Preparation and evaluation of a novel combined inactivated vaccine against Pasteurellosis and E. coli infection in Sheep

Abstract

Pneumonic Pasteurellosis is a common disease in sheep that affects the sheep industry. Also, E. coli, which affects young lambs and adult sheep, causing morbidity and mortality, threatens sheep's wealth. Therefore, an inactivated adjuvanted combined vaccine against pasteurellosis and E. coli infection was prepared to counteract their catastrophic effects. In this study sheep aged 6 weeks were divided into four groups. The first group was immunized with P. multocida (A, D, B6) and M. haemolytica (A, P. trehalosi type T) vaccine. The second was immunized with the E. coli (K99) vaccine. The third was immunized with a combined P. multocida, M. haemolytica, and E. coli vaccine. The fourth was kept as a non-vaccinated control group. All sheep were injected subcutaneously with two doses (2 weeks apart) of the vaccines (1 ml/dose). The vaccination of sheep was at six weeks of age. The highest antibody titers after boostering for groups vaccinated with P. multocida and M. haemolytica vaccines were as follows: the 1 st group and the 3 rd group for type A, B6, and P. trehalosi at the 4 th month, but P. multocida type D at the 5 th month and M. haemolytica type A at the 3 rd month. The 2 nd and 3 rd groups had the highest antibody titers for E. coli at the 3 rd month. Statistically, there were no significant differences between the results of the combined or single vaccines. Briefly, the combined inactivated vaccine against pasteurellosis and E. coli has good effects, with priority given to protecting sheep against these diseases and decreasing the stress on the livestock and the efforts of vaccination.