EPIDEMIOLOGY OF INFLUENZA 480 



Between 1729 and 1733 the disease, traveling from Russia west- 

 ward, spread over Europe in two great waves, one in 1729 and the 

 other in 1732. 



Another epidemic started on the shores of the Baltic in 1742. 



In 1757 1758 1 , 



-.^o Epidemics occurred ot which we have but poor 

 17ol -Ubz \ , . , 



geographical records. 

 1767 J 



Of the epidemic of 1742, Friedrich states that all but about one- 

 tenth of the entire population of Germany was attacked. 



From 1781 to 1782 an epidemic supposed to have started in China 

 spread through Siberia to Russia and thence to Europe. 



Another traveled approximately the same route in 1788. 



The same thing occurred between 1799 and 1803. 



In 1827 there was an outbreak in Europe less extensive than 

 most of the others. 



Between Iy330 anc i ig33 there were two or three pandemic waves, 

 the first one supposedly originating in China. 



Other outbreaks, again traveling from East to West, occurred 

 in 1836 and 1847. During this epidemic the Prussian Army is said 

 by Friedrich to have been attacked in its entire personnel. 



These brief data, which bring us up to the pandemic of 1889, are 

 condensed chiefly from Leichtenstern. 11 



The characteristics of influenza epidemics are summarized by 

 Leichtenstern in a manner which can be accepted as roughly describ- 

 ing the actual facts on the basis of experience with the last war- 

 epidemic. 1. The disease appears in true pandemic waves; 2, it 

 travels with tremendous speed over the globe ; 3, it is characterized 

 by sudden mass infection; 4, it is rapidly burnt out after several 

 weeks in one locality; 5, it is independent of season or weather; 

 6, it begins at first with an enormous morbidity and a relatively 

 slight mortality; 7, it is but slightly influenced by age, sex, or 

 occupation. 



The second characteristic which we have mentioned, namely, that 

 the disease seems to originate in one particular part of the world 

 and from there spreads out (such foci having been also described 

 as existing in Asia (Netter), China (Pearson), etc.), is at the present 

 time somewhat in dispute, Frost 12 and others believing that the 

 last two epidemics probably started in several places at once. 



11 Leichtenstern, Influenza in the 19th Century, 2nd Edit., Sticker, Leipzig, 1912. 



12 Frost, U. S. Public Health Serv. Eep., No. 550, August 15th, 1919. 



