Studies in Mexico in 1972 showed that diphacinone (Diphenadione) (2-diphenylacetyl-1,3-indandione) was effective in reducing both vampire bat (Desmodus rotundus) populations and the incidence of bat-transmitted rabies in cattle. Two highly selective methods were developed: treating cattle systemically and treating vampire bats topically. Since 1972, Denver Wildlife Research Center personnel have assisted Latin American Ministries of Agriculture in developing control campaigns. Brazil, Bolivia, Colombia, Costa Rica, Ecuador, Guyana, Panama, Venezuela, and Nicaragua have either undertaken or are considering operational vampire bat control programs.