Persistence of Salmonella enteritidis in young chickens.

One- and 7-day-old specific pathogen-free chickens were artificially infected with a field isolate of Salmonella enteritidis, phage type 13A. At intervals up to 42 days of age, birds were killed and liver, lung, spleen, brain, yolk sac, testis or ovary, duodenum, jejunum, ileum, caecum and colon collected for culture. In chickens infected at one day of age and killed 1, 4 and 7 days pi all tissues were infected. Thereafter most non-intestinal tissues (74%) and intestinal tissues (92%) were positive for S. enteritidis. In chickens infected at 7 days of age, all tissues were positive 1 dpi. After post-inoculation day 1, a few non-intestinal tissues (15%) were positive for S. enteritidis while 38% of intestinal tissues were positive.