Treatment - Replace fluid and electrolytes. Organisms bind to the intestinal wall penetrate into Peyer's patch where they invade macrophages and multiply. Intracellular survival is associated with inhibition of oxidative metabolic burst and protection from antibodies. Organisms spread from Peyer's patch to the liver, spleen and blood. In the blood organisms release endotoxins.
Immune response is humoral and cell mediated.
Symptom - High fever and headache. Treatment - Chloramphenicol, cephalosporin, ampicillin and quinolones. An oral vaccine is available. The agents are Sh. They are gram negative non-motile rods facultative anaerobes placed in groups based on their O antigen and biochemical reactions.