Bacterial Zoonoses
A bacterium is a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organised nucleus. The diseases caused by bacteria are known as bacterial diseases.
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Brucellosis
Brucellosis is an infectious disease that is characterized by undulant fever, sweating, muscle and joint pains and weakness. It is a zoonotic disease that can be caused by Brucella abortus, B. canis, B. melitensis, etc. It is commonly transmitted to humans from large animals like cows and buffaloes however transmission from dogs and cats is also a possibility in rare cases. This disease is present worldwide and causes massive economic losses in the livestock industry as well as in humans. It is challenging to diagnose Brucellosis in dogs and a one health approach is required in dealing with this disease. With the animals moving frequently across borders, this disease has the potential to spread across places where the incidence is rare.
Brucella canis in dogs is transmitted via ingestion, inhalation or contact with infected aborted material, vaginal secretions or semen. This species is mainly found in the reproductive organs of the host animals. Even after the disease is cured, an animal may remain a life-long shedder of this disease.
Different strains of Brucella are spread in humans via consuming undercooked meat or unpasteurized dairy. Infection can occur in rare cases via the inhalation of this bacteria. It can also spread from open wounds that get infected or very close contact with an affected animal.
In humans-
- Undulant fever
- Chills
- Malaise
- Splenomegaly
- Peripheral lymphadenomegaly
- Muscle and Joint ache
- Arthritis
- Swollen scrotum or testicles in men
These signs may persist for a long time even after a person is cured of the disease.
In animals-
- Dogs may get infected subclinically and they may or may not show signs of the disease
- Epidymitis, prostatitis and orchitis are common manifestations
- Unilateral or bilateral testicular atrophy
- Infertility
- Pregnant females may have a mid-late term abortion
- Vaginal discharge
- Arthritis
- Spinal pain
- Neurological dysfunction
- Muscle weakness
Serological tests like ELISA and Agar-gel immunodiffusion are available to evaluate antibody response. Culture of fluids like blood, vaginal discharge and semen can be done. PCR is another popular method used to diagnose this disease.
Sterilisation programmes should be conducted regularly to avoid the transmission of this disease. Reporting this disease to the government may help in controlling this disease. Pre-testing of breeding animals may help to understand the prevalence of this disease. Biosecurity should be given attention to. In clinics, hands should be washed thoroughly after routine examinations. Routine disinfection should be done with 2.5% sodium hypochlorite, quaternary ammonium compounds, or 70% ethanol with a minimum contact time of 10 minutes. Avoid eating undercooked meat or feeding it to your pets. Unpasteurised dairy products should not be consumed. People who deal with animals on a very regular basis should use appropriate protective gear like gloves, masks, etc. Currently, there are no vaccines for Brucellosis in humans or dogs. Strain 19 and RB51 vaccines are available for use in large animals.
To know more about brucellosis, please visit https://www.who.int/csr/resources/publications/Brucellosis.pdf