This article describes the advantages and disadvantages of different methods of challenge of pigs with the pathogen Er. rhusiopathiae and conducted a study to establish a reference method for the test of challenge of swine in the quality control of live and inactivated vaccines against swine erysipelas on indicators of efficacy∕immunogenicity.

Test infected pigs should mimic, to the extent possible, the natural route of infection. For this test, we described different methods with different routes of administration of the causative agent (scarification, intravenous, intramuscular, unotron, oral and conjunctiva), which creates significant difficulties in the assessment of research results for the quality control of live and inactivated vaccines against swine erysipelas on indicators of efficiency∕immunogenicity.

Different models of challenge and pathogenicity of different strains of   Er. rhusiopathiae is the cause of the different clinical signs and different time of development of the swine disease erysipelas.

The study of this question opens the way for the development of a standard test of pigs, challenge which allows the quality control of vaccines against swine erysipelas on indicators of efficiency∕immunogenicity according to the requirements of the European Pharmacopoeia 0064 and DSTU 6079:2009. These relevant provisions and determined the choice of directions of our research and methods of performance.

The purpose of this work was to establish a reference method for the test of pigs challenge with strains of Er. rhusiopathiae serovars 1 and 2.

1. Strains for the test of challenge the pigs. Material for test of challenge were strains of the causative agent of swine erysipelas isolated from pathological material of dead pigs (Er. rhusiopathiae RS/1 serovar 1a and Er. rhusiopathiae RS/2 serovar 2b).

2. Animals and procedure of challenge. Studies were conducted at the Kherson state enterprise – biological factory, Kherson, Ukraine. In the experiment, we used clinically healthy pigs 12 weeks of age (3 heads on each input method: intradermal methods and scarification, and serovars Er. rhusiopathiae, which was the total number of pigs in the experiment − 12), free from antibodies to the causative agent of swine erysipelas. Experimented pigs were introduced methods and intradermal methods and scarification with the lateral surface of the body at the border of the abdominal and chest walls of the culture
Er. rhusiopathiae RS/1 serovar 1a in a dose of 1.0×10⁶ CFU per 0.1 cm³ and the Er. rhusiopathiae RS/2 serovar 2b is 2.0×10⁷ CFU∕0.1 cm³, with control introduction appropriate method of 0.1 cm³ of sterile saline on the opposite side of the animal.

Results of the conducted researches it is established that in all the experimental pigs challenge with strains of Er. rhusiopathiae: RS/1 serovar 1a and Er. rhusiopathiae RS/2 serovar 2b intradermal methods of challenge and scarification were observed typical signs of the disease swine erysipelas.

The strains of Er. rhusiopathiae serovars 1a and 2b were pathogenic to pigs in doses of 1.0×10⁶ CFU ∕0.1 cm³ and 2.0×10⁷ CFU∕0.1 cm³, respectively, and can be used as a control.

It should be noted that, with inoculation of strains of the Er. rhusiopathiae RS/1 & RS/2 methods, intradermal challenge and scarification, we obtained almost identical development of the disease in the research of pigs with similar clinical manifestations and time of development of the disease, indicating the possibility of using both methods as a reference when conducting the test of pigs challenge.

However, in the evaluation of infected pigs by scarification, it is necessary to consider the possibility of inflammation of the skin (in the form of minor dermatitis) as a result of scratches during the scarification.

The development of typical clinical signs of the swine disease erysipelas is a reflection of a successful infection of pigs intradermal methods of challenge and scarification.

The proposed model of challenge of pigs (intradermal methods and scarification) can be recommended for quality control of vaccines against swine erysipelas on indicators of efficacy∕immunogenicity according to the requirements of the European Pharmacopoeia 0064 and DSTU 6079:2009.

Keywords: patogen of swine erysipelas, Erysipelothrix rhusiopathiae, immunogenicity, isolates, pathogenicity, serovars, strains.