Sydney veterinary researchers study bovine brucellosis
Animals have been used as sentinels for human diseases for a long time—think canary in a coalmine—but it is probably time for humans to pay back! A project being conducted by Sydney Faculty of Veterinary Science researchers Dr Navneet Dhand and Prof Michael Ward is exploring if animal health workers can be used as sentinels of bovine brucellosis.
Brucellosis is a zoonotic disease that spreads from animals to humans by direct and indirect contact. Infected dairy animals shed huge amounts of organisms at abortion or at subsequent normal calvings and often for long periods after parturition. Veterinarians and other animal health workers who regularly come in contact with infected materials such as aborted foetuses, genital discharge, placenta, urine etc. contract infection through cuts and abrasions on their skin, via conjunctiva or inhalation of infectious aerosols.
The Sydney Faculty of Veterinary Science researchers in collaboration with their research partners—Dr BB Singh, Prof JPS Gill and Dr Vishal Proch from India—are investigating if disease prevalence in animal health workers can predict the disease prevalence in animals. Thus instead of conducting expensive animal disease surveillance, the disease prevalence in animals can be extrapolated from that in animal health workers in the region who can be easily contacted and tested at a substantially lower cost than animals.
Siloed approaches to controlling brucellosis independently in animals or humans have failed in most resource limited developing countries where the disease is endemic. Brucellosis has been controlled or eradicated in many developed countries using vaccination and test-and-cull programs in conjunction with extensive disease surveillance in animals; however, such an approach is very expensive (for example, about US $150 million were spent each year in the US during the 1990s) and therefore, cannot be implemented successfully in developing countries. Moreover, this approach ignores the enormous differences in farmer perceptions, attitudes, culture, religion and social norms in these countries. For example, a test and cull approach for cattle cannot work in India because cows are considered sacred by Hindus and therefore society and the law do not permit slaughter. Similarly, in the absence of any government compensation, most animal surveillance programs have a paradoxical effect because farmers simply sell test positive animals to another farmer at an animal market, actually resulting in spread rather than control of the disease.
Dr Dhand and Prof Ward are using an entirely different plan to control brucellosis: a plan that suits the culture, norms and the economic situation of developing countries and abandons direct animal surveillance and test-and-cull as the key approaches.
They are investigating whether the disease can be detected using a clever One Health approach with humans as surrogate indicators of the disease in animals. Testing veterinarians will not only allow early detection of infection in them but will also enable detection of hotspots of the disease in animals allowing the animal health authorities to direct their limited disease control resources to that area. Control of infection in animals will eventually lead to control of disease in humans.
Dr Navneet Dhand commenced field activities of this One Health project early this month after organising a workshop for training researchers in designing field epidemiologic studies at the School of Public Health, Guru Angad Dev Veterinary and Animal Sciences University (GADVASU). He also represented the University of Sydney at the signing of a memorandum of understanding with GADVASU for collaborative research and training activities.
Sydney Veterinary School Doctor of Veterinary Medicine
Program title: Doctor of Veterinary Medicine (DVM)
Location: Sydney, New South Wales
Semester intake: March 2015
Program duration: 4 years
Application deadline: January 4, 2016; however it is recommended that students apply as soon as possible as this program can fill quickly.
The Sydney DVM is an exciting new graduate-entry veterinary program that commenced this year. The DVM replaces the school’s Bachelor of Veterinary Science, and is open to applicants with a completed bachelor’s degree who wish to study veterinary medicine in a postgraduate learning environment. The program is internationally recognised and accredited so graduates can work around the world.