Resistance to diminazine aceturate by Trypanosoma congolense from cattle in the Zambezi Valley of Zimbabwe

Joshua, R.A.; Obwolo, M. J.; Bwangamoi, O; Mandebvu, Evelyn

doi:10.1016/0304-4017(94)00780-g

Cited by 16 publications

(11 citation statements)

References 9 publications

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“…This situation can be troubling if major pathogenic trypanosomes species become resistant to the currently available drugs. Resistant strains of T. congolense and T. vivax have been isolated in Nigeria, Mozambique, Somalia, Zimbabwe and other African countries [51][52][53][54]. The measures to combat this nuisance are limited since Africa has a narrow market and insignificant efforts have been made to develop new drugs [55].…”

Section: Ethical Statementmentioning

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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Section: Ethical Statementmentioning

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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“…Moreover, in several African countries trypanocidal drug resistance is suspected to be present but has not been demonstrated using standardized tests. Currently, there are only 10 countries (Burkina Faso, Mali, Cameroon, Ethiopia, Kenya, Nigeria, Tanzania, Zambia, Uganda and Zimbabwe) in which large-scale surveys were carried out and in which area-wide drug resistance occurred in at least one region of the country [14], [15], [16], [17] and [18]. This lack of baseline information is mainly due to the fact that the current laboratory (Box 1) and field methods (Box 2) for the detection of drug resistance are laborious, expensive and time consuming.…”

Section: African Animal Trypanosomiasis and Drug Resistancementioning

confidence: 99%

Molecular tools for the rapid detection of drug resistance in animal trypanosomes

Delespaux

Geysen

Bossche

et al. 2008

Trends in Parasitology

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There are currently 17 African countries in which animal trypanocidal drug resistance has been reported. Largescale surveys were carried out in only ten of them. The lack of baseline information is mainly due to the fact that the methods currently available for the detection of drug resistance are laborious, expensive and time consuming. In this review the mechanisms involved in resistance to isometamidium and diminazene will be discussed, together with some new molecular detection tools that have been developed recently enabling faster diagnosis of drug resistance than conventional laboratory or field tests. African animal trypanosomiasis and drug resistanceTsetse fly-transmitted trypanosomiasis is an important constraint to livestock development in sub-Saharan Africa with estimated annual losses owing to the direct and indirect effects of the disease running into billions of dollars. Approximately 9 million km 2 of sub-Saharan Africa, representing about one-third of the total land, is affected by tsetse flies [1]. Within this region, some 46-62 million head of cattle and other livestock species are at risk of the disease [2]. Trypanosomiasis is controlled either by controlling the vector or by controlling the parasite, or a combination of both. Over the years, a large arsenal of vector-control tools has been developed. Nevertheless, the control of animal trypanosomiasis in often poor rural communities has and will continue to rely heavily on the use of trypanocidal drugs. This is not surprising considering the private nature (i.e. the easy, individual, nonconcerted use) of such treatments and the difficulties in maintaining cleared areas in the absence of barriers to re-invasion of tsetse flies. Only a small group of chemoprophylactic and chemotherapeutic trypanocidal compounds are currently in use and new compounds are unlikely to become available in the near future [3]. Geerts and Holmes [4] estimated that in Africa 35 million doses of veterinary trypanocidal drugs are administered each year with isometamidium chloride (ISM), ethidium bromide (EtBr) and diminazene aceturate (DA) estimated to represent 40%, 26% and 33%, respectively, of the total trypanocidal drug market by value [5]. ISM is mainly used as a prophylactic drug and provides on average 3 months' protection (2-22 weeks) against trypanosome infection. DA has only therapeutic properties and EtBr has limited prophylactic properties and is mainly used as a therapeutic agent [6]. Considering the well known mutagenic properties of EtBr, this drug should ideally be removed from the drug market, but in practice it is still widely used in many countries. Removing this drug from the market would not jeopardize the treatment of animal trypanosomiasis because it can be replaced either by DA for curative purposes or by ISM for prophylactic purposes. When trypanosomes are resistant to ISM, EtBr will be ineffective as cross-resistance is observed between the two drugs [7]. As a result of inappropriate trypanocidal drug-use practices, there is growing co...

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“…In Uganda, control of trypanosomiasis relies heavily on curative treatment of livestock and the use of tsetse traps. However, there has been significant problem of parasite resistance to trypanocides [ 12 , 13 ]. Yet the development of new efficacious drugs is considered unprofitable by most pharmaceutical industries considering that this is a disease that affects mainly the rural poor [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Heterogeneity in the prevalence and intensity of bovine trypanosomiasis in the districts of Amuru and Nwoya, Northern Uganda

et al. 2015

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BackgroundLivestock trypanosomiasis, transmitted mainly by tsetse flies of the genus Glossina is a major constraint to livestock health and productivity in the sub-Saharan Africa. Knowledge of the prevalence and intensity of trypanosomiasis is important in understanding the epidemiology of the disease. The objectives of this study were to (a) assess the prevalence and intensity of trypanosome infections in cattle, and (b) to investigate the reasons for the heterogeneity of the disease in the tsetse infested districts of Amuru and Nwoya, northern Uganda.MethodsA cross-sectional study was conducted from September, 2011 to January, 2012. Blood samples were collected from 816 cattle following jugular vein puncture, and screened for trypanosomes by HCT and ITS-PCR. A Pearson chi-squared test and logistic regression analyses were performed to determine the association between location, age, sex, and prevalence of trypanosome infections.ResultsOut of the 816 blood samples examined, 178 (22 %) and 338 (41 %) tested positive for trypanosomiasis by HCT and ITS-PCR, respectively. Trypanosoma vivax infection accounted for 77 % of infections detected by ITS-PCR, T. congolense (16 %), T. brucei s.l (4 %) and mixed (T. vivax/ T. congolense/T.brucei) infections (3 %). The risk of trypanosome infection was significantly associated with cattle age (χ2 = 220.4, df = 3, P < 0.001). The highest proportions of infected animals were adult males (26.7 %) and the least infected were the less than one year old calves (2.0 %). In addition, the risk of trypanosome infection was significantly associated with sex (χ2 = 16.64, df = 1, P < 0.001), and males had a significantly higher prevalence of infections (26.8 %) than females (14.6 %).ConclusionOur results indicate that the prevalence and intensity of trypanosome infections are highly heterogeneous being associated with cattle age, location and sex.

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Resistance to diminazine aceturate by Trypanosoma congolense from cattle in the Zambezi Valley of Zimbabwe

Cited by 16 publications

References 9 publications

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

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

Molecular tools for the rapid detection of drug resistance in animal trypanosomes

Heterogeneity in the prevalence and intensity of bovine trypanosomiasis in the districts of Amuru and Nwoya, Northern Uganda

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