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Gislam H, Burnside NG, Brolly M, Deribe K, Davey G, Wanji S, Suh CE, Kemp SJ, Watts MJ, Le Blond JS. Linking soils and human health: geospatial analysis of ground-sampled soil data in relation to community-level podoconiosis data in North West Cameroon. Trans R Soc Trop Med Hyg 2020; 114:937-946. [PMID: 33216129 PMCID: PMC7738663 DOI: 10.1093/trstmh/traa138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 10/26/2020] [Accepted: 11/02/2020] [Indexed: 12/02/2022] Open
Abstract
Background Podoconiosis is a form of leg swelling, which arises when individuals are exposed over time to red clay soil formed from alkaline volcanic rock. The exact causal agent of the disease is unknown. This study investigates associations between podoconiosis disease data and ground-sampled soil data from North West Cameroon. Methods The mineralogy and elemental concentrations were measured in the soil samples and the data were spatially interpolated. Mean soil values were calculated from a 3 km buffer region around the prevalence data points to perform statistical analysis. Analysis included Spearman's rho correlation, binary logistic regression and principal component analysis (PCA). Results Six elements, barium, beryllium, potassium, rubidium, strontium and thallium, as well as two minerals, potassium feldspar and quartz, were identified as statistically related to podoconiosis. PCA did not show distinct separation between the spatial locations with or without recorded cases of podoconiosis, indicating that other factors such as shoe-wearing behaviour and genetics may significantly influence podoconiosis occurrence and prevalence in North West Cameroon. Conclusion Several soil variables were statistically significantly related to podoconiosis. To further the current study, future investigations will look at the inflammatory pathway response of cells after exposure to these variables.
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Affiliation(s)
- H Gislam
- School of Environment & Technology, University of Brighton, Brighton, UK
| | - N G Burnside
- School of Environment & Technology, University of Brighton, Brighton, UK
| | - M Brolly
- School of Environment & Technology, University of Brighton, Brighton, UK
| | - K Deribe
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton, UK.,Centre for Environmental and Developmental Studies and School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - G Davey
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton, UK.,Centre for Environmental and Developmental Studies and School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - S Wanji
- Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - C E Suh
- Department of Geology, Environmental Science and Mining, University of Bamenda, Bamenda, Cameroon
| | - S J Kemp
- British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, UK
| | - M J Watts
- British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, NG12 5GG, UK
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Taylor RA, Berriman ADC, Gale P, Kelly LA, Snary EL. A generic framework for spatial quantitative risk assessments of infectious diseases: Lumpy skin disease case study. Transbound Emerg Dis 2018; 66:131-143. [PMID: 30102842 DOI: 10.1111/tbed.12993] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 12/27/2022]
Abstract
The increase in availability of spatial data and the technological advances to handle such data allow for subsequent improvements in our ability to assess risk in a spatial setting. We provide a generic framework for quantitative risk assessments of disease introduction that capitalizes on these new data. It can be adopted across multiple spatial scales, for any pathogen, method of transmission or location. The framework incorporates the risk of initial infection in a previously uninfected location due to registered movement (e.g., trade) and unregistered movement (e.g., daily movements of wild animals). We discuss the steps of the framework and the data required to compute it. We then outline how this framework is applied for a single pathway using lumpy skin disease as a case study, a disease which had an outbreak in the Balkans in 2016. We calculate the risk of initial infection for the rest of Europe in 2016 due to trade. We perform the risk assessment on 3 spatial scales-countries, regions within countries and individual farms. We find that Croatia (assuming no vaccination occurred) has the highest mean probability of infection, with Italy, Hungary and Spain following. Including import detection of infected trade does reduce risk but this reduction is proportionally lower for countries with highest risk. The risk assessment results are consistent across the spatial scales, while in addition, at the finer spatial scales, it highlights specific areas or individual locations of countries on which to focus surveillance.
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Affiliation(s)
| | | | - Paul Gale
- Animal and Plant Health Agency (APHA), Weybridge, UK
| | - Louise A Kelly
- Animal and Plant Health Agency (APHA), Weybridge, UK.,Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK
| | - Emma L Snary
- Animal and Plant Health Agency (APHA), Weybridge, UK
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Fyfe J, Picozzi K, Waiswa C, Bardosh KL, Welburn SC. Impact of mass chemotherapy in domestic livestock for control of zoonotic T. b. rhodesiense human African trypanosomiasis in Eastern Uganda. Acta Trop 2017; 165:216-229. [PMID: 27570206 DOI: 10.1016/j.actatropica.2016.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 08/17/2016] [Accepted: 08/24/2016] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Human African trypanosomiasis (HAT) comprises two fatal parasitic diseases. Uganda is home to both chronic T. b. gambiense (gHAT) and the acute zoonotic form T. b. rhodesiense (rHAT) which occur in two large but discrete geographical foci. The area affected by rHAT has been rapidly expanding due to importation of T. b. rhodesiense infected cattle into tsetse infested but previously HAT free districts. Migration of rHAT has resulted in a considerable human health burden in these newly affected districts. Here, we examined the impact of a single, district-wide, mass chemotherapeutic livestock intervention, on T. b. rhodesiense prevalence in cattle and on incidence and distribution of human rHAT cases in Kamuli and Soroti districts in eastern Uganda. METHODS A single mass intervention in domestic cattle (n=30,900) using trypanocidal drugs was undertaken in November and December 2002 under the EU funded Farming in Tsetse Controlled Areas (FITCA) programme. The intervention targeted removal of the reservoir of infection i.e. human infective T. b. rhodesiense parasites in cattle, in the absence of tsetse control. Interventions were applied in high-risk sub-counties of Kamuli district (endemic for rHAT) and Soroti district (where rHAT has been recently introduced). The prevalence of T. brucei s.l. and the human infective subspecies, T. b. rhodesiense in cattle (n=1833) was assessed before and 3 and 12 months after intervention using PCR-based methods. A combination of descriptive statistical analysis and spatial scan statistics were applied to analyse rHAT cases reported over a 5-year period (January 2000-July 2005). RESULTS A single intervention was highly effective at removing human infective T. b. rhodesiense parasites from the cattle reservoir and contributed to a significant decrease in human rHAT cases. Intervention coverage was higher in Kamuli (81.1%) than in Soroti (47.3%) district but despite differences in coverage both districts showed a reduction in prevalence of T. b. brucei s.l. and T. b. rhodesiense. In Kamuli, the prevalence of T. brucei s.l. decreased by 54%, from 6.75% to 3.11%, 3, months post-intervention, rising to 4.7% at 12 months. The prevalence of T. b. rhodesiense was 3% pre-intervention and no T. b. rhodesiense infections were detected 3 and 12, months post-treatment. In Soroti, the prevalence of T. brucei s.l. in cattle decreased by 38% (from 21% to 13%) 3 months after intervention decreasing to less than 10% at 12 months. The prevalence of T. b. rhodesiense was reduced by 50% at 12-months post-intervention (6%-3%). Most notably, was the impact of the intervention on the population dynamics between T. b. brucei and human infective T. b. rhodesiense. Before intervention in Kamuli district 56% of T. b. brucei s.l. circulating in cattle were T. b. rhodesiense; at both 3 and 12 months after intervention none of the re-infecting T. b. brucei s.l. were human infective, T. rhodesiense. For human rHAT cases, there was a seven-fold decrease in rHAT incidence after intervention in Kamuli district (5.54 cases/1,000 head of population 2000-2002 to 0.76 cases/1,000, 2003-2005). Incidence data suggests that the intervention had minimal impact on the number of rHAT cases in Soroti overall, but showed a significant decrease in the seasonal peak of cases in the year following treatment. CONCLUSION A single intervention, targeted at cattle, introduced at district level, in the absence of tsetse control, was highly effective at removing human infective rHAT parasites from the cattle reservoir and contributed to a significant decrease in human rHAT cases. The differential impacts observed between the two districts are related to both the different stages of rHAT endemicity in the districts, and levels of intervention coverage achieved in the cattle population. Treatment of cattle to remove the reservoir of rHAT infection offers a promising and cost effective approach for the control of rHAT. It is important that cattle are treated before relocation to prevent possible merger of the two HAT foci, which would complicate diagnosis and treatment of both gHAT and rHAT.
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Cadavid Restrepo AM, Yang YR, McManus DP, Gray DJ, Giraudoux P, Barnes TS, Williams GM, Soares Magalhães RJ, Hamm NAS, Clements ACA. The landscape epidemiology of echinococcoses. Infect Dis Poverty 2016; 5:13. [PMID: 26895758 PMCID: PMC4759770 DOI: 10.1186/s40249-016-0109-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 02/15/2016] [Indexed: 12/29/2022] Open
Abstract
Echinococcoses are parasitic diseases of major public health importance globally. Human infection results in chronic disease with poor prognosis and serious medical, social and economic consequences for vulnerable populations. According to recent estimates, the geographical distribution of Echinococcus spp. infections is expanding and becoming an emerging and re-emerging problem in several regions of the world. Echinococcosis endemicity is geographically heterogeneous and over time it may be affected by global environmental change. Therefore, landscape epidemiology offers a unique opportunity to quantify and predict the ecological risk of infection at multiple spatial and temporal scales. Here, we review the most relevant environmental sources of spatial variation in human echinococcosis risk, and describe the potential applications of landscape epidemiological studies to characterise the current patterns of parasite transmission across natural and human-altered landscapes. We advocate future work promoting the use of this approach as a support tool for decision-making that facilitates the design, implementation and monitoring of spatially targeted interventions to reduce the burden of human echinococcoses in disease-endemic areas.
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Affiliation(s)
- Angela M Cadavid Restrepo
- Research School of Population Health, The Australian National University, Canberra, New South Wales, Australia.
| | - Yu Rong Yang
- Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region, P. R. China.
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - Donald P McManus
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - Darren J Gray
- Research School of Population Health, The Australian National University, Canberra, New South Wales, Australia.
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - Patrick Giraudoux
- Chrono-environment lab, UMR6249, University of Bourgogne Franche-Comté/CNRS, Besançon, France.
- Institut Universitaire de France, Paris, France.
| | - Tamsin S Barnes
- The University of Queensland, School of Veterinary Science, Gatton, Queensland, Australia.
- The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Gatton, Queensland, Australia.
| | - Gail M Williams
- School of Public Health, The University of Queensland, Brisbane, Queensland, Australia.
| | - Ricardo J Soares Magalhães
- The University of Queensland, School of Veterinary Science, Gatton, Queensland, Australia.
- Child Health Research Centre, The University of Queensland, Brisbane, Queensland, Australia.
| | - Nicholas A S Hamm
- Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, Enschede, The Netherlands.
| | - Archie C A Clements
- Research School of Population Health, The Australian National University, Canberra, New South Wales, Australia.
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Muhanguzi D, Picozzi K, Hattendorf J, Thrusfield M, Kabasa JD, Waiswa C, Welburn SC. The burden and spatial distribution of bovine African trypanosomes in small holder crop-livestock production systems in Tororo District, south-eastern Uganda. Parasit Vectors 2014; 7:603. [PMID: 25532828 PMCID: PMC4300167 DOI: 10.1186/s13071-014-0603-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 12/11/2014] [Indexed: 11/10/2022] Open
Abstract
Background African animal trypanosomiasis (AAT) is considered to be one of the greatest constraints to livestock production and livestock-crop integration in most African countries. South-eastern Uganda has suffered for more than two decades from outbreaks of zoonotic Human African Trypanosomiasis (HAT), adding to the burden faced by communities from AAT. There is insufficient AAT and HAT data available (in the animal reservoir) to guide and prioritize AAT control programs that has been generated using contemporary, sensitive and specific molecular techniques. This study was undertaken to evaluate the burden that AAT presents to the small-scale cattle production systems in south-eastern Uganda. Methods Randomised cluster sampling was used to select 14% (57/401) of all cattle containing villages across Tororo District. Blood samples were taken from all cattle in the selected villages between September-December 2011; preserved on FTA cards and analysed for different trypanosomes using a suite of molecular techniques. Generalized estimating equation and Rogen-Gladen estimator models were used to calculate apparent and true prevalences of different trypanosomes while intra cluster correlations were estimated using a 1-way mixed effect analysis of variance (ANOVA) in R statistical software version 3.0.2. Results The prevalence of all trypanosome species in cattle was 15.3% (95% CI; 12.2-19.1) while herd level trypanosome species prevalence varied greatly between 0-43%. Trypanosoma vivax (17.4%, 95% CI; 10.6-16.8) and Trypanosoma brucei rhodesiense (0.03%) were respectively, the most, and least prevalent trypanosome species identified. Conclusions The prevalence of bovine trypanosomes in this study indicates that AAT remains a significant constraint to livestock health and livestock production. There is need to implement tsetse and trypanosomiasis control efforts across Tororo District by employing effective, cheap and sustainable tsetse and trypanosomiasis control methods that could be integrated in the control of other endemic vector borne diseases like tick-borne diseases.
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Affiliation(s)
- Dennis Muhanguzi
- Department of Biomolecular and Biolaboratory Sciences, School of Biosecurity, Biotechnical and Laboratory Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda. .,Division of Infection & Pathway Medicine, Centre for Infectious Diseases, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
| | - Kim Picozzi
- Division of Infection & Pathway Medicine, Centre for Infectious Diseases, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
| | - Jan Hattendorf
- Department of Public Health and Epidemiology, Swiss Tropical Institute, Socinstrasse 57, CH-4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, 4003, Basel, Switzerland.
| | - Michael Thrusfield
- Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, EH25 9RG, UK.
| | - John David Kabasa
- Department of Biosecurity, Ecosystems & Veterinary Public Health, School of Biosecurity, Biotechnical and Laboratory Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda.
| | - Charles Waiswa
- Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda.
| | - Susan Christina Welburn
- Division of Infection & Pathway Medicine, Centre for Infectious Diseases, School of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
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Wardrop NA, Fèvre EM, Atkinson PM, Welburn SC. The dispersal ecology of Rhodesian sleeping sickness following its introduction to a new area. PLoS Negl Trop Dis 2013; 7:e2485. [PMID: 24130913 PMCID: PMC3794918 DOI: 10.1371/journal.pntd.0002485] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/06/2013] [Indexed: 11/24/2022] Open
Abstract
Tsetse-transmitted human and animal trypanosomiasis are constraints to both human and animal health in sub-Saharan Africa, and although these diseases have been known for over a century, there is little recent evidence demonstrating how the parasites circulate in natural hosts and ecosystems. The spread of Rhodesian sleeping sickness (caused by Trypanosoma brucei rhodesiense) within Uganda over the past 15 years has been linked to the movement of infected, untreated livestock (the predominant reservoir) from endemic areas. However, despite an understanding of the environmental dependencies of sleeping sickness, little research has focused on the environmental factors controlling transmission establishment or the spatially heterogeneous dispersal of disease following a new introduction. In the current study, an annually stratified case-control study of Rhodesian sleeping sickness cases from Serere District, Uganda was used to allow the temporal assessment of correlations between the spatial distribution of sleeping sickness and landscape factors. Significant relationships were detected between Rhodesian sleeping sickness and selected factors, including elevation and the proportion of land which was "seasonally flooding grassland" or "woodlands and dense savannah." Temporal trends in these relationships were detected, illustrating the dispersal of Rhodesian sleeping sickness into more 'suitable' areas over time, with diminishing dependence on the point of introduction in concurrence with an increasing dependence on environmental and landscape factors. These results provide a novel insight into the ecology of Rhodesian sleeping sickness dispersal and may contribute towards the implementation of evidence-based control measures to prevent its further spread.
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Affiliation(s)
- Nicola A. Wardrop
- Geography and Environment, University of Southampton, Highfield Campus, Southampton, United Kingdom
| | - Eric M. Fèvre
- Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Neston, United Kingdom
| | - Peter M. Atkinson
- Geography and Environment, University of Southampton, Highfield Campus, Southampton, United Kingdom
| | - Susan C. Welburn
- School of Biomedical Sciences, University of Edinburgh, Chancellors Building, Edinburgh, United Kingdom
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