Mathematical modelling of Ebola Virus Disease in Serenje District with a Lusaka District overspill,Zambia

Abstract

The Ebola virus causes an acute, serious illness, which is often fatal. Despite improved control measures, Ebola Virus Disease (EVD) remains a public health concern in endemic areas as well as in unaffected areas. Ecological niche-mapping places Zambia within the ecological niche of filovirus infections. Furthermore, the annual migration of the straw-coloured fruit bats (Eidolon helvum) to Kasanka National Park in Serenje District puts Zambia at high risk of exposure to an outbreak of EVD. Thus, a mathematical transmission model using the Susceptible-Exposed-Infectious-Recovered (SEIR) epidemic model was developed to predict spread patterns of a potential EVD outbreak in Serenje and Lusaka districts as well as to determine the influence of intervention measures in disease spread. Following the introduction of one infected person into the rural district of Serenje, the model predicted that without any interventions an epidemic would reach its peak by day 46 and, should the disease spread to the urban district of Lusaka, it would reach its peak by day 40. The epidemic would have a devastating impact in the community, mostly in Lusaka District than in Serenje District with 42.4 percent and 34.4 percent of the population affected, respectively. The model further predicted that with implementation of control measures (community education and reduction of the burial time) the peak days would be delayed by 25 days and 22 days, and the number of EVD cases would be reduced by 10.5 % and seven percent in Serenje and Lusaka districts, respectively. Nevertheless, the intervention would extend the length of the outbreak by almost twice in Lusaka District compared to Serenje District. The overall effect of interventions would be more optimal in Serenje District than Lusaka District. Our model also predicted that community education would have the largest effect on the reduction in the number of cases during the outbreak compared to the effect of reducing the burial time of the deceased person. Preventive measures based mostly on community education should always be implemented to avoid such an outbreak. Furthermore, a good EVD preparedness plan should always be in place for effective risk management and control.