SPOROZOA 



Plasmodium vivax 



463 



Disease Produced. Tertian malaria in man. 

 Distribution. This is the commoner malaria of temperate 

 climates. 



EXOGENOUS 



OR 



-3EXLJAU 



Fig. 204. Diagram illustrating the life-cycle of the malarial parasite: 

 A, Sporozoites entering a red blood-cell; B, C, D, E, the organism in various 

 stages of development; F, G, the formation of sporocytes and their division 

 into spores which infect new red blood-cells. The series A to H represents 

 the cycle through which the organism passes in the human body; /, infected 

 red cell ingested by a mosquito. The organism may now develop through the 

 series /', K', L', M', to form microgametocytes and microgametes or through 

 /, K, L, Af , to form a macrogamete which unites with a microgamete to form 

 a fertilized ovum; P, the organism penetrates the stomach-wall of the mos- 

 quito and develops through the stages Q, R, S, T, U. From U large numbers 

 of slender spores are liberated into the body cavity. These pass to the salivary 

 glands of the mosquito and are injected when the insect again bites (Rees). 



Morphology and Life-history. The organism when first 

 recognized in the blood is small, with ameboid movements. It 

 penetrates the red blood-corpuscle, and develops until the interior 



