Disease-causing salmonellae have recently been re-classified into a single species, Salmonella enterica, which has numerous strains or serovars. Salmonella typhi is a well know serovar that causes typhoid fever. Other salmonellae are frequent causes of foodborne illness, and can especially be caught from poultry. In the mid to late 20th century, Salmonella enterica serovar Enteritidis was a common contaminant of eggs. This is much less common now with the advent of hygiene measures in egg production and the vaccination of laying hens to prevent samonella colonisation. Many different salmonella serovars also cause severe diseases in animals other than human beings.
Symptoms are usually gastrointestinal and can include nausea, vomiting, diarrhoea. These symptoms can be severe especially in the old and very young. Symptoms last generally up to a week, and can appear around 24 hours after ingestion of the bacterium.
The bacterium induces responses in the animal that it is infecting and this is probably what causes the symptoms rather than any direct toxin.
"I do not feel obliged to believe that the same God who has endowed us with
sense, reason, and intellect has intended us to forgo their use."
- Galileo Galilei
