Experimental infection of dogs with the nasal mite Pneumonyssoides caninum

Efficacy of selamectin in the treatment of nasal mite (Pneumonyssoides caninum) infection in dogs

In a laboratory study to evaluate the efficacy of selamectin for treatment of canine nasal mite infection, 12 purpose-bred beagles were experimentally infected with Pneumonyssoides caninum (P. caninum). Six of the dogs were treated with selamectin applied to the skin of the back at dosages of 6 to 24 mg/kg for three times at 2-week intervals. The remaining six dogs were an untreated control group. At necropsy 39 to 46 days after inoculation, no P. caninum mites were found in any of the treated dogs. In contrast, nasal mites were found in five of the untreated dogs. This difference was statistically significant at P=0.015.

Demonstration of circulating antibodies to Pneumonyssoides caninum in experimentally and naturally infected dogs

Antibodies to the canine nasal mite, Pneumonyssoides caninum, were demonstrated by ELISA in sera from four experimentally and 77 naturally infected dogs employing a crude P. caninum antigen. In sera from the four experimentally infected dogs, antibodies to P. caninum were first detected on day 11 post-inoculation (p.i.). Optical density (OD) values remained high throughout the observation period of 14 weeks. Two major protein bands with apparent molecular weights of 83 and 74kDa were visible by western blot (WB) from day 11 p.i. On day 14 p.i., another three major protein bands at 44, 37, and 34kDa were visible. The protein pattern then remained essentially constant until the end of the experiment except for some weak bands between 250 and 30kDa which were sometimes visible. In sera obtained from a non-inoculated control dog, no P. caninum antibodies were detected, neither by the ELISA nor by the WB. With sera from 77 naturally infected dogs with a verified diagnosis of P. caninum infection, the OD values varied between 0.24 and 0.95. When sera from four of these dogs were analysed by WB, the protein pattern observed was equivalent with that seen with sera from the experimentally infected dogs on day 25 p.i. Sera from four experimental Beagles, in which no P. caninum mites were found at necropsy, were also analysed by the P. caninum ELISA, the OD values demonstrated never exceeded 0.15. In addition, 48 sera obtained from dogs infected with or allergic to other arthropods were used for studies of possible cross-reactivity. With 10 sera, elevated OD values were found by the ELISA. Eight of them showed a similar banding pattern by the WB as did the experimentally infected dogs on day 25 p.i. This was, therefore, interpreted as an effect of a concurrent P. caninum infection.

Diseases associated with pronounced eosinophilia: a study of 105 dogs in Sweden

Records of 105 dogs with pronounced eosinophilia (>2.2 x 10(9) eosinophils/litre) were evaluated in a retrospective study to determine diseases associated with the abnormality in dogs in Sweden. Inflammatory disease in organs with large epithelial surfaces, such as the gut, lungs or skin, was found in 36 per cent of the dogs. A further one-quarter of the 105 cases were placed in the 'miscellaneous' category, which comprised various diseases found at low frequency. The most well defined diagnosis was pulmonary infiltrates with eosinophils in 12 per cent of the dogs. A further 11 per cent had parasitic disease caused by either sarcoptic mange or nasal mite. No atopic dog was found and rottweilers were over-represented in most disease groups. Pronounced eosinophilia, in many cases transient, seems to be associated with a variety of disorders in dogs. In the present study, rottweilers appeared to be more prone to a high eosinophil response than other breeds.