one population to the other, but when it does, it results in only very small rates of
survival. You may think of this strain as one that can only be passed on through
direct contact with bodily fluids such as saliva or blood. In contrast, the other strain
of the virus can travel through air. It is therefore more easy to contract the disease.
But this strain is also less lethal. Assume BETA 1 2 ¼ 0.00025, SURVIVAL RATE
1 ¼ 0.155, and all the other parameters as listed above. The first outbreak with the
disease is virtually the same for both strains but the subsequent dynamics are very
different. The virus of the second strain can stay in the population for long times
(Fig. 21.5). Can you explain why? Perform a sensitivity analysis of the contact rates
Fig. 21.4
Fig. 21.5
21.3 Two Infective Populations
171
survival. You may think of this strain as one that can only be passed on through
direct contact with bodily fluids such as saliva or blood. In contrast, the other strain
of the virus can travel through air. It is therefore more easy to contract the disease.
But this strain is also less lethal. Assume BETA 1 2 ¼ 0.00025, SURVIVAL RATE
1 ¼ 0.155, and all the other parameters as listed above. The first outbreak with the
disease is virtually the same for both strains but the subsequent dynamics are very
different. The virus of the second strain can stay in the population for long times
(Fig. 21.5). Can you explain why? Perform a sensitivity analysis of the contact rates
Fig. 21.4
Fig. 21.5
21.3 Two Infective Populations
171