causative agents of bovine babesiosis 

 (cattle tick fever, Texas fever). Of 

 no less Importance is bovine 

 anaplasmosls, a disease produced by 

 Anaplasma marginale also 

 transmitted by Boophilus ticks. 



In order to free southern United 

 States cattle of bovine babesiosis, 

 the Boophilus tick eradication program 

 was started in I906. The tick vector 

 was the most logical link to attack 

 in the disease chain. Following the 

 elimination of the Boophilus ticks, 

 the Babesia soon died out because the 

 other species of ticks were incapable 

 of transmitting the disease agents. 

 The livestock industry benefited by 

 being free of both Boophilus ticks 

 and babesiosis. 



Even when not transmitting disease 

 agents, Boophilus ticks are of 

 economic importance for the following 

 reasons: 



1 . They produce damage to the hide 

 which reduces its commercial value. 



2. They cause "tick worry", which 

 reduces the efficiency of the living 

 animal, resulting in lowered milk 

 production and reduced weight gains. 



3. They suck blood which results 



in anemia and occasionally death. 



4. Tick bites serve as portals of 

 entry for secondary disease agents, 

 and/or as sites for screwworm 

 infestations. 



Tick epidemiology, the study of the 

 various relationships between ticks, 

 their hosts, and the environment is 

 of tremendous importance to the 

 eradication program. Environmental 

 factors such as variations in 

 seasonal weather may play a very 

 important role in the yearly cycles 

 of. ticks. Temperature and humidity 

 affect the incubation period of 



eggs and survival of larvae. People 

 working in the Boophilus eradication 

 program must be constantly aware of 

 the changing ecological conditions 

 in the environment. Ideal weather 

 conditions may decrease natural 

 mortality and allow the ticks to 

 "overproduce". This increased tick 

 population can result in the 

 infestation of new hosts such as 

 deer, which are not normally 

 parasitized by Boophilus ticks. The 

 "spillover" to a new host is rare in 

 occurence. Such a "spillover" has 

 taken place with Boophilus anniilatus 

 and white-tailed deer in northern 

 Webb Cotmty, Texas. 



Adverse weather conditions that 

 cause a reduction in the survival of 

 the tick larvae will help the 

 eradication program only if we are 

 aware that the ticks are present in 

 an area and take appropriate action. 

 Low populations of Boophilus ticks 

 may not be detected for long periods 

 of time. Failure to detect ticks 

 can result in their spread to new 

 land areas and new infestations not 

 included within the active 

 surveillance program. 



Ecological disturbances by humans can 

 also affect the distribution of 

 Boophilus ticks. Land areas 

 previously poorly suited for ticks 

 often become a more suitable habitat 

 for ticks if scrub and brush are 

 replaced by grassland pasture. The 

 introduction of predators, such as 

 the fire ant, often influence the 

 incidence and distribution of tick 

 populations. Ecological changes may 

 increase or decrease the host 

 population, which in turn will affect 

 the survival of the tick. Such 

 ecological changes occured in 

 southern Texas with the introduction 

 of buffel grass and the 

 implementation of the screwworm 

 eradication program. These two 



