Asymptomatic Salmonella carriers – Incidence and Factors - project description
This project will investigate how many people in Norway remain carriers of Salmonella bacteria for an extended period of time after they have had a Salmonella infection and why.
Salmonella infection, or "Salmonellosis", is a disease caused by infection with Salmonella bacteria. The most common symptoms are diarrhoea, fever and abdominal pain. During the infection, patients excrete large numbers of Salmonella bacteria with their faeces. These bacteria can potentially infect other people via the faecal-oral route. The bacteria usually disappear from the gut and the faeces within a few weeks after the infection symptoms have stopped. But in some cases, the bacteria persist in the gut for several weeks, months or longer without causing symptoms. These asymptomatic carriers excrete Salmonella bacteria unknowingly, potentially infecting others.
In this project, we want to determine the proportion of cases that become asymptomatic Salmonella carriers after they have had a Salmonella infection. In addition, we will investigate if host, environmental or bacteria-specific factors contribute to a prolonged asymptomatic Salmonella carriage.
The study will be conducted as a casus-casus study, where participants will be recruited among all salmonellosis cases in Norway between January 2019 to September 2020. Participants will be asked to answer a questionnaire and to provide a faecal sample. The questionnaire will map potential host-related risk factors for Salmonella infection and carriage, such as contact with animals, medicine use and diet. The faecal sample will be used culture Salmonella bacteria in order to determine if the participant is an asymptomatic Salmonella carrier or not. If Salmonella bacteria are detected, then their genetic make-up (genome) will be characterised and compared with that of other Salmonella bacteria in order to detect bacteria-specific risk factors. A selection of faecal samples will also be used to characterise the entire bacterial community present in order to detect environment-specific risk factors.
The study will provide knowledge about the incidence of asymptomatic Salmonella carriers in Norway, which will be useful for revising the national infection control measures after end Salmonella infection.
See the full project description at Cristin for more information about results, researchers, contact information etc.
Karin Maria Nygård, Norwegian Institute of Public Health
Liselotte Buarø, Avdeling for molekylærbiologi, Norwegian Institute of Public Health
Emily Ann Macdonald, Norwegian Institute of Public Health
Line Vold, Norwegian Institute of Public Health
Solveig Jore, Norwegian Institute of Public Health
Kristian Franer, Norwegian Institute of Public Health
Lamprini Veneti, Avdeling for smitte fra mat, vann og dyr, Norwegian Institute of Public Health
Roberto La Ragione, University of Surrey
Hilde Marie Lund, Avdeling for smitte fra mat, vann og dyr, Norwegian Institute of Public Health