Costs Of Using “Tiny Targets” to Control Glossina fuscipes fuscipes, a Vector of Gambiense Sleeping Sickness in Arua District of Uganda

Introduction To evaluate the relative effectiveness of tsetse control methods, their costs need to be analysed alongside their impact on tsetse populations. Very little has been published on the costs of methods specifically targeting human African trypanosomiasis. Methodology/Principal Findings In northern Uganda, a 250 km2 field trial was undertaken using small (0.5 X 0.25 m) insecticide-treated targets (“tiny targets”). Detailed cost recording accompanied every phase of the work. Costs were calculated for this operation as if managed by the Ugandan vector control services: removing purely research components of the work and applying local salaries. This calculation assumed that all resources are fully used, with no spare capacity. The full cost of the operation was assessed at USD 85.4 per km2, of which USD 55.7 or 65.2% were field costs, made up of three component activities (target deployment: 34.5%, trap monitoring: 10.6% and target maintenance: 20.1%). The remaining USD 29.7 or 34.8% of the costs were for preliminary studies and administration (tsetse surveys: 6.0%, sensitisation of local populations: 18.6% and office support: 10.2%). Targets accounted for only 12.9% of the total cost, other important cost components were labour (24.1%) and transport (34.6%). Discussion Comparison with the updated cost of historical HAT vector control projects and recent estimates indicates that this work represents a major reduction in cost levels. This is attributed not just to the low unit cost of tiny targets but also to the organisation of delivery, using local labour with bicycles or motorcycles. Sensitivity analyses were undertaken, investigating key prices and assumptions. It is believed that these costs are generalizable to other HAT foci, although in more remote areas, with denser vegetation and fewer people, costs would increase, as would be the case for other tsetse control techniques

We remember… Elders’ memories and perceptions of sleeping sickness control interventions in West Nile, Uganda

The traditional role of African elders and their connection with the community make them important stakeholders in community-based disease control programmes. We explored elders’ memories related to interventions against sleeping sickness to assess whether or not past interventions created any trauma which might hamper future control operations. Using a qualitative research framework, we conducted and analysed twenty-four in-depth interviews with Lugbara elders from north-western Uganda. Participants were selected from the villages inside and outside known historical sleeping sickness foci. Elders’ memories ranged from examinations of lymph nodes conducted in colonial times to more recent active screening and treatment campaigns. Some negative memories dating from the 1990s were associated with diagnostic procedures, treatment duration and treatment side effects, and were combined with memories of negative impacts related to sleeping sickness epidemics particularly in HAT foci. More positive observations from the recent treatment campaigns were reported, especially improvements in treatment. Sleeping sickness interventions in our research area did not create any permanent traumatic memories, but memories remained flexible and open to change. This study however identified that details related to medical procedures can remain captured in a community’s collective memory for decades. We recommend more emphasis on communication between disease control programme planners and communities using detailed and transparent information distribution, which is not one directional but rather a dialogue between both parties

Where, when and why do tsetse contact humans? Answers from studies in a National Park of Zimbabwe

The original publication is available at http://journals.plos.org/plosntdsCITATION: Torr, S.J., Chamisa, A., Mangwiro, T.N.C. & Vale, G.A. 2012. Where, when and why do tsetse contact humans?: Answers from studies in a National Park of Zimbabwe. PLoS Neglected Tropical Diseases, s 6(8):e1791, doi:10.1371/journal.pntd.0001791.Background: Sleeping sickness, also called human African trypanosomiasis, is transmitted by the tsetse, a blood-sucking fly confined to sub-Saharan Africa. The form of the disease in West and Central Africa is carried mainly by species of tsetse that inhabit riverine woodland and feed avidly on humans. In contrast, the vectors for the East and Southern African form of the disease are usually savannah species that feed mostly on wild and domestic animals and bite humans infrequently, mainly because the odours produced by humans can be repellent. Hence, it takes a long time to catch many savannah tsetse from people, which in turn means that studies of the nature of contact between savannah tsetse and humans, and the ways of minimizing it, have been largely neglected. Methodology/Principal Findings: The savannah tsetse, Glossina morsitans morsitans and G. pallidipes, were caught from men in the Mana Pools National park of Zimbabwe. Mostly the catch consisted of young G. m. morsitans, with little food reserve. Catches were increased by 4–8 times if the men were walking, not stationary, and increased about ten times more if they rode on a truck at 10 km/h. Catches were unaffected if the men used deodorant or were baited with artificial ox odour, but declined by about 95% if the men were with an ox. Surprisingly, men pursuing their normal daily activities were bitten about as much when in or near buildings as when in woodland. Catches from oxen and a standard ox-like trap were poor indices of the number and physiological state of tsetse attacking men. Conclusion/Significance: The search for new strategies to minimize the contact between humans and savannah tsetse should focus on that occurring in buildings and vehicles. There is a need to design a man-like trap to help to provide an index of sleeping sickness risk.Financial support: UNICEF/UNDP/World Bank/FAO Special Programme for Research and Training in Tropical Diseases (Project no. A70598)http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0001791Publisher's versio

Catches of tsetse from vehicles leaving the Zambezi Valley of Zimbabwe at various seasons.

<p>Catches are the total number of tsetse caught from all vehicles passing the traffic barrier at the junction of the tarred road from Chirundu and the untarred road from Mana Pools National Park between December 2006 to November 2010. Each vehicle inspected was recorded as having come from either the untarred road from the Mana Pools National Park or the tarred road from Chirundu.</p

Numbers of tsetse alighting on various parts of men.

<p>Numbers of tsetse alighting on various parts of men.</p

Ovarian categories of female <i>G. m. morsitans</i> from (A) men, (B) ox and (C) traps.

<p>Percent distribution of ovarian categories of female <i>G. m. morsitans</i> from (A) men, (B) ox and (C) traps. Sample sizes of 257, 94 and 283 for men, ox and traps, respectively.</p

Catches of <i>G. m. morsitan</i>s from traps and humans.

<p>Transformed (Trans) and detransformed (Detrans) mean daily catches are the catches of male and female <i>G. m. morsitan</i>s combined from traps or men and the respective standard errors of the transformed means. The mean catches from humans are presented as a percent of that from the traps. In any one column, means not associated with the same letter differ at P<0.05.</p

Wing fray classes of male <i>G. m. morsitans</i> caught from men and ox.

<p>Percent distribution of wing fray classes of male <i>G. m. morsitans</i> caught from men (N = 211) and ox (N = 100).</p

Catches of <i>G. m. morsitans</i> from mobile and stationary men in various experiments.

<p>Transformed (Trans) and detransformed (Detrains) mean daily catches of male and female <i>G. m. morsitans</i> combined, from mobile and stationary men in a number of separate experiments. Means are accompanied by the standard error (SE) of the transformed means, and the index for efficacy, <i>i.e</i>., the detransformed mean catch of each treatment expressed as a proportion of the standard. In any one experiment, detransformed means not associated with the same letter differ at <i>P</i><0.05.</p><p>AOP = a synthetic blend of acetone, octenol and phenols found in natural host odour. See text for further details.</p>1<p>Expt 1: Aug-Dec 2009, 19 replicates. Expt 2: Jan-Apr 2010, 17 replicates. Expt 3: Apr-Jun 2010, 8 replicates. Expt 4: May-Jul 2010, 14 replicates.</p