Vaccines for Caprine Brucellosis: Status and Prospective

Brucellosis in goats is mainly caused by B. melitensis, although this pathogen may also infect cattle and other ruminants [1]. This pathogen has three different biovars [2]. B. melitensis was the first species in the genus Brucella described and was first isolated by Bruce in 1887 [3] from the spleens of soldiers dying of Mediterranean fever on the island of Malta. The origin of the disease remained a mystery for nearly 20 years until Themistocles Zammit accidentally demonstrated the zoonotic nature of the disease in 1905 by isolating B. melitensis from goat’s milk [4]. Initially it was believed that goats were not the source of infection since they did not become ill when inoculated with Brucella cultures [5]. However, the causing organism is mainly responsible for human brucellosis all over the world. Thus the prevention of human brucellosis largely depends upon the prevention and control of caprine brucellosis and similar to the control strategies against any infectious disease vaccination is the first and foremost step to the control animal brucellosis [6]. The most common methods for control of the ovine brucellosis are vaccination of animals and slaughter of infected flocks [7,8]. There is no human vaccine in contrast to animals where vaccination is supposed to be one of the most cost-effective measures to achieve eradication [9-11] and to improve human health in endemic areas [12,13].