12 MISC. PUBLICATION 631, IT. S. DEPT. OF AGRICULTURE 



MYIASIS OF THE ANAL REGION AND VAGINA 



A number of cases of myiasis of the anus, perianal region, rectum, 

 and vagina are on record. Many of them have occurred in persons 

 who have slept or have been left in a helpless condition during the day- 

 time either outdoors or in fly-infested rooms ; some of them, however, 

 may be due to the use of unsanitary toilets. 



Dove (3Jf) cites a case in Florida of an elderly woman, living alone, 

 who fell and lay helpless for several days; when discovered, she was 

 badly infested with screwworms which had entered the vagina and 

 were active in the sacral regions and the navel. About a quart of larvae 

 were obtained from the wounds. The case terminated fatally, although 

 the author does not state how much might have been due to the maggot 

 infestation and how much to exposure and other causes. 



The attractant to the fly sometimes is a fetid discharge or a preexist- 

 ing sore or diseased condition, such as a carcinoma. The various species 

 of flies which may be involved in this type of parasitism include 

 Callitroga americana, Chr^jsoinya bezziana, Wohlfahrtia magnified, 

 and semispecific myiasis producers belonging to the families Sar- 

 cophagidae and Calliphoridae. Maggots invading the vaginal and 

 rectal regions may be discharged with the urine or feces, and thus 

 lead to a mistaken diagnosis of intestinal myiasis. 



MYIASIS OF THE BLADDER AND URINARY PASSAGES 



Numerous instances, the oldest dating back to Plutarch, have been 

 recorded of dipterous larvae invading the urinary passages and blad- 

 der of human beings. Cases have been reported in patients of both 

 sexes and of all ages. Chevrel (27) , in a detailed study of the subject, 

 has summarized the work up to that time, and Mumford (91) has 

 added the description of several more cases. Other scattered literature 

 adds little information, except to indicate that this type of myiasis is 

 an actual, though uncommon, reality. 



It is possible that infestation may take place through the use of a 

 catheter, a syringe used for douching, or some other instrument which 

 has been stained with urine or other matter which, on decomposing, 

 has attracted flies to oviposit. In the majority of cases, however, in- 

 festation is probably a result of natural exposure, such as might come 

 from the use of unsanitary outdoor toilets or from sleeping during the 

 daytime with the body exposed. In such an event the female fly may 

 be attracted by discharges, especially those of an albuminous nature. 



Chevrel believes that the eggs are deposited on the prepuce or the 

 folds of the vulvar mucosa, where the moisture and warmth cause 

 them to hatch rapidly. After hatching they feed on the discharges 

 and gradually make their way upward through the urinary meatus. 

 This upward journey seems to be made without irritation to the host. 

 According to Chevrel, the ultimate stopping place of the larva is the 

 site of the infection that attracted the parent flies, namely, the urethra 

 in the case of gonorrheal patients and the bladder in the case of 

 nephritics and diabetics. The mucopurulent secretions furnish the 

 larvae with food ; they obtain sufficient oxygen to supply their meager 

 needs from pockets and folds in the urinary tract and in the bladder. 



Urinary myiasis is accompanied by pains in the lower abdomen, 

 especially in the area of the bladder or kidneys; urination is often 



