Atlanta, April 25 (Reuters): The global campaign to eradicate polio suffered a setback last year as the number of cases of the disease increased fourfold with India accounting for a major proportion of the rise, US health officials said.
The US Centers for Disease Control and Prevention yesterday said 1,920 confirmed cases of polio were reported by laboratories in 2002, up from 483 the previous year.
The agency attributed most of the rise to a large outbreak in India, one of the seven countries where the virus is still endemic.
Polio, which once afflicted millions of children, attacks the central nervous system, often causing paralysis, muscular atrophy and deformity. Five to 10 per cent of those infected die when their breathing muscles become paralysed.
The scourge, usually contracted by children through exposure to contaminated water, largely disappeared from the West as a result of vaccination programmes begun in the 1950s, but still exists in a few Asian and African nations.
Nigeria, Egypt, Somalia, Niger, Pakistan and Afghanistan also reported polio cases in 2002.
The battle against polio hit its biggest roadblock last year in Uttar Pradesh and Bihar, which reported the worst outbreaks since 1988 when the World Health Organisation embarked on a major eradication programme.
The two states accounted for 1,362, or 71 per cent, of the world’s cases in 2002. A reduction in the number and quality of mass vaccination programmes likely caused the epidemic, the centre said.
“In certain parts of the country, the vaccinators just didn’t reach all the kids they should have,” said Steven Stewart, a spokesman with its National Immunisation Programme.
Mass vaccination campaigns have been the linchpin of global efforts to stamp out the wild form of the polio virus as well as prevent the spread of its vaccine-derived form.
Wild polio can be prevented with a three-dose oral vaccine that contains an altered live form of the polio virus. In rare cases, the virus can reactivate inside a vaccinated person and escape into the environment through faeces.
Once in contact with the water supply, the virus then reverts to its wild strain and is free to spread to others who have not been immunised, as occurred during a deadly outbreak in 2000 and 2001 in Haiti and the Dominican Republic.
Fears that this could occur in India prompted the WHO and the government earlier this month to launch a major vaccination campaign to inoculate an estimated 80 million children in six states.
A number of follow-up vaccination campaigns are planned in the next year.
Although the outbreaks in the country offered a sobering snapshot of the difficulties faced in stamping out polio, there were still signs last year that the overall war against the disease was being won.
Ethiopia, Sudan and Angola, three countries where the virus had been endemic, were declared polio-free in 2002, and vaccinators’ access to children in Somalia and Afghanistan also improved considerably, said the centre.
The WHO hopes to wipe out polio by 2005.
“We have the tools and we have the strategies to finish this job,” WHO director-general Gro Harlem Brundtland said earlier this month.