One of the principles of eradicating a human infectious disease from the planet is that the disease cannot have another host. For example, smallpox only infected humans. It could greatly complicate -- and likely derail -- an eradication effort if, in addition to finding and isolating infected humans, a wily animal species was added to the mix.
The 2nd human infectious disease on the chopping block is Guinea Worm, or dracunculiasis. This infection, which is caused by an invasive worm which must be meticulously winded out of the body, has been beaten back to just a few African nations and, under the direction of President Carter's center, has been on its last legs (of course, worms don't have legs). The key to preventing infection is to keep those infected with the worm from placing themselves in water sources to prevent the worm from discharging its infectious form into the water in which others drink (filters are also used to prevent ingestion).
In 2016, there have been just 19 cases in Chad, Ethiopia, and South Sudan. However those 19 cases are not the full picture as they represent a 25% increase over the same period in 2015 (there were a total of 22 cases in 2015). More ominous to me is the discovery that dogs and baboons are getting infected. It's almost as if the worm, sensing its impending annihilation, has pulled out all stops to stave off extinction and jumped into other species in a manner reminiscent of the demon spirit in the movie Fallen. This phenomenon could make it very hard to fully eradicate this pathogen as wild dogs, for example, can easily contaminate drinking water sources and undo the progress that has occurred with human cases.
Of course, it is no accident that the disease persists in only specific countries as the underlying problem is access to safe drinking water untainted by guinea worm. Civilization, then, is the ultimate way to eradicate this disease. If civilizing forces accelerate sufficiently to bring safe drinking water to the Chad, Ethiopia, and South Sudan, the issue of infections in dogs and other animals may not be so pivotal as feared. However, the provision of safe drinking water is a Herculean task and, if it proves unachievable in the near term, the race between humans, a worm, and dogs will carry more import for the human race than the Olympics.