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3 I NFECTED PEOPLE NECE SARY FOR SPREAD OF DISEASE.-All the favorable conditions for the disease may prevail in a given locality and yet no hookworm disease will exist, unless the egfls of the parasite have been deposited there with the f eces of some infected person and allowed to develop. Hence, in cities, where sewerage systems are used, or the night soil collected and hauled away, regardless of climatic conditions, we do not find the disease. RURAL SECTIONS FAVORABLE TO ITs SPREAD.-Elsewhere, on the contrary, where open privies and, far too often, no privies at all, are used, millions upon millions of eggs are scattered over the earth, and develop into minute, infecting worms ready to attack and vic~imize any accessible member of the human family_ In the Southern States all the factors n ecessary for the propagation of the disease are found. We have the warmth, moisture, oxygen, and infected people, who pollute the soil. North of the Ohio and Potomac rivers the climate is too cold and, in the arid West, too dry to favor the disease. In these sections, therefore, the' disease is rare. HOOKWORM DISEASE AFFECTS A "IMALs.-Dornestic and wild animals suffer from hookworm disease. Cows, dogs, cats, and foxes, and many other animals in certain localities, have been known to sicken and die in large numbers from hookworm disease. For man it is indeed fortunate that the hookworms found in such animals do not molest him. The hookworrn which infests man belongs to a type separate and distinct from those found in animals. These facts considered, let us now direct our attention to the hookworm as a parasite and a disease producing factor. THE HOOKWORM: ITS LIFE CYCLE. HOOKWORM ECGs.-The hookwonn (see Figs. 1 and 2) germinates from an egg. This egg (Fig. 3), with myriads of others, passes with the excreta from the bowels of an infected person. A lack of oxygen in the human intestine prevents its hatching until it has passed from the body. FIG R E 1. A male hookworm, n atural size. FIGURE 2. A female hookworm, natural size. (P. H. & M. H. Service.) SIZE OF EGG.-The egg is far too small to be seen by the unaided eye. It must be magnified a hundred times to be recognized. So small is it that in a portion of feces no larger than the head of a small pin two or three dozen eggs may be found. In shape, size and markings if differs distinctly from the egg of any other worm. It is oval, rather bluntly rounded at the ends. The yolk is dark in appearance and is surrounded by a clear, transparent zone which separates it from the shell.
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Title | Page 7 |
Full Text | 3 I NFECTED PEOPLE NECE SARY FOR SPREAD OF DISEASE.-All the favorable conditions for the disease may prevail in a given locality and yet no hookworm disease will exist, unless the egfls of the parasite have been deposited there with the f eces of some infected person and allowed to develop. Hence, in cities, where sewerage systems are used, or the night soil collected and hauled away, regardless of climatic conditions, we do not find the disease. RURAL SECTIONS FAVORABLE TO ITs SPREAD.-Elsewhere, on the contrary, where open privies and, far too often, no privies at all, are used, millions upon millions of eggs are scattered over the earth, and develop into minute, infecting worms ready to attack and vic~imize any accessible member of the human family_ In the Southern States all the factors n ecessary for the propagation of the disease are found. We have the warmth, moisture, oxygen, and infected people, who pollute the soil. North of the Ohio and Potomac rivers the climate is too cold and, in the arid West, too dry to favor the disease. In these sections, therefore, the' disease is rare. HOOKWORM DISEASE AFFECTS A "IMALs.-Dornestic and wild animals suffer from hookworm disease. Cows, dogs, cats, and foxes, and many other animals in certain localities, have been known to sicken and die in large numbers from hookworm disease. For man it is indeed fortunate that the hookworms found in such animals do not molest him. The hookworrn which infests man belongs to a type separate and distinct from those found in animals. These facts considered, let us now direct our attention to the hookworm as a parasite and a disease producing factor. THE HOOKWORM: ITS LIFE CYCLE. HOOKWORM ECGs.-The hookwonn (see Figs. 1 and 2) germinates from an egg. This egg (Fig. 3), with myriads of others, passes with the excreta from the bowels of an infected person. A lack of oxygen in the human intestine prevents its hatching until it has passed from the body. FIG R E 1. A male hookworm, n atural size. FIGURE 2. A female hookworm, natural size. (P. H. & M. H. Service.) SIZE OF EGG.-The egg is far too small to be seen by the unaided eye. It must be magnified a hundred times to be recognized. So small is it that in a portion of feces no larger than the head of a small pin two or three dozen eggs may be found. In shape, size and markings if differs distinctly from the egg of any other worm. It is oval, rather bluntly rounded at the ends. The yolk is dark in appearance and is surrounded by a clear, transparent zone which separates it from the shell. |