A brief introduction to Salmonella

Salmonella is a group of bacteria that can infect animals and humans and considered as intracellular pathogens. The bacteria was first identified in 1880 and named after an American scientist called Salmon. Salmonella belongs to family Enterobacteriaceae and the genus called Gram negative rod shaped bacteria. Their shape like rod and can have flagella to move around.

                                                          Image credit goes to Ranil Appuhamy

There are around 2500 different types of bacterial species. Most human diseases caused by the bacteria belong into a subspecies called Salmonella enterica. It's estimated that tens of millions of human cases occur worldwide every year causing over 100,000 deaths. Salmonella can live quite happily in the intestine of many animals like cows, pigs, turtle, cats, dogs and birds like chicken and ducks. Other parts of the animals like feathers and furs or the place they are living can be contaminated by the bacteria. Some type of salmonella like S

almonella typhi lives only in humans.

From the above sources bacteria can spread either directly or indirectly. For example it can spread to the people directly who eats contaminated animal product like meat and eggs which has not cook properly. Eggs are very common factor of Salmonella outbreaks. They also spread through direct contact with infected animals or the environments. Salmonella can also spread indirectly by contaminated water, other food, utensils like knife and cutting boards or by hands someone who handled foods cancel. Salmonella is a common cause of food borne diseases in the world. People of salmonella infected can spread infection to others. Sometimes people can have salmonella for a long time without showing any symptoms.

 So what does Salmonella cause? It can cause two broad types of diseases depending on the type salmonella that causes infection. These are typhoidal and non-typhoidal salmonellosis.

Typhoidal salmonellosis

Typhoid Fever and paratyphoid fever is caused by either Salmonella typhi or Para typhi A, B or C. These two illnesses are similar. When these bacteria are ingested they can enter the bloodstream leading to symptoms like high fever stomach aches headaches, loss of appetite or a rash. These symptoms usually occur between 8- 14 days after being exposed to the bacteria in typhoid fever, and between 1-10 days after being exposed Para-typhoid fever. In some cases it could lead to serious complications like bleeding from gastrointestinal tract and infection of brain. The elderly and which have weak immune system are at a higher risk of complications.

                                                             Image credit goes to Ranil Appuhamy

Non-typhoidal salmonellosis

Non-typhoidal salmonellosis typically characterizes by gastroenteritis and commonly caused by Salmonella type like Salmonella enteriditis, Salmonella newport and Salmonella typhimurium. Symptoms are usually diarrhoea, fever, abdominal pain, nausea and vomiting. These symptoms usually occur between 6-72 hours after being exposed to the bacteria and can last for about 2-7 days. Although the disease can be relatively mild in most people could be quite severe to the young and elderly and also the people who has poor immune system. Sometimes the bacteria that cause non-typhoidal salmonellosis can enter the blood and infect other organs like brain, urinary tract and cause local complications.

                                                     Image credit goes to Ranil Appuhamy

So how can we prevent Salmonella infections?

Because salmonella is mainly a food borne disease so the most important thing is the safety of food. There are number of ways that can be achieved including..

•          Making sure the food preparation area are cleaned
•          Separating raw and cooked food to prevent cross contamination
•         Cooking food thoroughly
•          Keeping food at correct temperature
•          Using safe water and raw materials to prepare food

To reduce the chance of being infected high risk of food that contains bacteria should be avoided. This includes raw eggs, unpasteurized milk and raw meat. Fruits and vegetables should wash carefully, especially raw foods. Avoid the water which is not boiled or treated. It is important to wash hand during handling of food and food preparation time, after using the toilet and after contact with any animals those are sick.

People of salmonella infection can spread to other as long as the bacteria are presence into their feces. They should not prepare food for others if they have symptoms. They should seek medical advice from doctors and cannot go back to the work immediately. School and child care are very special for the food handlers and those who care for vulnerable people. Some people who have typhoid fever may require negative stool sample and clearance from the doctor that they are no longer infectious.

Diagnosis

Salmonella infections are usually diagnosed by identifying bacteria in stool sample and blood. Other types of blood test like those are check for antibody are sometimes used but are not as good. In some instances salmonella can be isolated sites like brain or urine if these sites are infected. Uncomplicated salmonella infections are usually managed by rest and adequate hydration. 

Treatment

Antibiotics are used some highly complicated cases like typhoidal fevers. There are some salmonella strains are resistance to antibacterial medications. This is a serious public health problem, because these infections are difficult to treat. There is vaccine that can protect specifically against typhoid fever. For more information about salmonella disease and it’s recovery should immediate consult with a physician of the nearer health care center.