Therapy and prevention of parasitic insects in veterinary medicine using imidacloprid.

Ectoparasitic insects play a major role in veterinary medicine. The flea, especially the cat flea (Ctenocephalides felis felis Bouch 1835) is the most important ectoparasite worldwide. The cat flea parasitizes not only on dogs and cats but also on other warm-blooded animals including humans. The veterinary importance of flea infestation are dermatological conditions due to allergic reactions to antigens in the flea saliva and the transmission of infectious agents like bacteria, viruses and helminths. Insecticides used in veterinary medicine today have to fulfil criteria of elimination of a existing flea infestation (therapy) and prevention (prophylaxis) of new infestation for weeks. Imidacloprid is a compound of the chemical class of CNI (chloronicotinyl insecticides syn. neonicotinoids) that fits these criteria. The high selectivity towards the site of action within insects together with the high safety margin on mammals allowed to develop imidacloprid as an insecticide for agricultural use and finally for the application as a veterinary medicine. The major features of imidacloprid chemistry, toxicology and the development and use as a veterinary medicinal remedy are described.