Improper method or heredity? Reasons for the failure of animal immunity

Animal immunity

In immunity, it is often encountered that the disease still occurs after animals have been vaccinated with a certain vaccine, which is often referred to as immune failure. There are many reasons for immune failure, most of which are caused by improper management in the production, transportation, storage and use of vaccines. here are some reasons for immune failure.

One is the vaccine itself. The vaccine itself is safe. After inoculating the live vaccine, the vaccine strain can reproduce and replicate in the body, and there will be mild symptoms of natural infection. After vaccination, animals will have varying degrees of adverse effects and immune side effects, which is a kind of external stimulation to the body itself, and a strong stimulus to animals that already carry viruses or bacteria, which increases the possibility of the disease. in practice, death occurs when animals are immunized because of the safety of the vaccine itself.

The second is the quality of vaccine. In the process of vaccine production, some adjuvants must be added, which may cause immune side effects; the quality of the vaccine is unstable due to differences in production equipment of vaccine manufacturers; factors in storage, transportation, storage and use of the vaccine may also reduce the titer of the vaccine, and vaccines have storage, transportation and storage requirements, which must be required for preservation and transportation. For example, attenuated vaccines and bacterial vaccines must be preserved at a low temperature, and the temperature should be relatively stable and cannot be frozen and thawed repeatedly, otherwise the titer of the vaccine will decrease rapidly; the vaccine will be exposed to sunlight or taken out for too long, the vaccine will not be used up within the prescribed time limit after dilution, or the refrigerator will lose power, and other factors will reduce the titer of the vaccine, resulting in immune failure.

Third, the vaccine is improperly diluted. All kinds of vaccines have corresponding diluents, and the corresponding diluents must be selected when they are used, such as improper use, or the use of contaminated or lax disinfection diluents, when drinking water is immunized, the drinking fountains are not cleaned and disinfected, or contain disinfectants, dilution can not be used up within a specified time limit, etc. will lead to poor immune effect or immune failure.

Fourth, the method of vaccination is inappropriate. There are many kinds of immunization methods, such as intramuscular injection, subcutaneous injection, drinking water and spray. If the vaccine is not vaccinated in the right way, or the vaccination site is incorrect, intramuscular injection should be given, or during intramuscular injection, a "flying needle" appears, and the vaccine is not injected or the vaccine flows out of the pinhole. Factors such as insufficient vaccine injection may lead to immune failure.

Fifth, the equipment disinfection is not strict. The instruments are not strictly disinfected in accordance with the regulations, and during injection, one animal does not change a needle and disinfect head by head, and some epidemic prevention personnel do not pay attention to details and do not change needles during injection without disinfection, which is easy to cause vaccine pollution and mechanical transmission of virus, resulting in cross-infection of the epidemic.

Sixth, the improper use of disinfectants. When disinfecting with iodine tincture, do not deiodinate, so that the iodine tincture comes into contact with the vaccine, resulting in vaccine failure.

The seventh is the interference between vaccines. Inoculate two or more vaccines at the same time, do not pay attention to the interference between the vaccines, and reduce the immune effect of the vaccine.

Eighth, the immunization procedure is unreasonable. The formulation of immunization procedure should be combined with the epidemic situation and reality of local epidemic disease. If the formulation of immunization procedure is unreasonable or the timing of immunization is improper, the immunization effect will be greatly affected. Vaccination too early, will be interfered by maternal antibodies, resulting in immune failure; vaccination too late, there will be immune blank period, easy to cause livestock disease. If many kinds of vaccines are immunized at the same time, the vaccines will inhibit each other, resulting in immune failure.

Nine is the stress factor. The immune function of animals is regulated by various systems of the body. when animals are vaccinated in the stress reaction period, the immune ability will be reduced, the immune response ability will be weakened, and the antibody level will be reduced.

Ten is the drug factor. Some drugs can affect the immune response of the vaccine. The use of antimicrobials or additives containing drugs in feed during immunization will lead to the decrease of immune cells in the animal body, which will affect the immune response and lead to immune failure.

National Day holiday is an environmental factor. Such as high temperature, cold, overcast and rain, excessive temperature difference, excessive humidity, noise and other sudden climate changes or environmental changes will cause animal immunity failure.

Twelve is the management factor. Excessive feeding density, poor ventilation, poor environmental hygiene and other reasons are easy to cause stress reaction in animals. There are a large number of pathogenic microorganisms in the feeding environment, animals are very vulnerable to infection, at this time vaccination will affect the effect of the vaccine, resulting in immune failure. Feeding moldy and deteriorated feed can lead to thymus lymphoid atrophy and decreased phagocytosis of macrophages, resulting in immunosuppression.

Thirteen are diseases and individual factors. When animals are vaccinated, some animals have been in the incubation period, and some have been infected with serious parasites, at this time vaccination will inevitably lead to animal disease. Sometimes animals are inoculated in a healthy state, and due to differences in breeds, epidemic side effects will occur after immunization.

Fourteen is a nutritional factor. Vitamins and other nutrients have significant effects on the immunity of animals. Nutrient deficiency, especially vitamin A, D, B, E, trace elements and protein, will affect the immune response of the body to antigen, and the immune response is obviously inhibited.

The fifteenth year is the cause of animal health. The health examination of animals before immunization is a very important work, which is the key link to ensure the quality of immunity and reduce death. Before vaccination, you should ask in detail about the animal medical history and carefully observe the health status of the animals to ensure that the animals are in a healthy state before they can be immunized.

Sixteen is drug abuse. Some antibiotics, antiviral drugs and hormones can inhibit the proliferation of lymphocytes, immune effect and affect the immune response.

Seventeen is the animal body infected with immunosuppressive diseases. Some animals will be immunosuppressed when they are infected with an epidemic disease. There are many diseases that lead to immunosuppression, such as classical swine fever, blue ear disease, porcine circovirus, pseudorabies, parvovirus, swine influenza, asthma, mycoplasma pneumoniae infection, infectious pleuropneumonia, salmonellosis, toxoplasmosis, parasitic diseases and so on. Inhibitory diseases mainly invade and damage the humoral or cellular immune central organs of animals, so that the production of lymphocytes is destroyed, reduced or unable to produce immunoglobulins, resulting in immune response dysfunction and immune dysfunction. Reduce the response of animal groups to vaccination, resulting in immunosuppression.

Eighteen is a genetic factor. The immune response of animal body to vaccination antigen is controlled by heredity, and its response is different, even if the immune response of different individuals of the same breed to the same vaccine is also different. Some animals are born with immune deficiency, which can easily lead to immune failure.