Brucella abortus differs in the multiplication within bovine chorioallantoic membrane explants from early and late gestation.

The ability of Brucella to infect and grow within extraplacentomal chorioallantoic explants (CAMs) derived from early and late gestational cattle was compared. Following inoculation of CAMs with equal numbers of strain 2308 B. abortus, the infectivity was approximately the same in CAMs from both ages, however, bacterial replication was significantly greater in late gestational CAMs than in early gestational CAMs. Co-culture of both early and late gestation CAMs or culture of both types of CAMs in the presence of tissue culture media collected from either early or late B. abortus inoculated CAMs failed to alter B. abortus growth rates and/or cytopathic effects.