Fowl Typhoid in Laying Hens: Description of the disease and Protection Conferred by a Live Salmonella Enteritidis Vaccine

Salmonella Gallinarum with the biotypes Gallinarum and Pullorum causes two septicaemic diseases in poultry: Fowl Typhoid and Pullorum Disease. The former Salmonella Pullorum serovar is not recognised anymore as such. Both biotypes are differentiated by a few biochemical and molecular tests. This bacterium is highly adapted to produce a septicaemic disease in birds. In general all other animals’ species are refractory to the disease. Mammals may be infected without showing any illness. In contrast to zoonotic Salmonella serovars, Salmonella Gallinarum do not cause any gastroenteric disease in humans transmitted throughout the food chain. Many animals, including men, may become asymptomatic carriers. Vectors such as rodents, flies, darkling beetles and red mites are very important reservoirs and sources of infection. Red mites may introduce Salmonella Gallinarum directly into the blood stream when they bite the hen.