76 



POULTRY DISEASES 



liver, kidneys and other abdominal organs, in which cases they 

 produce yellowish, pearl-like nodules or tubercles. 



An outbreak of this disease in Colorado was studied by the 

 author during the spring of 1912, in which several birds in a flock 

 of sixty became ill. They were dull and weak, with a partial loss 

 of appetite and a tendency to crane their necks when they tried 

 to swallow, became poor in flesh and after one to two or three 

 weeks died. The comb, in most instances, turned black shortly 

 before death. 



On autopsy there were found myriads of small, yellowish-white 

 specks over the abdominal air sacs, lungs and trachea. These 

 specks, when examined under the microscope, proved to be the 

 air-sac mite (Cytoclitcs mid as) as illustrated in Fig. 29. 



Treatment. — It is said that sulphur given with the feed 

 will be absorbed and eliminated by the lungs in sufficient 

 quantities to kill the parasites that infest them, but this is 

 doubtful. A 1 etter method of handling an outbreak of air- 

 sac disease among birds of average value is to kill all the 

 birds in an infested flock and disinfect the premises. None 

 of them should be sold, as they may find their way into other 

 flocks and infest them. It is a very serious disease and one 

 of which it is difficult to rid the flock. 



CHIGGER (JIGGER) OR RED MITE INFESTATION 



There are two varieties of chiggers found in this country, 

 one is the Tromhicliuni Iwlosericeum, the other the Dermanys- 

 siis gallince. 



Trombidium Holosericeum 

 This parasite is the common chigger (jigger) or red mite of 

 the henhouse. 



Description. — It is very small. The body is oval in shape; it is 



provided with four pairs of legs 

 in the adult state and three pairs 

 in the larval. The distal end of 

 each leg is provided with two 

 booklets or claws, with which it 

 clings to objects and which en- 

 able it to crawl about. Its 

 mouth parts are conical in shape, 

 as illustrated in the drawing. 

 (See Fig. 30.) 



Life History. — IMites lay their 

 eggs in the cracks and crevices 

 and filth of henliouses. If the 

 temperature is warm the eggs 

 hatch in a few days into the asex- 

 ual, six-legged state. After pass- 

 ing through a few molts it ar- 

 rives at the eight-legged, sexual 

 or adult state. The parasite 

 multiplies very fast in the warm- 

 and August, when conditions are 



■^if^i^rf. 



Fig. 30. Trombidium Holosericeum. 

 a, mouth parts; b, palpi; c, uterus. 



er parts of the summer, July 



more favorable for its propagation. 



