Year: 1967
Type: article
Abstract: The mosquito-borne viruses of the Pacific area which have caused epidemics in the recent past, exclusive of dengue and chikungunya viruses, are Japanese encephalitis, Murray Valley encephalitis, Venezuelan encephalitis, Western and St. Louis encephalitis, Ross River virus in Australia and yellow fever virus.By far the most important and major cause of epidemics from this list of viruses is Japanese encephalitis.The distribution in the Pacific of Japanese encephalitis is Japan, Okinawa, eastern U. S. S. R., Korea, China, Taiwan, the Philippine Islands, an undetermined number of countries of Southeast Asia, and India.The magnitudes of recent epidemics of Japanese encephalitis in the Pacific in the past five years are shown in Table 1.These data are admittedly somewhat inaccurate since they represent mostly clinically diagnosed cases from government records.Nevertheless in Japan this disease has involved at least 1200-2600 people during the last five years, with deaths fluctuating between 500 and 1300 or approximately 40-50 % of the cases.There are, of course, some other central nervous system diseases such as those caused by enteroviruses, included in these figures, but they still are a good reflection of Japanese encephalitis in Japan where there exists a relatively pure culture of the virus not contaminated by numerous other arboviruses.In Okinawa and eastern U. S. S. R. there have been fewer cases probably chiefly because total human populations are less than in Japan.However, in Korea, yearly fluctuations similar to Japan occurred during the past five years.The lowest year was 1963, with only 77 recorded cases, and again in 1964 when Japan was having a peak year, Korea recorded nearly 3,000 cases of Japanese encephalitis, and over 900 deaths (about 30 %).Certainly 1964 seemed to be a big year for Japanese encephalitis in northern parts of the Far East.No information is available concerning continental China, but in Taiwan, in contrast to Korea and Japan, there has been a fairly constant number of recorded cases, roughly 400-700 each year, with between 80 and 150 deaths.No cases were recorded in the Philippine Islands during the last five years, which may not mean that Japanese encephalitis is nonexistent in the Islands, but at least it means that there has not been a large recent epidemic.Thailand is the only country with any kinds of estimates for Southeast Asia.Dr. S. Halstead studied about 90 cases in Thailand in 1964 and Dr. P. Russell found about 30 cases with at least 3 deaths in 1965, some additional cases this year, and a few recent cases in South Vietnam.Dr. Carey and others have found cases of Japanese encephalitis in southern India in Madras State, but the numbers of cases have been less than 10 per year.Thus Japanese encephalitis in epidemic proportions occurs mostly in the temperate zones of the Far East, though the virus is endemic in the tropical regions.
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4250398254