Polio in retreat - a feature in Scientific American

An interesting article from Scientific American on global efforts to eradicate polio, and recent indicators of significant progress in regions of India where the virus used to be prevalent.

Polio in Retreat: New Cases Nearly Eliminated Where Virus Once Flourished

New cases in key Indian states are hovering near zero—unprecedented, historic lows—suggesting that a long-time goal of eliminating the virus is within reach in parts of world where it has long been considered intractable

The world’s largest, most intractable source of polio may be on the brink of elimination. In India the states of Bihar and Uttar Pradesh have produced more polio cases this decade—nearly 5,000—than any other location worldwide that has an active immunization campaign. Nigeria saw a handful more cases than the two Indian states because it effectively ceased immunizing in 2003 for a time due to false fears of the vaccine.

Now, even at the peak of polio season, new cases in Bihar, Uttar Pradesh and indeed all of India hover near zero—unprecedented, historic lows. In the past decade the peak months of August and September have seen an average of roughly 140 people, usually children, stricken by poliomyelitis, which attacks motor neurons in the nervous system and can cause paralysis. But for the past four weeks running, Bihar and Uttar Pradesh have hung zeros on the polio scoreboard, according to reports published as recently as October 28 by the Global Polio Eradication Initiative.

Data source: AFP Surveillance Bulletin—India Report for week 41, ending 16 October 2010 (pdf)

Members of the Initiative, a public-private partnership among agencies including the World Health Organization, U.S. Centers for Disease Control, UNICEF and Rotary International, are leery of drawing attention to the trend because it could change. “[W]e are cautious,” says Sona Bari, communications officer for polio at WHO. The CDC’s Steve Wassilak adds, “I would rather celebrate after the fact than before,” although “we can be allowed to think that we are close.”

Polio was supposed to be eradicated worldwide by 2000, per a goal set by the World Health Assembly in 1988. In fact, polio cases have been reduced by 99 percent globally from about 350,000 in 1988; sustained transmission of the virus has been eliminated from all but a handful of countries.

Read the rest of the article online at www.scientificamerican.com.

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