| LAC DPH Health Advisory:
Cluster of Brucella melitensis (Brucellosis) Infections Linked to Raw Dairy Consumption
May 5, 2026
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This message is intended for all primary care, emergency, and urgent care, internal medicine, pediatric, and infectious disease providers.
Please distribute as appropriate.
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- Los Angeles County Department of Public Health (LAC DPH) is investigating a cluster of Brucella melitensis cases linked to imported unpasteurized cheese.
- Brucellosis is transmitted through consumption of raw or unpasteurized dairy products from infected animals (including goats and cows); delayed or inadequate treatment can lead to serious, chronic disease.
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Healthcare professionals should consider brucellosis in individuals with fever, night sweats, fatigue, arthralgias, and a history of consuming informally imported dairy products (e.g., brought by family or friends) or consumption during travel to endemic areas.
- Notify your laboratory before submitting specimens if brucellosis is in the differential; Brucella poses a biosafety risk to laboratory personnel.
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Consult an infectious disease specialist if clinical suspicion is high, as early treatment reduces the risk of complications.
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LAC DPH is investigating a cluster of Brucella melitensis cases in adults residing in South Los Angeles County. Each case reported consuming unpasteurized cheese imported from Mexico.
Brucellosis is rare, with fewer than 15 cases reported in LA County annually. Most cases in LA County are linked to unpasteurized imported cheese, work with animals abroad, or accidental laboratory exposures.
While the risk to the general public at this time is low, this cluster of a rare infection is an important reminder that consuming raw or unpasteurized dairy products carries significant risk of infection.
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Brucellosis (also known as “Malta fever”, “undulant fever”, and “Mediterranean fever”) is considered one of medicine’s “great imitators.” Infections are systemic as Brucella bacteria enter the circulation via regional lymph nodes and seed throughout the body. The incubation period ranges from 1 to 4 weeks but may be as long as 6 months.
Brucellosis illness is characterized by acute or insidious onset of fever and one or more of the following: night sweats, arthralgia, headache, fatigue, anorexia, myalgia, weight loss, arthritis or spondylitis, meningitis, focal organ involvement (endocarditis, orchitis/epididymitis, hepatomegaly, splenomegaly).
Brucella species are designated federal Select Agents due to their low infectious dose and potential for aerosolization. Laboratories must be alerted if specimens from a suspect brucellosis case are being submitted.
See Brucellosis Reference Guide for more information.
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Actions Requested of Providers
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- Suspect: Consider brucellosis in patients presenting with fever, night sweats, fatigue, arthralgias, or other non-specific symptoms and a history of consuming unpasteurized dairy products either in the United States (e.g., informally imported dairy products brought by family or friends) or during travel to endemic countries.
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Test: Order Brucella serology and blood cultures. Use appropriate personal protective equipment (PPE) for aerosol-generating procedures (e.g. intubation). Notify your laboratory before submitting any samples so appropriate biosafety precautions can be taken. Note for laboratorians: Isolate speciation can be performed at the LAC Public Health Laboratory (PHL). Call 562-658-1360 for coordination. Submit isolates on slant with a copy of workup using appropriate packaging.
- Treat: Consultation with an infectious disease physician is strongly recommended. Standard treatment includes doxycycline for 6 weeks plus either streptomycin for 14 to 21 days or rifampin for 6 weeks. For pediatric or pregnant patients, consider rifampin plus TMP-SMX. If clinical suspicion is high, start treatment without laboratory confirmation as early treatment reduces risk for complications.
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Consider: Provide Post Exposure Prophylaxis (PEP) for high-risk exposures. People exposed to a common contaminated product or who had high-risk exposure to a confirmed case may benefit from PEP, as well as serologic and symptom monitoring.
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Report: Brucellosis must be reported to Public Health within 1 working day from identification. If a cluster is suspected (2 or more related cases), notify Public Health immediately (see information below).
- Educate: Advise patients to avoid raw or unpasteurized dairy products, including products with unknown pasteurization status, both locally and when traveling.
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Immediately notify Public Health of any suspected clusters (2 or more related cases). Report individual cases within one working day.
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Clusters - Immediately notify Public Health if a cluster of suspected cases is identified:
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Los Angeles County DPH Acute Communicable Disease Control:
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Weekdays 8:30am–5pm: call 213-240-7941.
- After-hours: call 213-974-1234 and ask for the physician on call.
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Long Beach Health and Human Services:
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- Weekdays 8am-5pm: call 562-570-4302.
- After hours: call the Duty Officer at 562-500-5537
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Pasadena Public Health Department:
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Weekdays 8am-5pm: call 626-744-6089.
- After hours: call 626-744-6043.
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Individual cases - Report suspected or confirmed brucellosis within one working day from identification:
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Los Angeles County DPH Acute Communicable Disease Control:
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Fax a CMR to 888-397-3778 or 213-482-5508 or send via secure email to RPU@ph.lacounty.gov, or
- Call 888-397-3993 weekdays 8:00 am-4:30 pm
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- Centers for Disease Control and Prevention:
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California Department of Public Health
- LAC DPH:
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This communication was sent by Dr. Sharon Balter, Director, Acute Communicable Disease Control Program, Los Angeles County Department of Public Health.
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To view this LAHAN in PDF format, view past communications, or sign-up to receive LAHANs, please visit ph.lacounty.gov/lahan.
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