LECTURE XXXI 



VERMINOUS BRONCHITIS, NASAL GRUB, AND 



CATARRH 



Verminous Bronchitis 



Cause. — This is a disease of the bronchial tubes and lungs, 

 caused by several species of minute roundworms. The worms 

 are similar in different domestic animals, but each animal has 

 its own species. They vary from about one to three inches in 

 length and are white or reddish to brown in color. There is 

 little danger of infection from one kind of domestic animal to 

 another. Sheep, goats, cattle, and pigs are subject to this 

 disease. Older animals may be aflfected, but frequently carry 

 the parasite without evident injury. 



Life history. — The mature worms, eggs, and embryos are 

 found in tlie bronchial tubes. Either eggs or embryos are de- 

 posited in the bronchial tubes. Some may be coughed up, then 

 swallowed and pass with the manure. Future hosts take in the 

 embryos witli food or drink, usually grass. The young parasites 

 then go to the lungs. Apparently, but the one host is necessary. 

 Wet pastures appear to be favorable to the spread of this 

 trouble. It is possible that the eggs or dried embryos may be 

 inhaled directly with particles of dust. The parasitism remains 

 long dormant, developing slowly. Embryos are very resistant 

 and tenacious of life. Some species have been shown to sur- 

 vive for months as embryos in water or moist earth. If dried 

 at certain stages of development, the embryos may revive in 

 moisture after a year, according to one good authority. 



Symptoms. — At first tlun-e is a bronchial catarrh ; later a 

 clironic anemia and pallor, with progressive loss of flesh and 

 strength and with sliortness of breath. There is a cough which 

 at first Is rather harsli, and later very weak. The cough is 

 worse when animals are excited and when they move around. 

 Sometimes small balls composed mainly of worms may be 

 coughed out and actually seen. Respiration is difficult and in 



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