Prevalence and risk factors of brucellosis in man and domestic animals: A review

Brucellosis is the most common worldwide zoonosis with 500,000 new cases every year in humans and infections in millions of animals. This infection is mainly acquired by humans through consumption of unpasteurized milk and milk products from infected animals. Exposure can also occur occupationally in those who work closely with animals through contact with aborted fetuses and reproductive secretions. Animals acquire the infection from other infected animals through direct contact and vertical transmission. This infection is prevalent in all continents of the world except Antarctica, but its impact is more felt in developing countries where it is endemic in animals and humans. In certain developed countries where the disease was eradicated, there seem to be a re-emergence of the disease as the disease appears to claim more territory. The risk factors of the disease may vary from country to country and region to region, but most risk factors are similar. Consumption of unpasteurized milk and milk products plays a very important role in the transmission of this infection from animals to humans, in addition to direct contact with infected animals and their secretions. The best way to control this ubiquitous infection is through the One Health approach which involves human health, animal health, and environmental health. This paper reviews the prevalence of brucellosis in some countries in various continents of the world and highlights the risk factors responsible for the persistence of this infection in animals and humans with a view to proffering solution to this age-old zoonosis that has defied eradication for many generations in many parts of the world.