Bench Aids for the Diagnosis of Filarial Infections

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A practical tool for the diagnosis of filarial infections. The bench aids consist of 46 full-color photomicrographs illustrating the characteristic features of the various species of microfilariae as they appear in different stained preparations at different magnifications. Each photomicrograph is produced with a measuring bar and accompanied by a short explanatory legend, which draws attention to distinctive features that help confirm diagnosis. Species covered include Wuchereria bancrofti, Loa loa, Brugia malayi, Brugia timori, Mansonella perstans, Mansonella ozzardi, Onchocerca volvulus, and Mansonella streptocerca. Commonly encountered artifacts and oddities that may confuse diagnosis are also pictured. Produced in a robust plasticized format, the six plates can be used as either a guide for laboratory and field workers in endemic countries or a teaching aid for students and trainees. The aim is to help the microscopist reach a quick and accurate diagnosis and avoid common errors. With this goal in mind, the bench aids include pertinent laboratory instructions as well as high-quality images. Instructions are provided for the preparation of thick blood films, for Giemsa and haematoxylin staining, for membrane filtration and the Knott concentration method, and for methods of tissue examination needed to detect the microfilariae of Onchocerca volvulus and Mansonella streptocerca that reside in the skin. Also included is a tabular comparative summary of the geographical distribution, vectors, habitat, periodicity, and key morphological and other diagnostic features for each of the most common human filarial parasites.