Identification of trypanosomes in animals, humans and Glossina
Gibson, W.
Bulletin de la Societe de Pathologie Exotique 87(5): 315-318
1994
ISSN/ISBN: 0037-9085 PMID: 7496192 Document Number: 436512
Biochemical methods now available for the identification of African trypanosomes are briefly reviewed, under the headings: species-specific DNA probes (dot blot hybridization, polymerase chain reaction (PCR)); subspecific DNA probes (Trypanosoma brucei gambiense [T. gambiense]; T. b. rhodesiense [T. rhodesiense] and T. b. brucei [T. brucei]). The method of choice depends on the number of trypanosomes present in a sample and the taxonomic level required. DNA probes based on repetitive DNA elements allow identification to subgeneric (e.g. Trypanozoon), species (e.g.Trypanosoma congolense, T. simiae) or subspecific (e.g. T. congolense savannah) levels. These probes are particularly useful for identification of trypanosomes in the fly midgut, where sufficient numbers (> 100) are present to allow the use of simple dot blot hybridization. Greater sensitivity has been achieved by amplification of these repetitive DNA sequences by PCR, so enabling small numbers (> one) of trypanosomes found in the fly mouthparts to be identified. At the subspecific level, isoenzyme analysis and restriction fragment length polymorphism (RFLP) analysis have been widely used to characterize isolates within the T. brucei species. 2 other techniques, karyotype analysis and random amplified polymorphic DNA (RAPD) analysis, are also useful for fingerprinting isolates. Molecular karyotypes are produced by size fractionation of chromosomal DNAs by pulsed field gel electrophoresis (PFGE).