Multiple factors affect macro-parasite transmission in distributed meta-population systems including age, behaviour, and environment. The traditional approach to modelling such systems exploits the "mean worm burden" (MWB) formulation. This (worm) burden however, is often overdispersed, and classical models either ignore it or make ad-hoc assumptions ('negative binomial distribution'). We argue that such reduction can often give distort model predictions for 'endemic state' or 'control interventions'. We propose a new modelling approach based on stratified host populations (according to burden). Here MWB dynamics is replaced with that of 'population strata'. The new (SWB) approach avoids many pitfalls of MWB, as it naturally accounts for overdispersion and accommodates other important factors/ measures of human infection and demographics. We analyzed SWB systems vs. MWB, developed proper calibration procedures for a typical field data, applied them to specific environment (Msambweni region of eastern Kenya), and explored some MDT control strategies proposed by WHO.
展开▼
