80 LEISHMAN BODIES AND LEISHMANIASIS 



the body fluids. They enter the deHcate endothelial cells which 

 line the blood and lymph vessels, and also the cells of the spleen, 

 Hver and lymph glands. Within the cell they have entered 

 they grow and multiply rapidly (Fig. 14C and D). The indi- 

 vidual parasites (Fig. 14A) are exceedingly small, about two /* 

 (less than y^t^To °^ ^^ inch) to four /j, in diameter. They are 

 round or oval in form with a large nucleus and a smaller para- 

 basal body shaped like a little rod and set more or less at a tan- 

 gent to the nucleus. 



In a short time, by dividing and re-dividing, the Leishman 

 bodies completely fill the cell they inhabit, causing it to enlarge to 

 many times its normal size (Fig. 14C). There may be as many 

 as several hundred parasites in a single enlarged cell. The 

 parasitized endothelial cells often seem to " run amuck," breaking 

 loose from their normal position on the lining of bloodvessels 

 and becoming free-living carnivorous cells like the white blood 

 corpuscles. When these parasite-filled cells finally burst, the 

 liberated parasites enter new cells, or are gobbled up by the 

 white blood corpuscles (Fig. 14E). It is probable that the para- 

 sites are ingested by bedbugs while inside free endothelial cells 

 or white corpuscles in the blood. 



The Disease. — The incubation period of kala-azar after in- 

 fection is not definitely known, but Manson cites one case where 

 an Englishman was attacked by a fever, which terminated in 

 kala-azar, within ten days after arriving in an endemic locality. 



A high fever usually marks the onset of the disease, and this 

 persists more or less irregularly for several weeks. Meanwhile 

 the spleen and liver enlarge enormously, increasing and decreas- 

 ing with the fluctuations of the fever. After several weeks the 

 fever drops and the patient becomes almost normal fot some 

 time, only to be attacked by the fever again, with an enlargement 

 of spleen and liver. These remittent attacks gradually dwindle 

 to the steady low fever, accompanied by sweating spells, rheu- 

 matism-like aches, high pulse rate, anemia and a general wasting 

 away, with the skin often a dark earthen color. Dysenteric 

 symptoms, with discharges of blood and mucus, are common, 

 especially in the late stages of the disease, and frequently after 

 death the intestine is found to be extensively ulcerated, with 

 numerous parasites in the walls of the ulcers. Parasites are 

 usually found most abundantly in the spleen, liver capillaries. 



