Polio is Back in Africa, says World Health Organization.

After two years with no reported cases, experts had hoped that the disease was gone from the African continent forever. Now, Nigeria joins Afghanistan and Pakistan on the short list of countries where polio is still actively infecting children.

Despite difficult and dangerous social and geographic circumstances, the World Health Organization and other involved groups say efforts to contain the virus will be swift and aggressive. Millions of doses of vaccine, thousands of vaccinators, and the health ministries and militaries of five different countries will be involved in the process.

Vaccinations will begin as soon as next week, starting in the two Borno state villages where paralyzed children have been found, and spreading in ever widening circles to include Nigeria, Chad, Niger, Cameroon, and the Central African Republic.

Authorities believe that the virus may have been circulating in the area for some time. Only about one in 200 cases produces paralysis. Sick and disabled children may have been overlooked or lost in the panicky political climate. Until very recently, threats by Boko Haram have made Borno too dangerous for the vaccination teams to travel. The vicious Islamic fundamentalist militia has murdered and kidnapped hundreds. Due to the violence, thousands of Kunari people have been displaced and living in refugee camps.

A mobile population is hard to reach, and this particular vaccine requires at least three doses over three or more weeks to be effective.

Now, after a prolonged effort by the Nigerian Army in cooperation with neighboring militaries, most villages in the area can be reached, at lest intermittently, and the population is returning home. It is believed that there are at least 200,000 unvaccinated children under 5 in the areas that have been altogether off limits for several years, and countless more in the surrounding areas that may not have been vaccinated.

The region is also regularly crossed by the nomadic Fulani people and their cattle. The Fulani rarely visit health clinics, so medic teams try to reach them by travelling to cattle markets or tribal festivals, or by accompanying the veterinarians who tend to the care of the herds.

In addition to the polio vaccinations, the medical teams encourage visits to temporary "health camps" by offering prenatal care, vitamins, food, and shots for other diseases like diphtheria, tetanus, and measles.

Containment of this outbreak is expected to be easier than the last big outbreak which was in the conservative northwest part of the country, and much easier than the ongoing struggles for containment in Afghanistan and Pakistan. In those places rumors persist, some spread by religious leaders, that the vaccination will sterilize girls, or that it contains pork or the AIDS virus.

This distrust of western medicine has hindered the decades-long effort to eradicate the disease. Since 1988, the world incidence of polio has been reduced by 99%, but holdout areas in the Middle East and Africa have prevented its complete disappearance.

Rotary International has led the eradication charge, along with the World Health Organization, UNICEF, and, more recently, the Bill and Melinda Gates Foundation.

Nigeria's Rotary International polio committee is helping to coordinate the current campaign. They report that in Borno both religious leaders and average residents accept the vaccine.

The new cases were discovered after the virus was detected in sewage samples. This strain was last seen in Chad, where many of the Nigerian families traveled as refugees, so it likely came to Borno with a returning family.