Paederus (Coleoptera: Staphylinidae) in Uganda. I: Outbreaks, clinical effects, extraction and bioassay of the vesicating toxin.

A brief review is made of the extensive, scattered and sometimes conflicting literature concerning outbreaks and effects of the vesicating Staphylinid beetles of the genus Paederus and their toxin. Observations are reported on outbreaks of Paederus sabaeus and Pachypaederus puncticollis which occurred in Uganda in 1961-62 and subsequently. Clinical effects seen in Kampala are described and a case of ocular involvement is reported in detail. It was found that the cuticle of P. sabaeus must be broken and haemolymph released for any reaction to follow, that the mucosa of the mouth is relatively little affected by the toxin, and that Pachypaederus puncticollis possesses similar vesicating properties to the Paederus species. Methods of extraction of toxin from the beetles using various solvents and a bioassay technique based on mean daily scores of reaction on mouse ears are described. Problems of treatment are discussed.