416 AGRICULTUEAL AND INDUSTRIAL BACTERIOLOGY 



of the mosquito, when they are inoculated into the person 

 bitten by the mosquito. It requires from 8 to 10 days from 

 the time the mosquito bites a person having the malarial 

 parasite in his blood until the mosquito can in turn trans- 

 mit the disease to another individual. 



The disease is commonly known as ague or chills and 

 fever. It is characterized by chills followed by fever at 

 intervals of 48 hours. During the period between attacks 

 of chill and fever the temperature is normal. It is interest- 

 ing to note that the chill and fever occur at the time when 

 the merozoites are breaking out of the red cells and attack- 

 ing new red blood corpuscles; 



The description given applies to Plasmodium vivax. In 

 quartan malaria the interval between paroxysms of chills 

 and fever is 72 instead of 48 hours. In the tropical type of 

 malaria, two forms are known, one in which the life cycle is 

 completed in 24 hours and fever consequently appears 

 daily, and a tertian type in which the fever occurs every 

 48 hours. 



Inasmuch as the disease can be transmitted only by the 

 bite of infected mosquitoes, it can be eliminated only by 

 preventing the breeding of these insects or by preventing 

 their transmitting the germ from infected individuals to 

 those who do not have the disease. Since mosquitoes breed 

 in stagnant water the disease has been eradicated in many 

 localities by drainage, by the use of oil on the surface of 

 water and by the introduction of fish which feed upon the 

 larvae of the mosquito. 



The Genus Eimeria (Coccidium) 



The organisms belonging to this group that infect animals 

 or man are intestinal parasites. The adult cells are oval 

 or spherical and not motile. The life history is quite com- 

 plex and varies with the different species. The most im- 

 portant form in North America probably is the Eimeria 



