The last time a child was stricken with wild poliovirus type 3 (WPV3) was three years ago this past Tuesday when a 11 month old child from Yobe, Nigeria was paralyzed on 10 November 2012.

Polio vaccine/Mai Mohamed, Egypt
Polio vaccine/Mai Mohamed, Egypt

Wild poliovirus type 2 (WPV2) was declared eradicated by the Global Certification Commission in September after not seeing a case since 1999. The only wild poliovirus type which has been reported since the last case in Nigeria in 2012 is wild poliovirus type 1 (WPV1).

The Global Polio Eradication Initiative (GPEI) says while this milestone is not a guarantee that WPV3 is gone, three years without the virus is a historic achievement and turns the focus of the world all the more sharply on stopping wild poliovirus type 1.

Pakistan reported their 39th WPV1 case of 2015 with one from Khyber in Federally Administered Tribal Areas (FATA) with onset of paralysis on 21 October.

In Laos, an additional case of circulating vaccine-derived poliovirus type 1 (cVDPV1) was reported in the past week, in Bolikhanh district of Borkihamxay province, with onset of paralysis on 29 September. The total number of cVDPV1 cases in 2015 is three.

All three cases come from the same village. Efforts are underway to further strengthen surveillance activities in other parts of the country, to determine if other sources of transmission are occurring elsewhere in the country.

Prior to this September, Lao’s last case of indigenous wild poliovirus was reported in 1993.

Globally in 2015, there has been 52 WPV1 cases, all reported from Pakistan and Afghanistan, and 17 cVDPV  cases with the majority reported from Madagascar.

Robert Herriman is a microbiologist and the Editor-in-Chief of Outbreak News Today and the Executive Editor of The Global Dispatch

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