Relationship between Psoroptes cuniculi and the internal bacterium Serratia marcescens.

The bacterium Serratia marcescens isolated from surface-sterilised Psoroptes cuniculi was found sensitive to the antibiotic Amikacin. Mites placed in this antibiotic for 48-72 h and then washed by centrifugation were found to be alive and S. marcescens-free. Two experimental infestations were undertaken in order to verify the ability of the S. marcescens-free mites to infect and to give ear skin lesions in healthy rabbits and to evaluate the differential ability of the S. marcescens-free and S. marcescens-infected mites to give ear skin lesions. All rabbits were found to be infested, but only rabbits infested with S. marcescens-free mites presented crusts in their ears, whereas mites and/or eggs were only detected in the ear cerumen of all rabbits infested with S. marcescens-infected mites. S. marcescens was isolated only from P. cuniculi mites taken from these latter rabbits. Results indicate that P. cuniculi mites do not need S. marcescens to live and to be able to infest a healthy rabbit. In addition, S. marcescens was not isolated from eggs and newly born larvae of S. marcescens-infected P. cuniculi, demonstrating that in a population of P. cuniculi this bacterium is not transmitted transovarially.

An evaluation of the application of infrared thermal imaging to the tele-diagnosis of sarcoptic mange in the Spanish ibex (Capra pyrenaica).

The application of infrared thermal imaging to the diagnosis of sarcoptic mange in the wild Spanish ibex (Capra pyrenaica) was evaluated. Seventy-three ibexes (35 males, 38 females) of varying ages were studied. Each animal was observed using conventional binoculars (OT) to detect lesions characteristic of mange. Infrared thermography (IR) was then performed and the resultant image judged negative or positive. The distance from the thermograph to the animal was measured, and the animal killed. Skin samples were taken for mite detection by routine laboratory diagnosis (LAB). The most sensitive and specific technique for the tele-diagnosis of sarcoptic mange in the Spanish ibex is OT, as it permits diagnosis over greater distances than IR, which sensitivity is impaired at distances >100m. When disease prevalence is low, such as in initial and final phases of an epidemic, a more sensitive technique would be valuable in detecting all affected animals.