26 



routastoiiium Tai'iiioides. 



Etiology. Pentastomum taenioides, Keed (Liiiguatiihi 

 taenioides, Neumann) l)elongs to the Lingnatulidae family of 

 the Arachnoidae (Fig. 2) ; the body of the parasite is tongue- 

 or lancet-shaped, wider at the anterior end, and gradually 

 ta])ering at the posterior extremity. The external cuticle con- 

 sists of about ninety rings and the margins of the body are 

 serrated so that the parasite becomes similar to a 

 ta])eworm. The mouth, which opens at the anterior 

 extremity, is surrounded by four hook-like stum]) 

 feet. The male is 10 to 20"mm.; the female, how- 

 ever, is 8 to 10 cm. long. Tlie ova (Fig. 3) are oval 

 in shape, 90 /x long by 70 /^ wide. Special organs of 

 reuse, of respiration and circulation are absent. 



The parasites grow from the larvae designated as 

 Pentastoinnm denticulatum (Liiigiiatiila. denticiilata). 

 These develop in the internal organs of herbivora. After the 

 killing of the host they get into the nose of the dog, either 

 directly or through the pharynx, or so that the ingested 

 larvae perforate the wall of the stomach and migrate into 

 the lungs, bronchi and finally into the nose (Gerlach). 

 Herbivora infect themselves by the ingestion of feed which 

 is accidently contaminated by larvae. The latter develop 

 further in the nasal or accessory cavities and mature in 

 six to seven wrecks. After copulation the female develops 

 up to one-half millon ova and these are discharged with 

 the nasal secretion, contaminate grass or feed and are taken 

 up l)y herbivora, in the body of which the larvae gradually 

 develop. In the meantime the larvae occasionally appear 

 to wander, getting into the lungs and bronchi, from Avliich 

 they are expelled with masses of secretion. 



reiitattomum Anatomlcal Changes. The parasite is gener- 



taenioides. ally fouud iu the Upper portion of the median nasal 

 ducts and in the cells of the ethmoid bone. It is 

 found exceptionally in the frontal sinuses, in the lower portion 

 of the nose and even in the pharynx (Gelle) ; the males are par- 

 ticularly lial)le to get into the larynx ^vhen wandering and hunt- 

 ing for the female. The number of parasites varies betw^een 

 one to eleven. 



At the site where the parasites are adherent the nasal 

 mucosa is usually reddened, swollen, covered with an abundant 

 secretion or infiltrated with small hemorrhages. Only excep- 

 tionally do we find more intense inflannnations ; occasionally 

 necrosis, especially in the cells of the ethmoid bone. (Concern- 

 ing the changes produced in the internal organs by the larvae, 

 see diseases of these orcrans.) 



Symptoms. The Pentastonuun taenioides sometimes does 

 not produce any sjanptoms at all; it causes, however, in the 



