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Biomedical subjects

P Dukes

Publications and source records attributed to P Dukes.

25 records · Page 2Linked to original sources
PubMed1983

Sleeping sickness in the Luangwa Valley of Zambia. A preliminary report of the 1982 outbreak at Kasyasya village.

Sleeping sickness (SS) in the Luangwa Valley of Zambia is widespread but generally sporadic and of low prevalence. Between March and June 1982 eleven SS cases were reported from Kasyasya village, a community of about 75 people in 12 households. Transmission most likely occurred in two periods between November 1981 and April 1982, when people were living in three groups of small farming homesteads adjacent to their fields and to woodland . Their main village was deserted for the duration of the cultivation season. The high incidence of SS at Kasyasya , particularly amongst adult females of one homestead , suggested that transmission occurred close to or within areas of habitation. Intimate contact between man, fly and the unknown reservoir was also indicated by the finding of only two, almost identical, T. rhodesiense zymodemes amongst Kasyasya cases. The zymodemes differed only by a single band in one enzyme (ALAT) of the twelve examined by starch-gel isoenzyme electrophoresis. There was no evidence for cyclical man-fly-man transmission, but mechanical transmission and single-fly transmission of a mature infection to several people may have occurred. Game animals feeding close to the homesteads were the most likely, but unproven, sources of the outbreak.

Adolescent↗
PubMedDate not supplied

A new method for isolating Trypanosoma brucei gambiense from sleeping sickness patients.

Low infectivity to laboratory mammals and low virulence make Trypanosoma brucei gambiense difficult to isolate and grow in amounts sufficient for biochemical characterization. We report the isolation of T.b. gambiense by feeding cryopreserved primary isolates to laboratory-reared Glossina morsitans morsitans, followed by rapid cultivation in vitro of procyclic forms dissected from infected tsetse fly midguts. This technique allows the characterization of hitherto unsampled populations and avoids selection due to long-term subpassage. Of 16 primary isolates from trypanosomiasis patients of the Fontem focus in Cameroon, 12 (75%) produced infections in tsetse whereas only 4 (25%) infected rats. Ten isolates were subsequently cultivated as procyclic forms in vitro; 2 failed to grow owing to bacterial contamination. In addition, 2 primary isolates from Côte d'Ivoire patients and a stock of low virulence from the Congo Republic were similarly grown. Only one primary isolate produced tsetse salivary gland infections, an observation consistent with the hypothesis that some populations of T.b. gambiense are intrinsically incompatible with G.m. morsitans.

Animals↗
PubMedDate not supplied

The substitution of procyclic for bloodstream form Trypanosoma brucei gambiense in isoenzyme studies.

Examination of 10 enzymes from 8 stocks of Trypanosoma brucei showed that procyclic forms could be substituted for bloodstream forms in isoenzyme studies. T. b. gambiense procyclic forms cultured in vitro offer a better source of material for genetic investigations because this species is usually of low infectivity and virulence to laboratory rodents. Using 6 stocks of T. b. gambiense and 2 stocks of T. b. brucei, enzyme patterns of bloodstream and procyclic forms were identical for isocitrate dehydrogenase, malic enzyme, two nucleoside hydrolases (utilizing inosine and deoxyinosine respectively), phosphoglucomutase and superoxide dismutase. Procyclic forms appeared to have greater threonine dehydrogenase activity than bloodstream forms. Consistent differences between bloodstream and culture forms were observed for alanine aminotransferase, aspartate aminotransferase and malate dehydrogenase. These agreed with known differences in the metabolism of procyclic and bloodstream forms.

Animals↗