Skip to main content

Table 1 Overview of the main characteristics of the ONCHOSIM and EPIONCHO models

From: Required duration of mass ivermectin treatment for onchocerciasis elimination in Africa: a comparative modelling analysis

Characteristics ONCHOSIM EPIONCHO
Basic model structure   
 Number and type of spatial locations modelled Single place Single place
 Population-based or individual-based Individual-based regarding humans and worms Population-based
 Way of representing infection in hosts Presence and density at individual level Mean density in population subgroups (e.g. age, sex, treatment compliance group). Prevalence as a function of mean density assuming an underlying negative binomial distribution
 Role of chance Stochastic Deterministic
 Interventions considered in previous publications Mass treatment, selective treatment (test and treat), vector control, Mass treatment, vector control
Features included in the model   
 Human population demographics Birth and death rate dynamically modelled; age and sex composition Birth and death rate, age and sex composition
 Heterogeneities in the human population Age, sex, life expectancy, level of exposure to blackflies, compliance with MDA, efficacy of treatment Age, sex, life expectancy, level of exposure to blackflies, compliance with MDA
 Blackfly population density Fixed input as annual biting rate (ABR); seasonal monthly biting rates Fixed input as ABR; seasonality in biting rates can be included
 Exposure to blackfly vectors Heterogeneous (dependent on age, sex, personal attractiveness to blackflies) Heterogeneous (dependent on age and sex)
 Uptake of infection by blackfly vectors Varying non-linearly (density-dependent) with infection intensity in human hosts Varying non-linearly (density-dependent) with infection intensity in human hosts
 Infection in blackfly vectors Density (average L3 load per fly) Density (average L3 load per fly)
 Excess mortality of infected flies No Yes
 Parasite acquisition in humans Proportional to mean number of L3 larvae inoculated, denoted by the success ratio Non-linearly (density-dependent) related to rate of exposure to L3 larvae
 Infection in humans Density (immature or mature worms, mf per skin snip) Density (non-fertile and fertile worms, mf per mg of skin)
 Diagnostic outcomes Mf count sampling to relate model predictions to data Sampling process and diagnostic performance of skin snipping not yet included