Collateral benefits of restricted insecticide application for control of African trypanosomiasis on Theileria parva in cattle: a randomized controlled trial

Muhanguzi, Dennis; Picozzi, Kim; Hatendorf, Jan; Thrusfield, Michael; Welburn, Susan C.; Kabasa, John David; Waiswa, Charles

doi:10.1186/1756-3305-7-432

Cited by 26 publications

(31 citation statements)

References 37 publications

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“…This was also the case with spraying a further 25% (i.e.75%) of the cattle population as the incremental benefit-cost ratio fell to 0.79 so that costs exceeded benefits, set alongside a negative incremental net benefit of USD -0.38 per bovine per year and thus negative returns set in at this point. These findings contrast with the observations in the trypanosomiasis prevalence studies [27], [34]. The authors state, "the increase in village RAP herd coverage was not significantly associated with a proportionate decrease in the trypanosomiasis prevalence.…”

Section: Discussioncontrasting

confidence: 69%

“…The 20 selected villages were randomly allocated to five RAP treatments [27]. All cattle were given two doses forty days apart of Veriben B12 (CEVA Santé Animale, containing diminazene aceturate, vitamin B12 (cyanocobalamin) and B12a (hydroxocobalamin) at 0.01 g/kg live body weight) to treat any pre-existing trypanosome infection [27], [34]. Treatment 1 (T1) cattle received no further treatments whereas treatments 2 to 4 (i.e.…”

Section: Selection Of Study Villages Households and Data Collectionmentioning

confidence: 99%

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Controlling Human And Animal African Trypanosomiasis Using Insecticide Treated Cattle: What Are The Costs And Benefits?

Okello

MacLeod

Muhanguzi

et al. 2020

Preprint

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Background The tsetse-transmitted African trypanosomiases affect humans and animals. Trypanosoma. brucei rhodesiense sleeping sickness, or human African trypanosomiasis is a zoonosis, for which cattle are the main reservoir of infection in south-eastern Uganda. Transmission of human and animal infective trypanosomes can be reduced by the application of deltamethrin insecticide to the belly and legs of cattle, thus reducing tsetse fly populations. Alongside an epidemiological study in southeastern Uganda, a farm level assessment was done to calculate the average and incremental benefit-cost ratios of spraying different proportions of the village cattle population using this restricted application protocol.Method A study comprising 2,400 semi-structured interviews was undertaken over a period of 18 months. Financial data on household income and expenditure on cattle provided the basis for the marginal analyses. The benefit of RAP to farmers was assessed using gross margin analysis whereas the costs were obtained from expenses incurred by farmers in participating in the RAP intervention. Subsequently, the RAP intervention villages were compared with a control village to determine the average and incremental benefit-cost ratio across all households.Results The benefit-cost analysis of spraying 25%, 50% and 75% of the cattle population yielded benefit-cost ratios of 6.22, 5.56 and 4.46. The incremental benefit-cost ratios from spraying each additional 25% of the population cattle were 14.32, 3.97 and 0.79 respectively, showing a very high return on investment in spraying 25% of the population, with returns reducing thereafter.Conclusion Comparing the gross margins per bovine of applying RAP to different proportions of the cattle population to a pre-intervention situation and a control, the study found that increasing the proportion of cattle sprayed yielded increasing benefits to farmers, but that these benefits were subject to diminishing returns. Given the high proportion of draft males in the cattle population (37%) their important contribution to livestock output and farmers’ preference for treating these animals, from a practical viewpoint this study recommends spraying only draft cattle to control trypanosomiasis in this area, although in areas or households with a lower proportion of draft males, farmers could be advised to also include cows.

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Section: Discussioncontrasting

confidence: 69%

Section: Selection Of Study Villages Households and Data Collectionmentioning

confidence: 99%

Controlling Human And Animal African Trypanosomiasis Using Insecticide Treated Cattle: What Are The Costs And Benefits?

Okello

MacLeod

Muhanguzi

et al. 2020

Preprint

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“…Treatment of cattle with insecticide offers the most cost-effective method of tsetse control [22] and in East Africa the risk of both tick- and tsetse-borne diseases of livestock provides a strong incentive for livestock keepers to treat their cattle regularly [23]. Effective control of savanna tsetse requires interventions conducted over large (>100 km 2 ) areas [24].…”

Section: Discussionmentioning

confidence: 99%

Assessing the effect of insecticide-treated cattle on tsetse abundance and trypanosome transmission at the wildlife-livestock interface in Serengeti, Tanzania

Lord

Lea

Allan

et al. 2020

Preprint

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23In the absence of national control programmes against Rhodesian human African 24 trypanosomiasis, farmer-led treatment of cattle with pyrethroid-based insecticides may be an 25 effective strategy for foci at the edges of wildlife areas, but there is limited evidence to 26 support this. 27 We combined data on insecticide use by farmers, tsetse abundance and trypanosome 28 prevalence with mathematical models to quantify the likely impact of insecticide-treated 29 cattle. 30 Sixteen percent of farmers reported treating cattle with a pyrethroid, and chemical analysis 31 indicated 18% of individual cattle had been treated, in the previous week. Treatment of cattle 32 was estimated to increase daily mortality of tsetse by 5 -14%. Trypanosome prevalence in 33 tsetse, predominantly from wildlife areas, was 1.25% for T. brucei s.l. and 0.03% for T. b. 34 rhodesiense. For 750 cattle sampled from 48 herds, 2.3% were PCR positive for T. brucei s.l. 35 and none for T. b. rhodesiense. Using mathematical models, we estimated there was 8 -29% 36 increase in mortality of tsetse in farming areas and this increase can explain the relatively low 37 prevalence of T. brucei s.l. in cattle. 38Farmer-led treatment of cattle with pyrethroids is likely, in part, to be limiting the spill-over 39 of human-infective trypanosomes from wildlife areas. 40 41 Author summary 42 The acute form of sleeping sickness in Africa is caused by the parasite Trypanosoma brucei 43 rhodesiense. It is transmitted by tsetse flies and can be maintained in cycles involving both 44 livestock and wildlife as hosts. Humans are incidentally infected and are particularly at risk 3 45 of infection near protected areas where there are both wildlife and suitable habitat for tsetse. 46In these regions, the tsetse vector cannot be eradicated, nor can infection be prevented in 47 wildlife. Here we use field studies of tsetse and livestock in combination with mathematical 48 models of tsetse population change and trypanosome transmission to show that use of 49 pyrethroid-based insecticides on cattle by farmers at the edge of protected areas could be 50 contributing to lowering the risk of sleeping sickness in Serengeti District, Tanzania. To our 51 knowledge, our study is the first to report farmer-led tsetse control, co-incident with tsetse 52 decline and relatively low prevalence of T. brucei s.l. in cattle. 53 54 Introduction 55 In East and Southern Africa, tsetse flies (Glossina spp) transmit Trypanosoma brucei 56 rhodesiense, which causes Rhodesian human African trypanosomiasis (r-HAT). Tsetse also 57 transmit T. congolense, T. vivax and T. brucei, the causative agents of animal African 58 trypanosomiasis (AAT) in livestock. 59 Trypanosoma brucei s.l., T. congolense and T. vivax can circulate in transmission cycles 60 involving livestock or wild mammals [1]. The extensive conservation areas of East and 61 Southern Africa that support tsetse, as well as wildlife, can therefore be foci for r-HAT and 62 AAT. At the interface of wildlife-and livestock areas, ...

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“…In Uganda, where cattle transmission predominates, cattle show a prevalence of T. brucei s.l. of 20-27% in highprevalence villages [25] and up to 17.5% at markets by PCR [26]. Although small ruminants can also be infected with T. brucei s.l., the low prevalence found in sheep and goats suggests that they are less important than cattle in maintaining transmission [27].…”

Section: Ciɵes -Townsmentioning

confidence: 99%

Transmission Dynamics of Rhodesian Sleeping Sickness at the Interface of Wildlife and Livestock Areas

Auty¹,

Morrison

Torr

et al. 2016

Trends in Parasitology

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Many wilderness areas of East and Southern Africa are foci for Rhodesian sleeping sickness, a fatal zoonotic disease caused by trypanosomes transmitted by tsetse flies. Although transmission in these foci is traditionally driven by wildlife reservoirs, rising human and livestock populations may increase the role of livestock in transmission cycles. Deciphering transmission dynamics at wildlife and livestock interface areas is key to developing appropriate control. Data are lacking for key parameters, including host distributions, tsetse density, and mortality rates, and the relative roles of livestock and wildlife as hosts in fragmented habitats, limiting the development of meaningful models to assist in the assessment and implementation of control strategies.

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Collateral benefits of restricted insecticide application for control of African trypanosomiasis on Theileria parva in cattle: a randomized controlled trial

Cited by 26 publications

References 37 publications

Controlling Human And Animal African Trypanosomiasis Using Insecticide Treated Cattle: What Are The Costs And Benefits?

Controlling Human And Animal African Trypanosomiasis Using Insecticide Treated Cattle: What Are The Costs And Benefits?

Assessing the effect of insecticide-treated cattle on tsetse abundance and trypanosome transmission at the wildlife-livestock interface in Serengeti, Tanzania

Transmission Dynamics of Rhodesian Sleeping Sickness at the Interface of Wildlife and Livestock Areas

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