Inference and Forecast of the Current West African Ebola Outbreak in Guinea, Sierra Leone and Liberia

Discussion Estimation of key epidemiological parameters for the current West African Ebola outbreak is challenging, as data are limited and a full understanding of spatial-temporal complexity of Ebola transmission dynamics in the region is still lacking. Findings with our simple SEIRX model suggest that growth of Ebola in West Africa may have slowed in Liberia but continues to rise in concert with earlier prediction for Guinea and Sierra Leone. Within these countries, differences in R0(t) may manifest but can be compensated for by adjustment of the mean infectious period. As all parameters are estimated simultaneously, such compensatory action is not unexpected given the quality of observations. While the latest estimate of R0(t) for Sierra Leone was marginally below 1, the estimated contact rate, β(t), 0.34 per day, was much higher than for the other two countries. Our estimates of critical Ebola epidemiological features adjust through time with each new set of observations (Figure 2). This movement, noted by others17 , will no doubt continue and may reflect both observational error and changes in transmission dynamics. For instance, should the virus mutate during serial passage, its epidemiological features may change in the future. More immediately, transmission dynamics may change due to shifts in population behavior, mobility, cultural practices, as information on and acceptance of the situation in affected communities changes, and as intervention measures improve or de...
Source: PLOS Currents Outbreaks - Category: Epidemiology Authors: Source Type: research