. Animal parasites and human disease. Insects as carriers of disease; Medical parasitology. GUINEA-WORM IN CYCLOPS 313. Fig. 132. Cyclops sp. (?), some species of which serve as intermediate hosts of guinea- worms. X about 25. suicide. The repeated birth of a Umited number of progeny each time the skin of the host comes in contact with water is therefore a successful solution to a problem which to a bhnd burrowing unmeditative worm must otherwise present insuper- able difficulties. ^V^len all her 3^oung have been deposited, under the stim- ulus of contact with water, the parent worm shrivels a
. Animal parasites and human disease. Insects as carriers of disease; Medical parasitology. GUINEA-WORM IN CYCLOPS 313. Fig. 132. Cyclops sp. (?), some species of which serve as intermediate hosts of guinea- worms. X about 25. suicide. The repeated birth of a Umited number of progeny each time the skin of the host comes in contact with water is therefore a successful solution to a problem which to a bhnd burrowing unmeditative worm must otherwise present insuper- able difficulties. ^V^len all her 3^oung have been deposited, under the stim- ulus of contact with water, the parent worm shrivels and dies and is soon ab- sorbed by the tissues on which she formerly preyed and through which she roamed. The embrj^o worms, safely deposited in water, unroll themselves and be- gin to swim about in a fashion peculiar to them- selves. Their bodies are somewhat flattened and they have a slender tail. Thej^ swim by a few quick sculling motions of the tail, followed by a pause, then a few more strokes, etc., in the manner of a tadpole. In turbid water they remain alive for two or three weeks but eventually perish unless they come in con- tact with a Cyclops, into the body of which they make their way. They usually enter by way of the mouth, sometimes as many as six or ten entering a single Cyclops. In a day or two they leave the stomach of Cyclops and enter the body cavity. In spite of the relatively large size of the worms the crustaceans seem to feel very little inconvenience, and seldom succumb even to very heavy infection. The young guinea-worms become fully developed in Cyclops in from four to six weeks, according to the temperature, mean- while having undergone one and perhaps two moults. They are then about one mm. (^V of an inch) in length, and ready to in- fect a new host. Entrance to the new host is probably accom- plished by the accidental drinking of a Cyclops with unfiltered water. The female worms become adult in their new host in about a year so the larvae can again
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmedical, bookyear1918
