New Brucellosis Vaccine by ICAR | 24 Sep 2020

Why in News

“Brucella abortus S19Δ per vaccine” is developed by the Indian Council of Agricultural Research’s -Indian Veterinary Research Institute (ICAR-IVRI) for brucellosis prevention in the dairy sector.

Key Points

  • Brucellosis: It is a bacterial disease caused by various Brucella species, which mainly infect cattle, swine, goats, sheep and dogs.
    • It is also known as Malta fever or Mediterranean fever.
    • Brucellosis is a zoonotic disease and endemic in India causing huge economic losses to dairy industry due to:
      • Infertility
      • Abortion
      • Birth of weak off springs
      • Reduced productivity
  • Old Vaccine:
    • B. abortus S19 strain: In India, calf-hood vaccination is practiced using live attenuated Brucella abortus S19 strain for control of the disease.
    • B. abortus S19 strain is a very strong immunogen and provides lifelong immunity.
      • An immunogen refers to a molecule that is capable of eliciting an immune response by an organism's immune system.
    • Drawbacks:
      • Residual virulence to humans and animals.
      • Not suitable for vaccination in adult animals.
      • Causes abortion when used in pregnant animals.
      • Interferes with sero-diagnosis of clinical infection.
  • New Vaccine: To overcome some of these drawbacks, a modified strain of B. abortus S19 has been developed at ICAR-IVRI. The newly developed strain is named as B. abortus S19Δ per.
    • It is developed under the Department of Biotechnology (DBT) funded “Brucellosis network program”.
      • The programme aims at studying the epidemiological status of Brucella infections in India and to develop novel diagnostics and vaccines.
    • In the process of modifying the S19 strain, lipopolysaccharide (LPS) structure of the organism was altered through deletion mutation.
      • Lipopolysaccharide is the major component of the outer membrane of Gram-negative bacteria.
      • A deletion mutation occurs when part of a DNA molecule is not copied during DNA replication.
    • Vaccine potential of S19Δ per has been evaluated in experimental small animal models and also in buffalo calves.
    • The vaccine has great demand in India and will be of immense help in the national control programme on brucellosis.
    • The vaccine has DIVA capability.
      • DIVA means differentiating infected from vaccinated animals. These vaccines, also termed as marker vaccines, can differentiate between naturally infected and vaccinated animals.

Infection to Humans

  • Brucellosis has infected over 3000 people in China.
  • Humans generally acquire the disease through:
    • Direct contact with infected animals or
    • Eating, drinking contaminated animal products, unpasteurized milk or
    • Inhaling airborne agents.
  • The US Centers for Disease Control and Prevention states that person-to-person transmission of brucellosis is “extremely rare” but some symptoms may reoccur or never go away.
  • Symptoms of Brucellosis include fever, sweats, malaise, anorexia (psychological disorder in which one eats less due to fear of weight gain), headache and muscle pain.
  • Treatment and prevention:
    • It is usually treated with antibiotics, including rifampin and doxycycline.
    • Avoiding unpasteurised dairy products and taking safety precautions such as wearing rubber gloves, gowns or aprons, when handling animals or working in a laboratory can help prevent or reduce the risk of getting brucellosis.
    • Other preventive measures include cooking meat properly, vaccinating domestic animals, etc.

Source PIB