Brucellosis
The disease brucellosis is the most important zoonotic disease worldwide. It affects both man and livestock. The etiological agents are gram-negative coccobacillae belonging to the genus Brucella. Brucella melitensis, B. abortus and B. suis have small ruminants, cattle and pigs respectively as their principle hosts.
Epidemiology of brucellosis
Epidemiology is complex. Different factors contribute to the prevalence and spread in livestock:
- the farming system and practices
- farm sanitation
- livestock movement
- mixing and trading of animals
- sharing of grazing grounds
- sharing of males for breeding
- contact with wildlife
Transmission from infected livestock to man
• Directly > through contact with infected animals or animal products
• Indirectly > through consumption of products, mainly raw milk and soft cheese prepared with unpasteurized milk
Brucella has a very low infecting level, making infection a genuine risk to those occupationally exposed to cattle, and to the public through the consumption of contaminated unprocessed dairy and meats.
Effects of brucellosis in infected animals
• abortion
• reduced fertility
• weak offspring
• reduced productivity
Effects of brucellosis in man
The disease may affect almost any organ and causes a variety of problems. If not treated early brucellosis may lead to severe and prolonged disability.
Impact
Brucellosis may have a deep economic and social impact. In particular pastoralists, who for their nutritional needs are often entirely dependent on their livestock, can be severely affected. Lack of resources and weak veterinary and medical services often hamper the control and management of this disease in these populations.
Prevention and control
Measures to control the spread and transmission of the pathogen:
• mass vaccination of livestock; this is a crucial measure that eventually will lead to a reduction of brucellosis in the human population
• restriction of trade and animal movement
• culling of infected animals
• improved farm sanitation
• pasteurization of milk (to reduce the risk of infection of the human population)
Treatment and diagnosis of human brucellosis
• Human brucellosis requires protractive treatment with a combination therapy.
• The diagnosis of brucellosis requires laboratory confirmation.
Culture is the gold standard, but culture facilities are rarely available in endemic areas and therefore one often resorts to serology. The Rose Bengal test may be used as a simple screening test and the serum agglutination test or ELISA are used for confirmation.
Approach
Improved diagnosis Early diagnosis and treatment is essential to increase the success of treatment and to reduce the risk of persistent diseases and complications. To facilitate early and rapid diagnosis we have developed a simple and robust point-of-care test for the serodiagnosis of human brucellosis.
Treatment Human brucellosis requires prolonged treatment with a combination of antibiotics. Treatment failure is high and relapses are common. Studies are supported to design improved treatment schedules and to identify risk factors for treatment failure and relapse.
Epidemiology of brucellosis Genotyping of Brucella isolates can be used to identify common sources of infection and to follow the spread and transmission of specific genotypes.
Brucella pathotypes Each different Brucella species that infects and causes disease in humans may cause a range of different disease presentations and complications. Genotyping of Brucella isolates may show whether different genotypes are associated with different disease characteristics and whether different Brucella pathotypes exist.
Brucellosis in livestock Few veterinary laboratories in endemic countries have experience with laboratory testing for brucellosis. A field test developed by KIT Biomedical Research may fulfill the need for a simple and robust test that may be used outside the established laboratory.
Focal points
Focus points
- Point-of-care test for human brucellosis
- Improved treatment reducing the risk of complications and relapse
- Molecular epidemiology and the control and prevention of brucellosis
- Pathogenesis of brucellosis
- Pen-side testing of livestock
Projects
Publications
- Smits, H.L. - Immunochromatographic Brucella-specific immunoglobulin M and G lateral flow assays for rapid serodiagnosis of human brucellosis.
- Smits, H.L. - Brucellosis.
- Smits, H.L. - The potential use of the leptospiral major outer membrane lipoprotein LIPL32 in the diagnosis of leptospirosis.
- Smits, H.L. - Brucellosis in India: a deceptive infectious disease
- Maas, K.S.J.S.M. - Evaluation of brucellosis by PCR and persistence after treatment in patients returning to the hospital for follow-up.
- Franco, M.P. - Human brucellosis
- Abdoel, T.H. - Rapid latex agglutination test for the serodiagnosis of human brucellosis
- Mendoza-Nunez, M. - Brucellosis in Household Members of Brucella Patients Residing in a Large Urban Setting in Peru