Parasitological detection of Trypanosoma brucei gambiense in serologically negative sleeping-sickness suspects from north-western Uganda
Loading...
Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Annals of Tropical Medicine & Parasitology
Abstract
Forty-five parasitologically confirmed cases of sleeping sickness were diagnosed in north-western Uganda
using a combination of two or three techniques. Forty of the cases were positive by the card agglutination
test for trypanosomiasis (CATT), four were negative and one was not screened by the CATT.
Trypanosomes isolated from the four CATT-negative but parasitologically positive cases were propagated
for detailed biochemical genetic analysis. The aim was to demonstrate whether these four stocks lacked the
LiTat 1.3 gene which encodes the antigen on which the CATT is based. All the DNA extracts isolated
from these CATT-negative stocks and from six CATT-positive stocks of Trypanosoma brucei gambiense
were targeted for amplification by the three variable-surface-glycoprotein genes thought to be ubiquitous
in T. b. gambiense. The LiTat 1.3 gene was shown to be present in all 10 stocks. Trypanosome carriers
may be CATT -negative because the CATT is not sensitive enough, because their parasites lack the LiT at
1.3 gene, or because their parasites have this gene but do not express it. The four sleeping-sickness cases
who gave negative CATT results in the present study have very important implications in the diagnosis
of T. b. gambiense infections using the CATT. Following treatment of the CATT -positive cases, the
CA TT -negative carriers of the trypanosomes remain as human reservoir hosts for continuous infection of
the population. Because CATT-negative individuals are rarely examined further, the general prevalence
of parasitologically positive but CATT-negative cases is unclear. This study demonstrates the value of
co-ordinated use of serological and parasitological techniques in the diagnosis of Gambian sleeping
sickness.
Description
Keywords
Parasitological detection, Trypanosoma brucei gambiense, Serologically negative sleepingsickness suspects, North-western Uganda
Citation
J. C. K. Enyaru, E. Matovu, M. Akol, C. Sebikali, J. Kyambadde, C. Schmidt, R. Brun, R. Kaminsky, L. M. Ogwal & F. Kansiime (1998) Parasitological detection of Trypanosoma brucei gambiense in serologically negative sleeping-sickness suspects from north-western Uganda, Annals of Tropical Medicine & Parasitology, 92:8, 845-850, DOI: 10.1080/00034983.1998.11813349