LEECHES IN MOUTH OR NOSE 317 



such extensive bleeding as to bring about the death of the host. 

 Of perhaps even greater importance, because more difficult to 

 avoid, are the bloodthirsty land-leeches which have already been 

 mentioned as infesting many tropical countries. Leeches serve 

 as intermediate hosts for many species of trypanosomes of fishes 

 and other aquatic animals, and it is not impossible that they may 

 be found to transmit some species to man. 



Leeches in the Mouth or Nose. — The leeches which habitu- 

 ally settle themselves in the mouth or nasal cavities of men or 

 animals are inhabitants of muddy-bottomed ponds, ditches, 

 reservoirs, troughs, etc., and enter the mouth or nose of their 

 host while he is drinking. According to Masterman, leeches of 

 the species Limnatis nilotica become so abundant in northern 

 Palestine in late summer and autumn that almost every horse 

 and mule passing through these parts has a bleeding mouth. 

 The Nile leech, Limnatis nilotica, is the most plentiful species 

 around the shores of the Mediterranean, but leeches of the 

 genus Hcemopis, with similar habits, also occur over a large part 

 of Europe. Troublesome aquatic leeches have been reported 

 by travelers in the lake regions of central Africa also, and in 

 some other warm countries, especially Formosa. 



The young leeches, which are usually the ones which enter 

 the mouth or nose during drinking, are only a fraction of an inch 

 in length, but the adults reach a length of several inches. The 

 average length of Limnatis nilotica is about one inch or less. 



A person while drinking from infected pools, especially in 

 dusk or at night, is very likely to suck in one or more of these 

 leeches. During the process of swallowing the parasites attach 

 themselves to the walls of the mouth or pharynx and may mi- 

 grate into the nose or larynx. Seldom, if ever, are the leeches 

 completely swallowed, and even if they should reach the stomach 

 they would probably be killed at once and digested. It is a 

 peculiar and indeed unfortunate fact that, while the leeches 

 which attack the surface of the body fill with blood and then 

 let go, those which settle on the mucous membranes keep their 

 hold for days or weeks, though they shift their positions, leaving 

 the old bites to continue bleeding. As already stated, the loss 

 of blood from the wounds made by the leeches is often sufficient 

 to cause an extreme or even fatal anemia, though the hemor- 

 rhages of clear blood are never great in quantity at any one time. 



