Causes of animal immune failure

After animal immunization, it can not resist the invasion of corresponding pathogens within the period of validity of immunization, and the infectious disease still occurs, or the failure of efficacy test can be regarded as the failure of immunization. There are many reasons for the failure of immunization, and some common reasons can be summarized into three major factors.

? First, vaccine factors

The main results are as follows: 1. the protective performance of the vaccine itself is poor or has a certain virulence.

2. The serotype or subtype of the vaccine virus (bacteria) strain is not consistent with that of the epidemic strain in the field, or the serotype of the epidemic strain has changed, or the vaccine is not selected properly or even the wrong vaccine is used.

3. Improper transportation and storage of the vaccine, or failure to use the vaccine in time after dilution, resulting in inefficacy or inefficacy of the vaccine, or the use of expired or deteriorated vaccine.

4. The interference between different kinds of vaccines.

? II. Animal factors

The main results are as follows: 1. When the live vaccine was inoculated, the higher maternal antibody or the residual antibody from the previous immunization interfered with the vaccine.

2. At the time of inoculation, the animals were already in latent infection, or pathogens were brought by vaccination personnel and tools during vaccination.

3. There are immunosuppressive diseases or other epidemic diseases in the fauna, which temporarily decrease the immunity and lead to the disease.

? III. Human factors

1. The work of immunization is not serious. For example, when drinking water is immunized, the drinking fountain is insufficient, the vaccine is diluted incorrectly or unevenly, the amount of vaccination is insufficient, and there are omissions in vaccination.

2. The way or method of immunization is wrong, for example, the inactivated vaccine that can only be injected is vaccinated by drinking water.

3. Immunosuppressive drugs were used before and after immunization, or antibiotics were used during live bacterial immunization.