Transmissions generated by various behavioral intervals. Interval type one begins after infection and terminates in chronic stage, the number of transmissions made in this interval is C̃s; interval type two begins after infection and terminates in acute stage, the number of transmissions made in this interval is C̃1; interval type three begins after re-sampling a new contact rate in the acute stage and terminates in the acute stage, the number of transmissions made in this interval is C1; interval type four begins after re-sampling a new contact rate in the acute stage and terminates in the chronic stage, the number of transmissions made in this interval is Cs; interval type five begins after re-sampling a new contact rate in the chronic stage and terminates in the chronic stage, the number of transmissions made in this interval is C2.