|Classification and external resources|
Salmonellosis is an infection with Salmonella bacteria. Most people infected with Salmonella develop diarrhea, fever, vomiting, and abdominal cramps 12 to 72 hours after infection. In most cases, the illness lasts four to seven days, and most people recover without treatment. In some cases, though, the diarrhea may be so severe, the patient becomes dangerously dehydrated and must be hospitalized.
At the hospital, the patient may receive intravenous fluids to treat the dehydration, and may be given medications to provide symptomatic relief, such as fever reduction. In severe cases, the Salmonella infection may spread from the intestines to the blood stream, and then to other body sites; this is known as typhoid fever and can cause death unless the person is treated promptly with antibiotics.
The elderly, infants, and those with impaired immune systems are more likely to develop severe illness. Some people afflicted with salmonellosis later experience reactive arthritis, which can have long-lasting, disabling effects. There are just two species of Salmonella, S. enterica and Salmonella bongori, with numerous subspecies.
The species Salmonella enterica and its many subspecies is largely associated with infections in humans, which are usually contracted from sources such as:
- Poultry, pork, and beef, if the meat is prepared incorrectly or is infected with the bacteria after preparation
- Infected eggs, egg products, and milk when not prepared, handled, or refrigerated properly
- Tainted fruits and vegetables
Reptiles, such as turtles, lizards, and snakes, carry the bacteria belonging to Salmonella bongori (which inhabits cold-blooded animals) in their intestines which can cause intestinal infections. A subspecies of S. enterica Salmonella typhi causes salmonella that can lead to typhoid fever, which often proves fatal. It is carried only by humans and is usually contracted through direct contact with the fecal matter of an infected person. Typhoid fever is more commonly found in underdeveloped countries, where unsanitary conditions are more likely to prevail, and which can affect as many as 21.5 million persons each year.
The bacterium induces responses in the animal it is infecting, and this typically causes the symptoms, rather than any direct toxin produced. Symptoms are usually gastrointestinal, including nausea, vomiting, abdominal cramps, and bloody diarrhea with mucus. Headache, fatigue, and rose spots are also possible. These symptoms can be severe, especially in young children and the elderly. Symptoms last generally up to a week, and can appear 12 to 72 hours after ingesting the bacterium.
After bacterial infections, reactive arthritis (Reiters syndrome) can develop. In sickle-cell anemia, osteomyelitis due to Salmonella infection is much more common than in the general population. Though Salmonella infection is frequently the cause of osteomyelitis in sickle-cell anemia patients, it is not the most common cause; the most common cause remains Staphylococcus infection.
An infectious process can only begin after living salmonellae (not only their toxins) reach the gastrointestinal tract. Some of the microorganisms are killed in the stomach, while the surviving salmonellae enter the small intestine and multiply in tissues (localized form). By the end of the incubation period, the macro-organisms are poisoned by endotoxins released from the dead salmonellae. The local response to the endotoxins is enteritis and gastrointestinal disorder. In the generalized form of the disease, salmonellae pass through the lymphatic system of the intestine into the blood of the patients (typhoid form) and are carried to various organs (liver, spleen, kidneys) to form secondary foci (septic form). Endotoxins first act on affected organs' vascular and nervous systems, manifested by increased permeability and decreased tone of the vessels, upset thermal regulation, vomiting and diarrhea. In severe forms of the disease, enough liquid and electrolytes are lost to upset the body's water-salt metabolism, to decrease the circulating blood volume and arterial pressure, and to cause hypovolemic shock. Septic shock also may develop. Shock of mixed character (with signs of both hypovolemic and septic shock) is more common in severe salmonellosis. Oliguria and azotemia develop in severe cases as a result of renal (kidney) involvement due to hypoxia and bacteremia.
||The examples and perspective in this section deal primarily with the United States and do not represent a worldwide view of the subject. (April 2009)|
Up to 2005
The U.S. Government reported as many as 20% of all chickens were contaminated with Salmonella in the late 1990s, and 16.3% were contaminated in 2005. In the mid- to late 20th century, Salmonella enterica serovar Enteritidis was a common contaminant of eggs. This is much less common now with the advent of hygiene measures in egg production, and the vaccination of laying hens to prevent Salmonella colonization. Various Salmonella serovars (strains) also cause severe diseases in animals.
In June 2006, the BBC reported the Cadbury chocolate manufacturer withdrew a number of products contaminated with Salmonella, which had resulted in up to 56 cases of salmonellosis. The causes had been traced to a leaking pipe at a Cadbury plant in Herefordshire in January 2006, though the announcement was not made until June.
In February 2007, the U.S. Food and Drug Administration (FDA) issued a warning to consumers not to eat certain jars of Peter Pan or Great Value peanut butter, due to risk of contamination with Salmonella Tennessee.
In March 2007, around 150 people were diagnosed with salmonellosis after eating tainted food at a governor's reception in Krasnoyarsk, Russia. Over 1,500 people attended the ball on March 1, and fell ill as a consequence of ingesting salmonella-tainted sandwiches.
About 150 people were sickened by salmonella-tainted chocolate cake produced by a major bakery chain in Singapore in December 2007.
From April 10, 2008 to July 8, 2008, the rare Saintpaul serotype of S. enteritidis caused at least 1017 cases of salmonellosis food poisoning in 41 states throughout the United States, the District of Columbia, and Canada. As of July 2008, the U.S. FDA suspected the contaminated food product was a common ingredient in fresh salsa, such as raw tomato, fresh jalapeño pepper, fresh serrano pepper, and fresh cilantro. It is the largest reported salmonellosis outbreak in the United States since 1985. New Mexico and Texas have been proportionally the hardest hit by far, with 49.7 and 16.1 reported cases per million, respectively. The greatest number of reported cases have occurred in Texas (384), New Mexico (98), Illinois (100), and Arizona (49). At least 203 reported hospitalizations have been linked to the outbreak, it has caused at least one death, and it may have been a contributing factor in at least one additional death. The CDC maintains "it is likely many more illnesses have occurred than those reported." If applying a previous CDC-estimated ratio of unreported salmonellosis cases to reported cases (38.6:1), an estimated 40,273 illnesses occurred from this outbreak.
As of 18 July 2008, the FDA removed raw tomatoes and cilantro as potential carriers; however, fresh jalapeño and serrano peppers still remain.
In December 2008 and January 2009, several Midwestern states, including Ohio (officially confirmed by state authorities), reported an outbreak of salmonellosis from Salmonella typhimurium that had sickened at least 50 people, due to contaminated dairy products such as cheeses.
On January 17, 2009, the FDA announced they had traced the source of an outbreak of Salmonella Typhimurium to a plant in Blakely, Georgia, owned by Peanut Corporation of America (PCA), and urged people to postpone eating commercially prepared or manufactured peanut butter-containing products and institutionally served peanut butter. Salmonella was reported to be found in 46 states in the United States in at least 3,862 peanut butter-based products, such as crackers, energy bars, and peanut butter cookies from at least 343 food companies. Dog treats were affected, as well. At least 691 people in more than 46 states became sick, and the Salmonella claimed at least 9 lives as of March 25.
Peanut butter and peanut paste manufactured by PCA were distributed to hundreds of firms for use as an ingredient in thousands of different products, such as cookies, crackers, cereal, candy and ice cream, all of which were recalled. Some products were also sold directly to consumers in retail outlets, such as dollar stores.
On March 14, 2009, expressing his own personal concern for the safety of his children who enjoy peanut butter, President Obama announced the establishment of the Food Safety Working Group, "an inter-agency effort to help overhaul the oversight system."  The announcement came days after the FDA, also responding, released its first "guidance" on dealing with Salmonella contamination.
An outbreak of salmonellosis caused by a rarer subspecies, Salmonella Bareilly, was reported in multiple states mostly in the East, having yet caused no deaths, but many episodes of sickness and some hospitalizations has been linked to the consumption of raw scraped ground tuna product.
Since July 2012, an outbreak of salmonellosis occurred in Northern Europe caused by Salmonella Thompson. The infections were linked to smoked salmon from the manufacterer Foppen, where the contamination had occurred. Most infections were reported in the Netherlands, over 1060 infections with this subspecies have been confirmed, as well as four mortalities.
The "Four-Inch Regulation" or "Four-Inch Law" is a colloquial name for a regulation issued by the U.S. FDA in 1975, restricting the sale of turtles with a carapace length of less than four inches (10 cm).
The regulation was promulgated, according to the FDA, "because of the public health impact of turtle-associated salmonellosis." There had been reported cases of young children placing small turtles in their mouths, which led to the size-based restriction.
The FDA has published guidelines to help reduce the chance of food-borne salmonellosis. Food must be cooked to 68–72°C (145–160°F), and liquids such as soups or gravies must be boiled. Freezing kills some Salmonella, but it is not sufficient to reliably reduce them below infectious levels. While Salmonella is usually heat-sensitive, it does acquire heat resistance in high-fat environments such as peanut butter.
Antibodies and vaccine development
Salmonella antibodies were first found in Malawi children in research published in 2008. The Malawian researchers have identified an antibody that protects children against bacterial infections of the blood caused by Salmonella. A study at Queen Elizabeth Hospital in Blantyre found that children up to two years old develop antibodies that aid in killing the bacteria. This could lead to a possible Salmonella vaccine.
Both salmonellosis and the Salmonella genus of microorganisms derive their names from a modern Latin coining after Daniel E. Salmon (1850–1914), an American veterinary surgeon. He had help from Theobald Smith, and together they found the bacterium in pigs.
- "FDA/CFSAN - Food Safety A to Z Reference Guide - Salmonella". FDA - Center for Food Safety and Applied Nutrition. 2008-07-03. Retrieved 2009-02-14.[dead link]
- McGhie EJ, Brawn LC, Hume PJ, Humphreys D, Koronakis V (2009). "Salmonella takes control: effector-driven manipulation of the host". Curr Opin Microbiol 12 (1): 117–24. doi:10.1016/j.mib.2008.12.001. PMC 2647982. PMID 19157959.
- Dworkin MS, Shoemaker PC, Goldoft MJ, Kobayashi JM (2001). "Reactive arthritis and Reiter's syndrome following an outbreak of gastroenteritis caused by Salmonella enteritidis". Clin Infect Dis 33 (7): 1010–14. doi:10.1086/322644. PMID 11528573.
- Volovskaya, ML. Epidemiology and Fundamentals of Infectious Diseases. Mir Publishers Moscow. pp. 91–96. ISBN 5-03-001548-5.
- Black, Jane; O'Keefe, Ed (2009). "Administration Urged to Boost Food Safety Efforts". Washington Post. Retrieved 2009-07-07. "Among them is a final rule, issued by the FDA, to reduce the contamination in eggs. About 142,000 Americans are infected each year with Salmonella enteritidis from eggs, the result of an infected hen passing along the bacterium. About 30 die."
- Burros, Marian (March 8, 2006). "More Salmonella Is Reported in Chickens". The New York Times. Retrieved 2007-05-13.
- Tran, Mark (2006-07-21). "Cadbury named over salmonella outbreak". London: Guardian Unlimited. Retrieved 2007-09-09.
- "Cases infected with the outbreak strain of Salmonella Saintpaul, United States, by state". For some states, such as California, the CDC has recently revised the tally of identified illness downward.
- August 8, 2008: Investigation of Outbreak of Infections Caused by Salmonella Saintpaul | Salmonella CDC
- Voetsch, et al. (2004-04-15). "FoodNet Estimate of the Burden of Illness Caused by Nontyphoidal Salmonella Infections in the United States". Clinical Infectious Diseases, 2004; 38:S3.
- Elizabeth Landau (2008-07-18). "FDA lifts warning on tomatoes". CNN.
- Recall of Products Containing Peanut Butter: Salmonella Typhimurium, U.S. Food and Drug Administration.
- Recall of Peanut-Containing Products: Salmonella Typhimurium (Current Update), U.S. Food and Drug Administration
- Investigation Update: Outbreak of Salmonella Typhimurium Infections, 2008–2009, Centers for Disease Control and Prevention
- "More peanut products recalled, U.S. probe continues". Reuters. 2009-01-19.
- MSNBC: http://www.msnbc.msn.com/id/28749159
- "Peanut Plant Had History of Health Lapses". The New York Times. 2009-01-27. Retrieved 2010-05-23.
- Weise, Elizabeth (March 2009). "Salmonella outbreaks lead to food-safety changes". USA Today.
-  "Multistate Outbreak of Salmonella Bareilly Infections Associated with a Raw Scraped Ground Tuna Product"
- Veelgestelde vragen Salmonella Thompson 15 oktober 2012, Rijksinstituut voor Volksgezondheid en Milieu [Frequently asked questions Salmonella Thompson 15 October 2012, Netherlands Institute for Public Health and the Environment].
- "Salmonella besmetting neemt verder af, 2 november 2012, Rijksinstituut voor Volksgezondheid en Milieu" [Salmonella infections continue to decline 2 November 2012, Netherlands Institute for Public Healthand the Environment].
- "Human Health Hazards Associated with Turtles". U.S. Food and Drug Administration. Archived from the original on 2007-06-09. Retrieved 2007-06-29.
- "Salmonella Questions and Answers". USDA Food Safety and Inspection Service. 2006-09-20. Retrieved 2009-01-21.
- "FDA issues peanut safety guidelines for foodmakers". Reuters. 2009-03-10.
- MacLennan CA, Gondwe EN, Msefula CL, et al. (April 2008). "The neglected role of antibody in protection against bacteremia caused by nontyphoidal strains of Salmonella in African children". J. Clin. Invest. 118 (4): 1553–62. doi:10.1172/JCI33998. PMC 2268878. PMID 18357343.
|Wikimedia Commons has media related to Salmonella.|
- CDC website, Division of Bacterial and Mycotic Diseases, Disease Listing: Salmonellosis
- CFIA Website: Salmonellae
- Protective salmonella antibodies found in Malawi children, Sub-Saharan Africa gateway, Science and Development Network,