Abstract
The study was undertaken to determine biochemic, serologic and immunologic characteristics of P. multocida isolated from naturally infected chickens and ducks of Bangladesh. A total of 345 isolates were studied. Accord- ing to the fermentative reactions in xylose, arabinose and dulcitol, 33.62% isolates were classified in Group II, 3.67% to Group III, 13.91% to Group IV and 48.69% to Group VI. Considering the type specific reactions in Rapid plate agglutination, Indirect hemagglutination and Gel-diffusion precipitin tests with 53 selected isolates from all biochemical groups, 39 (73.58%) were classified as serotype 1 (X-73), 12 (22.64%) as serotype 3 (P-1059) and two (3.77%) remained unclassified.
Immunogenic properties of the four types of bacterins such as Broth culture bacterin (BCB), Adjuvanated broth culture bacterin (ABCB), Washed cell bacterin (WCB) and Adjuvanated washed cell bacterin (AWCB) prepared with each
of
three selected field isolates were studied. These isolates belonged to three biochemical groups but represent- ing the serotypes 1 (X-73) and 3 (P-1059). Adjuvanated bacterins were found to elicit better immune response than non-adjuvanated bacterins. ABCB was found to be superior to BCB, and BCB proved to be superior to WCB and bacterins currently used in the field (P<0.05 to P <0.01). Mul-tiple comparison among the bacterins indicated that bacterins prepared with field isolates belonging to sero- type 1 (X-73) were highly immunogenic. Analysis of variance also indicated that dual vaccinated birds showed better protection than that of single vaccinated (P<0.01).
P. multocida was recovered from a small number of birds that survived challenge infection after vaccination. Localized lesions of chronic type of fowl cholera were found to develop in few vaccinated birds which survived challenge infection.