a, Split of the I group by level of symptoms (none/mild, moderate, severe), with varying contact (k) and infectiousness (π) indicated qualitatively by + (low), ++ (medium) and +++ (high). Infected groups may recover at different rates (γk). b, Multiple routes of transmission through individuals in the community (IC), hospital (IH) or awaiting funeral (F) with varying transmission rates (βk). c, Split of each group into age brackets (for example, I1, I2, …) to account for age-specific contact patterns and transmission rates (φi). Birth occurs only into the S1 group, death affects each group and aging is represented by flows between adjacent age brackets (for example, from I1 to I2) at a rate a.