One of the most striking cases is that reported by Blankmeyer (1914), of a woman whose illness began fourteen years previously with nausea and vomiting. After several months of illness she began passing larvæ and was compelled to resort to enemas. Three years previous to the report, she noticed frequent shooting pains in the rectal region and at times abdominal tenderness was marked. There was much mucus in the stools and she "experienced the sensation of larvæ crawling in the intestine." Occipital headaches were marked, with remissions, and constipation became chronic. The appetite was variable, there was a bad taste in the mouth, tongue furred and ridged, and red at the edges. Her complexion was sallow, and general nervousness was marked. As treatment, there were given doses of magnesium sulphate before breakfast and at 4 P. M., with five grain doses of salol four times a day. The customary parasiticides yielded no marked benefit. At the time of the report the patient passed from four to fifty larvæ per day, and was showing some signs of improvement. The nausea had disappeared, her nervousness was less evident, and there was a slight gain in weight.
The case was complicated by various other disorders, but the symptoms given above seem to be in large part attributable to the myasis. There is nothing in the case to justify the assumption that larvæ were continuously present, for years. It seems more reasonable to suppose that something in the habits of the patient favored repeated infestation. Nevertheless, a study of the various cases of intestinal myasis caused by these and other species of dipterous larvæ seems to indicate that the normal life cycle may be considerably prolonged under the unusual conditions.
The best authenticated cases of myasis of the urinary passage have been due to larvæ of Fannia. Chevril (1909) collected and described twenty cases, of which seven seemed beyond doubt. One of these was that of a woman of fifty-five who suffered from albuminuria, and urinated with much difficulty, and finally passed thirty to forty larvæ of Fannia canicularis.
It is probable that infestation usually occurs through eating partially decayed fruit or vegetables on which the flies have deposited their eggs. Wellman points out that the flies may deposit their eggs in or about the anus of persons using outside privies and Hewitt believes that this latter method of infection is probably the common one in the case of infants belonging to careless mothers. "Such infants are sometimes left about in an exposed and not very clean condition, in consequence of which flies are readily attracted to them and deposit their eggs."
Muscinæ—The larvæ of the common house-fly, Musca domestica, are occasionally recorded as having been passed with the feces or vomit of man. While such cases may occur, it is probable that in most instances similar appearing larvæ of other insects have been mistakenly identified.
Muscina stabulans is regarded by Portschinsky (1913) as responsible for many of the cases of intestinal myasis attributed to other species. He records the case of a peasant who suffered from pains in the lower part of the breast and intestines, and whose stools were mixed with blood. From November until March he had felt particularly ill, being troubled with nausea and vomiting in addition to the pain in his intestines. In March, his physician prescribed injections of a concentrated solution of tannin, which resulted in the expulsion of fifty living larvæ of Muscina stabulans. Thereafter the patient felt much better, although he suffered from intestinal catarrh in a less severe form.
