effect of the rapid and extreme degree of blood destruction occurring at the early stage of the disease. A paratyphoid bacillus having pathogenic properties has been isolated at this stage; it, too, vanishes on the appearance of the eruption. Chlamydozoa-like bodies have recently been described as occurring in certain spindle cells in the verruga tumours.
The disease is most prevalent during the summer months when the streams are in flood, the air hot, still, and moist, when malaria is epidemic, and when insect life is abundant. An insect transmitter is suspected, but as yet not determined. Townsend, who has made special studies locally on this point, dismisses ticks, bugs, and the ordinary human ectozoa, and inclines to regard a species of phlebotomus as the carrier.
Pathology,— A remarkable feature of this disease is the rapidity and extreme degree of blood-destruction. In bad cases the blood-count may drop in three or four days to 500,000 per c.mm., the picture being that of a pernicious anæmia. There is a marked polymorphonuclear leucocytosis with disappearance of eosinophiles; and during the later eruptive stage an eosinophilia with a mononuclear leucocytosis.
The granuloma begins as a neoplasm round the capillaries and resembles in its histology that of yaws (p. 665).
Symptoms.— The peculiar initial rheumatic-like pains and fever are apparently the same in character as those of yaws, only more severe, and, as in yaws, the constitutional symptoms subside on the appearance of the skin lesion— a granuloma macroscopically as well as microscopically identical with that of yaws. Just as in the latter disease, the eruption may be sparse or abundant, discrete or confluent. As in yaws, individual granulomata may fail to erupt; others may subside rapidly; others, again, may continue to increase, and then, after remaining stationary for a time, gradually wither, shrink, and drop off without leaving a scar. If difference there be in their clinical features between verruga and yaws, apparently it is more one of degree than of kind.
