Brucellosis in Dallas, Texas: a Case Series

Background:  While the epidemiology of Brucellosis is well described in systematic reviews and retrospective analyses in endemic countries, there is a paucity of similar data in the United States (US). With a recent outbreak of Brucellosis reported in Dallas County in 2016, we sought to characterize cases of Brucellosis at two Dallas teaching hospitals over the past 10 years.

Methods: A retrospective chart review of electronic medical records at Parkland Health & Hospital System and Clements University Hospital was completed for all patients over 18 who were diagnosed with Brucellosis, as defined by ICD9/10 codes, problem lists, and/or positive microbiologic or serologic data, between 1/1/2007 - 2/6/2017.  Demographic, epidemiologic, and clinical characteristics were collected.

Results: Out of 104 charts reviewed, 16 cases of Brucellosis (14 definite, 2 probable) were identified.  56% were male, the mean age was 45, and 94% were of Hispanic ethnicity. Recent travel was reported in 6/16 cases (5 to Mexico, 1 to India) and exposure to unpasteurized cheeses was reported in 13/16 cases. The majority of cases were seen in the summer months, and a sharp increase in incidence was noted in 2016 (Figure 1). Common symptoms included fever (16/16), chills (8/16), diarrhea (4/16), headache (4/16), malaise (4/16), and body aches (4/16). Laboratory abnormalities included leukopenia, thrombocytopenia, and elevated liver function tests. Other complications included epididymitis and/or orchitis (2/16), hepatomegaly (5/16), splenomegaly (4/16), and other splenic abnormalities (2/16).  Brucella discitis/osteomyelitis with spinal epidural abscess (1/16), possible neurobrucellosis (1/16) and recurrent disease (2/16) were also identified. The most common treatment regimen used was doxycycline/rifampin +/- gentamicin.

Conclusion: This case series represents one of the largest contemporary Brucella experiences described in the US. While not endemic in the US, the diagnosis of Brucellosis requires a high index of suspicion and should be considered in patients presenting with a febrile illness and a compatible travel history or exposure history, particularly to unpasteurized dairy products.