Detection and identification of trypanosomes by polymerase chain reaction in wild tsetse flies in Cameroon

Morlais, Isabelle; Grébaut, Pascal; Bodo, Jean-Marie; Djoha, S.; Cuny, G; Herder, Stéphane

doi:10.1016/s0001-706x(98)00014-x

Cited by 61 publications

(54 citation statements)

References 20 publications

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“…These results are in line with those reported in Southern Africa [23]. The high infection rate of trypanosomes belonging to Nannomonas , especially T. congolense, corroborates results obtained in tsetse flies of West, Central [25] and East Africa [23]. This is in line with the results obtained in domestic animals of the same area [22].…”

Section: Discussionsupporting

confidence: 91%

Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese) sleeping sickness focus of the Democratic Republic of Congo

et al. 2012

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BackgroundThe Malanga sleeping sickness focus of the Democratic Republic of Congo has shown an epidemic evolution of disease during the last century. However, following case detection and treatment, the prevalence of the disease decreased considerably. No active survey has been undertaken in this focus for a couple of years. To understand the current epidemiological status of sleeping sickness as well as the animal African trypanosomiasis in the Malanga focus, we undertook the identification of tsetse blood meals as well as different trypanosome species in flies trapped in this focus.MethodsPyramidal traps were use to trap tsetse flies. All flies caught were identified and live flies were dissected and their mid-guts collected. Fly mid-gut was used for the molecular identification of the blood meal source, as well as for the presence of different trypanosome species.ResultsAbout 949 Glossina palpalis palpalis were trapped; 296 (31.2%) of which were dissected, 60 (20.3%) blood meals collected and 57 (19.3%) trypanosome infections identified. The infection rates were 13.4%, 5.1%, 3.5% and 0.4% for Trypanosoma congolense savannah type, Trypanosoma brucei s.l., Trypanosoma congolense forest type and Trypanosoma vivax, respectively. Three mixed infections including Trypanosoma brucei s.l. and Trypanosoma congolense savannah type, and one mixed infection of Trypanosoma vivax and Trypanosoma congolense savannah type were identified. Eleven Trypanosoma brucei gambiense infections were identified; indicating an active circulation of this trypanosome subspecies. Of all the identified blood meals, about 58.3% were identified as being taken on pigs, while 33.3% and 8.3% were from man and other mammals, respectively.ConclusionThe presence of Trypanosoma brucei in tsetse mid-guts associated with human blood meals is indicative of an active transmission of this parasite between tsetse and man. The considerable number of pig blood meals combined with the circulation of Trypanosoma brucei gambiense in this focus suggests a transmission cycle involving humans and domestic animals and could hamper eradication strategies. The various species of trypanosomes identified in the Malanga sleeping sickness focus indicates the coexistence of animal and human African Trypanosomiasis. The development of new strategies integrating control measures for human and animal trypanosomiasis may enable the reduction of the control costs in this locality.

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Section: Discussionsupporting

confidence: 91%

Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese) sleeping sickness focus of the Democratic Republic of Congo

et al. 2012

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“…Currently, there are many different approaches reported for using PCR data to look at T. brucei s.l. in tsetse populations, including PCR of any organs found infected [25] (similar to this study although we did not include mouthparts), PCR of all organs in the fly if any organ is found infected on dissection/microscopy [59], [66] and PCR of whole tsetse flies [for example 27], [28]. This variety of protocols raises two important issues:…”

Section: Discussionmentioning

confidence: 99%

Using Molecular Data for Epidemiological Inference: Assessing the Prevalence of Trypanosoma brucei rhodesiense in Tsetse in Serengeti, Tanzania

et al. 2012

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BackgroundMeasuring the prevalence of transmissible Trypanosoma brucei rhodesiense in tsetse populations is essential for understanding transmission dynamics, assessing human disease risk and monitoring spatio-temporal trends and the impact of control interventions. Although an important epidemiological variable, identifying flies which carry transmissible infections is difficult, with challenges including low prevalence, presence of other trypanosome species in the same fly, and concurrent detection of immature non-transmissible infections. Diagnostic tests to measure the prevalence of T. b. rhodesiense in tsetse are applied and interpreted inconsistently, and discrepancies between studies suggest this value is not consistently estimated even to within an order of magnitude.Methodology/Principal FindingsThree approaches were used to estimate the prevalence of transmissible Trypanosoma brucei s.l. and T. b. rhodesiense in Glossina swynnertoni and G. pallidipes in Serengeti National Park, Tanzania: (i) dissection/microscopy; (ii) PCR on infected tsetse midguts; and (iii) inference from a mathematical model. Using dissection/microscopy the prevalence of transmissible T. brucei s.l. was 0% (95% CI 0–0.085) for G. swynnertoni and 0% (0–0.18) G. pallidipes; using PCR the prevalence of transmissible T. b. rhodesiense was 0.010% (0–0.054) and 0.0089% (0–0.059) respectively, and by model inference 0.0064% and 0.00085% respectively.Conclusions/SignificanceThe zero prevalence result by dissection/microscopy (likely really greater than zero given the results of other approaches) is not unusual by this technique, often ascribed to poor sensitivity. The application of additional techniques confirmed the very low prevalence of T. brucei suggesting the zero prevalence result was attributable to insufficient sample size (despite examination of 6000 tsetse). Given the prohibitively high sample sizes required to obtain meaningful results by dissection/microscopy, PCR-based approaches offer the current best option for assessing trypanosome prevalence in tsetse but inconsistencies in relating PCR results to transmissibility highlight the need for a consensus approach to generate meaningful and comparable data.

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“…On the other hand the use of species specific PCR is recommended as a more specific tool for identification of the Trypanosoma members when comparing to ITS-PCR [27]. Different types of PCR have also been used to detect trypanosomes in tsetse flies [9,11,36,[42][43][44] and in human blood [45].…”

Section: Villagementioning

confidence: 99%

Molecular Identification of Trypanosome Species in Cattle of the Mikumi Human/Livestock/Wildlife Interface Areas, Tanzania

Nhamitambo¹

2017

J Infect Dis Epidemiol

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Trypanosomosis is a major neglected disease of animals and man that causes great negative socio-economic impact in many African countries. It is caused by protozoan parasites of the blood from the genus Trypanosoma. Previous studies have investigated the prevalence and risk factors of trypanosomosis in Tanzania, but none has been done in the human/ livestock/wildlife interface areas of Mikumi National Park. The present study determined prevalence of trypanosomosis in cattle blood sampled in five villages of the Mikumi interface areas. Trypanosome species were identified using the nested ITS-PCR and SRA-LAMP. Acquired biodata and spatial information were used for the analysis of risk factors based on the proximity from the park. Data analysis for categorical variables was performed using Chi-square, Fishers exact test, Odds and Risk ratios. Maps were created using the ArcMap ™ version 10.1 GIS software (ESRI 2012). Overall prevalence was 51.47%. Infection significantly varied among the 5 villages (p = 0.0022). The study identified 7 different species of trypanosomes. Trypanosoma simiae had the highest rate of infection 48.15%, followed by T. theileri 26.67%, T. vivax 16.30%, T. brucei brucei 4.44%, T. congolense forest 2.22%, T. simiae tsavo 1.48% and T. congolense kilifi 0.74%. No zoonotic species were identified. High density vegetation (p = 0.0001) and human activity (livestock market and cattle movement) (p = 0.0001) were identified as strong risk factors for infection. Areas with charco dams (p = 0.0001) and those close to tsetse screens and traps (p = 0.0006) had significantly lower infection prevalence. Identifying risk factors, quantifying the risk and doing spatial analysis is essential to determine the control measures to be used in the affected rural communities.

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Detection and identification of trypanosomes by polymerase chain reaction in wild tsetse flies in Cameroon

Cited by 61 publications

References 20 publications

Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese) sleeping sickness focus of the Democratic Republic of Congo

Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese) sleeping sickness focus of the Democratic Republic of Congo

Using Molecular Data for Epidemiological Inference: Assessing the Prevalence of Trypanosoma brucei rhodesiense in Tsetse in Serengeti, Tanzania

Molecular Identification of Trypanosome Species in Cattle of the Mikumi Human/Livestock/Wildlife Interface Areas, Tanzania

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