A strain of polio that’s hit parts of Africa and the Middle East appears almost identical to one that has reached Indonesia, raising the prospect that a migrant worker may have brought it back to the world’s most populous Muslim nation, the World Health Organization said Tuesday.

An 18-month-old girl in the West Java village of Girijaya was diagnosed with polio on April 21, becoming the first Indonesian to contract the disease since 1995. Authorities say the strain is genetically similar to one in Nigeria, where the disease spread rapidly after Muslims boycotted the vaccine in 2003, fearing a U.S.-led plot to render them infertile or infect them with AIDS.

Seven other people in Girijaya are also suspected of having polio, prompting Indonesian health workers to conduct house-to-house vaccinations in the area, intensify surveillance and draw up plans to vaccinate 5.2 million children under age 5 by July.

“We’ve determined that (the Indonesian case) is genetically similar to the virus in Nigeria and is related to viruses in Saudi Arabia and Yemen,” said Sona Bari, a WHO spokeswoman in Geneva.

“There is a lot of travel from Sudan and the Arabian Peninsula,” she said. “It looks like it might have come from an Indonesian who worked in that area, but at this point we can’t say for sure.”

Indonesia is the 16th country re-infected since 2003, when Muslims in northern Nigeria began refusing to immunize their children at the urging of hard-line Islamic clerics. Almost all the cases have been traced to Nigeria, where the boycott continued for nearly a year before local officials stepped in.

In Sudan, which was declared polio-free in 2001, the paralyzing illness has infected 149 people. It also has spread to Saudi Arabia and Ethiopia, but vaccination campaigns averted major outbreaks.

In a report on the Indonesian case, the WHO said that the “outbreak may continue to spread in the immediate area of the case and outside. Circulation of the (virus) could be occurring in other provinces in Indonesia.”

Dr. Bardan Rana, a WHO medical officer investigating the case, said he expected to see a few more cases in Indonesia but that the government was doing everything necessary to contain the disease.

Other African and Middle Eastern countries where the virus has returned include Benin, Chad, Cameroon, Botswana, Burkina Faso, Central African Republic, Ghana, Guinea, Mali, Togo, Yemen and Ivory Coast.

Polio is still endemic in Nigeria, India, Pakistan, Niger, Afghanistan and Egypt.

Last year, some 1,267 people were infected in the world, with 792 of those in Nigeria, according to the WHO. After Nigeria, Sudan and Yemen are listed as the worst-affected countries.

When WHO launched its anti-polio campaign in 1988, the worldwide case count was more than 350,000 annually.

Polio is a waterborne disease that usually infects young children, attacking the nervous system and causing paralysis, muscular atrophy, deformation and sometimes death.