Zoonotic organisms in the agri-food chain
AFBI undertakes a wide programme of statutory, analytical and research work on the major bacterial pathogens of animal and public health significance in the Veterinary Sciences Division (VSD). Much of the current focus is on the microbiology, immunology and epidemiology of important mycobacterial diseases (bovine tuberculosis and paratuberculosis). Other areas of interest include brucellosis, the food-borne zoonoses (Salmonella, Campylobacter, Verotoxigenic E. coli), antimicrobial resistance, botulism, mycoplasmosis and cattle DNA identity and parentage testing.
The skill base comprises traditional and specialist microbiological methods, advanced molecular diagnostics, test development, pathogenesis, immunology, genetics, experimental design and wildlife ecology. In addition a veterinary epidemiology research area leads on a number of research projects and provides epidemiology input across VSD.
The laboratory is a National Reference Laboratory for both Salmonella and Brucella (NRL UK-NI) and a recognised centre of excellence in bovine TB research (pathogenesis, immunology and epidemiology).
The statutory and analytical work undertaken is in direct support of NI control programmes, and as required by European legislation. This includes culture and confirmation work for Salmonella spp, brucellosis and bovine TB using a combination of specialist culture and molecular techniques plus interferon gamma assays for bTB. All statutory tests are performed to EU and international methodology and to the ISO/IEC 17025:2017 accreditation quality standard.
Bovine tuberculosis (bTB)
Bovine TB is a notifiable and zoonotic disease, which is generally recognised as being the most difficult endemic animal disease problem across both the UK and Ireland. Control is required under both European (Council Directive 64/432/EEC, EU 2011) and international legislation. Failure to adequately control the disease or to comply with the requirements of European legislation would have serious trade implications and potentially endanger the export of meat, milk and other animal products from NI which is estimated to be worth somewhere in the region of £1 billion per annum.
AFBI VSD undertakes a range of laboratory testing in direct support of the NI bovine TB control program and as required by European legislation. This includes confirmation of disease in reactor and other samples using a combination of histology, culture and molecular confirmation; performance of supplementary (blood) testing using gamma interferon assays; and high resolution molecular genotyping (strain typing) of bTB isolates.
Bovine brucellosis
Brucellosis is a highly infectious disease in cattle, resulting in widespread production losses through abortion and infertility. It also presents a serious zoonotic risk, causing debilitating illness in humans. Similar to bTB, control of Brucella is required under European legislation and failure to do so would endanger trade in NI animal products as well as cause widespread production losses.
In October 2015 Northern Ireland was granted Official Brucellosis Freedom (OBF) status with laboratory testing continuing to ensure maintenance of disease freedom and to meet trade requirements.
The control of Brucella is entirely dependent on laboratory testing. The historical eradication programme and the new post OBF surveillance programme is supported by the AFBI VSD laboratory in terms of serological screening of blood samples (Chemical and Immunodiagnostic Sciences Branch) and follow on confirmatory culture (Bacteriology Branch). Results from this testing programme have been a primary factor in enabling DAERA to control and eradicate this disease in the NI herd.
In recent years, this culture confirmation has been supported by the application by VSD of high resolution strain typing methods, which is used by DAERA to help determine sources of infection.
Salmonellosis
Salmonella is the second most common food-borne infection in humans in the UK and most developed countries. In the mid 1990s over 30,000 laboratory confirmed human cases were recorded per annum in England and Wales, with the true number of cases estimated to be in the region of 100,000 per year. Human cases are almost entirely food-borne and linked directly or indirectly to animal products such as eggs, poultry and pork. The emergence of Salmonella Enteritidis in the late 1980s, for example, caused widespread public concern at that time and significant damage to reputation of the poultry industry.
The Salmonella Unit within Bacteriology Branch is the EU recognised National Reference Laboratory for NI for the analysis and testing of zoonoses (Salmonella) in accordance with the Zoonoses Directive 2003/99/EC and the Zoonoses Regulation (EC) No 2160/2003.
The unit undertakes a wide program of statutory testing in poultry flocks, confirmation and identification (serotyping) of isolates and surveillance for antimicrobial resistance. In addition, the laboratory acts as an expert source of information and advice to DAERA and other agencies in Northern Ireland.
Other Diseases
Botulism is a fatal disease of predominantly cattle and occasionally sheep caused by the consumption of feed containing Clostridium botulinum toxin. Cases of the disease increased significantly in NI in the early 2000s and were associated with the spreading of poultry litter.
AFBI work in this area has led to improvements in the diagnostic methods used through the detection of toxin in the intestinal contents of affected animals.