Relationship of increased fowl cholera outbreaks in turkeys with high environmental temperatures

The relationship of an increase in fowl cholera outbreaks in turkeys with a n increase in environmental temperatures during June, July, August, and Sep tember between 1959 and 1992 was analyzed. High environmental temperatures were found to be influential in the development of fowl cholera in turkeys. When the average monthly maximum environmental temperatures for 5 mo of Ju ly and 7 mo of August during the 13 yr between 1967 and 1979 were above 30. 5 C, there was a significantly (P < 0.05) higher number of fowl cholera out breaks in turkeys for each month than during the same months when the avera ge maximum temperatures were below 30.5 C. To test he hypothesis that an in crease in fowl cholera outbreaks was preceded by an increase in temperature , the pre- and postoutbreak temperatures for 46 selected outbreak clusters occurring between 1959 and 1992 were averaged. Both the average maximum and minimum temperatures for the latter 9 days of the preoutbreak period were highly significantly (P < 0.001) higher than those of the average cluster o utbreak day and the following four postoutbreak days. Also, for the nine in dividual days of the latter pre-outbreak period, the daily average maximum temperature was significantly (P < 0.05) higher for 3 days and partially si gnificantly (P < 0.10) higher for 3 days than that of the average cluster o utbreak day, and the daily average minimum temperature was significantly (P < 0.05) higher for 2 days and partially significantly (p < 0.10) higher fo r 1 day than that for the average cluster outbreak day.