Transmission Dynamics of Ascaris lumbricoides - Theory and Observation
Hollingsworth TD., Truscott JE., Anderson RM.
Mathematical models are playing an increasing role in the design and optimization of control programs for many infectious diseases. In the case of Ascaris lumbricoides, there is a long history of models to understand the biology and epidemiology and to design control programs. We outline the key insights which models have given on the dynamics of Ascaris transmission, describe the model structures and discuss how current and future models are informing the design of control programs in the era of both increased access to donate drugs and new statistical techniques to validate these models against reinfection data. We show how the "bounce-back" time following a treatment round, when infection levels monotonically increase to baseline levels, are driven by the life expectancy of the parasite and the basic reproductive number. We also show that the effect of treatment in subsets of the population, for example school children, depends on the extent to which different subpopulations interact with the egg output of the treated group. We discuss the outstanding policy questions which models can be used to answer and the data and model development required to address them. © 2013 Copyright © 2013 Elsevier Inc. All rights reserved.