Doramectin as a treatment for canine and feline demodicosis

Twenty-three dogs and three cats with generalised demodicosis were treated with weekly subcutaneous injections of doramectin at a dose of 600mcg/kg body weight. All dogs and cats responded to treatment by going into remission. The median time until skin scrape results were negative was eight weeks (range five to 20 weeks). Ten dogs remained in remission after the first treatment, five were lost to follow up and seven needed a second course of doramectin or were maintained in remission by monthly injections. Time to when skin scrape results were negative for the cats was two to three weeks with one cat still in remission four years later. The other two cats were euthanased due to their underlying disease whilst only four and six months into remission. Weekly subcutaneous doramectin injections are useful in the treatment of generalised demodicosis in dogs and cats. No systemic side effects of the drug were seen, the injection was painless and no reactions were seen at the sites.

Avian paramyxoviruses and influenza viruses isolated from mallard ducks (Anas platyrhynchos) in New Zealand

A comprehensive study using virological and serological approaches was carried out to determine the status of live healthy mallard ducks (Anas platyrhynchos) in New Zealand for infections with avian paramyxoviruses (APMV) and influenza viruses (AIV). Thirty-three viruses isolated from 321 tracheal and cloacal swabs were characterized as: 6 AIV (two H5N2 and four H4N6), 10 APMV-1 and 17 APMV-4. Of 335 sera samples tested for AIV antibodies, 109 (32.5%) sera were positive by nucleoprotein-blocking ELISA (NP-B-ELISA). Serum samples (315) were examined for antibody to APMV-1, -2, -3, -4, -6, -7, -8, -9 by the haemagglutination inhibition test. The largest number of reactions, with titres up to greater than or equal to 1/64, was to APMV-1 (93.1%), followed by APMV-6 (85.1%), APMV-8 (56%), APMV-4 (51.7%), APMV-7 (47%), APMV-9 (15.9%), APMV-2 (13.3%) and APMV-3 (6.0%). All of the H5N2 isolates of AIV and the APMV-1 isolates from this and earlier New Zealand studies had low pathogenicity indices assessed by the Intravenous Pathogenicity Index (IVPI) with the result 0.00 and Intracerebral Pathogenicity Index (ICPI) with results 0.00-0.16. Partial genomic and antigenic analyses were also consistent with the isolates being non-pathogenic. Phylogenetic analysis of the 10 APMV-1 isolates showed 9 to be most similar to the reference APMV-1 strain D26/76 originally isolated in Japan and also to the Que/66 strain, which was isolated in Australia. The other isolate was very similar to a virus (MC 110/77) obtained from a shelduck in France.

The effect of volatile fatty acids in acidified fermented piggery effluent on shiga-toxigenic and non-toxic resident strains of Escherichia coli

Aims: To examine the effects of acidified acidogenically fermented piggery effluent containing Volatile Fatty Acids (VFA) on shiga-toxigenic and resident strains of Escherichia coli (E. coli) as part of the development of a waste treatment process. Methods and Results: Four shiga-toxigenic E. coli strains (O157:H7, 091.H-, 0111.H-, and 0123.H-) and four non-toxic resident enzootic strains were all killed by 3 h treatment with fermented piggery effluent liquor (153 mmol l(-1) total VFA) at pH 4.3. The shiga-toxigenic strains showed greater sensitivity after 1 h of treatment. The fermented liquor at pH 6.8 was not inhibitory. Conclusions: The shiga-toxigenic strains were no more resistant to the toxic effects of VFA than the non-toxic strains tested. Significance and Impact of the Study: Shiga-toxigenic strains and resident enzootic non-toxigenic strains are equally susceptible to inactivation by this waste treatment process and by acidified VFA in general.

Effects of intravenous injection of Clostridium perfringens type D epsilon toxin in calves

In cattle, a neurological lesion similar to that produced in sheep and goats by Clostridium perfringens type D enterotoxaemia has been reported. However, no causal relationship has been established between this disease and the lesion in cattle. The effects of single and multiple intravenous injections of epsilon toxin in three calves aged 6 months were studied. A further calf was inoculated intravenously with saline solution and used as a control. Epsilon toxin invariably produced neurological signs within 2-60 min of the end of the injection process. Clinical signs consisted of loss of consciousness, recumbency, convulsions, paddling, opisthotonus, hyperaesthesia and dyspnoea. Gross changes consisted of severe acute pulmonary oedema, which was particularly marked in the interlobular septa. The histological lesions consisted of intra-alveolar and interstitial oedema of the lung and variable degrees of perivascular proteinaceous oedema in the internal capsule, thalamus and cerebellar white matter. No clinical or post-mortem changes were observed in the control calf. These results show that calves are susceptible to the intravenous injection of epsilon toxin, and that they can show at least some of the histological lesions produced in sheep and goats by this toxin. (C) 2002 Harcourt Publishers Ltd.

Neuro-angiostrongylosis in wild Black and Grey-headed flying foxes (Pteropus spp)

Objective To identify nematodes seen in histological sections of brains of flying foxes (fruit bats) and describe the associated clinical disease and pathology. Proceedures Gross and histological examination of brains from 86 free-living flying foxes with neurological disease was done as part of an ongoing surveillance program for Australian bat lyssavirus. Worms were recovered, or if seen in histological sections, extracted by maceration of half the brain and identified by microscopic examination. Histological archives were also reviewed. Results There was histological evidence of angiostrongylosis in 16 of 86 recently submitted flying foxes with neurological disease and in one archival case from 1992. In 10 flying foxes, worms were definitively identified as Angiostrongylus cantonensis fifth-stage larvae. A worm fragment and third stage larvae were identified as Angiostrongylus sp, presumably A cantonensis, in a further three cases. The clinical picture was dominated by paresis, particularly of the hind-limbs, and depression, with flying foxes surviving up to 22 days in the care of wildlife volunteers. Brains containing fifth-stage larvae showed a moderate to severe eosinophilic and granulomatous meningoencephalitis (n = 14), whereas there was virtually no inflammation of the brains of bats which died when infected with only smaller, third-stage larvae (n = 3). There was no histological evidence of pulmonary involvement. Conclusion This is the first report of the recovery and identification of A cantonensis from free-living Australian wildlife. While anglostrongylosis is a common cause of paresis in flying foxes, the initial clinical course cannot be differentiated from Australian bat lyssavirus infection, and wildlife carers should be urged not to attempt to rehabilitate flying foxes with neurological disease.

Very limited transmission of FMD following introduction into a sheep flock

IN contrast to previous international experience, sheep played a critical role in the source and spread of foot-andnmouth disease (FNID) in the 2001 outbreak in the UK. At many stages during the outbreak, sheep wvere associated with the emergence of disease in new, that is, previously non-infected, areas, and in areas which had been apparently cleared of disease some weeks or months earlier. Although some information about this disease in sheep is available (Donaldson and Sellers 2000), an understanding of the natural history of FNIF in sheep will be improved based on lessons learned from the 2001 outbreak. This short communication describes an outbreak of FNID in a sheep flock in north-east England, where there was strong epidemiological and laboratory evidence of very limited transmission of disease following introduction.