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African trypanosomiasis is associated with Trypanosoma evansi, T. vivax, T. congolense, and T. brucei pathogens in African animal trypanosomiasis (AAT) while T. b gambiense and T. b rhodesiense are responsible for chronic and acute human African trypanosomiasis (HAT), respectively. Suramin sodium suppresses ATP generation during the glycolytic pathway and is ineffective against T. vivax and T. congolense infections. Resistance to suramin is associated with pathogen altered transport proteins. Melarsoprol binds irreversibly with pyruvate kinase protein sulfhydryl groups and neutralizes enzymes which interrupts the trypanosome ATP generation. Melarsoprol resistance is associated with the adenine-adenosine transporter, P2, due to point mutations within this transporter. Eflornithine is used in combination with nifurtimox. Resistance to eflornithine is caused by the deletion or mutation of TbAAT6 gene which encodes the transmembrane amino acid transporter that delivers eflornithine into the cell, thus loss of transporter protein results in eflornithine resistance. Nifurtimox alone is regarded as a poor trypanocide, however, it is effective in melarsoprol-resistant gHAT patients. Resistance is associated with loss of a single copy of the genes encoding for nitroreductase enzymes. Fexinidazole is recommended for first-stage and non-severe second-stage illnesses in gHAT and resistance is associated with trypanosome bacterial nitroreductases which reduce fexinidazole. In AAT, quinapyramine sulfate interferes with DNA synthesis and suppression of cytoplasmic ribosomal activity in the mitochondria. Quinapyramine sulfate resistance is due to variations in the potential of the parasite's mitochondrial membrane. Pentamidines create cross-links between two adenines at 4–5 pairs apart in adenine-thymine-rich portions of Trypanosoma DNA. It also suppresses type II topoisomerase in the mitochondria of Trypanosoma parasites. Pentamidine resistance is due to loss of mitochondria transport proteins P2 and HAPT1. Diamidines are most effective against Trypanosome brucei group and act via the P2/TbAT1 transporters. Diminazene aceturate resistance is due to mutations that alter the activity of P2, TeDR40 (T. b. evansi). Isometamidium chloride is primarily employed in the early stages of trypanosomiasis and resistance is associated with diminazene resistance. Phenanthridine (homidium bromide, also known as ethidium bromide) acts by a breakdown of the kinetoplast network and homidium resistance is comparable to isometamidium. In humans, the development of resistance and adverse side effects against monotherapies has led to the adoption of nifurtimox-eflornithine combination therapy. Current efforts to develop new prodrug combinations of nifurtimox and eflornithine and nitroimidazole fexinidazole as well as benzoxaborole SCYX-7158 (AN5568) for HAT are in progress while little comparable progress has been done for the development of novel therapies to address trypanocide resistance in AAT.

One Health, « Une seule santé », est une stratégie mondiale visant à développer les collaborations interdisciplinaires pour la santé humaine, animale et environnementale. Elle promeut une approche intégrée, systémique et unifiée de la santé aux échelles locale, nationale et mondiale, afin de mieux affronter les maladies émergentes à risque pandémique, mais aussi s'adapter aux impacts environnementaux présents et futurs. Bien que ce mouvement s’étende, la littérature en français reste rare. Traduit de l’anglais, coordonné par d’éminents épidémiologistes et s'appuyant sur un large panel d' approches scientifiques rarement réunies autour de la santé, cet ouvrage retrace les origines du concept et présente un contenu pratique sur les outils méthodologiques, la collecte de données, les techniques de surveillance et les plans d’étude. Il combine recherche et pratique en un seul volume et constitue un ouvrage de référence unique pour la santé mondiale.

Introduction La gestion du risque de zoonoses résultant des interactions entre les animaux, les humains et l’environnement exige une action intégrée des secteurs de la santé humaine et animale, le soutien d’autres secteurs ou industries concernés par la gouvernance sanitaire et des apports clefs de la filière environnementale (Cook et al., 2004 ; Okello et al., 2011 ; Welburn, 2011 ; Zinsstag et al., 2012). Dans ...

Introduction Dans ce chapitre, nous passons en revue l’évolution de la gouvernance de la santé mondiale (GSM), depuis les premières années de la diplomatie internationale de la santé au xixe siècle, jusqu’à une remise en question des systèmes, des acteurs et des réseaux qui ont actuellement des intérêts dans la GSM aujourd’hui. En décrivant l’évolution des relations entre la politique et la pratique en matière de santé, les aute...

BackgroundThe endemic vector-borne diseases transmitted by tsetse and ticks impose heavy burdens on Africa’s livestock. Cattle offers the possibility of mitigating these losses at a cost affordable to livestock keepers, by applying deltamethrin just to the belly, legs and ears of cattle. Although studies have quantified the impacts of individual diseases on livestock productivity, little is known about the dual economic benefits of controlling both tsetse and ticks, nor about the number of cattle who need to be treated to confer these benefits. Alongside an epidemiological study in south-east Uganda, a farm level assessment was done to investigate the benefits and costs of spraying different proportions of the village cattle population using this restricted application protocol. MethodsA study comprising 1,902 semi-structured interviews was undertaken over a period of 18 months. Financial data on household income from and expenditure on cattle was collected and cost benefit analysis done, pre and post intervention and for different spraying regimes. The total cost of the intervention was obtained from the epidemiological study’s implementation costs and from expenses incurred by participating farmers enabling examination of benefit-cost ratios and incremental benefit-cost ratios for each treatment regime. ResultsThe benefit-cost analysis of spraying 25%, 50% and 75% of the cattle population yielded average benefit-cost ratios of 1.55, 3.85, 4.51 and 4.46. The incremental benefit-cost ratios from spraying each additional 25% of the cattle population were 11.38, 3.89 and 0.79 respectively, showing a very high return on investment for spraying 50% of the population, with returns reducing thereafter. ConclusionComparing the gross margins per bovine, the study found that increasing the proportion of cattle sprayed yielded increasing benefits to farmers, but that these benefits were subject to diminishing returns. From a practical viewpoint this study recommends spraying only draft cattle to control trypanosomiasis and tick-borne diseases in this area as they make 38.62% of the cattle population, approaching the 50% threshold. In areas with a lower proportion of draft males, farmers could be advised to also include cows.

While women in pastoralist communities are key stakeholders in the production of milk and dairy products for income generation, they are largely ignored in other areas of development such as health. The need to involve women self-help groups, in pastoralist areas in both animal health and human health development programmes, is essential, particularly given the high incidence of zoonotic diseases in these communities (Maudlin I, Eisler MC and Welburn SC, Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1530):2777-2787, 2009). Understanding the process and impact of social networks on livelihoods is essential for any development programme that aims to prevent and control zoonotic diseases. This study examines the roles and responsibilities of women self-help groups in Kachia Grazing Reserve and Bokkos, Jos Plateau, Nigeria.The findings show that groups promoting social, physical and psychological health strongly motivated women’s involvement in self-help groups. Self-help activities showed commitment to effect a change in their livelihoods, despite constraining environmental, cultural and social factors. Engagement of women’s self-help groups in livestock development programmes offers a powerful instrument for driving forward the One Health practice in pastoralist communities, promoting human, animal and environmental health and well-being.

BACKGROUND: A mixed methods study was undertaken in the Kachia Grazing Reserve of northern Nigeria. Surveys in March, June and October 2011 included focus group discussions, key informant and in-depth household interviews, concerning livelihood practices, animal health, ownership, and productivity. In May 2011, 249 Fulani families fleeing post-election violence entered the reserve with their livestock, increasing the number of households by one third.RESULTS: Despite being settled within a grazing reserve, over half of households sent all their cattle away on seasonal transhumance and another third sent some away. Cattle accounted for 96% of total tropical livestock units (TLU), of which 26% were cattle kept permanently outside the reserve. While all households cited livestock as their main source of income, 90% grew crops and 55% derived income from off-farm activities. A multiple correspondence analysis showed that for each extra member of a household its TLU value increased by 2.0 [95% CI, 1.4-2.7], while for each additional marriage its TLU increased by 15.7 [95% CI, 7.1-24.3]. A strong association was also observed between small herds, small households with only one wife, alongside marked geographical wealth differences within the reserve. New immigrant families had larger household sizes (33) and livestock holdings (122 TLU) than old settlers (22 people and 67 TLU). Prior to the mass immigration, the distribution of TLU per person was unimodal: 41% of households were classified as 'poor' and 27% as 'medium', whereas post-immigration it was bi-modal, with 26% classified as 'very poor' and 28% as 'medium'.CONCLUSIONS: While cattle remain the principal source of Fulani income and wealth, the inhabitants of Kachia Grazing Reserve have diversified their livelihood strategies to respond to changing circumstances and stress, especially the limited availability of grazing within the reserve and political insecurity outside, resulting in continued transhumance, the maintenance of smaller livestock holdings and pushing households into poverty.

Graphical abstract, Highlights • First molecular survey on tick-borne pathogens in dromedary camels from Nigeria. • First detection of Anaplasma platys and Theileria ovis in camels in Africa. • Results suggest camels may be carriers of Anaplasma platys in Nigeria., In April 2008, whole blood samples were collected from 36 dromedary camels in Sokoto, North-western Nigeria. Following PCR and reverse line blotting, twenty-two samples (61%) resulted positive for Ehrlichia/Anaplasma spp. and three (8%) for Theileria/Babesia spp., with three (8%) cases of co-infections being found. Both sequence and BLAST analyses identified Ehrlichia/Anaplasma spp. and Theileria/Babesia spp. positive cases as Anaplasma platys and Theileria ovis, respectively. This is the first report of the detection of A. platys and T. ovis in camels from sub-Saharan Africa. The epidemiological relevance of this finding is enhanced by the close living of these animals with both dogs and small ruminants. The high prevalence detected for A. platys suggests a possible role of camels as carriers of this infection.

Links to the interviews relating to this paper.

Background This paper presents a new agent-based model (ABM) for investigating T. b. rhodesiense human African trypanosomiasis (rHAT) disease dynamics, produced to aid a greater understanding of disease transmission, and essential for development of appropriate mitigation strategies. Methods The ABM was developed to model rHAT incidence at a fine spatial scale along a 75 km transect in the Luangwa Valley, Zambia. The method offers a complementary approach to traditional compartmentalised modelling techniques, permitting incorporation of fine scale demographic data such as ethnicity, age and gender into the simulation. Results Through identification of possible spatial, demographic and behavioural characteristics which may have differing implications for rHAT risk in the region, the ABM produced output that could not be readily generated by other techniques. On average there were 1.99 (S.E. 0.245) human infections and 1.83 (S.E. 0.183) cattle infections per 6 month period. The model output identified that the approximate incidence rate (per 1000 person-years) was lower amongst cattle owning households (0.079, S.E. 0.017), than those without cattle (0.134, S.E. 0.017). Immigrant tribes (e.g. Bemba I.R. = 0.353, S.E.0.155) and school-age children (e.g. 5–10 year old I.R. = 0.239, S.E. 0.041) were the most at-risk for acquiring infection. These findings have the potential to aid the targeting of future mitigation strategies. Conclusion ABMs provide an alternative way of thinking about HAT and NTDs more generally, offering a solution to the investigation of local-scale questions, and which generate results that can be easily disseminated to those affected. The ABM can be used as a tool for scenario testing at an appropriate spatial scale to allow the design of logistically feasible mitigation strategies suggested by model output. This is of particular importance where resources are limited and management strategies are often pushed to the local scale., Author Summary African trypanosomiasis is a parasitic disease which affects humans and other animals in 36 sub-Saharan African countries. The disease is transmitted by the tsetse fly, and the human form of the diseases is known as sleeping sickness. Infectious disease transmission has traditionally been modelled using techniques that consider the impact on a population as a whole (e.g. compartmentalised models such as SIR). For diseases such as sleeping sickness, which are often prevalent in sparsely populated rural environments, these models don’t always capture the spatial and demographic heterogeneity within an area, and the varying exposure to the disease that this can cause. This research introduces a novel agent-based model to the field, which incorporates spatial data for the Luangwa Valley case study, along with demographic data for its inhabitants. Tsetse and potential human and animal hosts are modelled at the individual level, allowing each contact and infection to be recorded through time. Through modelling at a fine-scale, we can incorporate detailed mechanisms for tsetse birth, feeding, reproduction and death, while considering what demographics, and which locations, have a heightened risk of disease.

BackgroundIdentifying hosts of blood-feeding insect vectors is crucial in understanding their role in disease transmission. Rhodesian human African trypanosomiasis (rHAT), also known as acute sleeping sickness is caused by Trypanosoma brucei rhodesiense and transmitted by tsetse flies. The disease is commonly associated with wilderness areas of east and southern Africa. Such areas hold a diverse range of species which form communities of hosts for disease maintenance. The relative importance of different wildlife hosts remains unclear. This study quantified tsetse feeding preferences in a wilderness area of great host species richness, Serengeti National Park, Tanzania, assessing tsetse feeding and host density contemporaneously.MethodsGlossina swynnertoni and G. pallidipes were collected from six study sites. Bloodmeal sources were identified through matching Cytochrome B sequences amplified from bloodmeals from recently fed flies to published sequences. Densities of large mammal species in each site were quantified, and feeding indices calculated to assess the relative selection or avoidance of each host species by tsetse.ResultsThe host species most commonly identified in G. swynnertoni bloodmeals, warthog (94/220), buffalo (48/220) and giraffe (46/220), were found at relatively low densities (3-11/km2) and fed on up to 15 times more frequently than expected by their relative density. Wildebeest, zebra, impala and Thomson’s gazelle, found at the highest densities, were never identified in bloodmeals. Commonly identified hosts for G. pallidipes were buffalo (26/46), giraffe (9/46) and elephant (5/46).ConclusionsThis study is the first to quantify tsetse host range by molecular analysis of tsetse diet with simultaneous assessment of host density in a wilderness area. Although G. swynnertoni and G. pallidipes can feed on a range of species, they are highly selective. Many host species are rarely fed on, despite being present in areas where tsetse are abundant. These feeding patterns, along with the ability of key host species to maintain and transmit T. b. rhodesiense, drive the epidemiology of rHAT in wilderness areas.

Background: Ticks and tick-borne diseases undermine cattle fitness and productivity in the whole of sub-Saharan Africa, including Nigeria. In this West African country, cattle are challenged by numerous tick species, especially during the wet season. Consequently, several TBDs are known to be endemic in Nigerian cattle, including anaplasmosis, babesiosis, cowdriosis and theilerioris (by Theileria mutans and Theileria velifera). To date, all investigations on cattle TBDs in Nigeria have been based on cytological examinations and/or on serological methods. This study aimed to ascertain the occurrence of tick-borne pathogens of veterinary and zoonotic importance in cattle in Nigeria using molecular approaches.Methods: In October 2008, 704 whole blood samples were collected from indigenous cattle in the Plateau State, Nigeria. Analysis for tick-borne pathogens was conducted by means of PCR-based reverse line blotting (RLB) and sequencing targeting a panel of five genera of microorganisms (i.e. Babesia, Theileria, Anaplasma, Ehrlichia and Rickettsia spp.).Results: In total, 561/704 (82.6 %) animals were found infected, with 465 (69.6 %) of them being infected by two or more microorganisms, with up to 77 possible combinations of pathogens detected. Theileria mutans was the most prevalent microorganism (66.3 %), followed by Theileria velifera (52.4 %), Theileria taurotragi (39.5 %), Anaplasma marginale (39.1 %), Anaplasma sp. (Omatjenne) (34.7 %), Babesia bigemina (7.9 %), Anaplasma centrale (6.3 %), Anaplasma platys (3.9 %), Rickettsia massiliae (3.5 %), Babesia bovis (2.0 %) and Ehrlichia ruminantium (1.1 %). Calves were found significantly less infected than juvenile and adult cattle.Conclusions: This study provides updated, molecular-based information on cattle TBDs in Nigeria. The molecular approach employed allowed the diagnosis of numerous positive cases including carrier statuses, multiple infections and novel pathogen detections within the indigenous cattle population. Moreover, the RLB method here described enabled the detection of veterinary agents not only pertaining to bovine health, including also those of zoonotic importance.The high prevalence recorded for T. mutans, T. velifera, A. marginale, T. taurotragi and Anaplasma sp. (Omatjenne), suggests they may be endemically established in Nigeria, whereas the lower prevalence recorded for other microorganisms (i.e. A. centrale and B. bovis) highlights a less stable epidemiological scenario, requiring further investigations.

Background A retrospective case-control study was undertaken to examine the spatial risk factors for human brucellosis in Kampala, Uganda. Methods Information on age, sex and month of diagnosis was derived from records from plate agglutination tests undertaken at Mulago Hospital, Kampala. Information on Parishes (LC2s) where patients reside was sourced from the outpatient registration book. In-patient fracture cases were selected for use as controls using 1:1 matching based on the age, sex and month of diagnosis. The locations of cases and controls were obtained by calculating Cartesian coordinates of the centroids of Parish level (LC2) polygons and a spatial scan statistic was applied to test for disease clustering. Parishes were classified according to the level of urbanization as urban, peri-urban or rural. Results Significantly more females than males were found to show sero-positivity for brucellosis when compared with the sex ratio of total outpatients, in addition female brucellosis patients were found to be significantly older than the male patients. Spatial clustering of brucellosis cases was observed including around Mulago Hospital (radius = 6.8 km, p = 0.001). The influence of proximity to the hospital that was observed for brucellosis cases was not significantly different from that observed in the controls. The disease cluster was confounded by the different catchment areas between cases and controls. The level of urbanization was not associated with the incidence of brucellosis but living in a slum area was a significant risk factor among urban dwellers (odds ratio 1.97, 95% CI: 1.10-3.61). Conclusions Being female was observed to be a risk factor for brucellosis sero-positvity and among urban dwellers, living in slum areas was also a risk factor although the overall risk was not different among urban, peri-urban and rural areas of the Kampala economic zone.

The Jos Plateau is an important cattle-producing area in Nigeria, with a high concentration of pastoral Fulani. In recent decades, pastoralist studies have focused on arid and semi-arid areas, with few based in the sub-humid zones, such as the Jos Plateau. There have been significant socio-economic and agricultural changes in this area over time which makes it necessary to assess current pastoral livelihood strategies. A pastoral livelihood analysis of 66 individual households/herds across 30 villages was conducted, using participatory methods and structured questionnaires. The majority of pastoral households are in the middle or better off wealth categories and only a few are poor in terms of livestock holdings. However, the majority are poor in terms of land holdings. Livestock sales remain the major source of income, but only 30% of households rely on this as their sole source of income. Sale of crops, milk and off-farm activities contributed income in other households. Comparison with previous livestock productivity levels on the Jos Plateau shows that natural resource conflict has increased, with negative effects on productivity, although vulnerability to shocks has decreased over the years. Overall productivity has decreased and calving rates were particularly low. The pastoral Fulani community is relatively well-off, compared to similar populations across West Africa. However, the high proportion of wealth concentrated in livestock and large numbers of land-poor households indicate that there is still a degree of vulnerability to the risks of drought/dry season, disease and conflict in pastoral livelihoods in the area.

Two-dimensional (2-D) motion sensors are activity motion sensors that use electronic accelerometers to record the lying, standing and walking behaviour of animals. They were used in this study with the aim of monitoring and quantifying the movement behaviour of traditionally managed cattle in the context of improving animal health and production in rural sub-Saharan Africa. Improvements in animal health and production could be made if data can be automatically collected on large numbers of animals and over prolonged periods of time. This data can then be used by stakeholders in making management and disease control decisions. This study was designed to assess whether the 2-D motion sensors were suitable for use on traditionally managed cattle in Kasero and Makale, two veterinary camps in Petauke District, Eastern Province of Zambia. It further aimed to provide a baseline for future research on traditional cattle movement behaviour. The study was carried out in a region where trypanosomiasis and tick-borne diseases are endemic and low haemoglobin values are often associated with these and other parasitic infections. An assessment was made on the effect on cattle movement behaviour of a treatment directed against tsetse-transmitted (trypanosoma congolense (Savannah type), trypanosoma vivax and trypanosoma brucei), tick-transmitted (theileria parva, anaplasma spp. and babesia spp.) and pasture-transmitted pathogens of African cattle. A structured questionnaire on livestock ownership and management practices showed that cattle owners considered trypanosomiasis and theileriosis the main constraints to improved cattle health and production in their traditional crop-livestock mixed farming system. A baseline study was conducted in which haemoglobin values were measured in 432 cattle in the two areas. In each area, ten pairs of co-grazing cattle were selected on the basis of one high and one low haemoglobin value in each pair. The co-grazing pairs were age and sex matched. Each animal had a motion sensor placed on its hind leg, to continuously measure and record its activity for two weeks. There were significant differences in haemoglobin levels between the two camps with Makale having lower levels than Kasero. Baseline data indicated that a larger proportion of sampled animals in Makale had trypanosomiasis while those in Kasero had theileriosis. Molecular parasitological results showed that the proportion of animals sampled in Makale that had trypanosomiasis was greater (21.4% [95%CI: 16.4 – 27.1]) than that in Kasero (1.4% [95%CI: 0.5 – 4.1]). However, Kasero had a greater proportion of animals positive for theileriosis (25.6% [95%CI: 20.2 – 31.9]) than Makale (2.4% [95%CI: 1.0 – 5.2]). A total of 204 cattle were screened for a three week treatment study in Makale. From this number, 40 animals with low circulating haemoglobin levels (