Malaria 599 



Canadian shores of Lake Erie. On the eastern coast, malaria was still 

 common in the Hudson River valley and along the shores of Long Island 

 Sound. Although it is uncertain when malaria reached the Pacific, the 

 early migrants evidently brought the disease overland to the lower 

 Columbia River valley and the Sacramento-San Joaquin valley in Cali- 

 fornia. An outbreak of chills and fever, possibly malaria, appeared among 

 the Indians of the Fort Vancouver region in 1829. Within three years, 

 about 90 per cent of the Indians had been exterminated. Another severe 

 epidemic, thought to have been malaria, attacked the California Indians 

 in 1833. The discovery of gold, which stimulated overland migration, 

 accelerated the introduction of new malarial strains. 



In most of these malarial areas, epidemic outbreaks occurred only 

 during the warmer months of the year, but the situation in the southern 

 and southeastern states was more serious. The status of malaria in the 

 southern states is reflected in the fact that, from 1841 to 1847, 25.8 per 

 cent of the patients admitted to Charity Hospital in New Orleans were 

 suffering from malaria.^ For the United States as a whole, malaria seems 

 to have reached a peak about 1855, and the next few years showed a 

 gradual decline in incidence. 



The Civil War interrupted this trend by introducing relatively sus- 

 ceptible Federal troops into malarial regions of the South. Movements 

 of the Confederate armies also contributed to the spread of malaria. 

 Information concerning malaria in the Confederate armies is scanty, but 

 it is known that the white Federal troops developed 1,163,184 cases of 

 malaria from May, 1861, to June, 1866. 



Immediately after the Civil War, outbreaks of malaria increased in 

 some parts of the South, and it is likely that Federal troops also took 

 southern strains of the parasites home with them. Malaria broke out 

 in Connecticut, for example, and spread into Rhode Island and Mas- 

 sachusetts, the outbreak reaching a peak in 1881. In the South, increased 

 incidence of malaria was favored by unsettled conditions. Failure of 

 drainage systems extended the breeding grounds for mosquitoes, and 

 the partial failure of southern agriculture led to much undernourishment 

 with increased susceptibility to malaria. During the period, 1870-1900, 

 malaria was still important in many areas now more or less free from 

 the disease — Indiana, southern and northern Illinois, southeastern Kan- 

 sas, Ohio and Michigan along the shores of Lakes Erie and Ontario. 

 Cases were still fairly common in Philadelphia, on Manhattan Island, 

 and in Massachusetts. 



Toward the close of the century, the incidence of malaria once more 

 began to drop. This trend has continued, and the recession has been 

 marked by the almost complete disappearance of malaria north of the 



- By way of contrast, malaria accounted for only 0.58 per cent of admissions to the 

 same hospital for the period, 1933-1940. 



