India is about to hit a milestone in its battle to eradicate the polio virus with no new cases reported in the past year, the country's health minister said on Thursday, a dramatic drop from being the country worst affected by the crippling disease.


A boy stands next to a polio awareness poster on a street in Meerut in Uttar Pradesh.

The last case was detected on January 13 in a two-year-old girl in the country's east. A full year without any new cases means India will no longer be classed as polio-endemic by the World Health Organisation, leaving only Afghanistan, Pakistan, and Nigeria.

We are excited and hopeful, at the same time, vigilant and alert, said Ghulam Nabi Azad in a statement, cautioning it was still important to remain vigilant.

This giant leap towards polio containment in a short span of two years is an endorsement of India's tireless and persistent efforts.

Just two years ago 741 Indians fell sick with polio, nearly half the world's cases that year. Until the 1950s the disease crippled thousands every year in rich nations. It attacks the nervous system and can cause irreversible paralysis within hours of infection.

It often spreads in areas with poor sanitation -- a factor that helped it keep a grip on India for many decades -- and children under five are the most vulnerable. But it can be stopped with comprehensive, population-wide vaccination.

The Polio Eradication Programme in India aims to immunize every child under five years of age with the oral polio vaccine.

The massive programme has seen millions of health workers fan out across the country, going door-to-door, village-to-village immunizing more than 170 million children every year with oral doses of the polio vaccine.

The number of polio cases dropped to 42 in 2010 compared with 741 the previous year. The last case in 2011 was reported from the state of West Bengal.

Health experts welcomed the India's milestone, but added caution.

India must maintain sensitive surveillance and high childhood immunity against wild polio virus to guard against any importation of polio until eradication is achieved globally, said the Global Polio Eradication Initiative in a statement.

In 2011, Pakistan and Afghanistan have both seen alarming increases in polio cases, and polio virus from Pakistan re-infected China ... as long as polio exists anywhere, it remains a threat everywhere.