Infected "carrier" hens harbor the bacteria in their ovaries. The bacteria pass into the egg during formation, meaning chicks are born already infected.
The disease was first described in 1900 by investigator Rettger, who isolated the organism from infected chicks and named it Bacillus pullorum . It is caused by Salmonella enterica serovar Gallinarum biovar Pullorum, a gram-negative, non-motile bacterium. While it has been largely eradicated from commercial poultry in many developed countries through rigorous testing and culling programs, it remains a significant threat in backyard flocks and some developing regions. Transmission: The Cycle of Infection bacillary white diarrhea
Within a brooder or hatchery, the disease spreads rapidly through contact with infected droppings, contaminated feed, water, or even through the air in forced-draft incubators. Clinical Signs and Diagnosis Bacillary White Diarrhea - ScienceDirect Infected "carrier" hens harbor the bacteria in their ovaries
A defining feature of BWD is its ability to transmit both horizontally and vertically: It is caused by Salmonella enterica serovar Gallinarum
Bacillary White Diarrhea (BWD), now formally known as , is a highly contagious bacterial infection caused by Salmonella pullorum . Historically a devastating "silent killer" in the poultry industry, it primarily strikes young chicks under three weeks of age, often resulting in mortality rates as high as 100% in susceptible flocks. Etiology and History