_The prevention and control_ depend on destruction of the cattle tick. In
the early history of the disease, shipping and driving of southern cattle
into and through the northern States caused outbreaks of tick fever and
heavy losses among northern cattle. This finally resulted in the locating
of the infected district, and the establishment of the Texas-fever
quarantine line in 1891 by Dr. D. E. Salmon.

Previous to this time Kilborne and Salmon proved that the cattle tick was
essential to the spread and production of the disease. A further study of
the life history of the tick resulted in the discovery that it could not
mature unless it became a parasite of horses, mules, or cattle. This has
led to the eradication of the tick in certain sections of the South, by not
allowing cattle access to a pasture or lot for a certain period, and by
freeing the animals from ticks by hand-picking, dipping and smearing.

The immunization of cattle that are shipped into an infected district for
breeding purposes is often practised. Immunity is obtained by introducing
the P. bigeminun into the blood, either by placing a few virulent young
ticks upon the animal, or by repeated inoculation with a very small
quantity of virulent blood.


QUESTIONS

1. Give the cause and treatment of actinomycosis.

2. Give the cause and treatment of emphysematous anthrax.

3. Give the cause of tick fever; distribution of the disease and methods of
control.