Restriction-endonuclease analysis of Australian isolates of Leptospira interrogans serovar hardjo from cattle with agalactia and abortion

SUMMARY Polyacrylamide gel electrophoresis and agarose gel electrophoresis were used to resolve restriction endonuclease digests of 20 Australian isolates of Leptospira interrogans cultured from urine samples of cattle with agalactia and abortion. The restriction endonuclease profiles of 19 isolates closely matched the profiles of L interrogans serovar hardjo subtype hardjobovis reference strains. The remaining isolate had a different restriction profile from subtype hardjobovis and subtype hardjoprajitno reference strains and was serologically identified as serovar pomona. Silver staining of polyacrylamide gels gave enhanced resolution of restriction fragments compared with the traditional method of ethidium bromide staining of agarose gels.     

Uptake of drugs from topically applied anti-inflammatory preparations applied to racing animals

Objective To determine whether a drug detected in the blood or urine of a racing animal could have penetrated through the skin from a topically applied preparation.
Design Blood and urine of dogs and horses were analysed after topical administration of three common nonsteroidal anti-inflammatory preparations.
Experimental method Dimethylsulphoxide was analysed using a gas chromatograph with a flame photometric detector. Phenylbutazone, its metabolites and lignocaine were analysed using a gas chromatograph with a mass selective detector.
Results Dimethylsulphoxide, phenylbutazone and ligno-caine were detected in dog urine after muliple applications of the preparations. The maximum concentration of dimethyl-sulphoxide in dog urine correlated with the concentration of dimethylsulphoxide in the preparation. Phenylbutazone penetrated the skin more effectively from the cream than from the solution or gel preparations. This penetration was independent of the concentration of dimethylsulphoxide.
Conclusion The superior penetration of phenylbutazone from the cream can be explained by it being present as a neutral molecule in an hydrophobic medium. It is proposed that phenylbutazone penetrates the skin of greyhounds most effectively by a hydrophobic lipid route which is likely to be different from the path by which dimethylsulphoxide penetrates the skin.     

Complete genome sequences and properties of Spartina mottle virus isolates from hybrid Bermuda grass (Cynodon dactylon × Cynodon transvaalensis)

Full genome sequences are presented for two isolates of Spartina mottle virus (SpMoV) from two accessions of the hybrid turf grass Cynodon dactylon × C. transvaalensis (Bermuda grass, green couch), originally from the USA but detected during post-entry quarantine in Australia. Both isolates had a genome of 9,346 nucleotides, encoding a single polyprotein of 3,029 amino acids and predicted to be cleaved into 10 mature proteins. Phylogenetic analysis strongly supported placement in a new genus within the family Potyviridae. The isolates possess 715–780 × 11–12 nm flexuous virions and produce cylindrical (pinwheel) inclusions in infected cells. They were mechanically transmitted to several species in the Poaceae including Zea mays (maize, sweet corn), Chloris gayana (Rhodes grass), and Echinochloa colona (awnless barnyard grass).     

CONTROL OF BLUETONGUE IN AN EPIZOOTIC SITUATION: AUSTRALIAN PLANS

Epizootics of BT outside Africa have occurred in the Middle East, Indian subcontinent, Spain and Portugal, and the United States of America. The disease has only been eradicated from a major region once, this being Spain and Portugal in 1956-60 when it was achieved by quarantine, compulsory vaccination and slaughter of some infected animals. Because of the serious economic effect that BT would have on the Australian sheep industry the policy in this country is to attempt eradication, if at all feasible. The prospects of eradication will be greatly enhanced if the disease can be diagnosed quickly, when the outbreak is still localised. The laboratory diagnosis of BT involves inoculation of blood samples, collected from febrile animals on the suspect property, into groups of susceptible sheep in insect-proof quarters. The diagnosis would be confirmed at the reference laboratory in South Africa by serological and other identity tests. The diagnosis of an outbreak that originated in the northern cattle areas might be very difficult, because of the probable mild clinical nature of the disease in cattle. It is suggested that sentinel sheep flocks be maintained in these areas in strategic places near likely points of entry. Control measures, based on current knowledge of the epizootiology and pathogenesis of bluetongue; are discussed. The disease is transmitted by Culicoides that ingest infected blood from viraemic ruminants. Control is based on reducing the number of viraemic ruminants in the infected area, reducing the population density of Culicoides, and reducing the availability of susceptible ruminants. It is vital to prevent the movement of potentially infected ruminants to new localities. Contingent plans for the eradication of an epizootic of BT in Australia have been prepared. These call for the creation of two control zones. In the inner infected area, which extends for about five miles around known infected farms, there would be an intensive disinsection programme with aerial and ground spraying. Ruminants in the infected area would probably be slaughtered. The quarantine zone would extend for another 50 miles and in this area there would be prohibition of the movement of ruminants from farms. Regular clinical inspections and serological surveys would be carried out to detect secondary outbreaks. If control measures failed, it might be necessary to mount urgently a massive vaccination campaign to prevent disastrous losses to the Australian sheep industry. The difficulties in obtaining sufficient quantities of monovalent vaccine from overseas at short notice are discussed. Plans have been made to produce BT vaccine in Australia, in a specially designed high security laboratory, should the need arise.