Salmonella Typhi possesses three main antigenic factors: the O, or somatic antigen; the Vi, or encapsulation antigen; and the H, or flagellar antigen.
Most cases of salmonellosis are caused by food infected with S. enterica, which often infects cattle and poultry, though also other animals such as domestic cats and hamsters have also been shown to be sources of infection to humans. However, investigations of vacuum cleaner bags have shown that households can act as a reservoir of the bacterium; this is more likely if the household has contact with an infection source, for example through members working with cattle or in a veterinary clinic.
Raw chicken and goose eggs can harbor S. enterica, initially in the whites of the eggs, although most eggs are not infected. As the egg ages at room temperature, the yolk membrane begins to break down and S. enterica can spread into the yolk. Refrigeration and freezing do not kill all the bacteria, but substantially slow or halt their growth. Pasteurizing and food irradiation are used to kill Salmonella for commercially-produced foodstuffs containing raw eggs such as ice cream. Foods prepared in the home from raw eggs such as mayonnaise, cakes and cookies can spread salmonella if not properly cooked before consumption. See Egg (food).
Research reports on salmonellosis from Technical University of Denmark, World Health Organization provide new insights.
Oct 14, 2009; According to recent research from Copenhagen, Denmark, "An international external quality assurance system (EQAS) for the...