On-station And Field Evaluation Of Inactivated Fowl Cholera Vaccine Produced From Local Pasteurella Multocida Isolates Ethiopia

Vaccination is one of the common preventive measures of fowl cholera. An experimentalrnstudy on-station and field evaluation was carried out from November 2017 to April 2018.rnThe objectives of this study were to evaluate the safety, immunogenicity and protectivernefficacy of inactivated fowl cholera vaccine recently developed at National VeterinaryrnInstitute of Ethiopia using local Pasteurella multocida isolate. The vaccine was producedrnwith titer of 2.5x108 cfu/ml and evaluated in 8 weeks old chickens (n=60) by injecting 1rnml through IM (Group I; n=20), 0.5 ml IM route (Group II; n=20) and 20 chickens keptrnas unvaccinated control. The sera were collected from all groups’ at day 0, 14, 21, 28,rnand 35 and subjected for antibody titer determination by indirect haemagglutination test.rnBoostered with the same dose and route after 21 days of primary vaccination. Finally, thernvaccinated and control chickens were challenged using virulent strains of Pasteurellarnmultocida at day 15 of post booster vaccination. The study at field level was conductedrnusing 200 chickens isolated in a separate compartment. The chickens were vaccinatedrnwith 0.5ml through IM route at day 0 and booster dose was given with 0.5ml after 21 dayrnof primary vaccination. Sera were collected at day 0, 21 and 35 and examined by indirectrnhaemagglutination test. Mean antibody titers of Group I were 1.6±1.2, 211.3±2.1,rn244.5±1.2, 319.8±1.2 and 502±1.2 at day 0, 14, 21, 28 and 35, respectively. In Group II,rnmean antibody titers were 1.3±1.2, 203.7±3.0, 234.2±1.2, 367.2±1.2.5 and 452.9±1.2 atrnday 0, 14, 21, 28 and 35, respectively. In Group III, mean antibody titer remain constant.rnIn case of protective efficacy, both 1 and 0.5ml dose had 87.5% protection. At fieldrnstudy, the mean antibody titers were 4.2±1.1, 310.4±1.0 and 532.6±1.0 at day 0, 21 andrn35, respectively. Formalin killed fowl cholera vaccine induces immune response andrnmean antibody titer increases after booster vaccination in both control and farmrncondition. The protective efficacy and immunogenicity between 1 and 0.5 ml dose of thernvaccine was found insignificant difference. Therefore, the use of 0.5ml dose with boosterrnvaccination at day 21 after primary vaccination is recommended.

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