Genetically discrete populations of <i>Trypanosoma congolense</i> from livestock on the Kenyan coast

Knowles, G.; Betschart, Bruno; Kukla, B.; Scott, J.R.; Majiwa, Phelix A.O.

doi:10.1017/s0031182000080100

Cited by 38 publications

(21 citation statements)

References 15 publications

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“…This result seems natural considering that it is thought to be an East African subgroup first isolated from livestock in 1982 on a ranch at Kilifi on the Kenyan coast [23]. Both Savannah and Forest were the endemic subgroups in Ghana and mixed infections between the two subgroups were recorded at 18.6%.…”

Section: Discussionmentioning

confidence: 90%

Molecular epidemiological studies on animal trypanosomiases in Ghana

et al. 2012

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BackgroundAfrican trypanosomes are extracellular protozoan parasites that are transmitted between mammalian hosts by the bite of an infected tsetse fly. Human African Trypanosomiasis (HAT) or sleeping sickness is caused by Trypanosoma brucei rhodesiense or T. brucei gambiense, while African Animal Trypanosomiasis (AAT) is caused mainly by T. vivax, T. congolense, T. simiae,T. evansi and T. brucei brucei. Trypanosomiasis is of public health importance in humans and is also the major constraint for livestock productivity in sub-Saharan African countries. Scanty information exists about the trypanosomiasis status in Ghana especially regarding molecular epidemiology. Therefore, this study intended to apply molecular tools to identify and characterize trypanosomes in Ghana.MethodsA total of 219 tsetse flies, 248 pigs and 146 cattle blood samples were collected from Adidome and Koforidua regions in Ghana in 2010. Initial PCR assays were conducted using the internal transcribed spacer one (ITS1) of ribosomal DNA (rDNA) primers, which can detect most of the pathogenic trypanosome species and T. vivax-specific cathepsin L-like gene primers. In addition, species- or subgroup-specific PCRs were performed for T. b. rhodesiense, T. b. gambiense, T. evansi and three subgroups of T. congolense.ResultsThe overall prevalence of trypanosomes were 17.4% (38/219), 57.5% (84/146) and 28.6% (71/248) in tsetse flies, cattle and pigs, respectively. T. congolense subgroup-specific PCR revealed that T. congolense Savannah (52.6%) and T. congolense Forest (66.0%) were the endemic subgroups in Ghana with 18.6% being mixed infections. T. evansi was detected in a single tsetse fly. Human infective trypanosomes were not detected in the tested samples.ConclusionOur results showed that there is a high prevalence of parasites in both tsetse flies and livestock in the study areas in Ghana. This enhances the need to strengthen control policies and institute measures that help prevent the spread of the parasites.

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Section: Discussionmentioning

confidence: 90%

Molecular epidemiological studies on animal trypanosomiases in Ghana

et al. 2012

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“…So far, T. ( N . ) congolense belonging to the Kenya coast group has been observed exclusively in the humid coastal region of Kenya (Majiwa et al 1985;Gashumba 1986; Knowles et al 1988). The most widespread group in the area is T. ( N . )…”

Section: Discussionmentioning

confidence: 99%

Sleeping sickness in Zaire: a nested polymerase chain reaction improves the identification of Trypanosoma (Trypanozoon) brucei gambiense by specific kinetoplast DNA probes

Schares¹,

Mehlitz²

1996

Tropical Med Int Health

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SummaryBlood samples coliected in the sleeping sickness focus of Boma, Zaire, from human patients and domestic animals were analysed by polymerase chain reaction (PCR) for the presence of trypanosome DNA. The comparison of PCR and miniature anion exchange centrifugation technique (m-AECT) results clearly shows that in domestic animals mixed infections (Trypanozoon/Trypanosoma [Nannomonas] congolense) are more frequently diagnosed by PCR than by m-AECT. Trypanozoon positive blood samples were further analysed for Trypanosoma (Trypanozoon) brucei gambiense. For that purpose amplified minicircle kinetoplast DNA (minicircle kDNA) was differentiated in gambiense and non-gambiense by hybridization with DNA probes. To analyse blood samples, especially those with low parasite numbers, the amplification step had to be improved by a nested PCR. Subsequent hybridization was done with kDNA probes generated by PCR from blood samples which had been obtained from a human patient infected with T. (T.) b. gambiense and a pig infected with Trypanozoon. The hybridization results clearly show that at least two genotypes of Trypanozoon parasites occur in the sleeping sickness focus of Boma, Bas-Zaire. One obviously corresponds to T. (T.) b. gambiense and was present in humans and two domestic animals (pig, dog). The other genotype seems to be associated with T. (T.) 6. brucei and could be detected only in the blood of domestic animals. This is the first time that field samples could be analysed by a technique which facilitates the molecular identification of T. (T. j b. gambiense without prior cloning, propagation, and/or isolation of the parasites. Therefore, this technique seems to be a promising tool to elucidate the significance of the animal reservoir for the epidemiology of the gambiense sleeping sickness in Africa.

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“…The parasites classi®ed as T. congolense are a collection of diverse trypanosomes (Godfrey 1982) that dier in a number of phenotypic (Young and Godfrey 1983;Knowles et al 1988) and genotypic features (Majiwa et al1993). However, the extent of variation within any one genotypic group remains unknown.…”

Section: Resultsmentioning

confidence: 99%

Physical and transcriptional organization of the ribosomal RNA genes of the savannah-type Trypanosoma congolense

Urakawa

Majiwa

2001

Parasitology Research

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Ribosomal RNA genes have been cloned from the major species of African trypanosomes. Complete nucleotide sequence composition of the small subunit (SSU) and portions of the large subunit (LSU) ribosomal RNA genes was determined for each of these trypanosome species. In contrast to the situation in Trypanosoma brucei, in savannah-type T. congolense the LSU ribosomal RNA is cleaved twice, to generate two additional prominent fragments. This leads to the different profiles observed when the rRNA molecules from these two trypanosome species are resolved in agarose gels. From the nucleotide sequences of the 18S RNA, a phylogenetic tree was derived depicting the relationships among the T. congolense complex of trypanosomes and the other species of trypanosomes.

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Genetically discrete populations of Trypanosoma congolense from livestock on the Kenyan coast

Cited by 38 publications

References 15 publications

Molecular epidemiological studies on animal trypanosomiases in Ghana

Molecular epidemiological studies on animal trypanosomiases in Ghana

Sleeping sickness in Zaire: a nested polymerase chain reaction improves the identification of Trypanosoma (Trypanozoon) brucei gambiense by specific kinetoplast DNA probes

Physical and transcriptional organization of the ribosomal RNA genes of the savannah-type Trypanosoma congolense

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