Road map for polio eradication--establishing the link with Millennium Development Goal no. 4 for child survival.

The global polio eradication program, started in 1988, initially targeted the year 2000 for the worldwide elimination of the disease. Although poliovirus transmission has been markedly reduced, it has not been eliminated. As we enter the 20th year of the campaign, poliovirus continues to infect and cause paralysis in localized areas of South Asia and sub-Saharan Africa. To combat this scourge, the World Health Organization, together with other worldwide partners, has newly committed to worldwide eradication by 2009. It appears that the delay has been caused by a combination of the failure of globalization to deliver the prosperity it initially promised and technical problems specific to polio eradication. We hope that the world can reach zero level status for polio report, but verification would take many years and extended research due to the nature of poliovirus. We propose a scientific joint enterprise by which the polio endgame is accelerate, at the same time that a special immunization program against multiple other vaccine-preventable diseases is initiated. This newly organized collaborative effort, we believe, will maximize the benefits achieved by polio eradication and reduce childhood disease and deaths, namely achieve the Millennium Development Goal no. 4, in sub-Saharan Africa, the region that especially needs such action.

Oral polio vaccines have not yet covered West Africa: survey of immunization coverage conducted in Niger.

Following the re-emergence of polio in West Africa, an investigation was conducted on the occasion when transients gather for the festival in Niger, where the oral polio vaccine (OPV) and BCG coverage among children under the age of 5 years can be evaluated. A total of 259 children were investigated, including 186 from settled families and 73 from unsettled families. OPV coverage was found to be as low as 32.4%, and 61.8% of all participants in the study had not received both OPV and BCG. There were more children who had not received the OPV in unsettled families than in settled families. As there are still unvaccinated children in Niger, polio continues to occur among them. Moreover, outbreaks can transfer to more densely-populated areas, causing much larger outbreaks. To stop the chain of transmission, it is essential to reconsider the strategy of mass vaccination in order to cover all children thoroughly, including transients.

Role of a sentinel surveillance system in the context of global surveillance of infectious diseases.

In some nation states, sustained integrated global epidemiological surveillance has been weakened as a result of political unrest, disinterest, and a poorly developed infrastructure due to rapidly increasing global inequality. The emergence of severe acute respiratory syndrome has shown vividly the importance of sensitive worldwide surveillance. The Agency for Cooperation in International Health, a Japanese non-governmental organisation, has developed on a voluntary basis a sentinel surveillance system for selected target infectious diseases, covering South America, Africa, and Asia. The system has uncovered unreported infectious diseases of international importance including cholera, plague, and influenza; current trends of acute flaccid paralysis surveillance in polio eradication; and prevalence of HIV, syphilis, hepatitis B, and hepatitis C in individual areas covered by the sentinels. Despite a limited geographical coverage, the system seems to supplement disease information being obtained by global surveillance. Further development of this sentinel surveillance system would be desirable to contribute to current global surveillance efforts, for which, needless to say, national surveillance and alert system takes principal responsibility.

Eradication of infectious diseases: its concept, then and now.

The concept of disease eradication emerged as recently as the mid-20th century. The successful eradication of smallpox resulted in the concept of the extinction of the causative agent in man as well as in the environment, leading to the cessation of all control measures including vaccination. Subsequently, world resources have been invested in global polio eradication and measles eradication in the Western Hemisphere. The former is apparently now at the "end game", the latter, after successful campaign in the Americas, aims at program development worldwide. However, both endeavors are being challenged by delays in schedules, unexpected technical problems, lack of global coordination, and ever-increasing political unrest. It is proposed that disease eradication be redefined as the extinction of the pathogen in man, not in nature, making for a more flexible approach in the post-eradication period. Smallpox eradication was a rare event. That concept is unrealistic in today's world.