KALA-AZAR 153 



jaundice, rheumatic pains in the joints, and ulcers on 

 the skin. 



The tongue is singularly clean and the bowels are 

 inclined to be constipated. There is usually an undue 

 degree of thirst. Later on, however, diarrhoea or dysentery 

 sets in, the latter being the most common immediate cause 

 of death. Less commonly the patient dies, after several 

 months of illness, of asthenia ; or some intercurrent disease, 

 such as pneumonia, carries him off. 



In places where the disease is epidemic, patients will 

 not infrequently be met with who say that several of their 

 relations have died of a similar disease within the previous 

 year or two. 



The incubation period of kala-azar is not definitely 

 known, though it is probably long, some months having 

 elapsed in many instances between the departure of 

 patients from infected places and the onset of symptoms. 

 In experimental inoculation of the similar parasite in 

 Delhi boil the period may be five months or even longer. 

 Considerable difficulty in determining the incubation 

 period arises from the circumstance that sometimes the 

 onset of the disease is very insidious, while in many cases 

 the earliest symptoms are mistaken for those of malarial 

 fever, or of typhoid fever. 



Three stages of the disease are commonly recognized : 

 those of the initial fever, of the secondary low fever, and 

 of cachexia. 



These stages are not sharply marked off from one 

 another, for the acute pyrexial attacks of the initial period 

 become gradually less severe, until they merge into the 

 chronic irregular fever of the secondary period, and after 

 this has persisted for some months the cachectic con- 

 dition is established. There is a gradual loss of ground 

 throughout the course of the disease, though periods of 

 temporary improvement may occur. 



The initial fever may resemble typhoid fever (fig. 45), or 

 in other cases malarial remittent fever, commencing with 

 chills, or less commonly with a rigor, mounting to a 



