Poliomyelitis in Laos, 1962–1963 Epidemic and immunity survey》.pdfVIP

T R O P I C A L P E D I A T R I C S Poliomyelitis in Laos, 1962-1963 E p i d e m i c a n d i m m u n i t y s u r v e y A poliomyelitis outbreak occurred among young children in Laos between October, 1962, and March, 1963. These children lived in towns in which no sanitary improvements or changes in pattern o[ li[e had been made. Postepidemic immunity studies suggested that polioviruses had been spreading extensively and that paralytic polio type 1 occurred at epidemic proportions in a population which normally might be expected to have a low incidence of paralytic disease. The occurrence and virulence o[ the 1962-1963 Laos outbreak can perhaps be explained by changes in the virulence o[ the prevalent polioviruses. Karen N. Olness, M.D., ~ Scott B. Halstead, Major, MC, USA, and Rapin Snitbhan, M.D. WASI-IINGTON, D. G. P A R A L Y T I C P O L I O M Y E L I T I S OUt- to survey immunity of a given population to breaks in developing areas of the world have poliomyelitis: Numerous immunity surveys been reported with increasing frequency have been conducted in recent years? 2-19 during recent years. 1 Some authors be- On the basis of these surveys, authors have lieve that this increase in poliomyelitis en- observed deficiency of one or more types of demicity and/or epidemicity is on the basis polio antibodies suggesting a pre-epidemic of improved sanitation, with resultant post- critical susceptibility or, retrospectively, have ponement of first exposure to the poliovirus. been able to decide what type of poliovirus Others pos