The principal pathological change produced by the hookworm consists in a profound anaemia, characterized by a great diminution in the hsemaglobin or coloring matter of the blood. In the young— who are unfortunately the most common sufferers — the alterations of the blood cause a retardation of development in every part of the body, and if the infection per sists, as is often the case, the victim is per manently stunted,— being often left for life a dwarf both mentally and physically.
.::Where the worms attach themselves to 'the nitscous membranes of the gut there is a local lesion, with more or less destruction of the epithelial coating, surrounded often by an area of swelling and redness. In some instances this process goes on until small ulcers are formed on the inner surface of the intestine. Of course under such circumstances there are found sometimes extensive inflammatory de posits in the mucosa, and even in the submucosa of the wall of the gut. Among the morbid changes produced by the parasite the dermatitis induced by its larva as they pass through the skin should not be fdrgotten. The symptoms produced by the presence of the hookworm in the alimentary canal of the human being may be in a general way inferred from what has been said of the pathological changes brought about by the parasite; naturally, the number of worms present in the in .1 tract—which may be from a very few to several thousand and the age and size of the individual attacked modify more or less their severity. No greater mistake could be made, however; than to as sume that such influences completely control the clinical picture, since individual susceptibility to the malign influences exerted by the parasite largely determines the severity of the resultant symptoms. On the other hand the degree of dermatitis produced is doubtless greatly in fluenced by the number of the larva that pass through the skin, but even here it is more than probable that some individuals react more pro nouncedly than others. It is of importance to emphasize the fact that where the individual has a light infection, or where there is a high degree of resistance to the disease-producing power of the parasite, few and insignificant symptoms may occur, and the victim may be only slightly indisposed, or even appear to be in l rfcct health. This is particularly apt to be the case in the negro. Under such circum stances, however, the matter should not be treated lightly, since such persons act as car riers of the disease, and are a grave menace to their neighbors under certain circumstances. When hookworm larva: in any considerable numbers attack the skin there is a feeling of irritation and burning, which is quickly fol lowed by swelling, an increase in the uncom fortable symptoms and a severe itching. In from 24-36 hours there form in the affected area small blisters, which, when numerous, are apt to coalesce; in another day the vesicles be come pustules, as a result of their watery con stituents becoming infected with the germs of suppuration. The tops of the pustules become scabs, and gradually fall off, leaving the raw surface beneath, and in effect forming sores; slowly these heal, so that in from two to three weeks, as a rule, the parts return to a normal condition,— though leaving the surface at tacked more or less discolored. The condition described is the so-called °ground itch." In the meantime no general effects are observed in the patient, except that at first the lymph nodes, or *glands,* are enlarged and tender in affected area, and there may be a slight rise in temperature, lasting only a short time. Follow ing this the victim appears to return to a per fectly normal condition,— it being six weeks or two months before he begins to exhibit the symptoms that result from the presence of the worms in the intestine. If the number of worms be sufficient and the patient does not de velop sufficient immunity there now begins a gradual decline in strength and general health of the' infected individual, accompanied by a certain amount of pallor, which may in extreme cases become the most prominent objective symptom of the affection. Usually the patient complains of slight tenderness and pains in the upper part of the abdomen, not uncom monly associated with more or less indigestion, and often constipation as well. The victim is often sluggish, and frequently, though by no means always, shows a disposition to avoid exertion of any character, but this is simply the result of a want of physical strength, which by no means warrants the somewhat unflatter ing characterization of "laziness,l' which has been so commonly and indiscriminately be stowed on it. Where the disease is severe the patient may in time become so weak that all labor is impossible,— not infrequently ac centuated by a shortness of breath that be comes manifest on the slightest exertion. In such cases the feet, legs, face and other parts of the body often become oedematous, and col lections of fluids may occur in the abdomen, pleural cavity, the pericardium and other serous sacs. As is the case in other profound anemias the patient looses little or no flesh. Where conditions such as those just described occur, death may result if the parasites are not expelled. On examination the blood shows in teresting but no characteristic changes. In severe cases there is a great and even extraor dinary diminution ire the red coloring matter of the blood—being sometimes as much as 90 per cent — but strange to say there is no corre sponding decrease in the number of the red cells, which are carriers of the coloring matter just mentioned,—in this respect resembling the alterations that occur in the ,peculiar anaemia of young girls called chlorosis; however, if the disease persists for a long time there is a very gradual falling off in the red cells, but even in such instances the number of these cellular ele ments rarely go below 50 per cent. In the average case of hookworm disease the number of red cells will be from 3,000,000-4,500,000 to the cu.mm. of blood. There are no marked
changes in the white cells,— though there is generally a slight increase in their number; not usually there will be found on examina tion the normal 6,000 cells to the cu.mm., but much more commonly there are 8, 9, 10 or even as many as 18,000. Differential count usually shows nothing but an increase in the osinophile cells,— they being generally from 5-8 per cent of the total number. The most striking and wholly pathetic effects of the hook worm are observed in the young. Where the parasite attacks its victims in early youth, and infection constantly recurs during the succeed ing years, it would be difficult to imagine that anything could produce more frightful results. In addition to the symptoms already described the wretched victim almost wholly ceases to de velop, and usually remains throughout life dwarfed, and a pitiful travesty on humanity. Under such circumstances the sufferer when between 20 and 30 may appear a youth of not more than 8 or 10, without beard, or hair about the pubes, physically weak and incredibly stupid; close inspection shows the skin of the (ace yellow and wrinkled, with a suggestion of old age, altogether at variance with an other wise boyish appearance. It is, of course, true that by no means all of the victims of this malady exhibit such terrible effects of the in fection, but even where the worms are gotten rid of comparatively early a failure to develop and a scanty beard are apt to remain through out life. Notwithstanding the serious character of this malady the prognosis is good if its true nature be discovered, and the proper remedies applied. Recovery almost invariably follows where the parasites are expelled, but con valescence is always slow,— it usually requiring from six to eight months for the sufferer to regain his normal health. The prophylaxis is simple. All that is necessary is for the stools to be passed in a properly constructed water closet, and adequate means taken to prevent the feces being scattered about the premise_ Those living in hookworm districts should be instructed as to the danger of children deficat ing in the horse-lot, in the garden and in other places in the neighborhood of their houses,—a habit very common among the negroes and poor whites in the backwood districts of the South Likewise the curing of those infected is of the first importance, as so long as they have the disease they are a constant source of danger to those with whom they live. The treatment is also very quick and simple. The day before the treatment is to beliven the patient must take no evening meal. It is good practice to give at bed time a dose of some good purgative. such as calomel or castor oil, and if it does not act well before morning a saline laxative should be administered as soon as the patient awakes. After the bowels act well the real treatment for expelling the worms is taken; of such drugs we have several. Perhaps the best and safest is oil of chenopodium, either alone or combined with 10 drops of chloroform with each dose; the medicament is given in two portions, one hour apart; the amount usually prescribed is in the ratio of two drops to each year of life up to 24, after which the quantity is not increased. Another excellent remedy fer hookworm is thymol; it is very important to have the drug finely powdered; it should also be administered in two doses at an interval of an hour,— the quantity being about two and a half grains to each year of life of the patient but is not increased after the 24th As this drug is poisonous, and has in a few instances caused death, it should be given with a great deal of care. In using it for the meat of hookworm disease it should be remem bered that the object is to cause it to lie 5, the intestine in contact with the worms joss sufficiently long for it to kill or stupefy them but to prevent its being absorbed into the cir culation of the patient as far as is Therefore we should give nothing that would dissolve the medicament, such dissolvents are: alcohol and anything containing it; butter and all oils; and, since thymol is slightly soluble in water, fluids and drinks of all kinds in greater quantities than absolutely necessary so long as the drug remains in the patient's Intestine. For the foregoing reason it is perhaps as well not to give castor oil in any stage of the treatment where thymol is to be used to expel the worms. In addition to the foregoing beta-naphthol, the oleoresin of the male fern, oil of eucalyptus and. several other drugs are sometimes given in the treatment of hookworm, but the results with the two agents first mentioned are so much superior that it is useless to go into details of their administration. Whatever the drug that is used to expel the worms it is well for the patient to have a suitable laxative some hours after it is given, he should remain in bed during the entire day that the treatment is ad ministered, and should take no food until late in the afternoon. After the worms are ex pelled nothing but good food is, as a rule, necessary, but it is thought by some that the administration of tonics, especially those con taining iron and other supposed blood-builders, is of benefit. The treatment of ground itch consists in keeping the parts cleaned and pro tected from external injury, together with some antiseptics and soothing ointment.
Bibliography.— Stiles, C. W., 'The Preva lence and Geographic Distribution of Hook worm Disease in the United States' (1903) ; id., 'Hookworm Disease in its Relation to the Negro' (1909) ; id., 'Hookworm Disease (or Ground-Itch Anemia) : Its Nature Treatment and Prevention' (1910) ; United States Public Health Service pamphlets (Washington, D. C.) ; 'Rockefeller Sanitary Commission for the eradication of Hookworm Disease' (Annual Reports).