Two outbreaks of colibacillosis in commercial caged layers

A severe septicemia of Escherichia coli etiology was diagnosed in two houses containing 51,570 and 76,200 layers with mortalities of 6.83% and 4.27%, respectively. Dead birds were removed every other day; however, on occasion, gathering was done on the third day. The disease started in 22-wk-old pullets, and 3 wk later was diagnosed in 82-wk-old birds in an adjoining house. The duration of mortality in house 1 was 12 wk and in house 2 was 13 wk. A non-lactose-fermenting E. coli was isolated. Another outbreak of colibacillosis was diagnosed with 7.8% mortality at a different farm containing 47,000 110-wk-old hens and 10,000 40-wk-old pullets. On this farm the duration of mortality was not provided. Antibiotic treatment failed to reduce losses; chlorine added to the drinking water was effective in controlling the spread of disease and in reducing mortality at both farms.