The Animal Parasites of Man

by Harold Benjamin Fantham; Max Braun; J. W. W. Stephens; Fred. V. Theobald

The Oestrides prefer to use the surfaces of wounds on the skin of man to lay their eggs, which develop into larvæ; but they often use their ovipositors[1190] to make a fresh wound. In this case there arise in the skin, and particularly in the subcutaneous connective tissue of the neck, in the region of the shoulder, as well as in other parts of the body painful, furuncle-like inflammations which are known under the name of gad-fly boils. These boils may become the size of pigeons’ eggs; if several are together, they appear to form a connected tumour. Each tumour is elastic and somewhat movable, and has an orifice through which the larva breathes and discharges its excreta. At times these turn to festers and gangrenous disintegrations, which may even cause the loss of a limb. Wilms[1191] had the opportunity a few years ago of observing a case of myiasis dermatosa oestrosa in Leipzig. The fistula which led to the larva was slit open and the larva extracted. As a notable characteristic of myiasis oestrosa Joseph states that the larvæ grow very slowly. The flight time of the Oestridæ is the hot summer months.

Adams[1192] observed on the Isthmus of Panama a number of cases of a skin disease which is caused by the larvæ of Dermatobia noxialis (Gusano-peludo-Muche). The larvæ penetrate not only the skin but also the mucous membrane of the pharynx and larynx, and from there proceed through the tissue to the subcutaneous cellular tissue. The infection seems to result from bathing.

The study of “thimni,” a human myiasis caused by Oestrus ovis, by Ed. and Et. Sergent,[1193] deals more with the zoology and with the geographical distribution of this insect in North Africa than with the clinical appearances of myiasis. [This paper deals with matters of great interest, with important facts.—F. V. T.]

The treatment consists in the removal of the larvæ (from the nose); in Brazil it is the custom to drop tobacco juice into the boil in order to kill the larvæ (Strauch[1194]).

One is only justified in speaking of myiasis intestinalis when there is no doubt that living fly maggots or flies themselves can be proved to have been found in the fresh contents of the stomach or intestine (Schlesinger and Weichselbaum[1195]). In the discussion of myiasis intestinalis we give the evidence of Schlesinger and Weichselbaum, as well as that of Wirsing,[1196] to which must be added a number of other investigations.

In a great number of acute cases apparently only the stomach was affected, there being no signs in the intestine. In these cases sudden illness is noticed, colic, sometimes unbearable pains in the region of the stomach, pyrosis, vomiting or continuous intense inclination to vomit, occasionally even with the mixture of blood. Frequently a general feeling of malaise, twinges of pain in the muscles, and attacks of giddiness were notified, very rarely fever. Generally all the symptoms disappeared in a short time when the larvæ had been removed by an act of vomiting or by washing out the stomach.

It is well to note that in the history of many cases the pains preceding the expulsion of the larvæ are stated to be extremely violent.

Acute myiasis of the intestinal canal frequently runs a course without special symptoms and is only an accidental condition; one has, however, in such cases to guard against errors. The fæces may be deposited in vessels or places where fly larvæ are in great numbers, or a subsequent infection of the fæces with the eggs or larvæ of flies may have taken place. Only when the inspection of the excrement immediately following defæcation proves the presence of living larvæ, and when there were certainly no fly larvæ in the vessel previously, can one speak of the passing of fly larvæ from the intestine. More frequent than the cases showing no special symptoms are those with pronounced disturbances in the intestinal passage, obstruction or diarrhœa (also constipation and diarrhœa alternately), violent and sometimes agonizing abdominal pains (Pottiez[1197]), which preceded the evacuation of the larvæ and subsided after their removal. General symptoms, like weakness, languor, transitory vague pains, loss of appetite, sickness, rarely fever, giddiness, attacks of faintness, epileptic attacks (Krause[1198]) are observed. In a few cases blood and pus have been noticed in the evacuation of the bowels.

In the cases of chronic myiasis of the intestine the aspect of the disease is dominated by the complex symptom of colitis mucosa.

The following features are noticeable, namely, the intermittent passing of blood, the influence over the expulsion of the larvæ of mechanical procedure (massaging of the abdomen), the duration of the process for several years, the sometimes enormous number of insects contained in the dejecta. Another clinically important factor is the passing of the larvæ in batches. While for some time no larvæ may appear in the stools, they may suddenly be ejected in great numbers, either because the conditions of feeding are not suitable, or because medicaments remove them from the intestine. The hæmorrhage is ascribed by Schlesinger and Weichselbaum directly to lesions of the mucous membrane caused by the larvæ; in the case reported by these writers there were found shreds of tissue as well as pus in the stool. The pains occurring spontaneously in the abdomen are at times influenced by position and attitude of the body, often they were more violent after rest and after evacuation of the bowels; often they were continuous, but in that case less intense; pressure on the abdomen is generally little felt. The condition of the blood was in two cases (Pasquale[1199] and Schlesinger and Weichselbaum) a marked chlorotic one. The state of nutrition seems almost always to suffer with prolongation of the disease, but in Peiper’s[1200] cases this was not so. The condition of the appetite was in some instances good, in others very bad. A frequent symptom is headache of a migraine-like character and neuralgic pains in different parts.