Department: Pathobiology and Population Sciences

Campus: Hawkshead

Research Centres: Veterinary Epidemiology, Economics and Public Health

Martin is a Lecturer in Epidmiology in the Veterinary Epidemiology, Economics and Public Health group (see out Google Scholar page here), the Centre for Emerging, Endemic and Exotic Diseases and an Honorary Lecturer in the Department of Infectious Disease Epidemiology at Imperial College London. He is also an active member of the London Centre for Negleted Tropical Disease Research and the Negelcted Tropical Disease Modelling Consortium. Martin is a mathematical epidemiologist interested in the control and elimination of tropical and zoonotic infectious diseases.

 

Martin has an MA in Biological Sciences from the University of Oxford, an MSc in the Control of Infectious Diseases from the London School of Hygiene and Tropical Medicine and a PhD in Infectious Disease Epidemiology from Imperial College London. Before joining the Royal Veterinary College, Martin worked at the Department of Infectious Disease Epidemiology at Imperial College London. There, he developed infectious disease transmission models to inform public health decision making on intervention strategies aiming to eliminate human helminthiases and statistical approaches to identifying atypical drug responses to anthelmintics that are potentially indicative of emerging drug resistance.

Martin is an Associate Editor for Parasites & Vectors and on the Editorial Board for Acta Tropica. He is a member of the Ghana and Nigeria Onchocerciasis Expert Committees (GOEC/NOEC), the Data Safety Monitoring Commitee for the LEDoxy clinical trials in Ghana and Tanzania, and the MoRiOn trial in Ghana, and he is a member of the Onchocerciasis Elimination Mapping Advisory Group. Martin is a Fellow of the Royal Statistical Society and of the Higher Education Academy.

Martin is interested in the development and application of mathematical transmission and statistical models to: inform the design and implementation of interventions against tropical and other infectious diseases; to assist with the design and optimisation of clinical trials of antiparasitic drugs, and to identify atypical antiparasitic drug responses potentially indicative of emerging drug resistance. Martin also has a number of methodological interests in statistical and mathematical aspects of infectious and non-infectious disease epidemiology.

A selection of Martin's major projects include:

Impact of increased praziquantel frequency on childhood fibrosis in persistent schistosomiasis morbidity hotspots (FibroScHot, 2018-2022) – European & Developing Countries Clinical Trials Partnership – This collaborative field trial is led by Dr Shona Wilson at the University of Cambridge and aims to test whether alternative intervention strategies can decrease the decrease the incidence of childhood periportal fibrosis in hotspots of persistent schistosomiasis. The RVC is leading the transmission modelling (Dr Martin Walker) and population genetics (Prof Joanne Webster) components of this project.

Data sharing platforms to improve treatment outcomes in neglected tropical diseases (2017-2020) - Wellcome - This is a large collaborative project that is led by Professor Philippe Guérin, Director of the Infectious Disease Data Observatory (University of Oxford) in collaboration with numerous partners, including from member institutions of the London Centre for Neglected Tropical Disease Research. The aim of the project is to develop a data sharing and analytical platform to improve outcomes and monitor for signs of reduced drug efficacy among drugs used to treat neglected tropical diseases, including schistosomiasis and the soil-transmitted helminthiases (STHs). The RVC is leading the schistosomiasis and STHs research themes of this project (Dr Martin Walker and Dr Julia Halder).

Towards improved interventions against human toxoplasmosis by identifying routes of transmission (2017-2018) London International Development Centre - This project, led by Dr Martin Walker (RVC), in collaboration with Professor Joanne Webster (RVC), Dr James Rudge (London School of Hygiene & Tropical Medicine) and Dr Jaya Shrivastava (Public Health England) aims to estimate the rate of acquisition of Toxoplasma gondii infection (aetiological agent of toxoplasmosis) by different routes of infection using serocatalytic models to analyse new serological data generated from human sera samples.

Mathematical modelling of novel macrofilaricidal drugs for river blindness: from patients to populations? (2016-2018) - Drugs for Neglected Diseases initiative - This project, jointly led by Dr Martin Walker and Professor Maria-Gloria Basañez (Imperial College London), involves the development of clinical trial simulators and infection transmission models to optimise the design of antifilarial drug trials and to assess the potential epidemiological impact of new treatments as complementary intervention tools to accelerate progress towards the elimination of filarial infections.

Evaluating variation among anthelmintic drug responses to support the control and elimination of human helminthiases (QuoVadis, 2015-2017)  - World Health Organization/TDR - This project, led by Dr Martin Walker in collboration with Professor Maria-Gloria Basañez (Imperial College London), involved evaluating variation in individuals’ responses to the drugs distributed to millions of people around the world as part of the World Health Organization’s strategy of preventative chemotherapy to control and eliminate human helminthiases. This work aimed to define expected levels of inter-person variation in drug responses for use as a reference to identify suspicious or suboptimal responses—potentially indicative of emerging drug resistance—in people exposed to multiple rounds of mass drug administration. The outcomes of this project were key in leverage funds for the Wellcome-funded project with the Infectious Disease Data Observatory.

Modelling alternative treatment strategies for onchocerciasis: moxidectin for control and elimination (2017-2018) - Medicines Development for Global Health - This project, jointly led by Dr Martin Walker (RVC) and Professor Maria-Gloria Basañez (Imperial College London), involved projecting the potential epidemiological impact of using moxidectin—repurposed from veterinary to human medicine—to accelerate progress towards the elimination of onchocerciasis (river blindness) in Africa. The work translated existing individual data from phase II and phase III clinical trials that show superiority of moxidectin over ivermectin—the current gold standard treatment for onchocerciasis—into population-level health benefits and revised timelines to elimination. The outcomes of the project formed part of the successfull submission to the United States Food and Drug Adminstration for the approval of moxidectin for use in humans to treat onchocerciasis (for a press release click here)

Routledge I, Walker M, Cheke RA, Nkot PB, Matthews GA, Baleguel D, Dobson HM, Wiles TL, Basáñez MG. Modelling the impact of larviciding on the population dynamics of Simulium damnosum (sl.): implications for vector control as a complenetary strategy for onchocerciasis elimination in Africa. Parasit Vectors 2018; 11: 316 https://doi.org/10.1186/s13071-018-2864-y

Verver S*, Walker M*, Kim YE, Fobi G, Tekle AH, Zouré HGM, Wanji S, Boakye DA, Kuesel AC, de Vlas SJ, Boussinesq M, Basáñez MG, Stolk WA. How can onchocerciasis elimination in Africa be acceleerated? Modelling the impact of increased ivermectin treatment frequency and complementary vector control. Clin Infect Dis 2018; 66: S267-S274 https://doi.org/10.1093/cid/cix1137

Whittaker C, Walker M, Pion SDS, Chesnais C, Boussinesq M, Basáñez MG. Loa loa: More than meets the eye? Trends Parasitol 2018 34: 261-262 https://doi.org/10.1016/j.pt.2018.02.002 

Whittaker C*, Walker M*, Pion SDS, Chesnais C, Boussinesq M, Basáñez MG. The population biology and transmission dynamics of Loa loa. Trends Parasitol 2018; 34: 335-350 https://doi.org/10.1016/j.pt.2017.12.003

Walker M*, Pion SDS, Fang H, Gardon J, Kamgno J, Basáñez MG, Boussinesq M. The macrofilaricidal efficacy of repeated doses of ivermectin for the treatment of river blindness. Clin Infect Dis 2017; 65: 2026-2034 https://doi.org/10.1093/cid/cix616

Halder JB, Benton J, Julé AM, Guérin PJ, Olliaro PL, Basáñez MG*, Walker M*. Systematic review of studies generating individual participant data on the efficacy of drugs for treating soil-transmitted helminthiases and the case for data sharing. PLoS Negl Trop Dis 2017; 11: e0006053 http://doi.org/10.1371/journal.pntd.0006053  

Doyle SR, Bourguinat C, Nana-Djeunga HC, Kengne-Ouafo JA, Pion SDS, Bopda J, Kamgno J, Wanji S, Che H, Kuesel AC, Walker M, Basáñez MG, Boakye DA, Osei-Atweneboana MY, Boussinesq M, Prichard RK, Grant WN. Genome-wide analysis of ivermectin response by Onchocerca volvulus reveals that genetic drift and soft selective sweeps contribute to loss of drug sensitivity. PLoS Negl Trop Dis 2017; 11: e0005816 https://doi.org/10.1371/journal.pntd.0005816

Easton AV, Oliviera RG, Walker M, O'Connell EM, Njenga SM, Mwandawiro CS, et al. Sources of variability in the measurement of Ascaris lumbricoides infection intensity by Kato-Katz and qPCR. Parasit Vectors 2017; 10: 256 http://dx.doi.org/10.1186/s13071-017-2164-y

Sahimin N, Lim YAL, Ariffin F, Behnke JM, Basáñez MG, Walker M, et al. Socio-demographic determinants of Toxoplasma gondii seroprevalence in migrant workers of Peninsular Malaysia. Parasit Vectors 2017; 10: 238 http://dx.doi.org/10.1186/s13071-017-2167-8 

Walker M*, Stolk WA*, Dixon MA, Bottomley C, Diawara L, Traoré MO, de Vlas SJ, Basáñez MG.  Modelling the elimination of river blindness using long-term epidemiological and programmatic data from Mali and Senegal. Epidemics 2017; 18: 4-15. http://dx.doi.org/10.1016/j.epidem.2017.02.005

Basáñez MG*, Walker M*, Turner HC, Coffeng LE, de Vlas SJ, Stolk WA. River Blindness: Mathematical Models for Control and Elimination. Adv Parasitol 2016; 94: 247-341. http://dx.doi.org/0.1016/bs.apar.2016.08.003

Deol AK, Webster JP, Walker M, Basáñez MG, Hollingsworth DT, Fleming FM, Montresor A, French MD. Development and evaluation of a Markov model to predict changes in schistosomiasis prevalence in response to praziquantel treatment: a case study of Schistosoma mansoni in Uganda and Mali. Parasit Vectors 2016; 9:543. http://dx.doi.org/10.1186/s13071-016-1824-7

Crellen R*, Walker M*, Lamberton PHL, Kabatereine NB, Tukahebwa EM, Cotton JA, Webster JP. Reduced efficacy of praziquantel against Schistosoma mansoni associated with multiple-rounds of mass drug administration. Clin Infect Dis 2016; 63: 1151-1159 http://dx.doi.org/10.1093/cid/ciw506

Lamberton PHL, Cheke RA, Walker M, Winskill P, Crainey JL, Boakye DA, Osei-Atweneboana MY, Tirados I, Wilson MD, Otoo S, Post RJ, Basáñez MG. Onchocerciasis transmission in Ghana: the human blood index of sibling species of the Simulium damnosum complex. Parasit Vectors 2016; 9:432. http://dx.doi.org/10.1186/s13071-016-1703-2

Bottomley C, Isham V, Vivas-Martínez S, Kuesel AC, Attah SK, Opoku NO, Lustigman S, Enyong PA, Walker M, Basáñez MG. Modelling Neglected Tropical Diseases diagnostics: the sensitivity of skin snips for Onchocerca volvulus in near elimination and surveillance settings. Parasit Vectors 2016; 9:343. http://dx.doi.org/10.1186/s13071-016-1605-3

Frempong KF*, Walker M*, Cheke RA, Tetwvi EJ, Gyan ET, Wilson MD, Boakye DA, Taylor MJ, Biritwum NK, Osei-Atweneboana MY, Basáñez MG. Does increasing treatment frequency address sub-optimal responses to ivermectin for the control and elimination of river blindness? Clin Infect Dis 2016 62:1338-1347. http://dx.doi.org/10.1093/cid/ciw144

Walker M*, Mabud T*, Olliaro PL, Coulibaly JT, King CH, Raso G, Scherrer AU, Stothard JR, Sousa-Figueiredo JC, Stete K, Utzinger J, Basáñez MG. New approaches to measuring anthelminthic drug efficacy: parasitological responses of childhood schistosome infections to treatment with praziquantel. Parasit Vectors 2016; 9:41 http://dx.doi.org/10.1186/s13071-016-1312-0

Stolk WA*, Walker M*, Coffeng L, Basáñez MG, de Vlass SJ. Required duration of mass treatment for onchocerciasis elimination in Africa. Parasit Vectors 2015; 8: 552. http://dx.doi.org/10.1186/s13071-015-1159-9

Turner HC, Walker M*, Lustigman S, Taylor DW, Basáñez MG. Human onchocerciasis: modelling the potential long-term consequences of a vaccination programme. PLoS Negl Trop Dis 2015; 9: e0003938. http://dx.doi.org/10.1371/journal.pntd.0003938

Turner HC, Walker M, Attah SK, Opoku NO, Awadzi K, Kuesel AC, Basáñez MG. The potential impact of moxidectin on onchocerciasis elimination in Africa: an economic evaluation based on the Phase II clinical trial data. Parasit Vectors 2015; 8:167. http://dx.doi.org/10.1186/s13071-015-0779-4

Lamberton PHL, Cheke RA, Winskill P, Post RJ, Walker M, Boakye DA, Osei-Atweneboana MY, Biritwum NK, Wilson MD, Tetteh-Kumah A, Basáñez MG. Onchocerciasis transmission in Ghana: persistence under different control strategies and the role of simuliid vectors. PLoS Negl Trop Dis 2015; 9:e0003688. http://dx.doi.org/10.1371/journal.pntd.0003688

Walker M, Specht S, Churcher TS, Hoerauf A, Taylor MJ, Basáñez MG. The therapeutic efficacy and macrofilaricidal activity of doxycycline for the treatment of river blindness. Clin Infect Dis 2015; 60:1199-1207. http://dx.doi.org/10.1093/cid/ciu1152

Walker M, Basáñez MG, Ouédraogo AL, Hermsen C, Bousema T, Churcher TS. Improving statistical inference on pathogen densities estimated by quantitative molecular methods: malaria gametocytaemia as a case study. BMC Bioinformatics 2015; 16:5. http://dx.doi.org/10.1186/s12859-014-0402-2

For a complete list of my publications see my Google Scholar page


* contributed equally

Martin supervisers with Professor Joanne Webster the PhD of Miss Inês Neves on the "Spatial and zoonotic epidemiology of schistosomiasis in an elimination landscape". He is co-supervisor with Professor Maria-Gloria Basañez of Mr Matthew Dixon (Imperial College London) , on modelling the transmission dynamics of cyisticercosis and taeniasis (prok tapeworm) and co-supervisor with Professor Maria-Gloria Basañez and Dr Samir Bhatt  of Mr Philip Milton (Imperial College London) on the spatial epidemiology and network dynamics of onchocerciasis.

Martin is co-leader with Professor Dave Brodbelt of the Population Investigation Skills module on the Bachelor of Veterinary Medicine course. He also leads the Veterinary Epidemioloy, Economics and Public Health statistical support service for undergraduate research projects (RP1, RP2). 

Martin is deputy leader for Dr Julian Drewe of the Epidemiology: The Bigger Picture module for Biological Science students and teaches epidemiology, statistics and mathematical modelling on the full range of undergraduate and postgraduate courses offered by the RVC. He also supervises all levels of student projects.

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