August 2018
Salmonellosis in Orange County
Salmonellosis is an infection caused by Salmonella bacteria. Illness usually develops after an incubation period of 6 to 48 hours, with symptoms most commonly including diarrhea, fever and abdominal cramps. Persons with Salmonella gastrointestinal disease generally recover in four to seven days; antibiotic treatment is not routinely recommended. Antibiotics are recommended for persons with severe illness, infections involving non-intestinal sites (such as bacteremia or meningitis), or in persons at high risk of medical complications (including infants younger than 3 months and persons with immunosuppressive illnesses or therapies).  

In 2017, Orange County had 366 confirmed cases of salmonellosis. Cases ranged in age from 3 months to 92 years. Fifty-two percent were female, 96 (27%) required hospitalization. From 2008 to 2017, the rate of salmonellosis in Orange County has fluctuated between 9.4 and 15.5 cases per 100,000 residents with no clear trend over time (See Figure 1 ). 
(Figure 1)
Clinicians and clinical laboratories should report all salmonellosis cases within one working day to Orange County Public Health (OCPH) at 714-834-8180.  Each case is investigated by OCPH staff to assess for a potential source and prevent transmission. In addition, all isolates of Salmonella bacteria are sent to the Orange County Public Health Laboratory (OCPHL) to determine strain type and perform DNA testing using pulsed field gel electrophoresis. The OCPHL participates in Pulsenet, which is a nationwide network of public health laboratories which compares “DNA fingerprints” of Salmonella strains identified from around the country to identify trends and outbreaks ( ).
The most common sources of infection are contaminated food.   Salmonella can also be passed person-to-person through the fecal-oral route, or from contact with colonized animals, particularly reptiles that are kept as pets. Infected persons should not go to school or work until diarrhea resolves. Infected persons who work in settings that pose a particular risk of spreading infection, such as foodhandlers or daycare workers, are required by the California Code of Regulations to refrain from working until they have been cleared by public health with two negative stool specimens.  In 2017, 18 Orange County cases required clearance by public health prior to return to work. Clearance required an average of 24 days, with a range of 3 to 105 days.

Cases ranged from 3 months to 92 years of age and 52% were female. Ninety six (27%) of Salmonella cases were hospitalized (See Figure 2 ).
(Figure 2)
Orange County investigated cases associated with 25 national, state or local clusters of Salmonella . A specific source is not found in the majority of such clusters. Outbreaks involving Orange County where a source was implicated included an outbreak of S. thompson at a local restaurant which caused illness in sixteen customers. Orange County also had cases associated with national clusters which were linked to live poultry ( more info here ) and cucumbers ( more info here ) (See Table 1 ).
(Table 1)
Sixty (17%) of Orange County cases in 2017 reported international travel during their potential exposure period. Of these, thirty seven (62%) reported travel to Mexico (see Table 2 ).

(Table 2)
(Figure 3)
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