Salmonellosis: Types, Causes, Risk Factors, Symptoms, Complications, Diagnosis and Treatment

It refers to all infectious diseases caused by a bacterium of the genus Salmonella.

Salmonella is bacteria that accumulate in the digestive system and can cause, for the most part, generalized infection or septicemia.

Salmonella is responsible for salmonellosis, typhoid, and paratyphoid.

The number of salmonelloses tends to increase in industrialized countries.

90% of reptiles, birds, and pets carry Salmonella and can transmit it to their owners.

For Salmonella, which causes typhoid and paratyphoid fever, 17 million infections are reported annually worldwide, especially in developing countries.

Prevention is mainly based on hand hygiene and raw meat.


Types of salmonellosis

There are two types of salmonellosis:

  • Salmonellosis or significant typhoid fever: typhoid fever can be severe in this type of salmonellosis.
  • Typhoid fever or Salmonella minor frequently occur in communities and are foodborne infections. Exceptionally, they can cause more severe organ damage.

Depending on the type of bacteria involved, salmonellosis can have forms of varying severity.

Causes of salmonellosis

Contamination by these bacteria is carried out by:

  • Ingestion of contaminated food of animal origin through feces (meat, poultry, eggs, or milk).
  • Ingestion of dirty vegetables (that are in contact with manure).

Pollution sources

People who live in areas of the world with poor sanitation are at increased risk for salmonellosis.


The responsible pathogens are Salmonella typhi, Salmonella paratyphi, Salmonella typhimurium, and Salmonella enteritidis.


In more than 90% of cases, the consumption of food contaminated with animal excrement is involved.

Salmonella-contaminated food does not necessarily have a visible discoloration or a suspicious odor.

These are mainly eggs (and products that contain them), meat, and poultry is eaten raw or undercooked.

However, any food, including fruits and vegetables, is likely to contain Salmonella, especially if it is washed with contaminated water or comes in contact with contaminated raw meat.

Even if the meat has been frozen properly, it can be risky.

As soon as the cold chain is broken, there is a risk of contamination.

This is why summer is more conducive to salmonella contamination.

Just cooking can be good for bacteria. Therefore, perfect hygiene during food preparation is essential to avoid contamination (see Prevention section).

Domestic animals

Salmonella is naturally present in the intestines of animals.

Many cases of salmonellosis in children have been associated with birds or reptiles, especially turtles and iguanas, and lizards and snakes, which are used as pets.

Contamination can occur simply by touching the animal (reptile skin is often contaminated) or its droppings.

However, this is not always the case; the mere touch of an object in contact with the animal can be enough.

The risk is higher when the infected person prepares a meal for other people.

Salmonella can be found everywhere in a home because it is a resistant bacteria that can survive for a time outside of a living host.

Risk factor’s

Some groups of people need to be even more vigilant, especially:

  • Those already have intestinal weakness due to another disease, such as Crohn’s disease.
  • Those with a weak immune system due to other diseases such as HIV and diabetes.
  • The elderly.
  • Pregnant women.
  • The little kids.
  • People whose stomach does not produce enough hydrochloric acid to destroy the bacteria. This can be caused by medications, chronic diseases, or gastric surgery.
  • People who travel to areas where food hygiene is given little importance.
  • People who have a pet animal, especially a reptile or a bird.

Symptoms of salmonellosis

The infection generally manifests as severe and feverish gastroenteritis that progresses for about fifteen days, and then the symptoms gradually diminish.

The most common manifestations of salmonellosis, after a period of one to two weeks without symptoms where the bacteria develop after passing through the intestinal tract, for about a week, a phase called invasion with:

  • A fever of average elevation, up to 40 ° C.
  • Headaches.
  • Digestive disorders, including nausea
  • Fatigue, with a loss of appetite, followed by weight loss.
  • Sometimes you can see an increase in the volume of the spleen.

Then, in the second week, the following symptoms are observed:

  • A fever maintained around 40 ° C.
  • Digestive signs with diarrhea and abdominal pain.
  • An inversion of the rhythm of sleep.
  • Sometimes an increase in the volume of the spleen.

Complications of salmonellosis

Salmonellosis usually does not have serious consequences. However, the elderly, infants and the debilitated may suffer from its symptoms more seriously.

The most common complication is dehydration. Therefore, it is advisable to hydrate the patient while the symptoms persist.

Serious complications occur if left untreated, during the third and fourth weeks, with symptoms such as intestinal perforations and enterorrhagia, abscesses, endocarditis, osteomyelitis, meningitis, or hepatitis.

It may take a few weeks for bowel function to return to normal.

In rare cases, the infection crosses the intestinal barrier and spreads to various body parts through the bloodstream.

If that is the case, it is necessary to treat the infection with antibiotics without delay.

Some people with Salmonella can develop a form of reactive arthritis 3 to 4 weeks after infection: Reiter’s syndrome. However, this symptom is exceptional.

People who have already been infected with Salmonella often become asymptomatic carriers of the bacteria for some time.

This means they do not have symptoms but excrete bacteria in their feces, whose contact with another individual can spread the bacteria.

This stage lasts on average for adults and the elderly for up to 12 weeks after infection and up to a year for children under five.

Less than 1% of people become chronic carriers.

Asymptomatic carriers can still be contagious, but the risk is relatively low, and the length of the contagious period is unknown.

Diagnosis of salmonellosis

A recent visit to tropical countries or North Africa can be an indication to make the diagnosis.

A blood test with study infection markers will almost always find an increase in C-reactive protein.

A blood culture, or blood culture, makes it possible to find the germ in question.

Serology performed on blood samples indicates salmonellosis corresponding to typhoid or paratyphoid type.

If the type O antibody titer is more significant than 100, they indicate a recent infection. These appear after the eighth day up to about two to three months.

Type H antibodies appear around days 10 and 12 and persist for several years.

When type O antibodies are observed without type H antibodies, it can be assured that the infection is recent.

When only the elevation of type H antibodies is observed, it can be inferred that salmonellosis is very old.

Stool testing is an effective method of diagnosing “gastroenteritis” type salmonellosis.

Salmonellosis treatment

The most common treatment of salmonellosis is the use of antibiotics such as ceftriaxone and ciprofloxacin, and in the case of sepsis, dexamethasone is used.

At the same time, the patient should be isolated to avoid transmission, and family members should be examined and treated if necessary.

It would help if you took antipyretics (against fever) and reduced traffic (against liquid stools).

Good hydration is also necessary due to the risk of dehydration.

Proper management of typhoid fever complications should be carried out, such as transfusions in case of bleeding, and surgery in case of digestive perforation, among others.

Salmonellosis is usually treated without medication for 4 to 7 days.

If there are chronic diseases before the poisoning, the doctor may prescribe an antibiotic, which is very rare.

The most important thing is to avoid dehydration by consuming enough fluids.

If diarrhea does not stop or the fever is too high, it is better to consult the doctor.

For as long as symptoms last, it is best to avoid eating:

  • Foods are rich in fat, sugar, and fiber.
  • The milk products.
  • Raw vegetables.
  • The meat.
  • Spicy foods.
  • Fruits, except bananas.

A blood culture test is required at the end of treatment to ensure a complete cure.