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1,097 results on '"Anderson, Roy M."'

4. 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

Author

Dyer, Clare E.F., Ng-Nguyen, Dinh, Clarke, Naomi E., Hii, Sze Fui, Nguyen, Hieu Quoc, Nguyen, Van-Anh Thi, Nguyen, Thai Van, Nguyen, Trong Van, Ngo, Tam Thi, Herath, H.M.P. Dilrukshi, Wand, Handan, Coffeng, Luc E., Marshall, Justine C., Gray, Darren J., Anderson, Roy M., Clements, Archie C.A., Kaldor, John M., Traub, Rebecca J., and Vaz Nery, Susana

Published
2023
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5. Predicted Impact of COVID-19 on Neglected Tropical Disease Programs and the Opportunity for Innovation

Author

Toor, Jaspreet, Adams, Emily R, Aliee, Maryam, Amoah, Benjamin, Anderson, Roy M, Ayabina, Diepreye, Bailey, Robin, Basáñez, Maria-Gloria, Blok, David J, Blumberg, Seth, Borlase, Anna, Rivera, Rocio Caja, Castaño, María Soledad, Chitnis, Nakul, Coffeng, Luc E, Crump, Ronald E, Das, Aatreyee, Davis, Christopher N, Davis, Emma L, Deiner, Michael S, Diggle, Peter J, Fronterre, Claudio, Giardina, Federica, Giorgi, Emanuele, Graham, Matthew, Hamley, Jonathan ID, Huang, Ching-I, Kura, Klodeta, Lietman, Thomas M, Lucas, Tim CD, Malizia, Veronica, Medley, Graham F, Meeyai, Aronrag, Michael, Edwin, Porco, Travis C, Prada, Joaquin M, Rock, Kat S, Le Rutte, Epke A, Smith, Morgan E, Spencer, Simon EF, Stolk, Wilma A, Touloupou, Panayiota, Vasconcelos, Andreia, Vegvari, Carolin, de Vlas, Sake J, Walker, Martin, and Hollingsworth, T Déirdre

Subjects
Rare Diseases, Infectious Diseases, Vector-Borne Diseases, Orphan Drug, Infection, Good Health and Well Being, COVID-19, Humans, Neglected Diseases, Pandemics, SARS-CoV-2, Tropical Medicine, neglected tropical diseases, coronavirus, modeling, Biological Sciences, Medical and Health Sciences, Microbiology
Abstract

Due to the COVID-19 pandemic, many key neglected tropical disease (NTD) activities have been postponed. This hindrance comes at a time when the NTDs are progressing towards their ambitious goals for 2030. Mathematical modelling on several NTDs, namely gambiense sleeping sickness, lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases (STH), trachoma, and visceral leishmaniasis, shows that the impact of this disruption will vary across the diseases. Programs face a risk of resurgence, which will be fastest in high-transmission areas. Furthermore, of the mass drug administration diseases, schistosomiasis, STH, and trachoma are likely to encounter faster resurgence. The case-finding diseases (gambiense sleeping sickness and visceral leishmaniasis) are likely to have fewer cases being detected but may face an increasing underlying rate of new infections. However, once programs are able to resume, there are ways to mitigate the impact and accelerate progress towards the 2030 goals.

Published
2021

7. Helminth Dynamics: Mean Number of Worms, Reproductive Rates

Author

Rao, Arni S. R. Srinivasa and Anderson, Roy M.

Subjects
Quantitative Biology - Other Quantitative Biology, 92D30, 62P10
Abstract

We derive formulas to compute mean number of worms in a newly Helminth infected population before secondary infections are started (population is closed). We have proved the two types of growth functions arise in this process as measurable functions., Comment: 13 pages

Published
2019
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8. Evaluating and mitigating the potential indirect effect of COVID-19 on control programmes for seven neglected tropical diseases: a modelling study

Author

Aliee, Maryam, Anderson, Roy M, Ayabina, Diepreye, Basáñez, Maria-Gloria, Blumberg, Seth, Caja Rivera, Rocio M, Chitnis, Nakul, Coffeng, Luc E, Davis, Christopher N, Deiner, Michael, Diggle, Peter J, Fronterrè, Claudio, Giorgi, Emanuele, Graham, Matthew, Hamley, Jonathan ID, Hollingsworth, T Deirdre, Keeling, Matt J, Kura, Klodeta, Lietman, Thomas M, Malizia, Veronica, Medley, Graham F, Michael, Edwin, Thumbi, S Mwangi, Mutono, Nyamai, Porco, Travis, Prada, Joaquín M, Rock, Kat S, Sharma, Swarnali, Spencer, Simon, Stolk, Wilma A, Touloupou, Panayiota, Vasconcelos, Andreia, Vegvari, Carolin, de Vlas, Sake J, Borlase, Anna, Le Rutte, Epke A, Castaño, Soledad, Blok, David J, Toor, Jaspreet, Giardina, Federica, and Davis, Emma L

Published
2022
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12. How Does the Proportion of Never Treatment Influence the Success of Mass Drug Administration Programs for the Elimination of Lymphatic Filariasis?

Author

Kura, Klodeta, primary, Stolk, Wilma A, additional, Basáñez, Maria-Gloria, additional, Collyer, Benjamin S, additional, de Vlas, Sake J, additional, Diggle, Peter J, additional, Gass, Katherine, additional, Graham, Matthew, additional, Hollingsworth, T Déirdre, additional, King, Jonathan D, additional, Krentel, Alison, additional, Anderson, Roy M, additional, and Coffeng, Luc E, additional

Published
2024
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16. How Does the Proportion of Never Treatment Influence the Success of Mass Drug Administration Programs for the Elimination of Lymphatic Filariasis?

Author

Kura, Klodeta, Stolk, Wilma A., Basáñez, Maria Gloria, Collyer, Benjamin S., De Vlas, Sake J., Diggle, Peter J., Gass, Katherine, Graham, Matthew, Hollingsworth, T. Deirdre, King, Jonathan D., Krentel, Alison, Anderson, Roy M., Coffeng, Luc E., Kura, Klodeta, Stolk, Wilma A., Basáñez, Maria Gloria, Collyer, Benjamin S., De Vlas, Sake J., Diggle, Peter J., Gass, Katherine, Graham, Matthew, Hollingsworth, T. Deirdre, King, Jonathan D., Krentel, Alison, Anderson, Roy M., and Coffeng, Luc E.

Abstract

Background: Mass drug administration (MDA) is the cornerstone for the elimination of lymphatic filariasis (LF). The proportion of the population that is never treated (NT) is a crucial determinant of whether this goal is achieved within reasonable time frames. Methods: Using 2 individual-based stochastic LF transmission models, we assess the maximum permissible level of NT for which the 1% microfilaremia (mf) prevalence threshold can be achieved (with 90% probability) within 10 years under different scenarios of annual MDA coverage, drug combination and transmission setting. Results: For Anopheles-Transmission settings, we find that treating 80% of the eligible population annually with ivermectin + albendazole (IA) can achieve the 1% mf prevalence threshold within 10 years of annual treatment when baseline mf prevalence is 10%, as long as NT <10%. Higher proportions of NT are acceptable when more efficacious treatment regimens are used. For Culex-Transmission settings with a low (5%) baseline mf prevalence and diethylcarbamazine + albendazole (DA) or ivermectin + diethylcarbamazine + albendazole (IDA) treatment, elimination can be reached if treatment coverage among eligibles is 80% or higher. For 10% baseline mf prevalence, the target can be achieved when the annual coverage is 80% and NT ≤15%. Higher infection prevalence or levels of NT would make achieving the target more difficult. Conclusions: The proportion of people never treated in MDA programmes for LF can strongly influence the achievement of elimination and the impact of NT is greater in high transmission areas. This study provides a starting point for further development of criteria for the evaluation of NT.

Published
2024

17. Improving the Cost-efficiency of Preventive Chemotherapy:Impact of New Diagnostics on Stopping Decisions for Control of Schistosomiasis

Author

Coffeng, Luc E., Graham, Matthew, Browning, Raiha, Kura, Klodeta, Diggle, Peter J., Denwood, Matthew, Medley, Graham F., Anderson, Roy M., De Vlas, Sake J., Coffeng, Luc E., Graham, Matthew, Browning, Raiha, Kura, Klodeta, Diggle, Peter J., Denwood, Matthew, Medley, Graham F., Anderson, Roy M., and De Vlas, Sake J.

Abstract

Background: Control of schistosomiasis (SCH) relies on the regular distribution of preventive chemotherapy (PC) over many years. For the sake of sustainable SCH control, a decision must be made at some stage to scale down or stop PC. These "stopping decisions"are based on population surveys that assess whether infection levels are sufficiently low. However, the limited sensitivity of the currently used diagnostic (Kato-Katz [KK]) to detect low-intensity infections is a concern. Therefore, the use of new, more sensitive, molecular diagnostics has been proposed. Methods: Through statistical analysis of Schistosoma mansoni egg counts collected from Burundi and a simulation study using an established transmission model for schistosomiasis, we investigated the extent to which more sensitive diagnostics can improve decision making regarding stopping or continuing PC for the control of S. mansoni. Results: We found that KK-based strategies perform reasonably well for determining when to stop PC at a local scale. Use of more sensitive diagnostics leads to a marginally improved health impact (person-years lived with heavy infection) and comes at a cost of continuing PC for longer (up to around 3 years), unless the decision threshold for stopping PC is adapted upward. However, if this threshold is set too high, PC may be stopped prematurely, resulting in a rebound of infection levels and disease burden (+45% person-years of heavy infection). Conclusions: We conclude that the potential value of more sensitive diagnostics lies more in the reduction of survey-related costs than in the direct health impact of improved parasite control.

Published
2024

18. How Does Treatment Coverage and Proportion Never Treated Influence the Success of Schistosoma mansoni Elimination as a Public Health Problem by 2030?

Author

Kura, Klodeta, Mutono, Nyamai, Basáñez, Maria Gloria, Collyer, Benjamin S., Coffeng, Luc E., Thumbi, S. M., Anderson, Roy M., Kura, Klodeta, Mutono, Nyamai, Basáñez, Maria Gloria, Collyer, Benjamin S., Coffeng, Luc E., Thumbi, S. M., and Anderson, Roy M.

Abstract

Background: The 2030 target for schistosomiasis is elimination as a public health problem (EPHP), achieved when the prevalence of heavy-intensity infection among school-Aged children (SAC) reduces to <1%. To achieve this, the new World Health Organization guidelines recommend a broader target of population to include pre-SAC and adults. However, the probability of achieving EPHP should be expected to depend on patterns in repeated uptake of mass drug administration by individuals. Methods: We employed 2 individual-based stochastic models to evaluate the impact of school-based and community-wide treatment and calculated the number of rounds required to achieve EPHP for Schistosoma mansoni by considering various levels of the population never treated (NT). We also considered 2 age-intensity profiles, corresponding to a low and high burden of infection in adults. Results: The number of rounds needed to achieve this target depends on the baseline prevalence and the coverage used. For low-and moderate-Transmission areas, EPHP can be achieved within 7 years if NT ≤10% and NT <5%, respectively. In high-Transmission areas, community-wide treatment with NT <1% is required to achieve EPHP. Conclusions: The higher the intensity of transmission, and the lower the treatment coverage, the lower the acceptable value of NT becomes. Using more efficacious treatment regimens would permit NT values to be marginally higher. A balance between target treatment coverage and NT values may be an adequate treatment strategy depending on the epidemiological setting, but striving to increase coverage and/or minimize NT can shorten program duration.

Published
2024

19. Improving the Cost-efficiency of Preventive Chemotherapy : Impact of New Diagnostics on Stopping Decisions for Control of Schistosomiasis

Author

Coffeng, Luc E, Graham, Matthew, Browning, Raiha, Kura, Klodeta, Diggle, Peter J, Denwood, Matthew, Medley, Graham F, Anderson, Roy M, de Vlas, Sake J, Coffeng, Luc E, Graham, Matthew, Browning, Raiha, Kura, Klodeta, Diggle, Peter J, Denwood, Matthew, Medley, Graham F, Anderson, Roy M, and de Vlas, Sake J

Abstract

BackgroundControl of schistosomiasis (SCH) relies on the regular distribution of preventive chemotherapy (PC) over many years. For the sake of sustainable SCH control, a decision must be made at some stage to scale down or stop PC. These "stopping decisions" are based on population surveys that assess whether infection levels are sufficiently low. However, the limited sensitivity of the currently used diagnostic (Kato-Katz [KK]) to detect low-intensity infections is a concern. Therefore, the use of new, more sensitive, molecular diagnostics has been proposed.MethodsThrough statistical analysis of Schistosoma mansoni egg counts collected from Burundi and a simulation study using an established transmission model for schistosomiasis, we investigated the extent to which more sensitive diagnostics can improve decision making regarding stopping or continuing PC for the control of S. mansoni.ResultsWe found that KK-based strategies perform reasonably well for determining when to stop PC at a local scale. Use of more sensitive diagnostics leads to a marginally improved health impact (person-years lived with heavy infection) and comes at a cost of continuing PC for longer (up to around 3 years), unless the decision threshold for stopping PC is adapted upward. However, if this threshold is set too high, PC may be stopped prematurely, resulting in a rebound of infection levels and disease burden (+45% person-years of heavy infection).ConclusionsWe conclude that the potential value of more sensitive diagnostics lies more in the reduction of survey-related costs than in the direct health impact of improved parasite control.

Published
2024

20. Patterns of individual non-treatment during multiple rounds of mass drug administration for control of soil-transmitted helminths in the TUMIKIA trial, Kenya: a secondary longitudinal analysis

Author

Oswald, William E, Kepha, Stella, Halliday, Katherine E, Mcharo, Carlos, Safari, Th'uva, Witek-McManus, Stefan, Hardwick, Robert J, Allen, Elizabeth, Matendechero, Sultani H, Brooker, Simon J, Njenga, Sammy M, Mwandawiro, Charles S, Anderson, Roy M, and Pullan, Rachel L

Published
2020
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22. Forecasting the effectiveness of the DeWorm3 trial in interrupting the transmission of soil-transmitted helminths in three study sites in Benin, India and Malawi

Author

Truscott, James E., Hardwick, Robert J., Werkman, Marleen, Saravanakumar, Puthupalayam Kaliappan, Manuel, Malathi, Ajjampur, Sitara S. R., Ásbjörnsdóttir, Kristjana H., Khumbo, Kalua, Witek-McManus, Stefan, Simwanza, James, Cottrell, Gilles, Houngbégnon, Parfait, Ibikounlé, Moudachirou, Walson, Judd L., and Anderson, Roy M.

Published
2021
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24. Modeling infectious disease dynamics in the complex landscape of global health

Author

Heesterbeek, Hans, Anderson, Roy M, Andreasen, Viggo, Bansal, Shweta, De Angelis, Daniela, Dye, Chris, Eames, Ken TD, Edmunds, W John, Frost, Simon DW, Funk, Sebastian, Hollingsworth, T Deirdre, House, Thomas, Isham, Valerie, Klepac, Petra, Lessler, Justin, Lloyd-Smith, James O, Metcalf, C Jessica E, Mollison, Denis, Pellis, Lorenzo, Pulliam, Juliet RC, Roberts, Mick G, Viboud, Cecile, and Collaboration, Isaac Newton Institute IDD

Subjects
Emerging Infectious Diseases, Infectious Diseases, Prevention, Infection, Good Health and Well Being, Animals, Basic Reproduction Number, Coinfection, Communicable Disease Control, Communicable Diseases, Communicable Diseases, Emerging, Disease Outbreaks, Global Health, Health Policy, Hemorrhagic Fever, Ebola, Humans, Models, Biological, Public Health, Zoonoses, Isaac Newton Institute IDD Collaboration, General Science & Technology
Abstract

Despite some notable successes in the control of infectious diseases, transmissible pathogens still pose an enormous threat to human and animal health. The ecological and evolutionary dynamics of infections play out on a wide range of interconnected temporal, organizational, and spatial scales, which span hours to months, cells to ecosystems, and local to global spread. Moreover, some pathogens are directly transmitted between individuals of a single species, whereas others circulate among multiple hosts, need arthropod vectors, or can survive in environmental reservoirs. Many factors, including increasing antimicrobial resistance, increased human connectivity and changeable human behavior, elevate prevention and control from matters of national policy to international challenge. In the face of this complexity, mathematical models offer valuable tools for synthesizing information to understand epidemiological patterns, and for developing quantitative evidence for decision-making in global health.

Published
2015

43. Study design and baseline results of an open-label cluster randomized community-intervention trial to assess the effectiveness of a modified mass deworming program in reducing hookworm infection in a tribal population in southern India

Author

Sarkar, Rajiv, Rose, Anuradha, Mohan, Venkata R., Ajjampur, Sitara S.R., Veluswamy, Vasanthakumar, Srinivasan, Rajan, Muliyil, Jayaprakash, Rajshekhar, Vedantam, George, Kuryan, Balraj, Vinohar, Grassly, Nicholas C., Anderson, Roy M., Brooker, Simon J., and Kang, Gagandeep

Published
2017
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