Detection of turkey coronaviral enteritis (bluecomb) in field epiornithics, using the direct and indirect fluorescent antibody tests.

In Minnesota, efforts have been made over the past 10 years to eliminate turkey coronaviral enteritis (TCE, bluecomb) by controlled depopulation and decontamination with a rest period before restocking. In 1973, clinical observations indicated that bluecomb was restricted to one limited area in Minnesota. Five epiornithics occurred during late 1973 and 1974, involving 5 different farms in this limited geographic area. During 1975, 3 epiornithics of TCE were investigated, involving 185,000 turkeys in 17 flocks, of which approximately 17,000 died. Naturally infected turkeys representing 7 operations between 1973 and 1976 were examined by both the direct fluorescent antibody test and indirect fluorescent antibody test (IFAT). The direct fluorescent antibody test detected coronaviral antigen in intestinal tissues during the acute phase of the disease, and the IFAT was highly useful in detecting TCE serum antibodies of turkey flocks that had recovered and were potential carriers. Therefore, an IFAT surveillance program was instituted for replacement flocks on farms where clinical epiornithics of TCE had occurred in 1974 through 1976. Operation 5 involved TCE epiornithics over a 2-year period and illustrate the importance of complete depopulation with an intensive decontamination program.