Pullorum disease salmonella spiC-rfaL double-gene knockout attenuated strain and DIVA vaccine application thereof

Abstract

The invention belongs to the field of fowl salmonellosis prevention and control and particularly relates to a pullorum disease salmonella spiC-rfaL double-gene knockout attenuated strain and preparation and application thereof. The attenuated strain is pullorum disease salmonella in which a spiC gene or an rfaL gene is not expressed. It is found through animal experiments that virulence of the mutant strain is remarkably reduced, and colonization time in a host body is shortened obviously. The attenuated strain is adopted for preparing pullorum disease salmonella live vaccine, after chickens are inoculated with the vaccine, no adverse reaction is generated, and strong virulence strain infection can be effectively eliminated. The host does not generate an anti-body aiming at O-antigen, by means of pullorum disease fowl typhoid multi-valence detection antigen, the attenuated stain can be effectively applied to glass plate agglutination experiments to distinguish immunized chickens and naturally infected chickens, and the characteristic of the DIVA vaccine is achieved.

Description

technical field [0001] The invention belongs to the field of prevention and treatment of poultry salmonellosis, and in particular relates to a double-gene knockout attenuated strain of Salmonella pullorum and its preparation and application. Background technique [0002] Pullorum is a multiple infectious disease caused by Salmonella Pullorum, which is very harmful to the chicken industry in my country. In addition to being able to spread horizontally, the pathogen can also spread vertically through eggs, resulting in a decrease in hatching rate and hatching rate. It usually infects chicks less than 20 days old. It is characterized by white diarrhea, showing the course of acute sepsis, and the morbidity and mortality are quite high. ; Adult chickens are mostly chronic or latent infection, generally without obvious clinical symptoms. The traditional way to prevent and treat this disease is to use antibiotics. Long-term use can easily cause many effects such as drug residues a...

AI Technical Summary

Problems solved by technology

The traditional way to prevent and treat this disease is to use antibiotics. Long-term use is likely to cause many effects such as drug residues and bacterial drug resistance. Therefore, the research on preventing pullorum with vaccines has attracted much attention.

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