Conflict of interest: use of pyrethroids and amidines against tsetse and ticks in zoonotic sleeping sickness endemic areas of Uganda

Abstract

BackgroundCaused by trypanosomes and transmitted by tsetse flies, Human African Trypanosomiasis and bovine trypanosomiasis remain endemic across much of rural Uganda where the major reservoir of acute human infection is cattle. Following elimination of trypanosomes by mass trypanocidal treatment, it is crucial that farmers regularly apply pyrethroid-based insecticides to cattle to sustain parasite reductions, which also protect against tick-borne diseases. The private veterinary market is divided between products only effective against ticks (amidines) and those effective against both ticks and tsetse (pyrethroids). This study explored insecticide sales, demand and use in four districts of Uganda where mass cattle treatments have been undertaken by the ‘Stamp Out Sleeping Sickness’ programme.MethodsA mixed-methods study was undertaken in Dokolo, Kaberamaido, Serere and Soroti districts of Uganda between September 2011 and February 2012. This included: focus groups in 40 villages, a livestock keeper survey (n = 495), a veterinary drug shop questionnaire (n = 74), participatory methods in six villages and numerous semi-structured interviews.ResultsAlthough 70.5% of livestock keepers reportedly used insecticide each month during the rainy season, due to a variety of perceptions and practices nearly half used products only effective against ticks and not tsetse. Between 640 and 740 litres of insecticide were being sold monthly, covering an average of 53.7 cattle/km2. Sales were roughly divided between seven pyrethroid-based products and five products only effective against ticks. In the high-risk HAT district of Kaberamaido, almost double the volume of non-tsetse effective insecticide was being sold. Factors influencing insecticide choice included: disease knowledge, brand recognition, product price, half-life and mode of product action, product availability, and dissemination of information. Stakeholders considered market restriction of non-tsetse effective products the most effective way to increase pyrethroid use.ConclusionsConflicts of interest between veterinary business and vector control were found to constrain sleeping sickness control. While a variety of strategies could increase pyrethroid use, regulation of the insecticide market could effectively double the number of treated cattle with little cost to government, donors or farmers. Such regulation is entirely consistent with the role of the state in a privatised veterinary system and should include a mitigation strategy against the potential development of tick resistance.

Controlling parasites, understanding practices: The biosocial complexity of a One Health intervention for neglected zoonotic helminths in northern Lao PDR

“…Paradoxically, however, our analysis also shows that participation may not be a public health panacea given the multitude of other challenges in people's daily life and the embedded nature of risk behaviours (see Bardosh et al (2013) on sleeping sickness in Uganda). Given the continued debate about the narrow focus of current MDA programmes and the need to integrate more holistic interventions Allen, 2011, 2013b), studies should explore the feasibility and "added-value" of engaging broader social determinants in the control of parasitic worms.…”

Exploring the potential of using cattle for malaria vector surveillance and control: a pilot study in western Kenya

“…The bioassays revealed that amitraz, an amidine acaricide widely used to control ticks [24] and previously described to have repellent activity [44], has neither repelling nor killing effects against Anopheles mosquitoes, whilst the deltamethrin formulation at the concentration and application rates recommended against ticks and tsetse had a moderate (<50% mortality) and short-lived (~1 week) impact on survival in experiments with free-flying mosquitoes in large field cages and in the field. We confirm observations from other studies [25] that cup bioassays largely overestimate the actual impact of the treatment on mosquito survival emphasizing the need for testing of insecticides under as natural conditions as possible.…”

“…Tsetse flies also transmit T. brucei rhodesiense which causes Rhodesian human African trypanosomiasis, a fatal zoonotic disease of humans found in East and southern Africa. Cattle can act as a reservoir host for T. b. rhodesiense [18, 19] and the treatment of cattle with pyrethroids [20] is an important component in managing this disease [21], particularly in south-east Uganda [22–24] where most cases of Rhodesian human African trypanosomiasis occur. Malaria is also co-endemic in most of the areas where ECF, animal and human African trypanosomiasis occur.…”

Developing an expanded vector control toolbox for malaria elimination

“…6 41 76 A particularly attractive aspect of targeting malaria vectors when they attack livestock is that there are already strong markets, subsidies, delivery systems and market intervention experience with these products in LMICS. 77 value markets exist for personal protection, veterinary health and construction materials in HICs. Such commodities could be exploited to leverage subsidisation or donation for malaria control in LMICs, in the same way that curative drugs for several neglected tropical diseases of humans are procured.…”