Cattle Fever Ticks in the U.S.: Back to 1906?

Authors: Perez De Leon, Adalberto - Beto; Pound, Joe; Kammlah, Diane; Davey, Ronald; Strickman, Daniel; MESSENGER, M - Animal And Plant Health Inspection Service (APHIS); DUHAIME, R - Animal And Plant Health Inspection Service (APHIS); HILLMAN, BOB - Texas Animal Health Commission; GEORGE, JOHN - Retired ARS Employee

Submitted to: Livestock Insect Worker's Conference Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/22/2009
Publication Date: 6/23/2009
Citation: Perez De Leon, A.A., Pound, J.M., Kammlah, D.M., Davey, R.B., Strickman, D.A., Messenger, M., Duhaime, R., Hillman, B., George, J. 2009. Cattle Fever Ticks in the U.S.: Back to 1906?. Livestock Insect Worker's Conference Annual Meeting. June 21-23, 2009. French Lick, IN

Interpretive Summary:

Technical Abstract: Keeping cattle fever ticks (CFT), Rhipicephalus (Boophilus) microplus and R. annulatus, eradicated from the United States and thus keeping the national cattle herd free of bovine babesiosis is a current and critical agricultural biosecurity issue of national relevance. Also known as “Texas fever”, bovine babesiosis remains foreign to the U.S., but it is a reportable disease according to the World Organization for Animal Health. It is estimated that the livestock industry realizes annual savings of at least 3 billion dollars since the U.S. was declared free of the ticks and bovine babesiosis. However, global change is impacting the ability of state and federal agencies to keep the national herd free of CFT (George 2008). Bovine babesiosis outbreaks in the U.S. are a real and imminent risk to the cattle industry perhaps due to shifts in the ecology of wild ungulate hosts that may support the maintenance and dissemination of CFT. During our presentation we will discuss the dynamics of factors influencing the apparent spread of CFT back into South Texas and immediate actions that can be taken to address this threat to the national food supply and prevent them from spreading back into their previous range in the U.S. The eradication of bovine babesiosis from the U.S. represents a very successful campaign in the history of disease eradication efforts. Babesia bovis and B. bigemina are the etiologic agents of bovine babesiosis, and B. bovis is considered the most economically important arthropod-borne pathogen of livestock worldwide (Bock et al. 2004). Following his decisive studies done in collaboration with Frederick L. Kilborne leading to our understanding of how the disease was transmitted to cattle by CFT, Theobald Smith stated, “Eliminate the ticks on cattle and you eradicate the ticks because they cannot live elsewhere” (Ojan and Stanek 2002). Thus, systematic dipping of cattle in vats containing an acaricide was the cornerstone of the Cattle Fever Tick Eradication Program, which was created in 1906. CFT were declared eradicated from the U.S. in 1943 with the exceptions of a persistent population in Florida that was eradicated in the early 1960’s and the permanent quarantine zone along the border with Mexico in South Texas that remains in place today (Bram and George 2000). The number of CFT outbreaks within and outside the permanent quarantine zone fluctuates with time. A significant incursion of CFT took place in the 1970s. Of a total of 170 outbreaks recorded in 1973, 112 occurred outside of the permanent quarantine zone. It took six years to re-eradicate the ticks. Once again, the level of CFT activity in the U.S. has increased to alarming levels during the last five years. The largest number of infested premises in the permanent quarantine zone was initially recorded in 2005, but that record was broken again in 2008 when CFT were detected in 85 premises (Table 1). A sustained spillover of CFT into the free zone also has been noted since 2004. This situation triggered the establishment of preventive quarantines by the Texas Animal Health Commission and the U.S. Department of Agriculture Animal and Plant Health Inspection Service – Veterinary Services to try to contain the CFT and eventually re-eradicate them from the U.S. In June 2009 the number of CFT outbreaks outside the permanent quarantine surpassed the total in 2008 and a zone covering almost a million acres was established under preventive quarantine in South Texas. Native and non-native species of wild ungulates figure prominently among the likely causes for the apparent re-invasion of the U.S. by CFT. Among them, white-tailed deer are regarded as the major complicating factor in eradication efforts since they are suitable hosts for CFT. CFT eradication in pastures vacated of cattle was considered impossible as long as white-tailed deer remained