Detailed description of sheep foot-and-mouth disease vaccine

Sheep foot-and-mouth disease vaccine is a type of animal vaccine injection, and the types of vaccines are different. For example, it includes traditional vaccines and inactivated vaccines. In addition, we should pay special attention to the use of these vaccines. The use methods of cattle O type or swine O type foot-and-mouth disease inactivated vaccines may also be different. But we all know that vaccination is an effective way to prevent the occurrence of epidemics.

1. Types of vaccines

1. Traditional vaccines

Most countries where FMD is prevalent adopt measures mainly based on planned immunization to prevent and control FMD, and traditional vaccines still play a dominant role in the prevention and control of FMD. 1.1 Attenuated vaccines are usually developed by using heterologous non-susceptible animals or continuous cell culture to attenuate the virus. However, due to the wide host range of the foot-and-mouth disease virus, it is difficult to balance the relationship between virulence and immunity. In addition, attenuated vaccines are genetically uncertain and long-term use may lead to persistent infection. Attenuated vaccines cultivated for a long time are not suitable for animal immunization in new epidemic areas.

2. Inactivated vaccines

The widely used foot-and-mouth disease vaccine is prepared by adding an appropriate amount of adjuvant formula to the inactivated whole virus. However, whole virus inactivated vaccines have the following limitations: (1) highly sealed facilities must be used in the vaccine production process; (2) the viruses used in most vaccines are prepared from cell culture suspensions infected with FMDV, which contain a variety of non-structural proteins. The use of these vaccines causes the body to produce a large amount of antibodies against non-structural proteins, making the differential diagnosis of immunized animals and infected animals quite difficult;

2. Usage

(1) The inactivated bovine O-type foot-and-mouth disease vaccine is made by selecting the strong bovine virus OA/58 with a broad antigenic spectrum, good antigenicity and immunogenicity as the virus strain. The virus antigen is prepared by inoculating it into a monolayer culture of the BHK-21 cell line, inactivating it with diethyleneimine (BEI), and adding mineral oil as an adjuvant to make an emulsion vaccine. It is a slightly pink or milky white viscous liquid. It is used for preventive and emergency vaccination of cattle, buffaloes, dairy cows and yaks of various ages, with the immunity lasting for 6 months.

(2) The inactivated swine foot-and-mouth disease vaccine type O is prepared by inoculating BHK-21 or IBRS-2 cell monolayers with virulent swine virus, harvesting the cell venom, inactivating it with diethyleneimine (BEI), and emulsifying it with an oil adjuvant. It is a milky white or light red viscous emulsion. After storage, a small amount of oil is allowed on the liquid surface and a trace amount of water is allowed at the bottom of the bottle (not more than 1/10 respectively). It will become a uniform emulsion when shaken. Used to prevent swine foot-and-mouth disease type O, the immunity lasts for 6 months.

3. Notes

1. Foot-and-mouth disease vaccine is an inactivated vaccine and is one of the most important weapons for preventing and controlling the occurrence and spread of foot-and-mouth disease. However, there are still some defects. Generally, it can only induce short-term immunity, that is, 4 months.

2. Choose and use effective vaccines. Before vaccination, you must first identify whether the vaccine is expired or ineffective, whether the potency is high, and whether the vaccine bottle is cracked or damaged. If demulsification occurs or stratification exceeds the specified amount (1/10), it cannot be used.