Brucellosis A zoonosis

Center for Food Security and Public Health Iowa State University Brucella spp. Gram negative, coccobacilli bacteria Facultative, intracellular organism Multiple species

Center for Food Security and Public Health Iowa State University Species Brucella melitensis: most common B. abortus B. suis B. canis

Center for Food Security and Public Health Iowa State University Transmission to Humans 1) Conjunctiva or broken skin contacting infected tissues: − Blood, urine, vaginal discharges, aborted fetuses, placentas 2) Ingestion: − Raw milk & unpasteurized dairy products − Rarely through undercooked meat

Center for Food Security and Public Health Iowa State University Transmission to Humans 3) Inhalation of infectious aerosols: − Pens, stables, slaughter houses 4) Inoculation with vaccines 5) Person-to-person (sexual, congenital, breast-feeding) is rare Incubation varies − 7-21 days to several months

Center for Food Security and Public Health Iowa State University Who is at Risk? 1) Occupational Disease − Cattle ranchers/ dairy farmers − Veterinarians − Abattoir workers − Meat inspectors − Lab workers 2) Hunters 3) Travelers

Center for Food Security and Public Health Iowa State University ) Consumers of unpasteurized dairy products

Center for Food Security and Public Health Iowa State University B. melitensis B melitensis is thought to be the most virulent and causes the most severe and acute cases of brucellosis; it is also the most prevalent worldwide.

Center for Food Security and Public Health Iowa State University Human Disease Flu-like illness is the most common presentation ( %). Fever is intermittent in 60% of patients with acute and chronic disease. Fever can be associated with a relative bradycardia. Constitutional symptoms include anorexia, asthenia, fatigue, malaise, and wt loss. Hepatosplenomegaly and lymphadenopathy (30%)

Center for Food Security and Public Health Iowa State University Human Disease Localized infection may be the presenting feature: Osteoarticular complications  Arthritis, spondylitis, osteomyelitis Genitourinary involvement:  Orchitis and epididymitis most common

Center for Food Security and Public Health Iowa State University Human Disease Neurological: − Depression, meningitis Cardiovascular: − Endocarditis resulting in death

Center for Food Security and Public Health Iowa State University Chronic brucellosis The diagnosis of chronic brucellosis is typically made after symptoms have persisted for 1 year or more. Low- grade fevers and neuropsychiatric symptoms predominate. Results of serologic studies and cultures are often negative

Center for Food Security and Public Health Iowa State University Diagnosis in Humans Culture of: − Blood, bone marrow, CSF, urine (50% +ve) − Subcultures are still advised for at least 4 weeks − BM culture has higher yield. Sensitivity is usually % Serum agglutination test − Fourfold or greater rise in titer − Samples 2 weeks apart − The 2-mercaptoethanol test detects IgG, and titers higher than 1:160 define active infection. A high IgG titer or a titer that is higher after treatment suggests persistent infection or relapse. IgM Ab indicate recent infection.

Center for Food Security and Public Health Iowa State University Serology ELISA typically uses the cytoplasmic proteins as antigens and measures IgM, IgG, and IgA, allowing better interpretation, especially in cases of relapse

Center for Food Security and Public Health Iowa State University Treatment of Choice Combination therapy − Doxycycline 100mg bd for 6 weeks + streptomycin 1g/d im for 2 wk or rifampicin 600mg/d for 6 wk − In pregnancy: rifadin+ co-trimoxazole CNS cases treat 6-9 months − Same for endocarditis cases plus surgical replacement of valves

Center for Food Security and Public Health Iowa State University Prognosis May last days, months or years Recovery is common Disability is often pronounced About 10% of treated cases relapse  Failure to complete the treatment regimen  Sequestered infection requiring surgical drainage Case-fatality rate: <2% usually from endocarditis

Center for Food Security and Public Health Iowa State University Prevention and Control Education about risk of transmission − Farmer, veterinarian, abattoir worker, butcher, consumer, hunter, public Wear proper attire if dealing with infected animals/ tissues − Gloves, masks, goggles Avoid consumption of raw dairy products

Center for Food Security and Public Health Iowa State University Prevention and Control Immunize in areas of high prevalence − Young goats and sheep − Calves − No human vaccine Eradicate reservoir − Identify, segregate, or cull infected animals