Brucellosis Flashcards
what are the 3 species of brucellosis that are important
B abortus
B melitensis
B suis
where is brucellosis distributed
High incidence:
North Africa
Mediterranean
Middle East
what are the human clinical impacts of brucellosis
Human infections rarely fatal but can cause substantial morbidity
Severe complications not rare (endocarditis and neurological complications)
Debilitating (sometimes chronic) manifestations common
Arthralgia
Myalgia
Back pain
Malaise
Variable and non-specific constellation of symptoms poses diagnostic challenges
what are the animal impacts of brucellosis
Sub acute or chronic disease affected many animal species
Cattle, sheep, goats, pigs — initial infection often not apparent
In sexually mature animals, infection localizes in reproductive systems
what reproductive effects does brucellosis have
Placentitis followed by abortion in pregnant females (usually in last third)
Epididymitis and orchitis in males
Subsequent pregnancies usually carried to term
Reduced reproductivity productivity and infertility in some animals
Milk drop
Hygromas
how is brucella transmitted from animal to animal
Profuse excretion of bacteria (even in the absence of abortion or other signs)
- In the placenta, fetal fluids, vaginal discharges and milk
- In semen
Most transmission attributable to direct or indirect contact after an abortion or parturition
Sexual transmission can occur
Artificial insemination can transmit disease (important in herds that are known to be Brucella free)
how is brucella transmitted from animal to humans
Direct or indirect contact with infected animals or environments
Direct inoculation via cuts and abrasions, conjunctiva or inhalation of aerosols
Ingestion of unpasteurized milk and raw meat/blood products
how is brucellosis transmitted from humans to humans
Transmission via blood transfusion, breast milk, tissue transplant and sexual transmission apparently possible but very rare
Negligible in wider epidemiology
what are the options for control in livestock
Some sanitation and management measures
Livestock vaccination B. abortus and B. melitensis
how is brucellosis controlled from animal to human transmission
What practices enable transmission?
How modifiable are these practices?
how is brucellosis controlled in humans
Identification and treatment of human cases
No licensed human vaccines
Challenging diagnosis
Non-specific clinical signs and diagnostic tool limitations
Combination antibacterial therapy
Duration 6 weeks > treatment failures and relapse
how is transmission to people prevented
Most human disease caused by B. melitensis
Higher risk of infection in livestock keeping communities as well as veterinary and abattoir workers
- Information sharing to advise against consuming unpasteurized milk and milk products
- Barrier precautions for hunters and professionals at risk (butchers, farmers, slaughterers and veterinarians)
- Careful handling and disposal of afterbirths, especially in cases of abortion
what is the most rational approach for preventing human brucellosis
control and elimination of infection in animals
vaccintaion of cattle, sheep, goats
eradication by testing and culling
what are the FAO recommendations for endemically infected countries
Aim to reduce prevalence and disease in susceptible species
- Limiting spread within and among flocks and herds
- Long-term vaccination as main tool
Vaccination:
- Increases resistance to infection (reduces the risk of abortion)
- Decreases the spread of infection (decrease the prevalence)
- Ultimately decreases incidence in human populations
But — current options are insufficient on their own to achieve eradication
how is brucellosis controlled in the UK
Notifiable disease and was eradicated from cattle in GB in 1979 becoming officially brucellosis free in 1985
The infection has been re-introduced on several occasions by imported cattle
