World health statistics quarterly. Rapport trimestriel de statistiques sanitaires mondiales
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Japanese encephalitis (JE) remains endemo-epidemic in several countries in East, South-East and South Asia. The disease has been under control in Japan since the 1970s owing to mass immunization using mouse-brain-derived inactivated vaccine and to reduced vector mosquito populations. The vector density which was once reduced by wide spraying of insecticides in rice fields showed an increasing trend after the 1980s as a result of mosquito resistance. ⋯ In spite of slight antigenic differences among JE virus isolates, JE vaccine produced by a classical Nakayama strain was effective in preventing overt JE in a field study in Thailand. The technology of mouse-brain-derived inactivated JE vaccine production was transferred from Japan to India, Thailand and Viet Nam. The production of JE vaccine in these countries is still on a pilot scale and insufficient for mass-immunization of susceptible target populations.(ABSTRACT TRUNCATED AT 250 WORDS)
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Available data indicate that pertussis remains an important disease during infancy and childhood, particularly among those who are inadequately immunized. Over the past 15 years, successful immunization programmes have been implemented in most countries in the world. Some problems have arisen in the industrialized world where pertussis had been well controlled previously. ⋯ All efforts should be directed to increase or maintain high immunization coverage with DPT immunization at the level of at least 90% in all districts. Surveillance of pertussis morbidity should be strengthened in all countries and ideally, pertussis should be a reportable disease. More information on the present epidemiological pattern of pertussis, especially age distribution of pertussis cases in developing countries, is needed to develop the policy of booster doses of DPT vaccine in children > 1 year.
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Poliomyelitis has been virtually eliminated from the industrialized countries by mass campaigns conducted with oral polio vaccine (OPV). In 1988, the World Health Assembly set the goal of global eradication of poliomyelitis by the year 2000. The current WHO strategy for eradication uses three primary activities beyond routine immunization with OPV. ⋯ Eradication of polio from the Region of the Americas is close and may have already been achieved. In other regions, the number of reported polio cases has declined, largely as a result of high immunization coverage. As more countries implement polio eradication strategies, the number of polio cases will continue to fall until eradication is achieved.
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Neonatal tetanus (NT) can be effectively prevented through immunization and clean delivery practices. However, NT claimed the lives of over 433,000 infants in 1991. It is endemic in 90 countries throughout the world. ⋯ NT consistently clusters in geographical areas and population groups where shared practices or the environment enhance the risk of cord contamination. 80% of the newborns who died of NT in 1991 were born in South-East Asia or Africa. Of the 90 countries endemic for NT, 10% produce 80% of the world's NT deaths. NT also clusters at country level.(ABSTRACT TRUNCATED AT 250 WORDS)