Growth of E. coli in blood is common in birds because of the absence of regional lymph nodes. Petechiae in thigh fat is a pathognomonic lesion of the septicaemial status. Sometimes this injury coexists with petechiae on the thigh muscles which have origin in mycotoxin contamination of coumarin group (aflatoxins). This condition may be exacerbated by the use of sulfonamides as a treatment for E.coli septicaemia.