October 2, 2013
Wild Poliovirus Outbreak Continues Its Grasp In Horn Of Africa And Neighboring Countries
Lawrence LeBlond for redOrbit.com - Your Universe Online
Three young patients from South Sudan in East-Central Africa who had been previously immunized with oral polio vaccine (OPV) have been found to have suspected cases of wild poliovirus type 1 (WPV1). The three patients are girls, two of whom are about two years of age and one is eight years old.
The girls had developed paralysis sometime between Aug 15 and Aug 24. Genetic sequencing is ongoing to provide a final confirmation of the lab results to determine the origin of these isolated viruses.
WPV1 has taken hold in the Horn of Africa, with 174 confirmed cases in Somalia, 14 cases in Kenya and three cases in Ethiopia since environmental samples first turned up this past February in Egypt. South Sudan has always been considered at high risk of re-infection because of the route of spread of the disease, and as such, the country has conducted two National Immunization Days (NIDs) in March and April 2013 and sub-NIDs in August.
If the newly reported cases turn out to be WPV1 infections, then rethinking may be in order on how to further respond to this outbreak. Currently, contingency plans for an emergency outbreak response are being finalized, including an immediate supplementary immunization activity (SIA) in and around the infected areas.
International experts are now being deployed to South Sudan to assist local authorities in investigations of possible WPV1 cases. This international presence will also plan for an appropriate outbreak response along with an intensified search for additional potential cases.
Teams are also assessing immunization rates in neighboring countries to determine overall population immunity levels. Additional SIAs will be conducted as needed to help fill any gaps in immunizations. Further sub-NIDs in neighboring countries are also scheduled for October and December 2013, and outbreak response is continuing in Somalia, Kenya and Ethiopia.
The World Health Organization (WHO) is urging all countries, especially those with frequent travel and contacts with poliovirus-affected regions, to strengthen surveillance for cases of acute flaccid paralysis (AFP) in order to quickly detect new cases and facilitate a rapid response. The WHO, through its regional offices, is continuing to provide support to countries in their planning and implementation of emergency response to this outbreak.
The WHO’s International Travel and Health arm recommends all travelers to and from polio-affected areas be fully vaccinated against polio.
The first cases of WPV1 in the Horn of Africa showed up on April 30, 2013, when a four-month-old girl was diagnosed with AFP in Kenya, along with two healthy contacts of the child testing positive for WPV1. They were the first cases in Kenya since July 2011.
Polio spread rampantly across the African continent in 2005, and into Yemen and the Horn of Africa, resulting in more than 700 cases. Since then, international outbreak responses have been adopted and new bivalent oral polio vaccines have been developed, which has been shown to significantly reduce the severity and length of polio outbreaks.