The Indian Council of Agricultural Research’s Indian Veterinary Research Institute (ICAR-IVRI) is in the spotlight for developing a new vaccine, dubbed “Brucella abortus S19Δ per vaccine”, aimed at preventing brucellosis in the dairy sector. This development has the potential to bring significant relief to the dairy industry which has suffered considerable economic losses due to brucellosis.
About Brucellosis
Brucellosis, also known as Malta fever or Mediterranean fever, is a bacterial disease caused by various strains of Brucella. Primarily, it affects cattle, swine, goats, sheep and dogs. In India, the disease is endemic and is considered a zoonotic disease, meaning it can be transmitted from animals to humans. Brucellosis tends to lead to infertility, abortion, the birth of weak offspring, and reduced productivity in dairy animals, thereby causing substantial economic losses.
The Old Vaccine: B. abortus S19 strain
To combat this disease, calf-hood vaccination using a live attenuated Brucella abortus S19 strain has been practiced in India. The S19 strain is a robust immunogen, capable of eliciting an immune response leading to life-long immunity. However, it exhibited several drawbacks, including residual virulence to humans and animals, unsuitability for adult animals’ vaccination, the tendency to cause abortion when used in pregnant animals, and interference with the sero-diagnosis of clinical infection.
The New Vaccine: B. abortus S19Δ per
Aiming to overcome these drawbacks, ICAR-IVRI developed a modified strain named B. abortus S19Δ per, under the auspices of the Department of Biotechnology (DBT) funded “Brucellosis network program”. The programme focussed on studying Brucella infections’ epidemiological status in India and developing novel diagnostics and vaccines. The modified S19 strain involved altering the bacteria’s Lipopolysaccharide (LPS) structure through a process called deletion mutation. The vaccine potential of the S19Δ per has been successfully evaluated in small animal models and buffalo calves, showing promising prospects for large-scale application.
Impact and Application of the New Vaccine
The new vaccine holds immense potential for use in the national control programme on brucellosis. It possesses a DIVA (Differentiating Infected from Vaccinated Animals) capability, which allows differentiation between naturally infected and vaccinated animals. This feature enhances the diagnostic accuracy and helps in better disease management.
Human Impact and Treatment of Brucellosis
Brucellosis is not just an animal issue; it also affects humans. Over 3000 cases have been reported in China. Humans generally contract the disease through direct contact with infected animals, consumption of contaminated animal products, or inhalation of airborne agents. While person-to-person transmission is extremely rare, the disease can cause fever, sweats, malaise, anorexia, headache, and muscle pain. Treatment usually involves a course of antibiotics such as rifampin and doxycycline. Prevention measures include avoiding unpasteurized dairy products, cooking meat properly, vaccinating domestic animals, and practicing safety measures when handling animals or working in laboratories.
