What is "poll evil"

Poll \Poll\, n. [Akin to LG. polle the head, the crest of a bird, the top of a tree, OD. pol, polle, Dan. puld the crown of a hat.]

1. The head; the back part of the head. ``All flaxen was his poll.''
   --Shak.

2. A number or aggregate of heads; a list or register of heads or individuals.

   We are the greater poll, and in true fear They gave us our demands.
   --Shak.

   The muster file, rotten and sound, upon my life, amounts not to fifteen thousand poll.
   --Shak.

3. Specifically, the register of the names of electors who may vote in an election.

4. The casting or recording of the votes of registered electors; as, the close of the poll.

   All soldiers quartered in place are to remove . . . and not to return till one day after the poll is ended.
   --Blackstone.

5. pl. The place where the votes are cast or recorded; as, to go to the polls.

6. The broad end of a hammer; the but of an ax.

7. (Zo["o]l.) The European chub. See Pollard, 3 (a) .

   Poll book, a register of persons entitled to vote at an election.

   Poll evil (Far.), an inflammatory swelling or abscess on a horse's head, confined beneath the great ligament of the neck.

   Poll pick (Mining), a pole having a heavy spike on the end, forming a kind of crowbar.

   Poll tax, a tax levied by the head, or poll; a capitation tax.

n. (context obsolete English) an inflammation identical with fistulous withers except that it is on the poll of a horse

Poll evil is a traditional term for a painful condition in a horse or other equid, that starts as an inflamed bursa at the anterior end of the neck between vertebrae and the nuchal ligament, and swells until it presents as an acute swelling at the poll, on the top of the back of the animal's head. The swelling can increase until it ruptures and drains. It can be caused by infection from Actinomyces bovis or Brucella abortus organisms, but may also occur due to parasite infestation, skin trauma, or badly fitting horse tack. Because of modern efforts to reduce the incidence of brucellosis in livestock, horses are less exposed to the Brucella abortus organism, and hence most modern cases of poll evil arise from trauma linked to a horse striking its head against poorly designed or low-clearance structures, or to improper use of equipment, particularly leaving a halter on the horse around the clock.

The term has been in use since at least the 1750s. Before modern antibiotics were developed, the condition was very difficult to treat. In the 18th century, it was treated with remedies such as vinegar, wine, elder flower and even turpentine. Today, cases caught early can be cleaned with peroxide, ice packs and diluted dimethyl sulfoxide solution, with antibiotics used to prevent or slow infection. If the infection has set in and there is a discharge, antibiotic treatment along with hot packs and surgery under local anesthesia to remove infected and dead tissue is usually required.

Fistulous withers is a similar condition but on the animal's withers.