The Salmonella blog supplements Marler Clark’s Web site about Salmonella, a site that provides information about Salmonella, the symptoms and risks of infection, testing and the detection of salmonellosis, and how to prevent Salmonella outbreaks.
While about-salmonella.com is informational in purpose, the Salmonella blog is intended be a forum for discussion among the site’s authors and users. The authors of the Salmonella blog conduct surveillance on matters related to Salmonella’s impact on individuals and families in different cities, states, and regions.
Please join us in a conversation about Salmonella that includes subjects such as outbreaks, recalls, and legal cases by commenting on posts that you find interesting.
About Salmonella and Salmonellosis
Salmonella is a bacterium that causes one of the most common enteric (intestinal) infections in the United States. In 2006, over 40,000 cases were reported to the Centers for Disease Control and Prevention (CDC). Overall, the incidence of Salmonella in the United States has not changed significantly since 1996. Only a small proportion of all Salmonella infections are diagnosed and reported to health departments. The CDC estimates that 1.4 million cases, 15,000 hospitalizations, and 400 deaths are caused by Salmonella infections in the United States every year.
People are infected by ingesting the bacteria. Salmonella are found in the intestinal tract of wild and domesticated animals and humans. Contaminated foods of animal origin, such as poultry, pork, beef, unpasteurized milk, or eggs, are often the source of infection. However, all foods, including vegetables, may become contaminated. Since Salmonella is found in the feces of animals, people may become infected when coming into contact with animals or their environment. Pets such as snakes, turtles, lizards and other reptiles, frogs and baby chicks/ducklings are known to transmit Salmonella to people. Also, an infected person can transmit the bacteria via the fecal-oral route.
Symptoms of Salmonella infection
The most common clinical presentation of a Samonella infection is acute gastroenteritis. Symptoms include diarrhea, and abdominal cramps, often accompanied by fever of 100°F to 102°F. Other symptoms may include bloody diarrhea, vomiting, headache and body aches. The incubation period, or the time from ingestion of the bacteria until the symptoms start, is generally 6 to 72 hours, however, in there is evidence that sometimes the incubation can be as long as 10 days. People with salmonellosis usually recover without treatment within 3 to 7 days.
In approximately 5 percent of non-typhoidal infections, patients develop bacteremia (Salmonella found in the blood). In a small proportion of those cases, the bacteria can cause a focal infection, where it becomes localized in a tissue and causes an abscess, arthritis, endocarditis, or other severe illness. A small proprotion of persons with a Salmonella infection develop a complication called reactive arthritis (Reiter’s Syndrome). Symptoms include inflammation of the joints, the genitourinary tract, or the eyes.
S. Typhi and Paratyphi generally cause a bacteremic illness of long duration. This illness is called enteric, typhoid, or paratyphoid fever. Symptoms start gradually, and include fever, headache, malaise, lethargy, and abdominal pain. In children, it can present as a non-specific fever. The incubation period for S. Typhi is usually 8 to 14 days, but it can range from 3 to 60 days.
Detection and treatment of Salmonella infection
Salmonella bacteria can be detected in stool. In cases of bacteremia or invasive illness, the bacteria can also be detected in the blood, urine, or on rare occasions in tissues. The test consists of growing the bacteria in culture.
Salmonella infections usually resolve in 3 to 7 days, and many times require no treatment. Persons with severe diarrhea may require rehydration. Antimicrobial therapy (or treatment with antibiotics) is not recommended for uncomplicated gastroenteritis. However, antimicrobial therapy is recommended for persons at increased risk of invasive disease, including infants younger than 3 months of age. When antibiotic treatment is indicated, ampicillin, amoxicillin, or trimethoprim/sulfamethoxazole is recommended. Ceftriaxone, cefotaxime or flouroquinolones are effective options for antimicrobial-resistant strains; except, fluoroquinolones are not approved for persons under 18 years of age. For persons with invasive disease, treatment with an expanded-spectrum cephalosporin is recommended, until it is known if the bacteria is susceptible to one of the more commonly used antibiotics listed above.
The selection of effective antibiotics is critical for the treatment of invasive Salmonella infections, but has become more difficult as antibiotic-resistance has increased. Antibiotic-resistant Salmonella have been isolated from various food products, and have been the causative agent in several foodborne disease outbreaks in the United States. Traceback investigations in outbreak settings have shown animals to be the ultimate source of infection. Antibiotic use in the animal industry is thought to contribute greatly to the prevalence of multidrug-resistant infections in humans.
Preventing Salmonella infection
To prevent salmonellosis, always wash your hands before and during cooking, and before eating. Cook poultry, pork, beef and eggs thorughly. Poultry should reach an internal temperature of 165 ºF, ground beef and pork should reach 160ºF, and eggs until the yoke is solid or until they reach 160ºF. Do not eat or drink foods containing raw eggs (e.g., homemade eggnog, hollandaise sauce, and undercooked French toast). Never drink raw (unpasteurized) milk. Wash hands, kitchen work surfaces, and utensils with soap and water immediately after they have been in contact with raw foods of animal origin. Avoid cross-contamination, by keeping raw foods of animal origin separate from foods that do not require further cooking.
Wash hands with soap after after contact with animals, their environment or their feces.
Reptiles, amphibians or birds, or any elements of their housing (such as water bowls) should never be allowed in the kitchen. Avoid eating in animal barns, and wash your hands with soap and water after visiting petting zoos or farm settings.
Avoid preparing food for others when you are experiencing diarrhea or vomiting, and wash your hands thoroughly after going to the bathroom.