Efficacy of selamectin in the treatment and control of clinical signs of flea allergy dermatitis in dogs and cats experimentally infested with fleas

OBJECTIVE: To determine whether treatment with selamectin would reduce clinical signs of flea allergy dermatitis (FAD) in dogs and cats housed in flea-infested environments. DESIGN: Randomized controlled trial. ANIMALS: 22 dogs and 17 cats confirmed to have FAD. PROCEDURE: Animals were housed in carpeted pens capable of supporting the flea life cycle and infested with 100 fleas (Ctenocephalides felis) on days -13 and -2 and on alternate weeks with 10 to 20 fleas. On day 0, 11 dogs and 8 cats were treated with selamectin (6 mg/kg [2.7 mg/lb]). Dogs were retreated on day 30; cats were retreated on days 30 and 60. All animals were examined periodically for clinical signs of FAD. Flea counts were conducted at weekly intervals. RESULTS: Throughout the study, geometric mean flea counts exceeded 100 for control animals and were < or = 11 for selamectin-treated animals. Selamectin-treated cats had significant improvements in the severity of miliary lesions and scaling or crusting on days 42 and 84, compared with conditions on day -8, and in severity of excoriation on day 42. In contrast, control cats did not have any significant improvements in any of the clinical signs of FAD. Selamectin-treated dogs had significant improvements in all clinical signs on days 28 and 61, but in control dogs, severity of clinical signs of FAD was not significantly different from baseline severity at any time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that topical administration of selamectin, even without the use of supplementary environmental control measures and with minimal therapeutic intervention, can reduce the severity of clinical signs of FAD in dogs and cats.     

Cerebellar abiotrophy in a family of Border Collie dogs

Cerebellar abiotrophies have a nonsex-linked, autosomal, recessively inherited basis in a number of species, and lesions typically reflect profound and progressive loss of Purkinje cells. In this report, an unusual form of abiotrophy is described for two sibling Border Collies. Extensive loss of the cerebellar granular cell layer was present with relative sparing of Purkinje cells of two female pups. The biochemical basis for this form of cerebellar abiotrophy is unknown, but the lack of disease in other siblings supports an autosomal recessive mode of inheritance.     

A Glasshouse Cropping Method for Screening Lettuce Lines for Resistance to Sclerotinia Sclerotiorum

A soil-based glasshouse crop procedure was developed to screen lettuce lines for resistance to Sclerotinia sclerotiorum. Six sequential crops of 19 different lettuce lines with a range of cultural morphologies, reported previously to exhibit some form of resistance to S. sclerotiorum, were planted in a glasshouse infested with S. sclerotiorum and natural disease development compared with a standard susceptible commercial butterhead cultivar, Rachel. Concomitantly, the same lettuce lines were planted in pots in a nearby glasshouse, were artificially inoculated with ascospores of S. sclerotiorum, assessed for infection and scored for disease severity. Most of lines exhibited resistance in at least one of the crop or direct inoculation assessments with wild form, PI 251246, and stem lettuce, Taiwan, exhibiting resistance in three of the assessments and wild form, PI 271938 (Lactuca serriola), and Iceberg (crisp) line, 74-1076, exhibiting resistance in all four assessments. Cos line, PI 250427, was less resistant than the standard control in all assessments. The crop based screen with predictable, natural disease development was the most discriminating overall assessment and enabled growth habit to be taken into account during the screening process which was not possible through the direct inoculation procedures. Nevertheless, the novel ascospore inoculation screening process provided information on the type of resistance expressed that could not be identified from the cropping procedure.     

Aetiology of diarrhoea in young calves

Faeces samples were collected from 302 untreated calves on the day of onset of diarrhoea and from 49 healthy calves at 32 farms experiencing outbreaks of diarrhoea. At least four diarrhoeic calves were sampled on each farm, and samples were examined for rotavirus, coronavirus, cryptosporidium, enterotoxigenic Escherichia coli and Salmonella species. Although all these enteropathogens were excreted more frequently by the diarrhoeic than by the healthy calves, the difference was significant overall only for rotavirus. Rotavirus was excreted by 18 per cent of healthy calves, coronavirus by 4 per cent, cryptosporidium by 14 per cent, and no enterotoxigenic E coli or Salmonella species were detected. The most common enteropathogen in diarrhoeic calves was rotavirus, which was excreted by more than half the diarrhoeic calves on 18 farms. Coronavirus was excreted at a similar high prevalence on one farm, cryptosporidium on five farms and enterotoxigenic E coli on three farms. Concurrent infection with two or more microorganisms occurred in 15 per cent of diarrhoeic calves. There was no difference in the isolation rate of campylobacters between diarrhoeic and healthy calves.     

Colostral and milk antibody titers in cows vaccinated with a modified live-rotavirus-coronavirus vaccine

Colostral and milk whey rotavirus (RV) and coronavirus (CV) antibody titers stimulated in 15 beef heifers by vaccination with a modified live-RV-CV vaccine were compared with titers in 15 nonvaccinated heifers. Geometric mean antibody titers to RV in colostral and 3-day milk whey from vaccinated heifers were 2,807 and 92, respectively, and in control heifers were 1,613 and 71, respectively. Geometric mean antibody titers to CV in colostral and 3-day milk whey of vaccinated heifers were 877 and 13, respectively, compared with titers were 877 and 13, respectively, compared with titers in nonvaccinated heifers of 731 and 7, respectively. Differences in antibody titers between vaccinated and nonvaccinated heifers were not significantly different.