EPIDEMIOLOGICAL, CLINICAL, AND PATHOMORPHOLOGICAL CHARACTERISTICS OF EPIDEMIC POLIOMYELITIS-LIKE DISEASE CAUSED BY ENTEROVIRUS-71

  • 1 January 1979
    • journal article
    • research article
    • Vol. 23  (3) , 284-295
Abstract
In May-Sept. 1975, an outbreak of epidemic disease clinically and pathomorphologically simulating nearly all known forms of poliomyelitis occurred predominantly among young infants in Bulgaria. Most cases presented benign aseptic meningitis, sometimes with a short period of general cerebral symptoms. Paralytic forms, such as bulbar polioencephalitis, anterior poliomyelitis, isolated pareses of the facial nerve, occasional cases of encephalomyocarditis, etc., were observed in about 21% of all cases. Over 1/4 of the paralytic cases with bulbar symptoms ended fatally. In March 1976 another sporadic fatal case of this disease was examined. No new cases occurred in 1977. Histopathological examinations in all fatal cases regularly revealed lesions in the grey matter of the medulla and spinal cord typical of acute anterior poliomyelitis and bulbar polioencephalitis, with some peculiar features of localization and depth of the involvement of the brain stem. The similarity to poliomyelitis and the precariously rapid increase in the incidence led to the decision to vaccinate the entire human population with Sabin''s live poliovirus vaccine simultaneously in the whole country to produce interference with the circulating agent. Although this appeared to have been partially achieved because soon the number of new cases began to decrease, no sharp and complete break in the incidence curve occurred. By the time of mass vaccination, the results of virological examinations were not yet available. Later, comprehensive complete evidence was obtained that over 25 fatal and many other typical cases of the disease were associated with an enteriovirus antigenically related to enterovirus 71. The diseases in Bulgaria in 1975 differ considerably in the frequency of paralytic forms and in severity from epidemics caused by enterovirus 71 in Sweden in 1973, Australia in 1972-1973, USA in 1969-1972 and Japan in 1972-1973.