State quarantines were placed on all infested and exposed premises, and 
an area quarantine was placed on approximately 600 square miles in Cameron 
County outside the systematic area. Systematic eradication procedures were 
inaugurated. The outbreak area includes an estimated 780 herds comprising 
18,319 cattle and 882 horses. 
Eleven dipping vats met the criteria required for use of dioxathion (Delnav) 
permitted dip and 19,201 cattle and 4,039 horses were treated with Del nav 
during a period of 4 months. 
Although Delnav was effective in destroying B. microplus, ranchers felt 
that cattle toxicity problems were greater than with arsenic and requested 
that the vats be charged with arsenic rather than Delnav. 
During the 4-month period, 19,201 cattle were dipped in Delnav and 64 calves 
died following two, three, or more dippings or sprayings. Most of these 
were 3 months of age or younger. Nearly all of 158 calves treated with 
atropine lived. Others showing milder signs of toxicity recovered without 
treatment. Owners thought that although some of the more severely affected 
calves lived they did not gain weight as well as they should. 
This is in contrast to the experience during the 1968 outbreak in Dimmit 
County where a total of 12 cattle deaths were associated with dipping or 
spraying with Delnav of 28,525 cattle. Only four of the 12 could be 
attributed to Delnav toxicity. The four deaths followed treatment using 
other than the approved procedures. 
TABLE 3.--Texas - Total Tick Collections Submitted. Fiscal Year 1971 
Field 
Submitted by: Tick Patrol Activities Stockyards Ports Other 
Month Totals 
July 37 15 39 | 4 96 
August 56 36 22 i) 5 128 
September 83 32 13 6 5 139 
Quarterly Totals 176 83 74 16 14 363 
October 54 13 6 0 3 76 
November 38 17 7 20 2 84 
December 25 2! 5 60 0 11 
Quarterly Totals lez 5 | 18 80 5) 271 
6-Month Totals 293 134 92 96 19 634 
January 7a 22 6 29 0 84 
February 49 30 15 7 | 102 
March 79 38 12 14 0 143 
Quarterly Totals (55 90 33 50 ! 329 
April 95 56 13 } 2 169 
May 102 134 21 5 28 290 
June 148 107 49 14 115 433 
Quarterly Totals 345 297 83 22 145 892 
FY 1971 Totals 793 521 208 168 165 (5855 
