Publications
643 results found
Rayment Gomez S, Maddren R, Liyew EF, et al., 2024, Spatial heterogeneity in mass drug administration from a longitudinal epidemiological study assessing transmission interruption of soil transmitted helminths in the Wolaita zone of southern Ethiopia (Geshiyaro Project)., PLoS Negl Trop Dis, Vol: 18
OBJECTIVES: Deworming programmes of soil-transmitted helminths are generally monitored and evaluated by aggregating drug coverage and infection levels at a district level. However, heterogeneity in drug coverage at finer spatial scales means indicators may remain above thresholds for elimination as a public health problem or of transmission in some areas. This paper aims to highlight the misleading information that aggregating data at larger spatial scales can have for programme decision making. METHODS: Drug coverage data from the Geshiyaro project were compared at two spatial scales with reference to the World Health Organisation's targets. District (woreda) and village (kebele) level were compared. The association between infection levels and drug coverage was analysed by fitting a weighted least-squares function to the mean intensity of infection (eggs per gram of faeces) against drug coverage. RESULTS: The data show clearly that when the evaluation of coverage is aggregated to the district level, information on heterogeneity at a finer spatial scale is lost. Infection intensity decreases significantly (p = 0.0023) with increasing drug coverage. CONCLUSION: Aggregating data at large spatial scales can result in prematurely ceasing deworming, prompting rapid infection bounce-back. There is a strong need to define context-specific spatial scales for monitoring and evaluating intervention programmes.
Al-Jawabreh R, Anderson R, Atkinson LE, et al., 2024, Strongyloides questions-a research agenda for the future., Philos Trans R Soc Lond B Biol Sci, Vol: 379
The Strongyloides genus of parasitic nematodes have a fascinating life cycle and biology, but are also important pathogens of people and a World Health Organization-defined neglected tropical disease. Here, a community of Strongyloides researchers have posed thirteen major questions about Strongyloides biology and infection that sets a Strongyloides research agenda for the future. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.
Collyer BS, Anderson R, 2024, The transmission dynamics of Strongyloides stercoralis and the impact of mass drug administration., Philos Trans R Soc Lond B Biol Sci, Vol: 379
The epidemiology of Strongyloides stercoralis is briefly reviewed with an emphasis on cross section and longitudinal studies of infection prevalence stratified by age, performance of different diagnostic tools, mass drug administration (MDA) impact and estimates of key population parameters within the complex life cycle of the parasite that determine transmission intensity and response to control measures. The paucity of studies is highlighted, and gaps in current knowledge identified about the population biology of this very prevalent infection in tropical and sub-tropical regions around the world. A stochastic individual based stochastic model is described in part to highlight gaps in knowledge. The impact of repeated MDA is simulated to illustrate some aspects of transmission dynamics of this helminth infection. Specifically, the impact and bounce back times in either the intervals between treatment rounds, or post the cessation of treatment, depend critically on the magnitude of two distinct components of the basic reproductive number R0. The absence of data on these key components is highlighted, as is the value of studies of longitudinal cohorts of people in regions of endemic infection post rounds of MDA to record how infection levels bounce back post treatment at individual and population levels of study. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.
Maddren R, Anderson RM, 2024, Measuring heterogeneities in soil-transmitted helminth transmission and control., Trends Parasitol, Vol: 40, Pages: 45-59
The global effort over the past decade to control soil-transmitted helminths (STH) has resulted in communities with endemic infection reaching low prevalence levels suitable for the validation of elimination as a public health problem (EPHP), defined by the World Health Organisation (WHO) as <2% of infections classified as moderate or heavy intensity. The spatial scale in which this is validated is currently undefined. As the burden of STH infection decreases, the degree of aggregation of infection within individuals in a population increases. Identifying these remaining pockets of infection requires fine-scale monitoring and evaluation (M&E) programmes that are rarely implemented within current national neglected tropical disease (NTD) control. This review examines various heterogeneities that characterise the epidemiology of STH infections, and discusses their impact on control policy formulation.
Dyer CEF, Ng-Nguyen D, Clarke NE, et al., 2023, Community-wide versus school-based targeted deworming for soil-transmitted helminth control in school-aged children in Vietnam: the CoDe-STH cluster-randomised controlled trial., Lancet Reg Health West Pac, Vol: 41
BACKGROUND: Soil-transmitted helminth (STH) infection control programs typically consist of school-based preventive chemotherapy (PC) targeted to school-aged children. STH reservoirs in untreated community members contribute to ongoing transmission in children. The CoDe-STH (Community Deworming against STH) trial, conducted in Dak Lak province, Vietnam, between October 2019 and November 2020, aimed to determine whether community-wide mass drug administration (MDA) is more effective than school-based targeted PC in reducing STH prevalence and intensity in children. METHODS: In this two-arm cluster randomised controlled trial, 64 primary schools were randomly assigned 1:1 to receive either school-based targeted PC ("school arm") or community-wide MDA ("community arm"). A single dose of albendazole 400 mg was used for deworming. The primary outcome was hookworm prevalence in schoolchildren, measured using quantitative real-time PCR. We also measured infection intensity for Necator americanus only, using qPCR cycle threshold (Ct) values converted into eggs per gram of faeces (EPG). Analysis was by intention to treat. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12619000309189). FINDINGS: The analysis included 4955 children in the school arm and 5093 children in the community arm. N. americanus was the dominant STH species. The relative reduction in hookworm prevalence was not significantly different between the school arm (30.1%, 95% confidence interval [CI] 20.5-36.9) and the community arm (34.6%, 95% CI 19.9-49.4). Due to lower baseline prevalence than expected, the study was underpowered to detect a difference in prevalence reduction between the study arms. The community arm showed significantly greater relative reduction in N. americanus infection intensity (56.0%, 95% CI 39.9-72.1) compared to the school arm (3.4%, 95% CI -24.7 to 31.4). The community arm also showed greater relative
Maddren R, Collyer B, Phillips AE, et al., 2023, Patterns of individual compliance with anthelmintic treatment for soil-transmitted helminth infections in southern Ethiopia over six rounds of community-wide mass drug administration., Trans R Soc Trop Med Hyg
BACKGROUND: The mainstay of soil-transmitted helminth (STH) control is repeated mass drug administration (MDA) of anthelmintics to endemic populations. Individual longitudinal compliance treatment patterns are important for identifying pockets of infected individuals who remain untreated and serve as infection reservoirs. METHODS: The Geshiyaro Project censused the study population in Wolaita, Ethiopia at baseline in 2018. Individual longitudinal compliance was recorded for six rounds of community-wide MDA (cMDA). The probability distribution of treatment frequency was analysed by age and gender stratifications. Probabilities of transmission interruption for different compliance patterns were calculated using an individual-based stochastic model of Ascaris lumbricoides transmission. RESULTS: The never-treated (0.42%) population was smaller than expected from a random positive binomial distribution. The observed compliance frequency was well described by the beta-binomial distribution. Preschool-age children (odds ratio [OR] 10.1 [95% confidence interval {CI} 6.63 to 15.4]) had the highest never-treated proportion of the age groups. Conversely, school-age children (SAC) and adults (OR 1.03 [95% CI 0.98 to 1.09]) had the highest always-treated proportion of the age groups. CONCLUSIONS: The study reports the largest dataset of individual longitudinal compliance to cMDA for STH control. Clear pattens are shown in the age-dependent distribution of individual compliance behaviour. The impact of compliance on the probability of elimination is significant, highlighting the importance of recording the full frequency distribution, not just the never-treated proportion.
Anderson R, 2023, Measuring mortality arising from the Covid-19 pandemic and the impact of vaccination., Eur J Epidemiol, Vol: 38, Pages: 1119-1123
Forbes K, Basáñez M-G, Hollingsworth TD, et al., 2023, Introduction to the special issue: challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs, Philosophical Transactions of the Royal Society B: Biological Sciences, Vol: 378, Pages: 1-8, ISSN: 0962-8436
Twenty neglected tropical diseases (NTDs) are currently prioritised by the World Health Organization for eradication, elimination as a public health problem, elimination of transmission or control by 2030. This issue celebrates progress made since the 2012 London Declaration on NTDs and discusses challenges currently faced to achieve these goals. It comprises 14 contributions spanning NTDs tackled by intensified disease management to those addressed by preventive chemotherapy. Although COVID-19 negatively affected NTD programmes, it also served to spur new multisectoral approaches to strengthen school-based health systems. The issue highlights the needs to improve impact survey design, evaluate new diagnostics, understand the consequences of heterogeneous prevalence and human movement, the potential impact of alternative treatment strategies and the importance of zoonotic transmission. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
Collyer BSS, Truscott JEE, Mwandawiro CSS, et al., 2023, How important is the spatial movement of people in attempts to eliminate the transmission of human helminth infections by mass drug administration?, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 378, ISSN: 0962-8436
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- Citations: 1
Phillips AE, Ower AK, Mekete K, et al., 2023, Baseline soil-transmitted helminth and schistosome infection in the Geshiyaro project, Ethiopia: A unique transmission interruption project using biometric fingerprinting for longitudinal individual analysis., PLoS Negl Trop Dis, Vol: 17
BACKGROUND: The Geshiyaro project aims to assess the feasibility of interrupting transmission of soil-transmitted helminths (STH) and schistosome (SCH) infection in the Wolaita zone of southern Ethiopia through high coverage community-wide mass drug administration (MDA), in combination with improved water, sanitation, and hygiene services and behaviour change communication delivered through the existing health care infrastructure. To accurately measure treatment coverage a population census was conducted enrolling individuals with biometric fingerprinting and barcoded ID cards. This paper details the baseline census and parasitology surveys conducted before the start of any interventions. METHODS: The census was conducted in five of the 15 Wolaita districts between October 2018 and December 2019, enrolling all consenting participants from every household. Simultaneously, a cross-sectional parasitology survey was conducted in 130 out of 361 randomly selected communities from all 15 districts, with 100 individuals across all age groups (infant to adult) per community providing stool and urine for analysis by duplicate Kato-Katz and a point-of-care circulating cathodic antigen (POC-CCA) to test for Schistosoma mansoni and STH, and microhaematuria and urine filtration for Schistosoma haematobium. Of the 130 communities, 30 were randomly selected for annual, longitudinal parasitological monitoring, with 150 randomly selected individuals from infant to adult providing two days of stool and urine samples for analysis by the same diagnostic tests per community. RESULTS: In total 97,919 households participated in the baseline census enrolling 466,071 individuals, with parasitological data obtained from 10,785 people. At baseline, 15.5% were infected with at least one STH species, with Ascaris lumbricoides (9.5%), followed by hookworm (7.2%) and Trichuris trichiura (1.8%). Substantial heterogeneity in STH prevalence was observed between communities ranging from 0% to 61% wher
Gomez SR, Maddren R, Liyew EF, et al., 2023, Predisposition to soil-transmitted helminth reinfection after four rounds of mass drug administration: results from a longitudinal cohort in the Geshiyaro project, a transmission elimination feasibility study in the Wolaita zone of southern Ethiopia, TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE, Vol: 117, Pages: 514-521, ISSN: 0035-9203
Maddren R, Phillips A, Gomez SR, et al., 2023, Individual longitudinal compliance to neglected tropical disease mass drug administration programmes, a systematic review, PLOS NEGLECTED TROPICAL DISEASES, Vol: 17, ISSN: 1935-2735
Hughes A, Ng-Nguyen D, Clarke NEE, et al., 2023, Epidemiology of soil-transmitted helminths using quantitative PCR and risk factors for hookworm and <i>Necator americanus</i> infection in school children in Dak Lak province, Vietnam, PARASITES & VECTORS, Vol: 16, ISSN: 1756-3305
Maddren R, Phillips A, Ower A, et al., 2023, Soil-transmitted helminths and schistosome infections in Ethiopia: a systematic review of progress in their control over the past 20 years (vol 14, 97, 2021), PARASITES & VECTORS, Vol: 16, ISSN: 1756-3305
Sheahan W, Anderson R, Aruldas K, et al., 2023, Overestimation of school-based deworming coverage resulting from school-based reporting, PLOS NEGLECTED TROPICAL DISEASES, Vol: 17, ISSN: 1935-2735
Anderson RM, Cano J, Hollinsworth TD, et al., 2023, Responding to the cuts in UK AID to neglected tropical diseases control programmes in Africa, TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE, Vol: 117, Pages: 237-239, ISSN: 0035-9203
Beukenhorst ALL, Koch CMM, Hadjichrysanthou C, et al., 2023, SARS-CoV-2 elicits non-sterilizing immunity and evades vaccine-induced immunity: implications for future vaccination strategies, EUROPEAN JOURNAL OF EPIDEMIOLOGY, ISSN: 0393-2990
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- Citations: 3
Kura K, Truscott JE, Collyer BS, et al., 2022, The observed relationship between the degree of parasite aggregation and the prevalence of infection within human host populations for soil-transmitted helminth and schistosome infections, TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE, Vol: 116, Pages: 1226-1229, ISSN: 0035-9203
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- Citations: 1
Hadjichrysanthou C, Beukenhorst AL, Koch CM, et al., 2022, Exploring the Role of Antiviral Nasal Sprays in the Control of Emerging Respiratory Infections in the Community, INFECTIOUS DISEASES AND THERAPY, Vol: 11, Pages: 2287-2296, ISSN: 2193-8229
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- Citations: 1
Phillips AE, Ower AK, Mekete K, et al., 2022, Association between water, sanitation, and hygiene access and the prevalence of soil-transmitted helminth and schistosome infections in Wolayita, Ethiopia, PARASITES & VECTORS, Vol: 15, ISSN: 1756-3305
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- Citations: 4
Borlase A, Le Rutte EA, Castano S, et al., 2022, Evaluating and mitigating the potential indirect effect of COVID-19 on control programmes for seven neglected tropical diseases: a modelling study, LANCET GLOBAL HEALTH, Vol: 10, Pages: E1600-E1611, ISSN: 2214-109X
Landeryou T, Maddren R, Gomez SR, et al., 2022, Longitudinal monitoring of prevalence and intensity of soil-transmitted helminth infections as part of community-wide mass drug administration within the Geshiyaro project in the Bolosso Sore district, Wolaita, Ethiopia, PLOS NEGLECTED TROPICAL DISEASES, Vol: 16, ISSN: 1935-2735
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- Citations: 2
Chong NS, Hardwick RJ, Smith SR, et al., 2022, A prevalence-based transmission model for the study of the epidemiology and control of soil-transmitted helminthiasis, PLOS ONE, Vol: 17, ISSN: 1932-6203
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- Citations: 1
Mohammed H, Landeryou T, Chernet M, et al., 2022, Comparing the accuracy of two diagnostic methods for detection of light <i>Schistosoma haematobium</i> infection in an elimination setting in Wolaita Zone, South Western Ethiopia, PLOS ONE, Vol: 17, ISSN: 1932-6203
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- Citations: 2
Kura K, Ayabina D, Hollingsworth TD, et al., 2022, Determining the optimal strategies to achieve elimination of transmission for <i>Schistosoma mansoni</i>, PARASITES & VECTORS, Vol: 15, ISSN: 1756-3305
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- Citations: 4
Landeryou T, Rabone M, Allan FL, et al., 2022, Genome-wide insights into adaptive hybridisation across the <i>Schistosoma haematobium</i> group in West and Central Africa, PLOS NEGLECTED TROPICAL DISEASES, Vol: 16, ISSN: 1935-2735
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- Citations: 4
Milne G, Hames T, Scotton C, et al., 2021, Does infection with or vaccination against SARS-CoV-2 lead to lasting immunity?, LANCET RESPIRATORY MEDICINE, Vol: 9, Pages: 1450-1466, ISSN: 2213-2600
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- Citations: 70
Anderson RM, 2021, An urgent need: vaccines for neglected tropical diseases, LANCET INFECTIOUS DISEASES, Vol: 21, Pages: 1621-1623, ISSN: 1473-3099
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Kura K, Hardwick RJ, Truscott JE, et al., 2021, What is the impact of acquired immunity on the transmission of schistosomiasis and the efficacy of current and planned mass drug administration programmes?, PLoS Neglected Tropical Diseases, Vol: 15, Pages: 1-17, ISSN: 1935-2727
Schistosomiasis causes severe morbidity in many countries with endemic infection with the schistosome digenean parasites in Africa and Asia. To control and eliminate the disease resulting from infection, regular mass drug administration (MDA) is used, with a focus on school-aged children (SAC; 5-14 years of age). In some high transmission settings, the World Health Organization (WHO) also recommends the inclusion of at-risk adults in MDA treatment programmes. The question of whether ecology (age-dependant exposure) or immunity (resistance to reinfection), or some combination of both, determines the form of observed convex age-intensity profile is still unresolved, but there is a growing body of evidence that the human hosts acquire some partial level of immunity after a long period of repeated exposure to infection. In the majority of past research modelling schistosome transmission and the impact of MDA programmes, the effect of acquired immunity has not been taken into account. Past work has been based on the assumption that age-related contact rates generate convex horizontal age-intensity profiles. In this paper, we use an individual based stochastic model of transmission and MDA impact to explore the effect of acquired immunity in defined MDA programmes. Compared with scenarios with no immunity, we find that acquired immunity makes the MDA programme less effective with a slower decrease in the prevalence of infection. Therefore, the time to achieve morbidity control and elimination as a public health problem is longer than predicted by models with just age-related exposure and no build-up of immunity. The level of impact depends on the baseline prevalence prior to treatment (the magnitude of the basic reproductive number R0) and the treatment frequency, among other factors. We find that immunity has a larger impact within moderate to high transmission settings such that it is very unlikely to achieve morbidity and transmission control employing current MDA prog
Anderson RM, Vegvari C, Hollingsworth TD, et al., 2021, The SARS-CoV-2 pandemic: remaining uncertainties in our understanding of the epidemiology and transmission dynamics of the virus, and challenges to be overcome, INTERFACE FOCUS, Vol: 11, ISSN: 2042-8898
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- Citations: 18
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