Colonial growth pattern of Salmonella
choleraesuis subsp. arizonae bacteria grown
on a blood agar culture plate
This section provides information on one of the nine zoonotic diseases which have been identified by a experts in a national consultation organised by RCZI in June, 2008  as focus or priority diseases for the next five years.

Salmonellosis is one of the most common and widely distributed foodborne diseases. Salmonellosis is caused by the bacteria Salmonella. Millions of human cases are reported worldwide every year and the disease results in thousands of deaths.

Salmonella spp. have been found in all species of mammals, birds, reptiles and amphibians that have been investigated. Fish and invertebrates can also be infected. Infections are particularly prevalent in poultry, swine and reptiles. Among reptiles, infections have been found in turtles, tortoises, snakes and lizards (including chameleons and iguanas). All species seem to be susceptible to salmonellosis under the right conditions but clinical disease is more common in some animals than others. Clinical cases are common in cattle, pigs and horses but are relatively uncommon in cats and dogs.

Colorised scanning electron micrograph shows
clustered Gram-negative Salmonella typhimurium
bacteria grown in pure culture
Salmonellosis in humans is generally contracted through the consumption of contaminated food of animal origin (mainly meat, poultry, eggs and milk), although many other foods, including green vegetables contaminated from manure, have been implicated in its transmission. A total of 2 501 different Salmonella serotypes have been identified up to 2004. While all serotypes can cause disease in humans, they are often classified according to their adaptation to animal hosts.

Salmonellosis constitutes a major public health burden and represents a significant cost to society in many countries. In the United States of America, an estimated 1.4 million non-typhoidal Salmonella infections, resulting in 168 000 visits to physicians, 15 000 hospitalizations and 580 deaths annually. Cost estimates per case of human salmonellosis range from approximately US$ 40 to US$ 4.6 million respectively for uncomplicated cases to cases ending with hospitalization and death. The total cost associated with Salmonella is estimated at US$ 3 billion annually in the United States. Data related to the cost of foodborne disease are generally not available from developing countries.

Global Situation

Recent Publications and Reviews

Confirmed and Suspected Outbreaks of Salmonellosis