But we now know that its extension did not depend upon the
direct contact of the sick with the nonimmune individuals and that
isolation of the sick from such contact is unnecessary and without
avail. On the other hand, complete isolation from the agent which is
responsible for the propagation of the disease is all-important. In the
absence of a yellow fever patient from which to draw blood the mosquito
is harmless, and in the absence of the mosquito the yellow fever patient
is harmless--as the experimental evidence now stands. Yellow fever
epidemics are terminated by cold weather because the mosquitoes die or
become torpid. The sanitary condition of our southern seaport cities is
no better in winter than in summer, and if the infection attached to
clothing and bedding it is difficult to understand why the first frosts
of autumn should arrest the progress of an epidemic. But all this is
explained now that the mode of transmission has been demonstrated.
Insanitary local conditions may, however, have a certain influence in
the propagation of the disease, for it has been ascertained that the
species of mosquito which serves as an intermediate host for the yellow
fever germ may breed in cesspools and sewers, as well as in stagnant
pools of water.
Pages:
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382