The polio eradication programme in the country has taken a knocking again. From near-eradication in 2005 when only 66 cases were reported to 879 in 2007 and 559 in 2008, 89 cases have already been reported this year ahead of the July-September peak season. Worse, India is being blamed, along with Nigeria, for exporting the disease to polio-free countries in Africa this year.

According to a report by the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) published in the June 17 edition of the Journal of the American Medical Association, wild polio virus originating from India and Nigeria have been responsible for spreading polio in 15 countries in Africa which were polio-free for sometime.

The CDC defined importation as detection of one or more polio cases in a country resulting from virus transmission that genetic analysis shows to have first circulated in another country — it is an outbreak when the imported virus causes two or more cases.

The report describes 32 wild polio virus importations resulting in 96 polio cases during January 2008-March 2009. Of these, 29 importations which resulted in 68 cases were found to be from Nigeria. Three wild polio viruses originated from India and resulted in 28 cases. These viruses were either imported directly or after transmission through another country. The outbreaks caused by India-origin virus have been mostly in Angola and the Central African Republic.

According to the report, the virus was traced to India through comprehensive genomic sequencing provided by the global polio laboratory network. This allows tracing of the origins of virus importations and estimation of the duration of circulation in a chain of transmission. The CDC report mentions that the transmission from India and Nigeria happened previously between 2002 and 2006 but was controlled.