Involvement of the upper respiratory tract in orally induced salmonellosis in mice

The possible involvement of the tissues of the head and neck during the early pathogenesis of orally or intragastrically induced murine salmonellosis was examined. Viable counts of Salmonella in the local lymphoid tissues and draining nodes indicated that the ileal Peyer's patches were primarily involved in the development of a subsequent enteric fever, irrespective of the method of oral challenge. Contamination of drinking water with a high concentration of salmonellae produced infection of the ileal Peyers patches and the eventual development of systemic disease. The cervical lymph nodes were sporadically involved early in the infection, but this involvement soon became general, with large numbers of salmonellae in the cervical nodes by 36 hr. A lower concentration of salmonellae in drinking water led to primary involvement of the ileal Peyers patches; upper respiratory tract involvement was detected much later in the infection. Intragastrically invected mice exhibited the same low-level infection of the cervical lymph nodes as that in mice infected via drinking water. Thus systemic infection apparently results from infection of the ileal Peyers patches; a small percentage of the animals develop a concurrent upper respiratory tract infection that may be responsible for the development of carrier states after enteric infection.