2012 outbreak of Salmonella

S. Typhimurium has traditionally been an uncommon serotype of Salmonella; however, beginning in January 2012 through the end of 2012, the number of cases steadily rose, with 18 human cases in the United States alone (spread among eight states).[9] The infection caused one death and four hospitalizations.[9] These infections stem from contact with pet hedgehogs or with the animals' surroundings.[9] No one pet provider was linked to the infected hedgehogs.[9]

One epidemic of Salmonella enterica I 4,5,12:i:- in the United States in February 2012 affected 46 people across 22 states.[10] The outbreak seemed to be linked to the handling of live or frozen feeder mice and rats for reptile and amphibian pets.[10] A similar outbreak occurred in the United States and United Kingdom in 2009 and 2010 from the same two breeders implicated in this 2012 occurrence.[10] Also, more than a third of those infected were young children, highlighting their propensity for infection.[10]

The outbreaks in 2012 that occurred due to contact with live poultry were of five different serotypes of Salmonella bacteria originating in three distinct locations. The first infections were reported in February 2012.[11] Spanning 23 states, there were 93 humans infected with the Montevideo serotype of Salmonella.[11] All were infected with this strain from contact with baby ducklings or chicks from the Estes Hatchery located in Springfield, Missouri.[11] This outbreak resulted in one casualty.[11] One month later (March 2012), 46 people in the United States were infected with Salmonella Hadar through contact with live poultry.[12] There were no deaths, and the infected humans were located in 11 different states.[12] The specific hatchery name is withheld, but it was concluded by the CDC that this strain of Salmonella originated in one unnamed hatchery in Idaho.[12] In the same month, one of three strains of Salmonella – Infantis, Newport, or Lille – were contracted by 195 people from contact with live poultry (whether for purposes of agriculture or pet keeping).[13] Of those infected, two died from infection.[13] This particular outbreak, though stemming from only the Mt. Healthy Hatchery in Ohio, expanded across 27 states.[13]

First investigated at the end of March 2012, there were a total of 84 cases of infected humans across 15 states of the United States by November 2012.[14] These people's salmonellosis (either from Salmonella Sandiego or Salmonella Newport) stemmed from contact with small turtles or their habitats.[14] Some of these turtles were purchased from street merchants.[14] No one source of the Salmonella contaminations was identified, and no human deaths occurred.[14] Due to past outbreaks, there is a law in place making it illegal to sell or own a turtle with a shell length less than four inches, as these seem to generally be the sources of most Salmonella bacteria in small turtles.[14]

First reported in April 2012, an outbreak of salmonellosis caused by rarer serotypes, Salmonella Bareilly and Salmonella Nchanga, was reported in 28 states, mostly in the Eastern U.S., having caused no deaths, but 425 cases of illness and 55 hospitalizations.[15] This outbreak was linked to the consumption of raw scraped ground tuna product.[15] The source was frozen raw yellowfin tuna product aka Nakaochi Scrape manufactured by Moon Marine USA Corporation.[15] This product was voluntarily recalled after the CDC discovered strains of Salmonella in the packages.[15] The company eventually recalled another type of canned tuna for fear it may have been contaminated, too.[15] This outbreak was significant in that it was the first salmonellosis case in the United States connected to raw, scraped tuna products, as well as being the first time S. Nchanga was discovered in food products in the United States.[15]

In July 2012, an outbreak of salmonellosis occurred in the Netherlands and the United States.[16] According to the National Institute for Public Health and the Environment, by the end of 2012, 1060 people in the Netherlands and 100 in the United States contracted salmonellosis from smoked salmon infected with Salmonella Thompson.[17][18] On November 2, the RIVM confirmed that there were 4 deaths and over 1060 cases linked to S. Thompson in the Netherlands.[17] The infections were linked to smoked salmon from the manufacturer Foppen, where the contamination had occurred.[16] A recall involving a quarter million customers was undertaken in the United States.[19][20] The CDC did not classify this as an outbreak because there were not a verified number of people infected from only this source in the U.S.[3]

Because animals are the main transporters of Salmonella, crops can become infected. This generally occurs because of the use of manure-based fertilizers on farms. Some animals do not appear sick (especially infected poultry); however, they carry the Salmonella in their intestines and when they defecate, the bacteria spreads to the soil.[6] Sometimes, the sick animals manifest the illness in ways similar to humans with similar consequences. They may have diarrhea, fever, and then die if they are not treated.[6] After their death, the other animals raised with them can become infected through contact with their feces.[6] Therefore, if this infected manure is used as a fertilizer for crops, then the crops will contain trace amounts of infectious Salmonella bacteria that can spread to humans after the crops are harvested.[6]

Poultry can become infected by living close together in hatcheries, where multiple animals are defecating. Some poultry are hatched to be sold domestically, while others are hatched for production to be consumed later. If live poultry are infected and sold domestically, they can infect other animals who may be around them in a domestic situation e.g. other pets.[12] Because poultry do not show symptoms, infections are usually not obvious until humans or other animals in contact with the poultry become ill.[6]

Notice of lack of tomatoes due to Salmonella outbreak in 2012

East Coast tomatoes tend to have higher rates of Salmonella infection than West Coast tomatoes.[21] This seems to be due to the microbiome of the East Coast of the United States, where there are far less soil bacteria that destroy Salmonella versus the microbiome of the West Coast where these bacteria are abundant.[21] Because of the anti-salmonella bacteria limiting its spread, fewer people on the West Coast report cases of salmonellosis.[21] Additionally, street-sold natural tomatoes have been consistently tied to outbreaks of Salmonella. Street-sold (unregulated) items are independently produced and sold to consumers. This does not include fresh produce markets. These strong links to salmonellosis is in due in part do the lack of Food and Drug Administration (FDA) oversight on unregistered vendors. Another cause of Salmonella bacteria growth may be due to contact with contaminated irrigation water.[21][22] The tomatoes (or any plant) are much more likely to become infected if the soil in which the roots are located are contaminated or if the actual blossom is contaminated.[21][22] These two entry points lead to the most likely scenarios in which a healthy tomato plant may become infected with some serotype of Salmonella.[22]