Submitted to: Avian Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 5, 2005
Publication Date: May 1, 2005
Citation: Withanage, G.K., Sasai, K., Fukata, T., Miyamoto, T., Lillehoj, H.S., Baba, E. 2005. Increased lymphocyte subpopulations and macrophages in the ovaries and oviducts of laying hens infected with salmonella enterica serovar enteritidis. Avian Pathology 32:583-590.
Interpretive Summary: The incidence of Salmonella Enteritidis (SE) isolation associated with food poisoning has dramatically increased in many countries. Chickens appear to be the major reservoir of this organism with eggs and poultry products being the most important sources of salmonellosis. Ability to control foos poisoning caused by Salmonella depends upon our ability to understand host immunity to this pathogen and development of novel vaccine. In order to understand how Salmonella contaminates poultry meat, ARS scientists in collaboration with scientists at University of Osaka conducted series of studies to investigate Salmonella contamination of poultry reproductive tracts. The results indicated that the reproductive organs of laying hens are important sites for Salmonella colonization and for egg contamination. In order to develop a strategy to reduce Salmonella contamination of the intact eggs, understanding the local immune responses in the reproductive organs in chickens will be important. Additional studies based upon the results of this study will enhance our understanding of the nature of host protective mechanisms involved against Salmonella and will help poultry industry to better manage salmonellosis.
Salmonella enterica serovar Enteritidis (SE) is a causative agent for human food poisoning cases throughout the world. The ovaries and the oviducts of the laying hens are the major sites of SE colonization from which vertical transmission to eggs occurs. In this study Salmonella-induced changes in T lymphocytes, B-lymphocytes and macrophages in the ovaries and oviducts were assessed after primary and secondary experimental inoculations of laying hens with SE. Statistically significant increases in the numbers of T cells (both CD4+ and CD8+) and macrophages were observed at 7 to 14 days after primary inoculation followed by a peak in B-cell numbers from the 14th day post-primary inoculation onwards in the secretary areas of the oviducts. The peak in lymphocyte numbers immediately preceded a decline in the rate of SE recovery from the reproductive tract beginning at day 14. The correlation of decreased Salmonella recovery with elevated lymphocyte and macrophage numbers strongly suggests that local cell-mediated immunity is involved in controlling SE infection in the ovaries and oviducts