DUSHANBE, April 24, 2010, Asia-Plus – Tajikistan at high risk of transmission after importation of poliovirus, the World Health Organization (WHO) Regional Office for Europe reported on April 23.
The World Health Organization has deployed a team of experts to investigate a polio outbreak in the south-west of Tajikistan, in the area bordering Afghanistan and Uzbekistan. Together with its partners at the Global Polio Eradication Initiative, WHO will also support the Ministry of Health of Tajikistan in conducting a mass immunization campaign.
A sharp increase in early April of acute flaccid paralysis (AFP) cases prompted Tajikistan’s government to contact WHO about a possible polio outbreak. As part of a joint investigation by the Tajik national health authorities and WHO, laboratory tests by the WHO collaborating center in Moscow confirmed poliovirus as the cause of the outbreak. WHO immediately alerted all other countries of this new public health risk in eastern central Asia, as required under the International Health Regulations. This is the first outbreak from imported poliovirus in the WHO European Region since it was certified polio-free in 2002.
As of April 22, 128 AFP cases have been reported and 10 children have died. All cases are in the south-west of the country, in an area bordering Afghanistan and Uzbekistan. Poliovirus has been isolated in diagnostic specimens from seven of these cases. Genetic sequencing of the virus is being done to further characterize the virus. Uzbekistan has also reported three AFP cases, which are under investigation.
Afghanistan, Pakistan, India and Nigeria are the four remaining polio-endemic countries in the world, although recent outbreaks were registered in several countries in Africa due to importation. Tajikistan’s last case of clinically confirmed polio was in 1997. Reported vaccination coverage nationwide was 87% in 2008, which is the last year for which complete data are available to WHO.
At the Tajik government’s request, technical experts from WHO have started a detailed outbreak investigation and response in accordance with standard international guidelines established by the World Health Assembly in 2006. WHO has also alerted the governments of Kazakhstan, Kyrgyzstan, Turkmenistan and Uzbekistan to intensify surveillance for AFP cases and to rapidly plan and conduct national or subnational polio immunization campaigns.
Tajikistan will hold three nationwide vaccination campaigns in a short time frame to halt the outbreak. The campaign will be managed by the Tajik Ministry of Health, with support from WHO, the United Nations Children’s Fund (UNICEF), the United States Centers for Disease Control and Prevention (CDC) and other partners in the Global Polio Eradication Initiative. Rotary International has already offered an emergency grant to begin the vaccination campaign.
Poliovirus travels long distances easily and polio-free regions will continue to be at risk until poliovirus transmission is stopped in the remaining endemic countries. The WHO European Region was certified polio-free in 2002, following over three years without transmission of indigenous wild poliovirus in the presence of certification-standard surveillance. The outbreak in Tajikistan has no immediate implications for the European Region’s certification.
This outbreak, however, demonstrates the need to maintain high population immunity until transmission of polio has been interrupted worldwide. The outbreak coincides with the annual European Immunization Week campaign which begins on April 24 2010 to raise awareness of vaccine-preventable diseases and the importance of immunization.
WHO, together with its partners, will continue to provide technical and field support until the outbreak is brought under control. WHO does not recommend restrictions on international travel and trade in case of the detection of poliovirus, but emphasizes that standard recommendations regarding the vaccination of travelers to and from a polio-infected area apply until a polio outbreak
