Cross protection of goats primed with formalin-killed Pasteurella multocida B2 againts live Mannheimia haemolytica A2 infection

Abstract

Pasteurella multocida B2 and Mannheimia haemolytica A2 are among the bacteria that caused haemorrhagic septicaemia in cattle and buffaloes worldwide. A study was conducted from 24th September until 5 November 2006 to determine the cross protection ability of formalin-killed Pasteurella multocida B2 inoculated goats against live Mannheimia haemolytica A2 infection. This study will give better understanding in developing homologous and heterologous protection against the bacteria. Nine clinically healthy goats aged between seven to nine months were divided equally into three groups. Group 1 and 2 were exposed to formalin-killed P. multocida B2 at the bacterial load of 10th colony forming unit (cfu)/mL, twice intranasally with two weeks interval. Two weeks after the second exposure, Group 1 were challenged with M haemolytica A2 while group 2 with P. multocida B2. Group 3 was remained as the control unexposed group. One goat in Group 2 died on day 3 post-exposure while the remaining survived. On seventh week, all of the goats were slaughtered. Mild gross lesions were observed on the vital organs of goats in Group 1 and 2 upon post mortem.