PARASITES AXD PARASITIC DISEASES OF HORSES 39 



Symptoms. — The sucking louse obtains its food by puncturing the 

 skin of the horse and sucking blood and lymph. When not feeding 

 it moves about on the hair and skin. The biting lice do not suck blood 

 from the host, but apparently feed on particles of hair, scales, and 

 exudations from the skin. The irritation and itching which result 

 from either or both methods of feeding are shown by the efforts of 

 infested animals to obtain relief. Infested horses rub and bite them- 

 selves, and often kick and stamp and manifest extreme uneasiness and 

 irritation. 



The coat becomes rough; the frequent rubbing destroys the hair in 

 patches and often causes bruises or wounds in the skin. If lice are 

 present in sufficient numbers to cause considerable itching and irrita- 

 tion they can usually be found, especially if the infested animal is 

 placed in the sunshine. All species of horse lice are easily seen with 

 the naked eye and often congregate in groups or colonies on parts of 

 the animal. The favorite locations are the sides of the neck, around 

 the flanks, and under the jaws. In cases of gross infestation, however, 

 lice may be found all over the body and legs. 



When horses are lousy, close examination should be made to learn 

 what kind or species of lice is present. It is not especially impor- 

 tant, from a practical standpoint, to distinguish between the two 

 species of biting lice, but it is important to know whether the animals 

 are infested with biting or sucking lice or with both kinds. 



Method of spreading. — More cases of infestation originate from 

 direct contact with lousy animals than in any other way. Under 

 reasonably good sanitary conditions stables, yards, and other prem- 

 ises which have contained lousy horses are not a source of great danger 

 to horses free from lice. It seems probable, however, that occasionally 

 lice may become dislodged from their host and drop on mangers, 

 floors, etc., and from these locations find then way to a new host. 



When separated from their host sucking lice live about 3 days, 

 the biting lice not to exceed 10 days. Ordinarily eggs are not deposited 

 except on the host, but when the hair to which they are attached is 

 removed and kept under favorable conditions they may continue to 

 hatch for as long as 20 days. The newly hatched lice live only 2 or 

 3 days unless they find a host. It is therefore possible for premises 

 to remain infested for 25 or 30 days from the time they were occupied 

 by infested horses. When lousy horses are clipped the hair should be 

 burned and the ground or floor where the clippings dropped should 

 be thoroughly treated with an insecticide. 



Lice may be carried from one animal to another on currycombs, 

 brushes, and blankets, or by harness, saddles, and other equipment 

 moved directly from a lousy horse to one free from lice. Currycombs 

 and brushes should be treated each time a horse is groomed. Harness, 

 saddles, blankets, and other equipment used on lousy animals should 

 not be put on horses that are free from lice unless the equipment has 

 been thoroughly cleansed. 



When cleaning stables and yards remove all litter and manure 

 down to a smooth surface, then spray well with a good insecticide. 

 The coal-tar creosote dips, diluted in accordance with the instructions 

 printed on the label of the container, are suitable for ridding premises 

 of the lice. 



