From Big Medical Encyclopedia

PANDEMIC (pandemia; grech, pandemia all people in general) — extraordinary strong epidemic which extended to territories of the countries, continents; the highest extent of development of epidemic process.

Items of various diseases since ancient times devastated the cities and the countries; therefore they became history under such names as «a general disease», «a morovy ulcer». Three largest P. of plague are known: «Justinian's plague» (6 century), at a cut died apprx. a half of the population of Byzantium; plague of 14 century («black death»), at a cut from 100 million population of Western Europe 25 million died; the pandemic of plague of 19 — 20 centuries which captured China, India, Eastern Europe and America.

7 pandemics of cholera are described. The first the Item (1817 — 1823) extended from India to Ceylon, China, Japan, the Middle East and Russia. The second the Item (1828 — 1837) captured India, China, the Middle East, the European part of Russia, Western Europe, America, Australia. During the third the Item (1844 — 1864) cholera extended from India to China, the country of the Middle East, Russia, America. The fourth the Item (1865 — 1875) captured China, Japan, Europe, Russia. At the fifth the disease passed the Item (1883 — 1896) through Iran, Central Asia to Russia, Turkey, Western Europe, at the sixth (1900 — 1926) — from India to China, Japan, Russia, and then to Europe and America. In the specified years the number of patients with cholera made millions. The feature the seventh P. which began in 1960 is change of the activator — a classical cholera vibrio on a vibrio El-Tor.

P. of flu are not less known. In 1580 the disease captured Asia, Europe and America. In 18 century there were seven P. of flu. In 20 century (1918 — 1920) so-called «Spaniard» was registered in Europe, Russia, America, China, India. The death toll from «Spaniard» is estimated in 20 million people. In 20 century also other P. of flu were noted.

Pandemic distribution in the past was quite often accepted by such infectious diseases as natural smallpox, malaria, a sapropyra, etc.

Extent of distribution inf. diseases, including and pandemic (see. Epidemic ), it is caused by the various reasons: the index of contageousness determined by pathogenicity of the activator and a susceptibility of the person to an infection; frequent antigenic variability of the activator (e.g., influenza virus); in the ways of transmission of infection (there is P. inf more often. the diseases which are transmitted in the airborne way); tension of immunity in collective; brevity of an incubation interval (e.g., at plague, flu and, etc.); population density; extent of contact мея^ду people; intensity of the international political, cultural and commercial relations; development of high-speed automobiles; wars, emigration, pilgrimage; besides, scientific and economic opportunities in fight against epidemics are of great importance.

Achievements in the field of medicine and sciences, adjacent to it, scientific validity protivoepid, actions, led emergence of means of specific prevention to the fact that pandemic distribution inf. diseases to the middle of 20 century practically stopped. The exception makes flu — a disease with a high index of contageousness, an effective airborne way of transmission of infection, often low level of tension of collective immunity as a result of antigenic variability of an influenza virus, a short incubation interval. Due to the high epid, potential of the flu extending as chain reaction in the conditions of dense population of the cities and use of high-speed transport, organizational and all-sanitary actions often are ineffective.

Bibliography: Baroyan O. V. Results of semicentennial fight against infections in the USSR, page 9, M., 1968; Gromashevsky L. V. General epidemiology, M., 1965.

S. P. Burgasov.