Diagnosis of Gambian trypanosomiasis in man by isolating trypanosomes from blood passed through DEAE-cellulose.

A method is described whereby small numbers of trypanosomes in blood can be concentrated free of blood cells on to a slide. Infected blood is passed through a column of DEAE-cellulose, which adsorbs the blood cells, and the organisms are separated from the eluate by centrifugation. By this technique trypanosomes were detected in 24% of 41 Nigerian patients with suspected Gambian trypanosomiasis, but whose cervical lymph glands were not infected; of these, only 5% were positive in thick blood films. Trypanosomes were also found in 91% of 21 gland-positive patients, of which only 19% were positive in thick blood-films. The organisms could not be found in 5 patients recently treated with either pentamidine or suramin-sodium and melarsen, and disappeared within two hours from the blood of another patient given melarsoprol. Trypanosomes were not found in 3 samples of infected cerebrospinal fluid passed through DEAE-cellulose. Although 2 gland-positive patients and 1 patient with a patent parasitaemia failed to give positive results, column-separation of suspected blood is a potentially valuable aid in the parasitological diagnosis of Gambian trypanosomiasis.