The Widal test measures the capacity of antibodies against LPS and flagella in the serum of individuals with suspected typhoid fever to agglutinate cells of S. Typhi.
Typhoid enteritis is an acute systemic infection caused primarily by Salmonella typhi. The pathologic events of typhoid fever are initiated in the intestinal tract after oral ingestion of the typhoid bacillus. These organisms penetrate the small bowel mucosa, making their way rapidly to the lymphatics, and then spreading systemically. Hyperplasia of the reticuloendothelial system, including lymph nodes, liver, and spleen, is characteristic of typhoid fever. Peyer patches in the small bowel become hyperplastic and may subsequently ulcerate, complicated by hemorrhage or perforation.
