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The past matters: estimating intrinsic hookworm transmission intensity in areas with past mass drug administration to control lymphatic filariasis.
Parasit Vectors. 2017 May 23; 10(1):254.PV

Abstract

BACKGROUND

Current WHO guidelines for soil-transmitted helminth (STH) control focus on mass drug administration (MDA) targeting preschool-aged (pre-SAC) and school-aged children (SAC), with the goal of eliminating STH as a public health problem amongst children. Recently, attention and funding has turned towards the question whether MDA alone can result in the interruption of transmission for STH. The lymphatic filariasis (LF) elimination programme, have been successful in reaching whole communities. There is the possibility of building upon the infrastructure created for these LF-programmes to enhance the control of STH. Using hookworm as an example, we explore what further MDA coverage might be required to induce interruption of transmission for hookworm in the wake of a successful LF programme.

RESULTS

Analyses based on the model of STH transmission and MDA impact predict the effects of previous LF control by MDA over five years, on a defined baseline prevalence of STH in an area with a defined transmission intensity (the basic reproductive number R0). If the LF MDA programme achieved a high coverage (70, 70 and 60% for pre-SAC, SAC and adults, respectively) we expect that in communities with a hookworm prevalence of 15%, after 5 years of LF control, the intrinsic R0 value in that setting is 2.47. By contrast, if lower LF coverages were achieved (40, 40 and 30% for pre-SAC, SAC and adults, respectively), with the same prevalence of 15% at baseline (after 5 years of LF MDA), the intrinsic hookworm R0 value is predicted to be 1.67. The intrinsic R0 value has a large effect on the expected successes of follow-up STH programmes post LF MDA. Consequently, the outcomes of identical programmes may differ between these communities.

CONCLUSION

To design the optimal MDA intervention to eliminate STH infections, it is vital to have information on historical MDA programmes and baseline prevalence to estimate the intrinsic transmission intensity for the defined setting (R0). The baseline prevalence alone is not sufficient to inform policy for the control of STH, post cessation of LF MDA, since this will be highly dependent on the intensity and effectiveness of past programmes and the intrinsic transmission intensity of the dominant STH species in any given setting.

Authors+Show Affiliations

London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, St. Mary's Campus, Imperial College London, London, W2 1PG, United Kingdom. m.werkman@imperial.ac.uk. The DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD, United Kingdom. m.werkman@imperial.ac.uk.London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, St. Mary's Campus, Imperial College London, London, W2 1PG, United Kingdom. The DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD, United Kingdom.London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, St. Mary's Campus, Imperial College London, London, W2 1PG, United Kingdom.London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, St. Mary's Campus, Imperial College London, London, W2 1PG, United Kingdom. The DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD, United Kingdom.London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, St. Mary's Campus, Imperial College London, London, W2 1PG, United Kingdom. The DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD, United Kingdom.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28535806

Citation

Werkman, Marleen, et al. "The Past Matters: Estimating Intrinsic Hookworm Transmission Intensity in Areas With Past Mass Drug Administration to Control Lymphatic Filariasis." Parasites & Vectors, vol. 10, no. 1, 2017, p. 254.
Werkman M, Truscott JE, Toor J, et al. The past matters: estimating intrinsic hookworm transmission intensity in areas with past mass drug administration to control lymphatic filariasis. Parasit Vectors. 2017;10(1):254.
Werkman, M., Truscott, J. E., Toor, J., Wright, J. E., & Anderson, R. M. (2017). The past matters: estimating intrinsic hookworm transmission intensity in areas with past mass drug administration to control lymphatic filariasis. Parasites & Vectors, 10(1), 254. https://doi.org/10.1186/s13071-017-2177-6
Werkman M, et al. The Past Matters: Estimating Intrinsic Hookworm Transmission Intensity in Areas With Past Mass Drug Administration to Control Lymphatic Filariasis. Parasit Vectors. 2017 May 23;10(1):254. PubMed PMID: 28535806.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The past matters: estimating intrinsic hookworm transmission intensity in areas with past mass drug administration to control lymphatic filariasis. AU - Werkman,Marleen, AU - Truscott,James E, AU - Toor,Jaspreet, AU - Wright,James E, AU - Anderson,Roy M, Y1 - 2017/05/23/ PY - 2016/12/20/received PY - 2017/05/05/accepted PY - 2017/5/25/entrez PY - 2017/5/26/pubmed PY - 2018/2/24/medline KW - Interrupting transmission KW - Lymphatic filariasis KW - Mass drug administration impact KW - Soil-transmitted helminths KW - Transmission models SP - 254 EP - 254 JF - Parasites & vectors JO - Parasit Vectors VL - 10 IS - 1 N2 - BACKGROUND: Current WHO guidelines for soil-transmitted helminth (STH) control focus on mass drug administration (MDA) targeting preschool-aged (pre-SAC) and school-aged children (SAC), with the goal of eliminating STH as a public health problem amongst children. Recently, attention and funding has turned towards the question whether MDA alone can result in the interruption of transmission for STH. The lymphatic filariasis (LF) elimination programme, have been successful in reaching whole communities. There is the possibility of building upon the infrastructure created for these LF-programmes to enhance the control of STH. Using hookworm as an example, we explore what further MDA coverage might be required to induce interruption of transmission for hookworm in the wake of a successful LF programme. RESULTS: Analyses based on the model of STH transmission and MDA impact predict the effects of previous LF control by MDA over five years, on a defined baseline prevalence of STH in an area with a defined transmission intensity (the basic reproductive number R0). If the LF MDA programme achieved a high coverage (70, 70 and 60% for pre-SAC, SAC and adults, respectively) we expect that in communities with a hookworm prevalence of 15%, after 5 years of LF control, the intrinsic R0 value in that setting is 2.47. By contrast, if lower LF coverages were achieved (40, 40 and 30% for pre-SAC, SAC and adults, respectively), with the same prevalence of 15% at baseline (after 5 years of LF MDA), the intrinsic hookworm R0 value is predicted to be 1.67. The intrinsic R0 value has a large effect on the expected successes of follow-up STH programmes post LF MDA. Consequently, the outcomes of identical programmes may differ between these communities. CONCLUSION: To design the optimal MDA intervention to eliminate STH infections, it is vital to have information on historical MDA programmes and baseline prevalence to estimate the intrinsic transmission intensity for the defined setting (R0). The baseline prevalence alone is not sufficient to inform policy for the control of STH, post cessation of LF MDA, since this will be highly dependent on the intensity and effectiveness of past programmes and the intrinsic transmission intensity of the dominant STH species in any given setting. SN - 1756-3305 UR - https://www.unboundmedicine.com/medline/citation/28535806/The_past_matters:_estimating_intrinsic_hookworm_transmission_intensity_in_areas_with_past_mass_drug_administration_to_control_lymphatic_filariasis_ L2 - https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-017-2177-6 DB - PRIME DP - Unbound Medicine ER -