. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 110 TRYPANOSOMES AND SLEEPING SICKNESS different parasite. The real method of multiphcation was first discovered by Vianna in the bodies of man and animals who had died of the disease. Vianna found in various tissues, especially in the walls of the heart, the striped muscles, the central nervous system and various glands, greatly swollen cells which served as cysts, enclosing a mass of rapidly dividing trypanosomes, varying in number from just a few to many hundreds. In younger cysts the parasites are r
. Animal parasites and human disease. Medical parasitology; Insects as carriers of disease. 110 TRYPANOSOMES AND SLEEPING SICKNESS different parasite. The real method of multiphcation was first discovered by Vianna in the bodies of man and animals who had died of the disease. Vianna found in various tissues, especially in the walls of the heart, the striped muscles, the central nervous system and various glands, greatly swollen cells which served as cysts, enclosing a mass of rapidly dividing trypanosomes, varying in number from just a few to many hundreds. In younger cysts the parasites are round in form and exactly resemble Leishman bodies (Fig. 26A), while in older cysts the flageUum can be seen on many individuals and the trypanosome form becomes evident (Fig. 26B). When the enclosing cell has swollen to the bursting point, the swarming mass of trypanosomes is liberated. Each parasite, unless destroyed, then penetrates a new cell somewhere in the body, usually near where it originated, and begins the process of reproduction again. Only in the early acute stage of the disease can the parasites live in the blood, since the blood serum rapidly reacts by the formation of antibodies,- and be- comes deadly to trypanosomes. Chagas believed that the para- sites could Uve within the corpuscles as well as in the serum, but later work does not confirm this. On account of the development of antibodies in the blood serum, the parasites are very seldom found in the blood of chronic cases of the disease, though their cysts may be abundant in various tissues and glands in the body. Fig. 27. Trypanosoma cruzi in Life CyclC in BugS, and TranS- biood of ape said to be inside cor- njigsion. — The intermediate host puscles. (After Chagas.) of Trypanosoma cruzi is a large black and red bug, Triatoma megista, known to the natives as "; It is related to the cone-nose, Triatoma sanguisuga, of our southern states. The barbeiro is a fierce blood-sucking insect which i
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