Putting an end to diseases of all kinds has long been on the wish list of scientists and those stricken. But while it might be human nature to yearn for a pestilence-free tomorrow, those in the eradication trenches know that some battles will be won and others are losing fights.

The worldwide eradication of polio is an ethical obligation the developed world should shoulder, according to a Perspectives piece in the Lancet. No sooner said than done…or at least begun.

The World Health Organization and the United Nations Children’s Fund launched an effort in April to vaccinate 77 million children in 16 West African countries against the disease. In May, WHO vaccinated 1.1 million children in Tajikistan after a polio outbreak there. Tajikistan has seen 129 confirmed polio cases over the last few months; 83 percent were in children under five. Two deaths have been confirmed. This is the first outbreak of polio in WHO’s European region since it was declared a “polio-free zone” in 2002, according to a report from IRIN. By the end of May, 6.3 million doses of vaccine had been distributed.

Since the introduction and widespread use of polio vaccine began in the 1950s, the disease has retreated. It is endemic in only four countries—India, Pakistan, Afghanistan, and Nigeria.

Claudia Emerson, program leader in ethics at the University of Toronto’s McLaughlin-Rotman Centre for Global Health and lead author ofthe Lancet paper, states that polio is close to eradication. When the Global Polio Eradication Initiative was launched in 1988, there were 350,000 cases of polio. In 2009, only 1,600 cases were reported. Only one disease—smallpox—has ever been eradicated.

“Polio is next in line,” Emerson stated. “It’s really running a marathon. We’re close to the finish line and it doesn’t make much sense to stop short of the finish line. We have a moral duty to do that.”

Polio isn’t the only affliction scientists want to see heading for the exit. A May 14 special issue of Science focused on eliminating malaria.

“The global research community must take up the challenge to work toward the eradication of malaria,” wrote Seattle Biomedical Research Institute’s Stefan Kappe and co-authors. They promote using a strategy that would kill the parasite in the mosquitoes that carry the disease.

With nearly 250 million cases of malaria causing about 800,000 deaths annually, quashing it will be more difficult than stamping out polio—if not impossible.

“Basically, we haven’t got a hope in hell of eradicating malaria,” McGill University biologist Jonathan Davies said in an interview with the Natural Hazards Center. “There are several strains going around. There are animal reservoir hosts. Even if we removed it from the human population, it might then re-infect us in the future through an animal host.”

Davies said that it is often easier and cheaper to control diseases in affected populations. Reducing a disease's prevalence in its area of greatest impact is more effective and efficient, he writes in an article published online in the Proceedings of the Royal Society B: Biological Sciences.

“With polio, the difference is that we have it within our grasp,” he added. “We could actually eliminate this disease. At the moment, it’s really not feasible for malaria. Even within the United States, there have been huge efforts to remove the vector, there’s still malaria present in the U.S., just at a very low level, a low prevalence.”