Reuters -The World Health Organization has suggested a budget of $2.6 billion for its polio eradication efforts in 2010-2012, but says it faces a shortfall of about half of funds for that period.

“We are going to the rich world donors at a time when their budgets are tight,” Gates, the founder of software giant Microsoft, told reporters during a visit to Nigeria’s capital Abuja.

“But between what our foundation will do, what the others will do, I feel quite sure that we will be able to fund that fight,” he added.

The Bill & Melinda Gates Foundation, which has been active in fighting child and infectious diseases in poor countries, will commit more than $150 million of its $34 billion fund this year to mass polio immunization and surveillance programs.

The number of worldwide cases has declined this year, most significantly in Nigeria which has recorded its lowest level of infections ever with only three so far in 2010. That is down from a total of 288 cases last year.

KEY TO ENDING POLIO

Nigeria, one of four countries where polio is endemic, is considered key to wiping out the virus which spread out from the northern half of the country to 17 African nations in the last few years.

Dr Bruce Aylward, director of the polio eradication initiative of WHO, said there were still many children in Nigeria that are not receiving vaccines and a large outbreak could re-occur if governments and donors become complacent.

“The reality is that it can easily explode again, where you could have thousands of children paralyzed again every single year in this country,” Aylward said.

For example, polio was recently found in Tajikistan for the first time in 10 years and quickly spread, paralyzing 152 children in a few months, WHO said.

Nigeria has struggled to contain polio since some northern states imposed a year-long vaccine ban in mid-2003. Some state governors and religious leaders in the predominately Muslim north claimed the vaccines were contaminated by Western powers to spread sterility and HIV/AIDS among Muslims.

Traditional leaders throughout the country pledged in January 2009 to support immunization campaigns, however, and are pushing parents to have their children vaccinated.

Immunizations of children in Nigeria’s north rose to 71 percent this year, up from 63 percent in 2009. WHO has set a goal of 80 percent in Africa’s most populous nation.

Polio, which spreads in areas with poor sanitation, attacks the nervous system and can cause irreversible paralysis within hours of infection. Children under the age of 4 are the most vulnerable to the disease that until the 1950s crippled thousands of people every year in rich nations.