1 622 THE MYIASES AND ALLIED CONDITIONS 



1. MuscidcB (Subfamily: Muscinae). — Genera: Musca, Calliphora, 

 Chrysomyia, Cordylobia, and Lucilia. 



2. SarcophagidcB. — Genera: Sarcophaga, Sarcophila,andCynomyia. 

 ^. AnthomyidcB. — Genus: Fannia. 



4. (EstridcB. — Genera: Hypoderma,Gastrophilus, Qistrus(Cephalo- 

 myia), (Estromym, Spilogaster. For zoological details on flies see 

 Chapter XXXIIL, p. 814. 



Less important families are: — TachinidcB, Micropezidcs, Syrphidce, 

 PhoridcB, TherevidcB, Sepsidce, and DrosophilidcB. 



The larvae appear to be attracted by fsecal or urinary substances, 

 and also by any purulent or putrefactive discharges. 



Pathology. — The changes produced in the body by these larvae 

 appear to depend upon the question of food. In such positions as 

 the alimentary tract they appear to do little harm, probably because 

 there is plenty of food available without hurting the tissues of the 

 host; on the other hand, in the nose, ear, and eye they may cause 

 much destruction of tissue, firstly by eating into the tissues, secondly 

 b}^ the microbic infections which follow in their track, and in this 

 way they may cause the death of the host. 



Symptomatology. — ^As may be expected from the last paragraph, 

 the symptoms of the victim may vary from nil, local signs of destruc- 

 tion of tissue, with inflammation and pus formation, to signs of 

 general septicaemia. 



Diagnosis. — ^This is usually easy, and depends upon the discovery 

 of the larvae, which, indeed, are usually sufficiently obvious to the 

 patient and practitioner alike. 



Treatment. — ^When the larvae live in passages such as the nose or 

 ear it is usual to expel them by douches of chloroform water; when 

 in the alimentary canal, by anthelmintic treatment ; when in the 

 skin, by the knife and forceps, or simply by the latter. The asso- 

 ciated inflammation as well as the conditions causing the original 

 stinking discharge which attracted the flies require treatment, other- 

 wise the patient will again be in danger of infection. 



Prophylaxis. — Any person suffering from a purulent or odoriferous 

 discharge in any part of the body should be especially careful to 

 avoid myiasis by sleeping under mosquito curtains until this disease is 

 cured. Other people should be careful not to sleep in the open with- 

 out some protection, especially in the daytime, and in certain cases — 

 as, for example, Dermatohia cyaniventris — to use mosquito curtains. 



Varieties. — ^The various forms of myiasis may be classified as 

 follows: — 



A, Internal or Cavity Myiases • — 

 I. Rhinal myiasis. 

 II. Aural myiasis. 



III. Ocular myiasis. 



IV, Urinary myiasis. 



V. Vaginal myiasis, 



VI. Gastro-intestinal myiasis. 



