Acaricides for controlling ticks on cattle and the problem of acaricide resistance

Abstract

INTRODUCTION During the nineteenth century, as the number of cattle in the world was increased to feed the human populations of recently industrialized nations, there was a growing awareness of the relationship between infestations of cattle with ticks and disastrous epizootics of disease in herds of cattle. Problems with tick-borne diseases were related to the introduction of improved breeds of cattle into tick-infested areas because of their greater productivity than well-adapted indigenous breeds. Also, cattle infested with ticks and infected with tick-borne disease agents were moved into areas where these tick species had not previously existed (Shaw, 1969). A severe outbreak of disease in cattle, almost certainly bovine piroplasmosis, occurred in Lancaster County, Pennsylvania, in 1796. Epidemiological evidence indicated a relationship between the disease problem and a recent shipment of cattle into the state from South Carolina, a southern state: Experience soon showed that the invariable result following the transportation of southern cattle into the Northern States was the death of all northern cattle along the roads and on the pastures over which the southern cattle had traveled, although the latter animals remained perfectly healthy. In the same way northern cattle taken south almost invariably succumbed to the malady. (Mohler, 1906.) The disease was called ‘Texas fever’ or ‘cattle fever’ and by 1885 resulted in the prohibition of movements of southern cattle into the northern states.