=Leeches.= These taken in with the water will sometimes fasten
themselves on the walls of the pharnyx or even on the lips of the
larnyx, producing cough, sore throat, difficulty of swallowing, bleeding
from the nose (or mouth), or dyspnœa. They are to be removed as
recommended above under parasites of the nasal chambers.
=Œstrus Larva.= =Bots.= In horses and mules the larva of the œstrus
sometimes attaches itself to the mucous membrane of the pharynx or even
of the larynx producing chronic irritation, cough and even dyspnœa. A
chronic sore throat with nasal discharge, occurring in autumn or winter,
in the absence of fever or constitutional disorder may be found to
depend on these parasites and to recover when these have been removed by
the hand.