scheme using reference antisera in a haemagglutination inhibition test.

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