Modeling the economics of insecticide and trypanocide-treated cattle interventions against trypanosomiasis disease within a multi-host situation

Jamah, Tokpa Darwolo (2017-03)

Thesis (MSc)--Stellenbosch University, 2017.

Thesis

ENGLISH SUMMARY: Trypanosomiasis, sleeping sickness in humans and nagana in animals, is vectored by tsetse flies (Glossina genus), which have acquired their infection from feeding on an infectious host. Its control or elimination is a major challenge faced by farmers in keeping their cattle herd free of the disease, in large areas of sub-Saharan Africa. We conducted an economic evaluation of two tsetse control interventions, namely: treatment of infected cattle with trypanocides known as trypanocide-treated cattle (TTC), and use of insecticide-treated cattle (ITC), as measures of controlling or eliminating the disease. The two forms of the disease considered are: (i) one caused by Trypanosoma vivax, affecting mainly the livestock, and (ii) one caused by Trypanosoma brucei rhodesiense which is present mainly in humans. A benefit-cost analysis was performed for the former, while a cost-effectiveness was carried out for the latter because of the impossibility of assigning a monetary value to the benefit of saving a human life. We adapted two models that best describe the biology of T. vivax infection and then extended both models to incorporate the biology of the T. b. rhodesiense infection. Both the ITC and TTC Models against T. vivax and T.b. rhodesiense infections disease states (prevalence and incidence rates) were analyzed and sensitivity analysis was also conducted. The results fully support findings from established literature. The models’ economic evaluation indicates that ITC intervention yields higher benefit-cost ratios and a higher cost-effectiveness ratio (CER), or number of cases prevented per dollar spent, than the TTC intervention. These results support previous findings about the comparative advantage of ITC over TTC for trypanosomiasis control and elimination using static models. We recognize, however, that the approach will only be viable when there is a sufficient density of cattle within the tsetse infested area.

AFRIKAANSE OPSOMMING: Tripanosomiase, ook bekend as slaapsiekte in mense en nagana in diere, word versprei deur tsetsevlieë (Glossina genus), wat besmetting opdoen deur op aansteeklike gashere te voed. Die beheer of uitskakeling van die siekte is ’n groot uitdaging wat boere in groot dele van sub-Sahara Afrika in die gesig staar. Ons het ’n ekonomiese evaluering van twee tsetse beheer metodes, naamlik: behandeling van besmette beeste met trypanocides oftewel trypanocide behandelde beeste (TTC) en die toedien van insekdoders, oftewel insekdoder behandelde beeste (ITC) as bepalers van die beheer of die uitskakeling van die siekte. Die twee vorms van die siekte wat in ag geneem is, is: (i) een veroorsaak deur Trypanosoma vivax, wat hoofsaaklik die vee beinvloed en (ii) een veroorsaak deur Trypanosoma brucei rhodesiense, wat hoofsaaklik die mens beinvloed. ’n Voordeel-koste ontleding is uitgevoer vir eersgenoemde, terwyl ’n koste-effektiwiteit vir laasgenoemde uitgevoer is, aangesien ‘n mens se lewe nie in geldwaarde uitgedruk kan word nie. Ons het twee modelle wat die biologie van T. vivax infeksie die beste beskryf uitgebrei en ook die biologie van die T. b. rhodesiense infeksie in beide modelle ingesluit. Beide die ITC en TTC modelle vir T. vivax en T. b. rhodesiense infeksies is ontleed en sensitiwiteits analises is gedoen. Die prevalensie en insidensie koerse bepaal deur die modelle stem ooreen met die resultate gevind in die literatuurstudie. Ekonomiese evaluering van die modelle dui aan dat die ITC ingryping hoër voordeel-koste verhoudings oplewer en ’n hoër kostedoeltreffendheidsverhouding of aantal gevalle voorkom per dollar bestee as die TTC ingryping het. Hierdie resultate ondersteun vorige bevindings oor die vergelykende voordeel van ITC oor TTC vir tripanosomiase beheer en uitskakeling met behulp van statistiese modelle. Ons bevind egter dat die benadering slegs lewensvatbaar sal wees as daar ’n voldoende digtheid van vee binne die tsetse besmette area is.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/101428
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