Salmonella Unit

Food borne diseases-salmonella



Salmonellais a common layman’s name for the food borne disease salmonellosiscaused by a strain of bacteria with the generic name salmonella. Itis most famous as a cause of food poisoning characterized by mild tosevere diarrhea, fever, and abdominal cramps 12 to 72 hours afterinfection. In the US alone, salmonella infections are reported inover 42,000 cases annually thus making it one of the most commoninfections. The infection is lethal with 19,000 cases resulting inhospitalization and 380 deaths annually. There are only two speciesof salmonella namely, Salmonellabongoriand Salmonellaenteric.However, these two species have several subspecies with the two mostcommon being Salmonellaserotype Typhimurium and Salmonella serotype Enteritidis(Salmonellosis 2014).

Infectionmostly occurs after consumption of contaminated food. Food can becontaminated through food processing or handling. Other than that,individuals may contaminate the food via hands after handlingcontaminated things. Some of the things that harbor salmonella andcause infection include human feces of infected persons, feces ofanimals especially rodents such as hamsters and rabbits, and anyother feces of infected animals. Given that the bacteria invade thedigestive system in the body, feces of infected animals and humanscarry a high concentration of the bacteria. Therefore handling suchcontaminants and failing to properly wash hands can lead tocontamination of food directly or indirectly.

Onceingested through the mouth, salmonella shows its resilienceimmediately by surviving the first test of saliva in the mouth. Italso survives the low pH of the stomach’s digestive juices thattarget killing of pathogens and breaking down food. Past the stomach,the bacteria reach the small intestines where they invade the innerepithelial walls. The body’s immune system responds through theimmune protein interleukin-22 (IL-22) which produces oxygen radicalsto kill the salmonella through sequestration of essential nutrientssuch as iron, zinc and manganese. These radicals kill some butbenefits more salmonella. This happens because the released radicalscreate a sulfur compound called tetrathionate from which salmonellacan obtain oxygen and thus is able to “breathe”. This enables thesalmonella to outnumber the good bacteria in the gut which onlymultiplies through fermentation. By also inducing an inflammatoryreaction in the intestines, the body results to diarrhea in anattempt to get rid of the salmonella which also aids in distributingit. Large-scale distribution leads to outbreaks which are common inthe US (Salmonella 2014).

Forexample starting from February to September 2014, CDC reported a mildsalmonella outbreak touching 43 states. Over 360 cases were reportedand the infected persons ranged from infants to over 90 year olds. Nodeaths were reported. The outbreak was traced to poultry and thecommon strains were identified as SalmonellaInfantis, SalmonellaNewport, or SalmonellaHadar. Withsymptoms occurring 72 hours after infection severe cases of diarrhearequire medical intervention. However, in most cases, the diarrheacan clear by itself in 5-7 days. However, oral or intravenoushydration maybe required. For severe cases, antibiotic therapy isrecommended. In some rare cases, bloodstream infection maybereported.

Preventionmethods for salmonella are pretty simple. It requires washing handswith soap and water every time after visiting the bathroom and beforeany meal. One should also avoid eating undercooked foods especiallyanimals products because salmonella is common in most animals’guts. By extension, handling raw meat and animals products should beavoided. Handling of pets and especially rodents and animals shouldbe controlled. When touched, one should always wash hands with cleanwater and soap afterwards. Infected persons should also be barredfrom preparing meals or handling water to avoid contamination. On thelong term public awareness and education goes a long way in enablingindividuals to be more responsible for their health and preventoutbreaks.


Salmonellosis- Topic Overview. (2014) WebMed.Retrieved from,

Salmonella.(2014) CDC. Retrieved from,