Salmonellosis is an "infection that affects" the gastrointestinal tract and is caused by such bacteria Salmonella. Humans get sick through the consumption of contaminated food or water or through contact with infected animals, person-to-person infection is very rare.

Salmonella infections are the second most frequent cause of foodborne infections to humans in Europe.

There are around 2500 types of salmonellae that cause gastroenteritis.


After ingestion, salmonellae multiply in the intestinal tract and invade the mucosa. The infection and its severity depend on the amount of salmonella ingested and on the state of health of the person: it can occur in such a light form as not to cause disturbances (asymptomatic ) or cause diarrhea, vomiting, fever and abdominal cramps (gastroenteritis) approximately 8–72 hours after ingestion.

Among the ailments caused by salmonellosis:

  • chills
  • headache
  • presence of blood in the stool
  • diarrhea
  • He retched
  • fever
  • abdominal cramps

Salmonellosis usually heals within a few days but, in some cases, diarrheal episodes can be so frequent that they cause dehydration, which manifests itself with reduced frequency to urinate, dry mouth and tongue, reduced watery eyes and sunken eyes.

In this circumstance, especially if the ailments are very debilitating, the person is old or very young, or has other diseases that can aggravate the situation, hospitalization may be required.


Salmonellosis is contracted in most cases by consuming raw or undercooked contaminated foods.

The foods that most commonly contain the bacterium are:

  • raw or undercooked meats
  • raw eggs or sauces and sweets, prepared with raw eggs
  • unpasteurized milk and fresh cheeses made with unpasteurized milk
  • fruit and vegetables, irrigated with contaminated water

Usually foods contaminated with salmonella do not show evident alterations, both in appearance and in organoleptic properties (smell, taste, consistency).

If the contaminated food is consumed by several people (in the case of consumption in restaurants, canteens or because it is distributed on a large scale, for example in supermarkets), salmonellosis epidemics can occur, with more people infected. In this case it is important that cases are reported to the local health authorities (AUSL) to allow their intervention and block the spread of contaminated food.

Risk factors

There are situations that can increase the risk of contracting a "salmonella infection:

  • consumption of raw or undercooked food and poor attention to hygiene measures, in food preparation
  • use of medicines that can interfere with the body's natural defenses, such as antacids (drugs that decrease the acidity of the stomach and can make it easier for the bacterium to survive)
  • inflammatory bowel disease
  • recent use of antibiotics, which may have altered the intestinal microbial flora and thus favor the infection of salmonellae
  • travel to countries with poor sanitary conditions, where you are most likely to get the infection
  • reduced functioning of the body's defense system, immunodeficiencies or drug therapies that lead to impaired immune system such as, for example, corticosteroids, anti-rejection drugs


The "ascertainment (diagnosis) of salmonellosis involves the identification of the bacterium from the analysis of the faeces (coproculture) of the sick person and its subsequent identification.

Identification of the type of salmonella is important, especially in the case of food-borne outbreaks which are a serious public health problem.

In the event of an epidemic, the local health authorities, to identify the source of contagion and block the epidemic, collect information from the people involved, on the foods eaten before the infection, on the places where they were consumed, on any travel or other aspects which may have caused the infection.


In the gastrointestinal forms without complications, the infection generally resolves in 4-7 days and does not require special care except maintaining good hydration, with rehydrating oral solutions, to compensate for the loss of water and mineral salts that occurs with vomiting and diarrhea. In general, antibiotics are not prescribed, also due to the risk that they prolong the time of elimination of the bacterium through the faeces. We also advise against the use of antidiarrheal drugs in order not to slow down the natural defense mechanism used by the body. to expel the germs. In case of persistent diarrhea for several days, fever or dehydration, you should contact your doctor who will prescribe the most appropriate therapy. Referral to a doctor is also indicated in the case of infection in children, the elderly or immuno -compromise.


Salmonellosis, in general, is not a life-threatening disease.However, in fragile categories such as infants and children, the elderly, pregnant women, immuno-compromised individuals, or with other serious ongoing illnesses, dangerous complications can occur that require specific medical attention or hospitalization. They include:

  • dehydration, due to persistent diarrhea
  • bacteremia, caused by the passage of the bacterium from the intestinal mucosa into the blood

The most frequent signs of dehydration are:

in children:

  • irritability or sleepiness
  • poor urine output. In infants, the amount of urine is considered low when more than three hours elapse between one urination (urination) and the next. Children and adolescents can spend up to eight hours or more without urinating if they are dehydrated.
  • poor tearing with crying
  • pale skin with sunken eyes
  • cold hands and feet
  • worsening of general conditions

in adults:

  • thirst
  • dry mouth and kneaded
  • dry and inelastic skin
  • sunken eyes
  • fatigue and lack of energy
  • loss of appetite
  • nausea
  • feeling lightheaded
  • dizziness
  • muscle cramps
  • rapid heartbeat

In severe cases, delirium and loss of consciousness may be present.

Bacteremia often causes high fever, weakness, and malaise that last for several days.

In some predisposed individuals, salmonellosis can cause an autoimmune-based inflammatory disease called Reiter's syndrome which manifests itself with:

  • eye irritation (conjunctivitis)
  • pain in urinating (urethritis)
  • joint pain


Salmonella is not easily transmitted directly from individual to individual, but it is still important to follow basic behavior and hygiene rules:

  • hand washing with soap and running water after using the bathroom
  • diaper change
  • cleaning of pet litter boxes or cages

In the kitchen when preparing meals it is important to:

  • use two different cutting boards for cutting meat and vegetables, or clean the cutting board or the surface on which the meat was cut before placing the vegetables on it
  • washing hands with soap after handling raw meat, before touching the salad
  • avoid using the same tools (forks, knives, spoons, plates) for raw and cooked foods
  • keep raw meat and fish well separated from other foods in the fridge
  • put leftover food back into the refrigerator as quickly as possible after a meal
  • pay attention to the expiry date of foods, including packaged ones, especially vegetables, meats, eggs
  • cook the meat well
  • limit or possibly avoid the use of raw eggs and milk and their derivatives

There are no specific vaccinations against salmonellae. Available vaccines only protect against Salmonella typhi which causes typhoid fever. If you plan to travel to countries where typhoid fever is widespread, it is advisable to contact a travel medicine center to evaluate the indications for vaccination.

Sometimes people can eliminate salmonellae with stool in the absence of disturbances, and this elimination can persist for days or months. These people are called "healthy carriers". Recognition of healthy carriers is of particular importance in the context of hospital staff and food industry workers.


EpiCentro (ISS). Salmonella

Mayo Clinic. Salmonella infection (English)

Centers for Disease Control and Prevention (CDC). Salmonella (English)

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