Salmonellosis

There has been two recent multistate outbreaks of Salmonella.  One caused by Salmonella Typhimurium linked to ground beef, with 20 people so far being infected.  The outbreak has been linked to ground beef purchased from Hannaford Supermarkets.  Another outbreak associated with Salmonella enteritidis linked to eating food from a Mexican-style fast food restaurant chain.  With these recent outbreaks I can’t think of a better time to discuss Salmonella.

What is Salmonellosis?

Salmonellosis is an infection caused by a bacteria called Salmonella (gram negative rod shaped bacilli).  There are more than 2,400 different variations or serovars of Salmonella that have been identified and cause disease in humans.  However, S. typhimurium and S. enteritidis account for the most illnesses in humans in the US.

Is it common?

In the United States alone there are at least 40,000 cases reported every year.  Keep in mind these are only the reported cases experts believe that there are between 400,000 and 4 million infections each year.


Clinical signs in people

• Diarrhea, fever, abdominal cramps, nausea typically for 2 to 7 days 
• Most recover without treatment but in some the diarrhea can be so severe that they require hospitalization.  These individuals are at risk of the bacterial infection spreading through out the body which can cause death unless properly treated.  
• Infections are most severe in the young, elderly and people with impaired immune systems 

How do you become infected?

Salmonella live in the intestinal tracts of animals, birds, reptiles and humans.  Salmonella infections are zoonotic.  Most infections are usually the result of people eating food that is contaminated with animal feces.  Foods involved typically include feces-contaminated beef, poultry and pork, gravies, eggs, milk and milk products, shellfish and fish.  Proper cooking of food kills Salmonella. However, infected food handlers can also contaminate food.

Pets and Salmonella

Salmonella can also be found in the feces of pets especially if they eat a raw diet.  This is why I do not recommend ever feeding your pet a raw diet.  Unfortunately, raw diets have become popular with the idea that a raw diet more closely resembles the natural diet that the feline and canine body is intended to consume.  However, cooking food is what removes parasites and bacteria from food.  Studies have found that the majority of dogs eating raw diets are shedding Salmonella in their feces.  Even if these dogs are asymptomatic for infection they are shedding Salmonella, which puts people and other animals at risk for infection.   

Clinical signs of dogs infected with Salmonella are very similar to human infections and include fever, diarrhea, lethargy, anorexia, vomiting and just like people they are at risk for sepsis.  Dogs can also be chronically infected with Salmonella.  Dogs become infected the same way people do and the young are generally more severely infected.   

Reptiles and young birds are another important source of Salmonella, so make sure you wash your hands after handling any turtles, lizards, snakes or birds.  Children under 5 years old should now own reptiles.  Remember infections are most severe in young children.     


Prevention

• Cook your food thoroughly
• Do not consume raw eggs or milk
• Wash your hands as well as kitchen surfaces and utensils immediately after contact with raw meat/poultry
• Wash your hands after contact with animals, especially reptiles and birds  

For more information on Salmonella and the recent outbreaks please visit CDC.