Instructions for the prevention of malarial fever : for the use of residents in malarious places.

Date:
1900
Catalogue details

Licence: In copyright

Credit: Instructions for the prevention of malarial fever : for the use of residents in malarious places. Source: Wellcome Collection.

    12/28 page 2
    of parasites may increase again, either spontaneously or because the patient has exposed himself to the sun, or to chill, fatigue, and so on. Such relapses may occur even many years after the patient has left the malarious locality where he acquired the original infection—as, for instance, after his return from Africa to England. Between the relapses the parasites continue to live in him in comparatively small numbers ; but, of course, after they have once become quite extinct, no relapses will occur— unless as the result of a fresh infection. Besides fever, the parasites often cause other symptoms, such as enlargement of the spleen, anaemia, and darkening of the skin. Quinine kills the parasites. 2. How Parasites in general Live.—Men, animals, or plants in which parasites live are called their hosts. All parasites or their eggs pass, in some way or other, from one host to another—that is, from an infected man, animal, or plant, to a healthy one. Parasites have many different and, so to speak, ingenious ways for effecting this transference. A large number of them employ a second species of animal as a go-between. Thus tape-worms and the worms which cause trichinosis live a part of their lives in swine as well as in men. Swine eat human offal, and men eat swine ; and these parasites thus transfer themselves alternately from the one to the other. Insects are often employed in this manner. Thus dogs often have a minute worm in the blood which enters the dog’s flea, and returns to the same or another dog when this flea happens to be swallowed. Again, guinea-worm is carried by a water-insect; and the worm which causes elephantiasis is carried by mosquitoes. We know also two important diseases of cattle, called Tsetse-fly disease and Texas tick-fever, which are carried, one by the Tsetse-fly and
    digitised image 1
    digitised image 2
    digitised image 3