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Density of Parasites in Various Organs and the Relation to Numbers of Trypomastigotes in the Blood during Acute Infections of Trypanosoma cruzi in Mice *
Author(s) -
HANSON WILLIAM L.,
ROBERSON EDWARD L.
Publication year - 1974
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1974.tb03689.x
Subject(s) - cecum , biology , ileum , duodenum , jejunum , stomach , anatomy , spleen , trypanosoma cruzi , lymph , pathology , medicine , endocrinology , immunology , parasite hosting , ecology , biochemistry , world wide web , computer science
SYNOPSIS Quantitative methods were used to (a) determine the density of Trypanosoma cruzi in organs of CF 1 mice following intraperitoneal inoculation of 50,000 trypomastigotes of a Brazil strain of T. cruzi and (b) study the relation of the numbers of these intracellular stages to the numbers of trypomastigotes in the blood. Tissue stages (predominantly amastigotes) in heart, skeletal muscle (triceps), diaphragm, cerebrum, cerebellum, and musculature of stomach, duodenum, esophagus, jejunum, cecum, and rectum increased in numbers during the 1st 3 weeks of infection, reached maximum density 21–28 days after inoculation and subsequently declined in numbers until mice were histologically negative for intracellular parasites by 30–40 days. The density of tissue stages in the urinary bladder, uterine body, and ileum was similar with the exception that maximum numbers of parasites were observed slightly earlier at 15 days. The greatest density of intracellular stages was seen in heart, urinary bladder, diaphragm, and triceps muscle where mean counts of 44.6–60.0 × 10 6 parasites/cc of muscle were recorded while maximum density of parasites in the uterine body, cerebrum, stomach, cerebellum, duodenum, esophagus, jejunum, ileum, cecum, and rectum was 13.0 × 10 6 /cc of muscle or less. Amastigotes were not observed in sections of lymph node, thymus, salivary glands, liver, spleen, or kidney and only a single pseudocyst containing 5 amastigotes was seen in lung. With the exception of the brain and lung, intracellular parasites were located exclusively in the musculature. Trypomastigotes in the blood increased during the 1st 3 weeks of infection, reached maximum numbers 21–28 days after initiation of infection, and subsequently decreased until by 30–40 days parasites were observed only rarely in the blood of a few animals. Thus generally close correlation was noted between the numbers of intracellular stages of T. cruzi in the organs and trypomastigotes in the blood throughout acute Chagas’ disease in mice as evidenced by the concomitant increase in numbers of both stages, the coincidence of days of maximum parasite levels, and the simultaneous decline in numbers of both stages. The mean number of parasites/pseudocyst section varied in the organs studied. Of the 15 positive organs studied, the pseudocyst sections in skeletal muscle contained the highest mean number of parasites (64.3 parasites/pseudocyst section) and those pseudocyst sections seen in the musculature of the small intestine contained the lowest mean number (5.5–6.8 parasites/pseudocyst section respectively in ileum and jejunum). Serial sections of skeletal muscle, heart, urinary bladder, and stomach revealed the largest pseudocysts in skeletal muscle while those in the musculature of the urinary bladder were the smallest.