Written by - Karen Leggett

I'm Gwen Outen with the VOA Special English Health Report.

An aid worker vaccinating a child in India.

In most of the world, the campaign to stop polio by the end of this year has already succeeded.  Fewer than one thousand three hundred new cases of the disease were reported last year.  But problems continue.

Last week, Indonesia reported its first new cases of polio since nineteen ninety-five.  And Yemen has its first cases since nineteen ninety-six.  Medical investigators believe that the virus in both countries came from Nigeria. 

In two thousand three, many parents in northern Nigeria decided not to have their children vaccinated against polio.  Muslim religious leaders had told them that the Western-made vaccine was harmful. 

Vaccination campaigns have started again in Nigeria.  But, as people traveled, the virus spread to countries that were polio-free. 

Polio attacks the nervous system.  It can affect the muscles in the legs, arms and lungs.  The virus is spread by human waste.  Some victims die. 

The Global Polio Eradication Initiative began in nineteen eighty-eight.  At that time, the virus was found in one hundred twenty-five countries.  By two thousand three, there were only six: Nigeria, India, Pakistan, Niger, Afghanistan and Egypt. 

Now, experts say the spread of polio is re-established in six other countries, all in Africa.  And cases have been found in several more. 

The Indonesian government plans to vaccinate more than five million children under age five.  Health workers have already been going house-to-house in West Java, where the polio cases were discovered. 

The World Health Organization says genetic tests linked the virus to West Africa.  It says the virus is similar to viruses recently found in Saudi Arabia and Yemen.

World health officials say that, nationally, more than ninety percent of Indonesian babies are vaccinated against polio.  But they also note that some areas of the country have much lower levels of protection.

In Yemen, sixty-nine percent of children are vaccinated.  More than twenty cases of polio have been found. 

The virus spreads most quickly in Africa during the rainy season that starts in July.  Health workers are trying to vaccinate as many children as possible by then.

Some experts still believe it is possible to stop polio in two thousand five.  But the job has gotten more difficult.

This VOA Special English Health Report was written by Karen Leggett.  Our reports are online at voaspecialenglish.com.  I'm Gwen Outen.