DISEASES OF SWINE 515 



tainty. Irritating applications, such as undiluted kerosene, can- 

 not safely be used on pregnant sows, as abortion may follow their 

 use. (Wis. B. 184.) 



The hog louse is a common parasitic pest on swine in Vir- 

 ginia, and one that requires vigorous and persistent treatment to 

 eradicate. The hog louse is one of the largest of the lice which 

 attacks domestic animals. They are readily seen traveling about 

 among the bristles, usually on the neck, back of the ears, moving 

 with a peculiar sliding motion. The eggs or nits are small, white, 

 oval bodies attached to the bristles. Hog lice are found on almost 

 any part of the body, but are most common about the neck, ears 

 and back of the elbow. 



These are blood-sucking parasites, and by biting the hog and 

 abstracting blood, they cause much irritation of the skin. The 

 animal rubs on posts and other objects, making the coat look rough 

 and harsh. The parasites and eggs are easily found upon exam- 

 ination. The parasites are transmitted from one animal to an- 

 other by contact, or from infested bedding or quarters. 



Dipping the animals three or four times at intervals of ten 

 days will usually free them from these parasites, providing the 

 sleeping quarters are thoroughly cleaned and disinfected. In dip- 

 ping to kill lice the coal tar dips of the creolin type are better than 

 lime and sulphur. If the hog wallows are kept well filled with 

 water, to which some of the creolin dips are added every ten days 

 the hogs will usually free themselves from lice. Another good 

 way is to tie gunny sacks or other coarse cloths around rubbing 

 posts and keep these cloths saturated with crude petroleum. (Va. 

 B. 189.) 



But one specie of .lice attack hogs. It is a common parasite, 

 however, and often appears in formidable numbers on unthrifty 

 pigs. The hair affords the lice but little protection, and vigorous, 

 healthy hogs are able to dislodge the pests by rubbing against the 

 sides of the pen and against one another. When hogs reach the 

 abattoir during the warm weather, the adult louse is seldom found 

 on them, but plenty of "nits" are usually seen. The lice become 

 dislodged during the shipment and in the pens by the frequent 

 soakings with water that the hogs receive, and by their rubbing 

 against each other. 



It is only when a hog is unthrifty or sick that lice are a serious 

 menace to the animal. When in this condition, the hog seems to 

 be unable to dislodge them and they multiply very rapidly. The 

 bite of the hog louse is very irritating and it lives by sucking the 

 blood of its host. The irritation from the bites makes it almost 

 impossible for the hog to rest, and if sick, they help to increase the 

 anemic (bloodless) condition. Lice are a serious handicap to grow- 

 ing pigs, interfering with their appetite and general nutrition. 

 They are said to cause urticaria (nettle rash or heat sores). 



Because of the thinness of the hair and the size of the para- 

 site, it is quite easily seen. The favorite seats are back of the ears, 

 along the neck, under the breast, back of the arms and on the inside 



