616 Malaria 



or else a relapse. As the infection progresses, duration of the vivax rigor 

 may increase from 5-10 minutes to 1-3 hours. In quartan malaria, rigors 

 usually begin with temperatures of less than 100° F., although a tempera- 

 ture of 103-104° sometimes follows the first one. However, a rigor is not 

 always present in the quartan paroxysm. The paroxysm of malignant 

 tertian is often initiated by a sensation of chilliness, and in perhaps less 

 than a third of the cases, by a definite rigor. The factors inducing the 

 rigor are not definitely known. The appearance of specific toxins has not 

 been demonstrated, and similar symptoms can be induced by intra- 



105-1 



103 



101 



no r- 



97- 



95 



mQlignani f erf fan - 

 guar fan 

 f erf /an 



DAYS 



Fig. 13. 7. Diagrammatic comparison of temjierature curves in malignant 

 tertian, quartan, and tertian malarias. 



venous injection of foreign proteins or denatured normal serum. The 

 merozoites and residual protoplasm released at merogony presumably 

 could serve as such foreign proteins. 



The fever stage overlaps the rigor. The temperature begins to rise 

 well before the end of the chill, or even near its beginning. As a result, 

 the patient soon feels hot instead of cold. Although duration of the fever 

 is variable, most of the surviving merozoites have penetrated corpuscles 

 before the fever disappears. In the vivax paroxysm, the fever may last 

 for 3-6 hours and the temperature curve (Fig. 13.7) generally shows an 

 abrupt rise, a sharp peak and a fairly rapid decline. A progressive de- 

 crease in the temperature peaks may be expected toward the end of a 



