Publications
31 results found
Phillips AE, Tohon Z, Dhanani NA, et al., 2020, Evaluating the impact of biannual school-based and community-wide treatment on urogenital schistosomiasis in Niger, PARASITES & VECTORS, Vol: 13, ISSN: 1756-3305
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- Citations: 5
Mekete K, Ower A, Dunn J, et al., 2019, The Geshiyaro Project: a study protocol for developing a scalable model of interventions for moving towards the interruption of the transmission of soil-transmitted helminths and schistosome infections in the Wolaita zone of Ethiopia, Parasites and Vectors, Vol: 12, ISSN: 1756-3305
BACKGROUND: National deworming programmes rely almost exclusively on mass drug administration (MDA) to children to control morbidity caused by these parasitic infections. The provision of other interventions, consisting of preventive chemotherapy at high population level coverage together with water, sanitation and hygiene (WaSH) and changes in risk behaviour, should enable sustainable control of soil-transmitted helminths (STH) and schistosomiasis and ultimately interrupt transmission. METHODS/DESIGN: Two interventions will be implemented by the project: (i) community-wide biannual albendazole and annual praziquantel treatment with a target of 80-90% treatment coverage ("expanded MDA"); and (ii) provision of WaSH with behaviour change communication (BCC), within the Wolaita zone, Ethiopia. The project has three study arms: (i) expanded community-wide MDA, WaSH and BCC; (ii) expanded community-wide MDA only; and (iii) annual school-based MDA (the current National STH/schistosomiasis Control Programme). The impact of these interventions will be evaluated through prevalence mapping at baseline and endline (after four rounds of MDA), combined with annual longitudinal parasitological surveillance in defined cohorts of people to monitor trends in prevalence and reinfection throughout the project. Treatment coverage and individual compliance to treatment will be monitored by employing fingerprint biometric technology and barcoded identification cards at treatment. WaSH utilisation will be evaluated through school and household level observations and annual WaSH assessment survey. Complementary qualitative surveys will explore practices, cultural and social drivers of risk behaviours, uptake of WaSH and treatment, and assessing the impact of the BCC. DISCUSSION: The study has the potential to define an 'End Game' for STH and schistosomiasis programmes through provision of multiple interventions. Interrupting transmission of these infections would eliminate the ne
Viana AG, Gazzinelli-Guimarães PH, Castro VND, et al., 2019, Discrepancy between batches and impact on the sensitivity of point-of-care circulating cathodic antigen tests for Schistosoma mansoni infection., Acta Trop, Vol: 197
The Kato-Katz (KK) technique is the mainstay mapping tool for the diagnosis of Schistosoma mansoni infection, despite showing poor sensitivity in cases of low-intensity infections. As an alternative, a rapid point-of-care circulating cathodic antigen diagnostic test (POC-CCA) has been commercially developed that involves a simple urine assay to detect S. mansoni, rather than a stool-based parasitological examination. Although POC-CCA has proven to be a more sensitive test than KK, it is not yet clear how to interpret discordant results between the two tests, particularly for situations in which the KK result is positive and the POC-CCA result is negative. Thus, the objective of this study was to evaluate the degree of diagnostic variability between different POC-CCA batches with respect to results obtained with KK. For this purpose, we collected urine and stool samples of school-aged children from areas of low and moderate endemicity in Brazil, and compared different POC-CCA batches results with those of KK-positive individuals. We found a statistically significant difference between the results obtained from various POC-CCA batches using the same urine samples, regardless of the degree of endemicity and the intensity of infection in positive KK samples. In addition, there was poor agreement between the KK and POC-CCA results in some batches of the rapid test, resulting in false negatives. These findings raise concerns around quality control checks of POC-CCA, especially in light of the high cost and increasing reliance on this new diagnostic method as control programs move towards a goal of elimination.
Phillips AE, Gazzinelli-Guimarães PH, Aurelio HO, et al., 2018, Urogenital schistosomiasis in Cabo Delgado, northern Mozambique: baseline findings from the SCORE study., Parasites & Vectors, Vol: 11, ISSN: 1756-3305
BACKGROUND: The results presented here are part of a five-year cluster-randomised intervention trial that was implemented to understand how best to gain and sustain control of schistosomiasis through different preventive chemotherapy strategies. This paper presents baseline data that were collected in ten districts of Cabo Delgado province, northern Mozambique, before treatment. METHODS: A cross-sectional study of 19,039 individuals was sampled from 144 villages from May to September 2011. In each village prevalence and intensity of S. haematobium were investigated in 100 children first-year students (aged 5-8 years), 100 school children aged 9-12 years (from classes 2 to 7) and 50 adults (20-55 years). Prevalence and intensity of S. haematobium infection were evaluated microscopically by two filtrations, each of 10 ml, from a single urine specimen. Given that individual and community perceptions of schistosomiasis influence control efforts, community knowledge and environmental risk factors were collected using a face-to-face interview. Data were entered onto mobile phones using EpiCollect. Data summary was made using descriptive statistics. Chi-square and logistic regression were used to determine the association between dependent and independent variables. RESULTS: The overall prevalence of urogenital schistosomiasis was 60.4% with an arithmetic mean intensity of infection of 55.8 eggs/10 ml of urine. Heavy infections were detected in 17.7%, of which 235 individuals (6.97%) had an egg count of 1000 eggs/10 ml or more. There was a significantly higher likelihood of males being infected than females across all ages (62% vs 58%; P < 0.0005). Adolescents aged 9-12 years had a higher prevalence (66.6%) and mean infection intensity (71.9 eggs/10 ml) than first-year students (63.1%; 58.2 eggs/10 ml). This is the first study in Mozambique looking at infection rates among adults. Although children had higher le
Phillips AE, Gazzinelli-Guimaraes PH, Aurelio HO, et al., 2017, Assessing the benefits of five years of different approaches to treatment of urogenital schistosomiasis: A SCORE project in Northern Mozambique., PLoS Neglected Tropical Diseases, Vol: 11, ISSN: 1935-2727
BACKGROUND: In Mozambique, schistosomiasis is highly endemic across the whole country. The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) coordinates a five-year study that has been implemented in various African countries, including Mozambique. The overall goal of SCORE was to better understand how to best apply preventive chemotherapy with praziquantel (PZQ) for schistosomiasis control by evaluating the impact of alternative treatment approaches. METHODS: This was a cluster-randomised trial that compared the impact of different treatment strategies in study areas with prevalence among school children of ≥21% S. haematobium infection by urine dipstick. Each village was randomly allocated to one of six possible combinations of community-wide treatment (CWT), school-based treatment (SBT), and/or drug holidays over a period of four years, followed by final data collection in the fifth year. The most intense intervention arm involved four years of CWT, while the least intensive arm involved two years of SBT followed by two consecutive years of PZQ holiday. Each study arm included 25 villages randomly assigned to one of the six treatment arms. The primary outcome of interest was change in prevalence and intensity of S. haematobium among 100 children aged 9-to-12-years that were sampled each year in every village. In addition to children aged 9-to-12 years, 100 children aged 5-8 years in their first-year of school and 50 adults (aged 20-55 years) were tested in the first and final fifth year of the study. Prevalence and intensity of S. haematobium infection was evaluated by two filtrations, each of 10mL, from a single urine specimen. PRINCIPAL FINDINGS: In total, data was collected from 81,167 individuals across 149 villages in ten districts of Cabo Delgado province, Northern Mozambique. Overall PZQ treatment resulted in a significant reduction in the prevalence of S. haematobium infection from Year 1 to Year 5, where the average prevalence
Clements MN, Donnelly CA, Fenwick A, et al., 2017, Interpreting ambiguous 'trace' results in Schistosoma mansoni CCA tests: estimating sensitivity and specificity of ambiguous results with no gold standard, PLoS Neglected Tropical Diseases, Vol: 11, ISSN: 1935-2727
BackgroundThe development of new diagnostics is an important tool in the fight against disease. Latent Class Analysis (LCA) is used to estimate the sensitivity and specificity of tests in the absence of a gold standard. The main field diagnostic for Schistosoma mansoni infection, Kato-Katz (KK), is not very sensitive at low infection intensities. A point-of-care circulating cathodic antigen (CCA) test has been shown to be more sensitive than KK. However, CCA can return an ambiguous ‘trace’ result between ‘positive’ and ‘negative’, and much debate has focused on interpretation of traces results.Methodology/Principle findingsWe show how LCA can be extended to include ambiguous trace results and analyse S. mansoni studies from both Côte d’Ivoire (CdI) and Uganda. We compare the diagnostic performance of KK and CCA and the observed results by each test to the estimated infection prevalence in the population.Prevalence by KK was higher in CdI (13.4%) than in Uganda (6.1%), but prevalence by CCA was similar between countries, both when trace was assumed to be negative (CCAtn: 11.7% in CdI and 9.7% in Uganda) and positive (CCAtp: 20.1% in CdI and 22.5% in Uganda). The estimated sensitivity of CCA was more consistent between countries than the estimated sensitivity of KK, and estimated infection prevalence did not significantly differ between CdI (20.5%) and Uganda (19.1%). The prevalence by CCA with trace as positive did not differ significantly from estimates of infection prevalence in either country, whereas both KK and CCA with trace as negative significantly underestimated infection prevalence in both countries.ConclusionsIncorporation of ambiguous results into an LCA enables the effect of different treatment thresholds to be directly assessed and is applicable in many fields. Our results showed that CCA with trace as positive most accurately estimated infection prevalence.
Shen Y, King CH, Binder S, et al., 2017, Protocol and baseline data for a multi-year cohort study of the effects of different mass drug treatment approaches on functional morbidities from schistosomiasis in four African countries, BMC INFECTIOUS DISEASES, Vol: 17
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- Citations: 13
Truscott JE, Gurarie D, Alsallaq R, et al., 2017, A comparison of two mathematical models of the impact of mass drug administration on the transmission and control of schistosomiasis, Epidemics, Vol: 18, Pages: 29-37, ISSN: 1878-0067
The predictions of two mathematical models describing the transmission dynamics of schistosome infection and the impact of mass drug administration are compared. The models differ in their description of the dynamics of the parasites within the host population and in their representation of the stages of the parasite lifecycle outside of the host. Key parameters are estimated from data collected in northern Mozambique from 2011 to 2015. This type of data set is valuable for model validation as treatment prior to the study was minimal. Predictions from both models are compared with each other and with epidemiological observations. Both models have difficulty matching both the intensity and prevalence of disease in the datasets and are only partially successful at predicting the impact of treatment. The models also differ from each other in their predictions, both quantitatively and qualitatively, of the long-term impact of 10 years’ school-based mass drug administration. We trace the dynamical differences back to basic assumptions about worm aggregation, force of infection and the dynamics of the parasite in the snail population in the two models and suggest data which could discriminate between them. We also discuss limitations with the datasets used and ways in which data collection could be improved.
Ezeamama AE, He C-L, Shen Y, et al., 2016, Gaining and sustaining schistosomiasis control: study protocol and baseline data prior to different treatment strategies in five African countries, BMC Infectious Diseases, Vol: 16, ISSN: 1471-2334
BackgroundThe Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in 2008 to answer strategic questions about schistosomiasis control. For programme managers, a high-priority question is: what are the most cost-effective strategies for delivering preventive chemotherapy (PCT) with praziquantel (PZQ)? This paper describes the process SCORE used to transform this question into a harmonized research protocol, the study design for answering this question, the village eligibility assessments and data resulting from the first year of the study.MethodsBeginning in 2009, SCORE held a series of meetings to specify empirical questions and design studies related to different schedules of PCT for schistosomiasis control in communities with high (gaining control studies) and moderate (sustaining control studies) prevalence of Schistosoma infection among school-aged children. Seven studies are currently being implemented in five African countries. During the first year, villages were screened for eligibility, and data were collected on prevalence and intensity of infection prior to randomisation and the implementation of different schemes of PZQ intervention strategies.ResultsThese studies of different treatment schedules with PZQ will provide the most comprehensive data thus far on the optimal frequency and continuity of PCT for schistosomiasis infection and morbidity control.ConclusionsWe expect that the study outcomes will provide data for decision-making for country programme managers and a rich resource of information to the schistosomiasis research community.
Rassi C, Kajungu D, Martin S, et al., 2016, Have You Heard of Schistosomiasis? Knowledge, Attitudes and Practices in Nampula Province, Mozambique, PLOS Neglected Tropical Diseases, Vol: 10, ISSN: 1935-2727
Background: Schistosomiasis is a parasitic disease which affects almost 300 million people worldwide each year. It is highly endemic in Mozambique. Prevention and control of schistosomiasis relies mainly on mass drug administration (MDA), as well as adoption of basic sanitation practices. Individual and community perceptions of schistosomiasis are likely to have a significant effect on prevention and control efforts. In order to establish a baseline to evaluate a community engagement intervention with a focus on schistosomiasis, a survey to determine knowledge, attitudes and practices relating to the disease was conducted.Methodology/Principal Findings: A representative cross-sectional household survey was carried out in four districts of Nampula province, Mozambique. Interviews were conducted in a total of 791 households, using a structured questionnaire. While awareness of schistosomiasis was high (91%), correct knowledge of how it is acquired (18%), transmitted (26%) and prevented (13%) was low among those who had heard of the disease. Misconceptions, such as the belief that schistosomiasis is transmitted through sexual contact (27%), were common. Only about a third of those who were aware of the disease stated that they practiced a protective behaviour and only a minority of those (39%) reported an effective behaviour. Despite several rounds of MDA for schistosomiasis in the recent past, only a small minority of households with children reported that at least one of them had received a drug to treat the disease (9%).Conclusion/Significance: Poor knowledge of the causes of schistosomiasis and how to prevent it, coupled with persisting misconceptions, continue to pose barriers to effective disease prevention and control. To achieve high levels of uptake of MDA and adoption of protective behaviours, it will be essential to engage individuals and communities, improving their understanding of the causes and symptoms of schistosomiasis, recommended prevention mechanis
Gurarie D, Yoon N, Li E, et al., 2015, Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa., Parasites and Vectors, Vol: 8, ISSN: 1756-3305
BACKGROUND: Effective control of schistosomiasis remains a challenging problem for endemic areas of the world. Given knowledge of the biology of transmission and past experience with mass drug administration (MDA) programs, it is important to critically evaluate the likelihood that MDA programs will achieve substantial reductions in Schistosoma prevalence. In implementing the World Health Organization Roadmap for Neglected Tropical Diseases it would useful for policymaking to model projections of the status of Schistosoma control in MDA-treated areas in the next 5-10 years. METHODS: Calibrated mathematical models were used to project the effects of different frequency and coverage of MDA for schistosomiasis haematobia control in present-day endemic communities, taking into account uncertainties of parasite biology and input data. The modeling approach in this analysis was the Stratified Worm Burden model developed in our earlier works, calibrated using data from longitudinal S. haematobium control trials in Kenya. RESULTS: Model-based simulations of MDA control in typical low-risk and higher-risk communities indicated that infection prevalence can be substantially reduced within 10 years only when there is a high degree of community participation (>70 %) with at least annual MDA. Significant risk for re-emergence of infection remains if MDA is suspended. CONCLUSIONS: In a stable (stationary) ecosystem, Schistosoma reproduction and transmission are sufficiently robust that the process of human infection continues, even under pressure from aggressive MDA. MDA alone is unlikely to interrupt transmission, and once mass treatment is suspended, the prevalence of human infection is likely to rebound to pre-control levels over a period of 25-30 years. MDA success in achieving very low levels of infection prevalence is highly dependent on treatment coverage and frequency within the local human population, and requires that both adults and children be included in
Mitchell KM, Foss AM, Prudden HJ, et al., 2014, Who mixes with whom among men who have sex with men? Implications for modelling the HIV epidemic in southern India, Journal of Theoretical Biology, Vol: 355, Pages: 140-150, ISSN: 1095-8541
In India, the identity of men who have sex with men (MSM) is closely related to the role taken in anal sex(insertive, receptive or both), but little is known about sexual mixing between identity groups. Both rolesegregation (taking only the insertive or receptive role) and the extent of assortative (within-group)mixing are known to affect HIV epidemic size in other settings and populations. This study explores howdifferent possible mixing scenarios, consistent with behavioural data collected in Bangalore, south India,affect both the HIV epidemic, and the impact of a targeted intervention. Deterministic models describingHIV transmission between three MSM identity groups (mostly insertive Panthis/Bisexuals, mostlyreceptive Kothis/Hijras and versatile Double Deckers), were parameterised with behavioural data fromBangalore. We extended previous models of MSM role segregation to allow each of the identity groups tohave both insertive and receptive acts, in differing ratios, in line with field data. The models were used toexplore four different mixing scenarios ranging from assortative (maximising within-group mixing) todisassortative (minimising within-group mixing). A simple model was used to obtain insights into therelationship between the degree of within-group mixing, R0 and equilibrium HIV prevalence underdifferent mixing scenarios. A more complex, extended version of the model was used to compare the predicted HIV prevalence trends and impact of an HIV intervention when fitted to data from Bangalore.With the simple model, mixing scenarios with increased amounts of assortative (within-group) mixingtended to give rise to a higher R0 and increased the likelihood that an epidemic would occur. When thecomplex model was fit to HIV prevalence data, large differences in the level of assortative mixing wereseen between the fits identified using different mixing scenarios, but little difference was projected infuture HIV prevalence trends. An oral pre-exposure prophylaxis (P
Garba A, Lamine MS, Djibo A, et al., 2013, Safety and efficacy of praziquantel syrup (Epiquantel (R)) against Schistosoma haematobium and Schistosoma mansoni in preschool-aged children in Niger, ACTA TROPICA, Vol: 128, Pages: 318-325, ISSN: 0001-706X
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- Citations: 12
Phillips AE, Molitor J, Boily MC, et al., 2013, Informal confidential voting interviewing in a sexual risk assessment of men who have sex with men (MSM) and transgenders (hijra) in Bangalore, India, SEXUALLY TRANSMITTED INFECTIONS, Vol: 89, Pages: 245-250, ISSN: 1368-4973
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- Citations: 11
Mitchell K, Foss A, Prudden H, et al., 2011, BALANCING THE "SUPPLY AND DEMAND" OF SEX ACTS: IMPLICATIONS FOR MODELLING THE HIV EPIDEMIC AMONG MEN WHO HAVE SEX WITH MEN IN SOUTHERN INDIA, Publisher: B M J PUBLISHING GROUP, Pages: A170-A171, ISSN: 1368-4973
Prudden H, Foss A, Mitchell K, et al., 2011, USING MATHEMATICAL MODELLING TO INVESTIGATE THE ROLE OF THE HIDDEN "POPULATION OF MEN WHO HAVE SEX WITH MEN (MSM) ON THE HIV EPIDEMIC IN SOUTHERN INDIA", Publisher: B M J PUBLISHING GROUP, Pages: A168-A168, ISSN: 1368-4973
Ibironke OA, Phillips AE, Garba A, et al., 2011, Diagnosis of Schistosoma haematobium by detection of specific DNA fragments from filtered urine samples., Am J Trop Med Hyg, Vol: 84, Pages: 998-1001
Definitive diagnosis of Schistosoma haematobium infection in adult patients is a clinically important challenge. Chronically infected adults pass few eggs in the urine, which are often missed when current diagnostic methods are used. In the work presented here, we report on an alternative diagnostic method based on presence of the S. haematobium-specific Dra 1, 121 bp repeat fragment in human urine. A novel method of collecting the urine specimens in the field and filtering them through heavy Whatman No. 3 paper was introduced. After drying, the samples remained viable for several months at room temperature. To test the potential use of this method, 89 urine specimens from school children in Kollo District, Niger, were examined. In all, 52 of 89 (58.4%) were positive for hematuria, 4 of 89 (49.4%) were positive for eggs, and 51 of 89 (57.3%) showed parasite-specific DNA. These were compared with 60 filtered urine specimens obtained from random samples of adults from two study sites in Nigeria, one endemic and one non-endemic for S. haematobium. In the 30 patients from the endemic site, all 10 samples with detectable eggs and 7 of the 20 egg-negative samples were DNA positive. It was concluded that the urine filter paper method was sufficiently sensitive to detect low and cryptic infections, that DNA detection was more sensitive than egg detection, and that the filtration method facilitated specimen collection and transport from the field.
Phillips AE, Gomez GB, Boily M-C, et al., 2010, A systematic review and meta-analysis of quantitative interviewing tools to investigate self-reported HIV and STI associated behaviours in low- and middle-income countries, INTERNATIONAL JOURNAL OF EPIDEMIOLOGY, Vol: 39, Pages: 1541-1555, ISSN: 0300-5771
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- Citations: 107
Phillips AE, Gomez GB, Boily MC, et al., 2010, A systematic review and meta-analysis of quantitative interviewing tools to investigate self-reported HIV and STI associated behaviours in low- and middle-income countries., Int J Epidemiology. (in press).
Phillips AE, Lowndes CM, Boily MC, et al., 2010, Men who have sex with men and women inBangalore, South India, and potential impact on the HIV epidemic, Sex Transm Infect, Vol: 86, Pages: 187-192
Foss A, Johnson H, Prudden HJ, et al., 2010, Potential impact on HIV transmission of a rectal microbicide used by men who have sex with men in southern India, 2010 International Microbicides Conference
Johnson HC, Foss A, Phillips AE, 2009, Transmission dynamics of HIV among men who have sex with men in Bangalore, India: Insights from mathematical modelling, Royal Society for Tropical Medicine & Hygiene
Phillips AE, Garba A, Mahamdou A, et al., 2009, Rapid Assessment of Schistosoma Haematobium infection in Niger using school-based questionnaires, American Society of Tropical Medicine & Hygiene
Phillips AE, Garba A, Amadou S, et al., 2009, Surgical management of scrotal hydroceles under local anaesthetic in lymphatic filariasis endemic communities in Niger, 6th European Congress on Tropical Medicine and International Health
Phillips AE, Boily MC, Lowndes CM, et al., 2008, Understanding the importance of sexual identity and its contribution to men who have sex with men risk behaviour in Bangalore, India, XVII International AIDS conference
Phillips AE, Boily MC, Lowndes CM, et al., 2008, Sexual identity and its contribution to MSM risk behavior in Bangaluru (Bangalore), India: the results of a two-stage cluster sampling survey., J LGBT Health Res, Vol: 4, Pages: 111-126, ISSN: 1557-4091
In India, there are categories of MSM (hijras, kothis, double-deckers, panthis and bisexuals), which are generally associated with different HIV-risk behaviors. Our objective was to quantify differences across MSM identities (n = 357) and assess the extent they conform to typecasts that prevail in policy-orientated discourse. More feminine kothis (26%) and hijras (13%) mostly reported receptive sex, and masculine panthis (15%) and bisexuals (23%) insertive anal sex. However, behavior did not always conform to expectation, with 25% and 16% of the sample reporting both insertive and receptive anal intercourse with known and unknown noncommercial partners, respectively (p < 0.000). Although behavior often complied with stereotyped role and identity, male-with-male sexual practices were fluid. Reification of these categories in an intervention context may hinder our understanding of the differential HIV risk among MSM.
Phillips AE, Boily MC, Lowndes CM, et al., 2007, Understanding Sexual Behaviour related to HIV infection among MSM and Transgenders in Karnataka, India: Overcoming barriers to interviewing hard to reach populations, Infectious Diseases in Poor Countries and the Social Sciences
Phillips AE, Lowndes CM, Boily MC, et al., 2007, Comparison of Information Confidential Voting and Face-to-Face Interviewing in collecting sexual risk data from MSM and transgenders (Hijra) in Bangalore, 17th International Society for Sexually Transmitted Disease Research
Phillips A, Ajanga A, Blair L, et al., 2005, Preliminary study on the epidemiology of Schistosomiasis, hookworm and malaria, and their impact on anaemia in pre-school children, Ukerewe Island, Tanzania, Royal Society of Tropical Medicine
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