Quantifying the risk of spillover reduction programs for human health
Fig 7
The predicted disease burden of Lassa virus infection for the case of lifelong immunity (left panel) and waning immunity (right panel).
The black line is the theoretical prediction for each case as a function of the force of spillover. The red dots show the force of spillover estimated for actual sites in West Africa where systematic serosurveys have been conducted. The blue dots show hypothetical populations with a force of spillover estimated for seroprevalences of ,
, and
. For the case of waning immunity, the expected duration of immunity is set to 15.63 years (ω = 0.064) as estimated by [34]. Note that the burden of zoonotic disease is significantly greater with waning immunity because reinfection is possible. Parameter values were as described in the S1 Text. Birth rate of the human population was set to b = 24.75 which yields a local population size of 1500.