Since I work on a daily basis with DA Henderson, the man who led the only successful effort to eradicate smallpox from the planet (see his excellent book), the eradication of other infectious diseases are always something I track.
Since smallpox, only the cattle disease rinderpest has been eradicated.
Two major eradication efforts are currently underway with varying degrees of success. One is focused on polio, the other on guinea worm disease. Polio remains in 8 countries; guinea worm disease (dracunculiasis) in 4.
To eradicate polio is actually a tripartite task, as the disease is caused by three types of poliovirus. Poliovirus type 2 was eliminated in 1999 and type 3 is likely on the verge of eradication. Type I is a different story, however, and has proven difficult to extinguish and has been abetted by social and political developments conducive to its spread.
In 2013, polio cases increased by approximately 62% (from 2012) largely as a result of importation of cases to countries from which it had been previously driven out (Cameroon, Kenya, Somalia, Ethiopia, and Syria).
Polio remains endemic in 3 countries: Afghanistan, Pakistan, and Nigeria. In Afghanistan and Pakistan there have been several reports of violence directed against vaccinators by the Taliban. There is also an excellent book on the topic of polio in Pakistan detailing the structural problems involved there.
Guinea worm disease, on the other hand, experienced a 73% decline in cases from 2012 and remains in South Sudan, Ethiopia, Mali, and Chad.
As the new year unfolds, it will be fascinating to track the progress--and setbacks--of these two programs. For a good overview of eradication in general, see this book.