DEAD AND DYING BRAZILIAN FREE-TAILED BATS (TADARIDA-BRASILIENSIS) FROM TEXAS - RABIES AND PESTICIDE EXPOSURE

Twenty-three dead and dying Brazilian free-tailed bats from roosts in downtown Mineral Wells, Pale Pinto County Texas, were tested for rabie s and for anticholinesterase (antiChE) effects of organophosphorus (OF ) and carbamate pesticides. Seventeen of the 23 bats tested positive f or rabies. The cause of death or dying in five of the nonrabid bats is unknown; however, one of the six nonrabid bats had a ChE activity lev el equivalent to only 27% of the control mean and may have been expose d to a pesticide. Three bats (including the bat with depressed ChE) co ntained sufficient ingesta to analyze for antiChE compounds, but no an tiChE compounds could he identified in the samples. Exposure may be de rmal and pulmonary as well as dietary. It is feasible that other bat d eaths not explained by rabies were attributable to a pesticide but mis sed due to postmortem reactivation of the ChE enzyme. The largest grou p of rabid bats was young males (13 of 17, 76.5%), and the largest gro up of nonrabid bats was older females (3 of 6, 50%). All older females were nonrabid, perhaps survivors of tile disease in previous years. R abid bats had a lower mean fat index and weighed less than nonrabid ha ts. Four bats (not including the low ChE bat) showed external bleeding , and none was rabid; thus the incidence of bleeding was greater among nonrabid bats than among rabid bats. The four affected bats came from roosts in three different buildings, making a roost-treatment with an anticoagulant chemical seem unlikely.