Relationships between tsetse challenge and trypanosome prevalence in trypanotolerant and susceptible cattle

Leak, S.G.A.; Collardelle, C.; Coulibaly, L.; Dumont, Pierre; Feron, A.; Hecker, P.; D'Ieteren, G.D.M.; Jeannin, Pascale; Minengu, M.; Minja, S.H.; Mulatu, W.; Nankodaba, G.; Ordner, G.; Rowlands, G.J.; Sauveroche, B.; Tikubet, Getachew; Trail, J.C.M.

doi:10.1017/s1742758400012704

Cited by 4 publications

(6 citation statements)

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“…land cover, consistent link to a particular vector species). However, looking at the literature some common factors are associated with prevalence variability: annual and seasonal differences in sampling time, cattle abundance at watering places, micro-environmental ecological conditions [ 40 – 42 ], variations in tsetse and other hematophagous fly (mainly Stomoxis spp. and tabanids) densities and their respective vectorial capacity and seasonality [ 43 – 45 ] and the trypanotolerance/susceptibility of local cattle breeds [ 25 , 40 , 46 ].…”

Section: Discussionmentioning

confidence: 99%

“…However, in our study, the tsetse abundance was not adjusted for the tsetse infection rate rendering the estimation of the real tsetse challenge impossible and consequently, the link between the tsetse challenge and AAT prevalence [ 68 ]. Further experimental data is thus needed to know if a reduction in tsetse challenge would lead to a significant reduction in trypanosomosis prevalence [ 40 ]. Furthermore, the link between AT and trypanosomosis prevalence is weakened by the fact that cattle bred in PAs located far from rivers and/or suitable tsetse habitats, travel longer distances to reach watering points and grasslands in the dry season: cattle is being brought to the vectors.…”

Section: Discussionmentioning

confidence: 99%

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Spatial distribution of Glossina sp. and Trypanosoma sp. in south-western Ethiopia

Abdi

Tasew²,

Olani

et al. 2015

Parasites Vectors

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BackgroundAccurate information on the distribution of the tsetse fly is of paramount importance to better control animal trypanosomosis. Entomological and parasitological surveys were conducted in the tsetse belt of south-western Ethiopia to describe the prevalence of trypanosomosis (PoT), the abundance of tsetse flies (AT) and to evaluate the association with potential risk factors.MethodsThe study was conducted between 2009 and 2012. The parasitological survey data were analysed by a random effects logistic regression model, whereas the entomological survey data were analysed by a Poisson regression model. The percentage of animals with trypanosomosis was regressed on the tsetse fly count using a random effects logistic regression model.ResultsThe following six risk factors were evaluated for PoT (i) altitude: significant and inverse correlation with trypanosomosis, (ii) annual variation of PoT: no significant difference between years, (iii) regional state: compared to Benishangul-Gumuz (18.0 %), the three remaining regional states showed significantly lower PoT, (iv) river system: the PoT differed significantly between the river systems, (iv) sex: male animals (11.0 %) were more affected than females (9.0 %), and finally (vi) age at sampling: no difference between the considered classes. Observed trypanosome species were T. congolense (76.0 %), T. vivax (18.1 %), T. b. brucei (3.6 %), and mixed T. congolense/vivax (2.4 %).The first four risk factors listed above were also evaluated for AT, and all have a significant effect on AT. In the multivariable model only altitude was retained with AT decreasing with increasing altitude. Four different Glossina species were identified i.e. G. tachinoides (52.0 %), G. pallidipes (26.0 %), G.morsitans submorsitans (15.0 %) and G. fuscipes fuscipes (7.0 %). Significant differences in catches/trap/day between districts were observed for each species. No association could be found between the tsetse fly counts and trypanosomosis prevalence.ConclusionsTrypanosomosis remains a constraint to livestock production in south-western Ethiopia. Four Glossina and three Trypanosoma species were observed. Altitude had a significant impact on AT and PoT. PoT is not associated with AT, which could be explained by the importance of mechanical transmission. This needs to be investigated further as it might jeopardize control strategies that target the tsetse fly population.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Spatial distribution of Glossina sp. and Trypanosoma sp. in south-western Ethiopia

Abdi

Tasew²,

Olani

et al. 2015

Parasites Vectors

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“…At present, infection rates in cattle of 5-10% are normal, and are maintained at this level only through regular block treatment of animals with trypanocides. The inability of control strategies to severely curtail trypanosomiasis under conditions of very low tsetse fly challenge is unusual, contrasting sharply with the expected relationship between tsetse fly challenge and cattle infection in other areas (Leak et al, 1990).…”

Section: Trypanosomiasis In Cattlementioning

confidence: 94%

Trypanosome infection rates in tsetse flies (Diptera: Glossinidae) and cattle during tsetse control operations in the Kagera River region of Rwanda

Mihok

Otieno

Tarimo

1992

Bull. Entomol. Res.

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Trypanosome infections were monitored in three species of tsetse fly (Glossina pallidipes Austen, G. morsitans centralis Machado, and G. brevipalpis Newstead) at four locations in the Kagera River region of Rwanda from May 1989 to September 1990. Two of the four areas (Mpanga Ranch and Bukora Ranch) were subjected to tsetse fly suppression operations with odour-baited traps. Proboscis infections of the Trypanosoma congolense and T. vivax types accounted for roughly equal numbers of the 207 mature infections detected (3.8%). Variation in infection rates was area-specific rather than tsetse species-specific. Order of magnitude differences in tsetse fly densities among areas were not correlated with differences in infection rates at the start of tsetse fly suppression operations. Similarly, declines in population density on both control and experimental areas were not associated with significant changes in infection rates. The prevalence of trypanosomiasis in cattle at Bukora Ranch was not affected by a roughly 90% reduction in Glossina densities. T. congolense accounted for 79% of the infections at an overall prevalence rate of 5.5%. Trypanosomiasis in cattle persisted at extremely low densities of about 0.1 fly/trap/day. Treatment of cattle with diminazene aceturate (BereniP) suggested that many T. congolense parasites were drug resistant, and hence, were cycling among cattle due to the few Glossina present.

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“…The biology and ecology of trypanosomes and tsetse support these results, for they define a highly non-linear relationship between tsetse challenge and trypanosomosis prevalence in cattle (35). Large decreases in disease prevalence can be achieved only with near eradication of tsetse populations.…”

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confidence: 74%

“…Most countries in Africa lack the institutional environment necessary for any large-scale, widely dispersed, sustained and intense development efforts (35,45). In most cases, trypanosomosis and the tsetse fly will be fundamentally uncontrollable -where controlling refers to having power over or being in command of a phenomenon.…”

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confidence: 99%

Managing animal trypanosomosis in Africa: issues and options

Omamo

D'Ieteren²

2003

Rev. Sci. Tech. OIE

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Public campaigns against trypanosomosis are several decades old in many parts of Africa (11, 23, 27, 32). However, both the disease and the vector thereof, the tsetse fly, are still very present on the continent (30). Conservative estimates put the number of cases of human trypanosomosis in Africa at 300,000 (68). Annual direct and indirect economic losses on the continent from animal trypanosomosis have been estimated to be at least US$1.6 billion (60) and as high as US$5 billion (44). This clearly shows the inefficacy of past and current approaches to managing the disease. The focus in this paper is on tsetse-transmitted animal trypanosomosis (although many of the arguments and conclusions probably also apply to human trypanosomosis. Non tsetse-transmitted animal trypanosomosis is acknowledged as important in certain areas, but this form of transmission, considerably less significant than the tsetse-based form, is not given specific consideration in this paper). The disease is considered to have been addressed in Africa in three 'wrong' ways, each one related to the others. The first is that most operations against trypanosomosis have been motivated by inappropriate objectives. The second is that the links are poor between research on the disease and the policy environment within which interventions are planned and implemented. The third is that the social science research agenda that would promote relevance and effectiveness in programme design and implementation has been largely unrecognised and thus, equally unexamined. The following three sections focus on these three 'wrongs,' including the implications of the 'wrongs' for research and policy-making for the sustainable management of trypanosomosis in Africa. A summary and broad conclusions finalise the paper. Inappropriate objectives Outcomes of development initiatives are based on the relations between objectives, constraints, and instruments. Among these, objectives are key. When the objectives are more relevant and feasible the identification of constraints on their achievement

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Relationships between tsetse challenge and trypanosome prevalence in trypanotolerant and susceptible cattle

Cited by 4 publications

References 4 publications

Spatial distribution of Glossina sp. and Trypanosoma sp. in south-western Ethiopia

Spatial distribution of Glossina sp. and Trypanosoma sp. in south-western Ethiopia

Trypanosome infection rates in tsetse flies (Diptera: Glossinidae) and cattle during tsetse control operations in the Kagera River region of Rwanda

Managing animal trypanosomosis in Africa: issues and options

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