Author
Purdy, Charles | |
COOLEY, J - TX TECH HEALTH SCI CTR | |
STRAUS, DAVID - TX TECH HEALTH SCI CTR |
Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/6/1997 Publication Date: N/A Citation: N/A Interpretive Summary: There are 12 Pasteurella haemolytica (Ph) serotypes which may be recovered from ruminant animals. Cross protection induced in the ruminant by these serotypes is not understood. The Ph1 bacteria are very important in causing acute bovine respiratory tract disease in market stressed feeder/stocker calves. Pasteurella haemolytica serotypes 1, 2, and 6 are recovered frequently from stressed feeder calves. Therefore, we wanted to determine the amount of cross protection induced by these 3 serotypes in a goat model. We determined, as expected, that goats immunized and challenged with the same serotype were protected. P. haemolytica 1 immunized goats were also protected against a serotype 6 challenge. P. haemolytica 2 immunized goats were not protected against a Ph1 challenge, but were protected against Ph6 challenge. There appears to be some cross protection between some of the Ph serotypes, and this should be considered when developing vaccines against this organism. Technical Abstract: Cross-protection studies employing three serotypes of Pasteurella haemolytica (Ph) were performed in goats, using exposure by transthoracic injection. Sixty-four weanling male Spanish goats were randomly allotted to sixteen groups. Protection was assessed by the absence or smallness of the induced lesion at the lung challenge site. Mean volume of consolidated dlung tissue for the Ph1 immunized goats challenged with Ph1, Ph2, and Ph6 were 28.29 cm**3, 8.36 cm**3, and 16.29 cm**3, respectively. Mean volume of consolidated lung tissue for the Ph1 immunized goats challenged with Ph1, Ph2, and Ph6 were 4.38 cm**3, 0.25 cm**3, and 1.90 cm**3, respectively. Mean volume of consolidated lung tissue for the Ph2 immunized goats challenged with Ph1, Ph2, and Ph6 were 9.68 cm**3, 0.05 cm**3, and 3.39 cm**3, respectively. Mean volume of consolidated lung tissue for the Ph6 immunized goats challenged with Ph1, Ph2, and Ph6 were 14.05 cm**3, 1.27 cm**3, and 4.53 cm**3, respectively. These data demonstrate protection in immunized goats challenged with the homologous serotype of P. haemolytica. Ph1 immunized animals were protected against serotype 2 challenge as well as serotype 6 challenge. Ph2 immunized animals were not protected against serotype 1 challenge, but were protected against transthoracic Ph6 challenge. Ph6 immunized animals were not protected against serotype 2 challenge but were protected against transthoracic Ph1 challenge. There appears to be some cross-protection amongst the P. haemolytica serotypes and this should be taken into consideration when developing vaccines against this organism. |