was made on the Leuoxytce3on thftion in chickens from April 1964 to theendof 1966. Thexesultxeveth1thatthethfationwas duetoL caulleryi, L. sahrasi, andL. andrewsi. Theexisnieof theksttwosrthes wererco-nifirmeifor the fnst time in Taiwan. Of the three sreaes of Lewxcytecx L. caulleryi had the strongest thog-enerzity and brought severe losses to the poultry industry, However,
& thftion cccured rarely from June 1966, L. sabrai had considerably high jthogenthty aiiainst chickens. However it virulence and prevalerce were milder than
those of L. caulleryi. There was still no control measure, Most of the aiDed thickens in Taiwan were due to the L, sah-asi infAon or leukosis complex. L, andrewsi had low athogenthty and the prevalence was also lirnitl alt-hough its gametcyt could stuy as longas 39CJdays frstheblcodsixeamofthethfetd chickens. Thelifecydeofthis jarasie, as wellas of L. sahasi, is still unknown.