Fig. 4

Impact of annual mass drug administration (MDA) alone at 80 % coverage on the model-predicted community-level microfilariae (mf) prevalences of lymphatic filariasis (LF) for each study site. Note that the prevalence values on the y-axis are on a logarithmic scale. Simulations at MDA coverage of 80 % were carried out for three decades using the best-fit parameter vectors obtained by model-fitting to the baseline mf age-prevalence data in each site (cf. Fig. 1). The MDA start time is indicated by 0 on the x-axis. The horizontal dashed line in each plot represents the model-derived extinction threshold signifying 95 % probability of elimination (site-specific numerical values are provided in Table 2), whereas the vertical dashed line denotes the time-point since the start of mass treatment at which the modelled community-level mf prevalences had reduced/crossed below their respective 95 %-EP threshold values for all the best parameter vectors. Note that in these simulations, models were run forward for each site without the effect of drug treatments after the time-points indicated by the vertical lines were crossed