346 



and mounted before TOUT suggestion as to experimentation -was read. You are in 

 position, however, to experiment very niucli more advantageously than we would 

 he with living material which had been sent through the mails. — [March 25. 1893.] 



Gapes in Fo-wls. 



Poultrymen know that the disease known as •■gapes" in fowls is due to a worm 

 lodged in the windpipe, and some of them helieve the worm to be a parasite of the 

 common angle or earth-worm. 



Is there any foundation for such belief f An afiswer through Insect Life may 

 gratify others as well as myself. — [George Wentz, Maryland. May 20. 1893. 



Eeply by Dr. C. W. Stiles of the Bureau of Aximae I^tdustry. — In reply 

 to your letter dated May 22. 1893, inclosing a communication from [Mr. George TVentz. 

 of Catonsville, Md., permit me to state that the disease of poultry known as 

 "gapes," '"verminous tracheoboronchitis," or ••syngamosis."is caused by anematode 

 (round-worm) to which Siebold has given the name Si/ngamus trachealis. The para- 

 site belongs to a family (Strojigylidc^) the members of which do not require any inter- 

 mediate host for their development. Accordingly,, we should not expect to find this 

 worm as an obligatory parasite of the earth-worm. It is, however, beyond question 

 that chickens may occasionally become infested with the parasite in question by 

 swallowing earth-worms. This point will be evident from the following account of 

 the life-history of the parasite. 



The adult parasites are found in the trachea of poultry, the male being very firmly 

 attached to ti le female. Numerous eggs are formed in the female parasite and in each 

 egg a small embryo is developed. Females 20"^™ in length have fully developed em- 

 bryos in their uterus. According tc Cobbold and Megnin these eggs with the con- 

 tained embryos are not laid, but they escape from the adult worm only after a rup- 

 ture of the body. This fact is easily understood when we recall that the male is 

 intimately united with the female at the height of the vulva, so that the genital 

 opening is practically sealed. 



If the adult parasite is now coughed up by the atiected chicken, or if it becomes 

 liberated through the death of the fowl, the eggs will become scattered on the 

 ground. They may remain unchanged for some time, or in a warm moist medium 

 the embryo may escape. Should these eggs or embryos be swallowed by other 

 chickens, they will gain access to the trachea and cause the •■ gapes.'' If an earth- 

 worm bhould happen to swallow any of these embryos or eggs, the latter will retaiQ 

 their vitality for some time and will infect with gapes any chicken which happens 

 to devour this particular earth-worm. Thus it is clear that the earth-worm may 

 transmit gapes to chickens by acting as a carrier of the embryos or eggs, dut that 

 the earth-worm is not a necessary factor in the transmission of this disease is equally 

 apparent. 



The following experiments will undoubtedly be of interest to your correspondent: 



Dr. Walker observed that the embryos of 6'. tracheaJis would retain their vitality 

 when swallowed by earth-worms, and that birds contracted " gapes" upon swallow- 

 ing these earth-worms. . For AValker's ex|ieriments see Second Annual Keport, 

 Bureau of Animal Industry. F. S. Department Agriculture, 1885. pp. 274-277.) 



MegTiin infected a parrot with "gapes" by feeding to it some of the female parasites 

 containing embryos. (For Megnin's experiments, see a translation of his article in 

 First Annual Eeport Bureau of Animal Industry, 1884, pp. 281-296.) 



Ehlers fed eggs of ^. trachealis, containing embryos, to birds, and after twelve 

 days he foimd copulated parasites in the trachea. 



From the accotmt given above it is clear that fowls may contract "gapes " by any 

 of the following means : 



(1) By swallowing eggs or embryos of ^. trachealis which happen to be in their 

 food or drinking water. 



