Salmonella

DISEASE ASSOCIATED FACTSSalmonellosis”: Any of several bacterial infectionscaused by species of Salmonella, ranging from mild

toserious infections.Two main kinds in humans: enteric fever (typhoid

andparatyphoid), and gastroenteritis (non-typhoidal)Bacterium of 2501 identified strains, as of 2001.

Manydifferent diseases are caused by more than 1,400serotypes of this bacteria genus

OTHER FACTS“Salmonella” derived from Dr. Salmon, a U.S.

veterinarysurgeon, who discovered and isolated the strain entericaor choleraesuis from the intestine of a pig in 1885. The bacteria are ingested orally by contaminated food

orwater.Refrigeration prevents growth but does not kill

bacteria.Heating at 57-60°C or 134-140°F has shown to beeffective in killing the bacteria.Optimal growth: 37°C or 98.6°F

PRINCIPAL HABITATS FOR DIFFERENTTYPES OF SALMONELLATheir principal habitat is the intestinal tracts

and bloodstream of humans, and in the intestinal tracts of a wide variety of animals.

The WHO groups Salmonella into different types:

- Typhoidal (enteric) Salmonella (example: S. typhi)

٠causes typhoid and paratyphoid fever٠restricted to growth in human hosts٠principal habitat is in intestinal tracts and thebloodstream

PRINCIPAL HABITATS FOR DIFFERENTTYPES OF SALMONELLANontyphoidal Salmonella (example: S. enteritidis,

S.typhimurium)٠prevalent in gastrointestinal tracts of a broad range ofanimals, including mammals, reptiles, birds and insects.٠cause a whole range of diseases in animals and humans,mainly gastroenteritis.٠usually transferred animal-to-person, through certain foodproducts: fresh meat, poultry, eggs and milk, fruits,

vegetables, seafood٠house and exotic pets, contamination through contact with

their fecesSalmonella most restricted to certain animals such as

cattle and pigs; infrequently in humans; if these strains do cause disease in humans, it is often invasive and life threatening.

TRANSMISSIONFood borne: Transmitted via improperly

prepared, previously contaminated food or water- Meat: poultry, wild birds, pork- Dairy: eggsPet turtles and lizards Three clinical forms of salmonellosis- Gastroenteritis (S. typhimurium)- Septicemia (S. choleraesius)- Enteric Fevers (i.e. S. typhi – Typhoid Fever)Especially: the elderly, infants,

immunocompromised patients (AIDS, sickle cell anemia)

HISTORY: CARRIER STATUS Typhoid Mary” Mallon was the first famouscarrier of typhoid fever in the U.S. Some individuals have natural immunity toSalmonella. Known as “chronic carriers”, theycontract only mild or asymptomatic disease, butstill carry the bacteria in their body for a longtime. These cases serve as natural reservoir forthe disease. Approximately 3% of persons infected with S.typhi and 0.1% of those infected with nontyphoidalsalmonellae become chronic carrierswhich may last from a few weeks to years. One such case was Mary Mallon, who washired as a cook at several private homes in theNew York area in the early 1900’s.

Mary MallonMary Mallon caused several typhoid outbreaks,

moving from household to household, always disappearing before an epidemic could be traced back to the particular household Mary was working in. All together, she had worked for seven families, with 22 cases of typhoid and one death.

She was finally overtaken by the authorities in 1907 and committed to an isolation center on North Brother Island, NY. There she stayed until she was released in 1910, on the condition that she never accept employment involving food handling.

But: She was found to work as a cook and to cause typhoid outbreaks again. She was admitted back to North Brother Island, where she lived until her death in 1938.

OUTBREAKSMore recently reported outbreaks in the U.S.

involve different kinds of Salmonella strains, predominantly S. enteritidis and S. typhimurium.

In 1985, a salmonellosis (S. typhimurium) outbreak involving 16,000 confirmed cases in 6 states by low fat milk and whole milk from one Chicago dairy

Largest outbreak of food-borne salmonellosis in the U.S. Investigations discovered that raw and pasteurized milk had been accidentally mixed.

OUTBREAK OR BIOTERRIORISM?Oregon 1984: a Buddhist religious cult known

as the Rajneeshees, sought to eventually run the whole country by first winning the local election by using salmonella bacteria.

They brewed a "salsa" of salmonella and sprinkled it on the town's restaurant salad bars.

Ten restaurants were hit and more than 700 people got sick

First large scale bioterrorism attack on American soilA community-wide outbreak of salmonellosis

resulted; at least 751 cases were documented in a county that typically reports fewer than five cases per year. Health officials soon pinned down salmonella as the cause of the sudden outbreak, but put the blame on food handlers

In 1984, who could have imagined bioterrorism?

RECENT OUTBREAKS?Multi-state Outbreak:- Salmonella saintpaul: Since April 2008, 1438

persons ill in 43 states. Vehicle – tomatoes, jalapenos peppers and serrano peppers grown in Mexico.

- Salmonella tennessee: Since August 2006 until February 2007, 425 persons ill in 44 states. Vehicle – Peter Pan and Great Value peanut butter.

Louisiana Outbreak:- Salmonella braenderup : April 2007, 31 cases after

eating at church luncheon. Vehicle: possibly barbeque chicken or corn bread dressing (epi link)

PREVENTION: TYPHOIDAL SALMONELLATyphoidal S.:- Generally treated with antibiotics- Vaccinations available; the CDC currently

recommends vaccination for persons traveling to developing countries

- Education of general public, especially in developing countries; identification of all carriers and sources of contamination of water supplies

- Avoid risky foods & drinks: buy bottled water or boil water for at least 1 minute;

COOK and CLEAN food thoroughly, avoid raw vegetables

and fruits-WASH YOUR HANDS WITH SOAP AND WATER!!!

PREVENTION: NON-TYPHOIDAL SALMONELLAPasteurization of milk-products; Eggs from

known infected commercial flocks will be pasteurized instead of being sold as grade A shell eggs.

- Tracebacks, on-farm testing, quality assurance programs, regulations regarding refrigeration, educational messages for safe handling and cooking of eggs

- Cross-contamination: uncooked contaminated foods kept separate from cooked, ready-to-eat foods