The isolation and genetic heterogeneity of Trypanosoma brucei gambiense from north-west Uganda

Enyaru, John; Allingham, R.; Bromidge, Teresa; Kanmogne, Georgette D.; Carasco, J. F.

doi:10.1016/0001-706x(93)90066-k

Cited by 27 publications

(13 citation statements)

References 23 publications

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“…Its absence from two of the present isolates, NW4 and NW15, shows the dif® culty of distinguishing T. b. gambiense from other trypanosomes of the T. brucei group in Uganda. Although six of eight Ugandan isolates were found not to have this gene in an earlier investigation (Enyaru et al, 1993), absence of the VSG 117 gene, seen in stock NW8 in the present study, has not been seen before in isolates from north± western Uganda. These results are further evidence of the microheterogeneic nature of T. b. gambiense in this area (Enyaru et al, 1993).…”

Section: Discussioncontrasting

confidence: 73%

“…Although six of eight Ugandan isolates were found not to have this gene in an earlier investigation (Enyaru et al, 1993), absence of the VSG 117 gene, seen in stock NW8 in the present study, has not been seen before in isolates from north± western Uganda. These results are further evidence of the microheterogeneic nature of T. b. gambiense in this area (Enyaru et al, 1993). VSG 117 could not be detected in some stocks of T. b. gambiense Type II from West Africa, T. b. rhodesiense and T. b. brucei (Brom idge et al, 1993).…”

Section: Discussioncontrasting

confidence: 73%

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Parasitological detection of Trypanosoma brucei gambiense in serologically negative sleeping-sickness suspects from north-western Uganda

Enyaru¹,

Matovu²,

Akol³

et al. 1998

Annals of Tropical Medicine And Parasitology

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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 LiTat 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 CATT-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.

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Section: Discussioncontrasting

confidence: 73%

Section: Discussioncontrasting

confidence: 73%

Parasitological detection of Trypanosoma brucei gambiense in serologically negative sleeping-sickness suspects from north-western Uganda

Enyaru¹,

Matovu²,

Akol³

et al. 1998

Annals of Tropical Medicine And Parasitology

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“…To ensure the correct identification of our strain within T . b. gambiense group 1, we checked by PCR the presence of TgsGP [53] and LiTat 1.3 [71,72]. Cultures were maintained at 37 °C in humidified atmosphere containing 5% CO 2 .…”

Section: Methodsmentioning

confidence: 99%

Trypanosoma brucei gambiense Adaptation to Different Mammalian Sera Is Associated with VSG Expression Site Plasticity

et al. 2013

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Trypanosoma brucei gambiense infection is widely considered an anthroponosis, although it has also been found in wild and domestic animals. Thus, fauna could act as reservoir, constraining the elimination of the parasite in hypo-endemic foci. To better understand the possible maintenance of T. b. gambiense in local fauna and investigate the molecular mechanisms underlying adaptation, we generated adapted cells lines (ACLs) by in vitro culture of the parasites in different mammalian sera. Using specific antibodies against the Variant Surface Glycoproteins (VSGs) we found that serum ACLs exhibited different VSG variants when maintained in pig, goat or human sera. Although newly detected VSGs were independent of the sera used, the consistent appearance of different VSGs suggested remodelling of the co-transcribed genes at the telomeric Expression Site (VSG-ES). Thus, Expression Site Associated Genes (ESAGs) sequences were analysed to investigate possible polymorphism selection. ESAGs 6 and 7 genotypes, encoding the transferrin receptor (TfR), expressed in different ACLs were characterised. In addition, we quantified the ESAG6/7 mRNA levels and analysed transferrin (Tf) uptake. Interestingly, the best growth occurred in pig and human serum ACLs, which consistently exhibited a predominant ESAG7 genotype and higher Tf uptake than those obtained in calf and goat sera. We also detected an apparent selection of specific ESAG3 genotypes in the pig and human serum ACLs, suggesting that other ESAGs could be involved in the host adaptation processes. Altogether, these results suggest a model whereby VSG-ES remodelling allows the parasite to express a specific set of ESAGs to provide selective advantages in different hosts. Finally, pig serum ACLs display phenotypic adaptation parameters closely related to human serum ACLs but distinct to parasites grown in calf and goat sera. These results suggest a better suitability of swine to maintain T. b. gambiense infection supporting previous epidemiological results.

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“…Human pathogenic trypanosomes of the subspecies T. brucei are morphologically indistinguishable from those found only in other animals; and this has greatly hampered research on animal reservoirs. However, with the advent of biochemical and molecular markers some trypanosome stocks circulating in animals were shown to be similar to those found in man 1–5 . The importance of both wild and domestic animals in the epidemiology of T.b.…”

Section: Introductionmentioning

confidence: 99%

Detection of T.b. rhodesiense Trypanosomes in Humans and Domestic Animals in South East Uganda by Amplification of Serum Resistance‐Associated Gene

Enyaru¹,

Matovu²,

Nerima³

et al. 2006

Annals of the New York Academy of Sciences

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The human serum resistance-associated (SRA) gene was identified in 28 (80%) of the 35 T.b. rhodesiense trypanosomes from parasitologically confirmed sleeping sickness cases, using the primers designed by Radwanska and in 27 (77.1%) of the same 35 T.b. rhodesiense trypanosomes using the primers designed by Gibson. However, about 20% of the 35 T.b. rhodesiense trypanosomes could not be detected by SRA-polymerase chain reaction (PCR) even when an aliquot of the first PCR was used in the second PCR, indicating that the gene may be absent in those trypanosomes or the trypanosomes could be having another variant of SRA not detectable by these primers since three variants of SRA genes have so far been identified or the amount of trypanosomal DNA extracted from infected blood was too low to be detected. The trypanosome isolates that are SRA gene negative may indicate the presence of some T.b. rhodesiense trypanosomes with modified or lack SRA genes or simple loss of the SRA gene from the expression site in which it resides during antigenic variation. Analysis of trypanosomes derived from domestic animals showed that 79 (90.8%) of the 87 trypanosomes isolated from cattle were positive by Trypanosoma brucei (TBR)-PCR, indicating that they were Trypanozoon while 8 (9.2%) of the trypanosome isolates which were negative by TBR-PCR could be T. vivax, T. congolense, or T. theileri. When subjected to SRA-PCR, 10 (11.5%) of the 87 trypanosomes isolates derived from cattle were positive, indicating that there could be T.b. rhodesiense circulating in cattle, which is similar to the percentage of T.b. rhodesiense previously obtained in cattle in Serere, Soroti district.

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The isolation and genetic heterogeneity of Trypanosoma brucei gambiense from north-west Uganda

Cited by 27 publications

References 23 publications

Parasitological detection of Trypanosoma brucei gambiense in serologically negative sleeping-sickness suspects from north-western Uganda

Parasitological detection of Trypanosoma brucei gambiense in serologically negative sleeping-sickness suspects from north-western Uganda

Trypanosoma brucei gambiense Adaptation to Different Mammalian Sera Is Associated with VSG Expression Site Plasticity

Detection of T.b. rhodesiense Trypanosomes in Humans and Domestic Animals in South East Uganda by Amplification of Serum Resistance‐Associated Gene

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