The US during WWII made an all out war on Syphilis (the infamous study on African American with untreated Syphilis was part of this war, but as a "control" and "Study" group as oppose to the all out attack on Syphilis). By 1957 Syphilis had almost disappeared from the US, if the US had kept up its attack from 1957 onward, that it had done since the 1940, Syphilis was expected to be gone by 1960. The problem was the Recession of 1957, which cut back revenue and thus Congress and the President decided to make budget cuts, which included cutting back the money on Syphilis, on the ground less people were actually being help then had been the case in the 1940s.
Congress just could NOT accept the concept that as a disease goes down, its gets harder and harder to get to the remaining elements. Such reductions are much like half life of radioactive elements. If a half life is 10 years, half is gone in 10 years, but it takes another 10 years for another 25% of the original to be gone (50% half life of the remaining 50% radioactive elements is is just 25% of the original). After 30 years, you are down to 12.5%, after 40 years 6.25%, 50 years. 3.125%.
Stopping a disease is similar, easy to eliminate the first 50%, but the next 25% cost as much as the first 50%. This goes on and on. Now, sooner or later you get to a point where the disease can not spread and is gone (Small pox did this in the 1980s), but to get to that point you have to spend the same amount of money to get smaller and smaller areas of infection.
In the later 1950s, the US Government war on Syphilis was getting to a point, most infections were from overseas, domestic spread of the disease was almost, but not quite, gone. Then Congress killed the funding, and Syphilis slowly regained its ability to spread.
Now, due to efforts to reduce AIDS, most Syphilis from domestic sources finally disappeared in the 1990s, yes, a 40 year delay due to a budget cut. Same thing can happen again, unless we are careful, and this Congress is not known to be careful.