Why some vaccinated sheep continue to shed MAP in faeces?


Johne’s disease is a chronic debilitating disease of sheep causing significant economic losses to farmers in Australia. Research conducted in the past 15 years has shown that vaccination of sheep with Gudair® substantially reduces disease associated mortalities but animals in some flocks continue to shed the causative organisms (Mycobacterium avium subsp paratuberculosis; MAP) in their faeces and remain infectious. This PhD project will investigate management, biosecurity, host and pathogen factors responsible for differential effectiveness of the Gudair® vaccine in different flocks.


Associate Professor Navneet Dhand, Professor Richard Whittington, Dr Karren Plain, Dr Kathrin Schemann

Research Location

Sydney School of Veterinary Science

Program Type



In this project up to 100 sheep farms that have been vaccinating lambs with Gudair® for more than 6 years will be enrolled. Presence or absence of MAP shedding in these flocks will be measured using pooled faecal culture and qPCR and information about their management and biosecurity practices will be obtained via face-to-face interviews. Data from interviews and faecal results will be analysed to identify and quantify the factors associated with presence of shedding. This will enable identification of management and biosecurity practices that could be implemented by producers in conjunction with vaccination for effective control of OJD on their farms. In addition, the PhD candidate will conduct genetic evaluations to understand host and pathogen factors associated with MAP shedding.

Additional Information

A PhD scholarship valued at $30,000 per annum (tax exempt) is available to an Australian/New Zealand citizen or an Australian Permanent Resident enrolled full-time for 3 years. Students should also apply for Research Training Program (RTP) Stipend and University of Sydney Postgraduate Awards (UPA). International students should apply for RTP for international students. The applicant must be a veterinary, agriculture or science graduate with interest in infectious diseases of animals, farm animal health, epidemiology and biostatistics. The candidate should have a driving license and should be willing to travel. The successful candidate will be based at Camden within a large multidisciplinary and supportive team. This project is part of an integrated new research program aimed at understanding key factors involved in host resilience in the face of endemic infection, linking environmental, pathogen and host factors.

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Johne’s disease, Mycobacterium, sheep, Vaccination, veterinary, animal health, epidemiology, farm animals, disease control

Opportunity ID

The opportunity ID for this research opportunity is: 2205

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