The outbreak of a Contagious Disease is a common situation. It's often caused by a high rate of Poverty and the lack of a good State Health Service.
Due to the nature of the disease, everyone in the nation is affected by it and wants it to be solved. The disease can quickly ruin the economy as it lowers Productivity both directly and indirectly, by also lowering the national Lifespan. The number of people who are Retired will shrink too, both from the disease and the lower life expectancy younger citizens have. Finally, the disease makes the nation less attractive to tourists, making it impossible to have a Tourism Boom.
The easiest way of fixing the disease is to enact or boost the funding to a state health service.