Sub-project 1 – August 2021
FMDV inactivation in tissues for safe transport
Transporting diagnostic samples from the farm to laboratories when dealing with possible emergency animal diseases can result in the laboratory being put under quarantine, if it does not have the correct biosecurity levels (BSL3) to handle pathogens such as foot-and-mouth disease (FMD). It is therefore important to ensure virus will be inactivated, preferably by the time the sample leaves the farm. SP1 has been focusing on this aspect for FMD virus for some time.
Experimental work using live FMD virus has been disrupted by the COVID-19 pandemic, as these experiments are performed in overseas labs. Our collaborators at the Friedrich Loeffler Institute (FLI) in Germany have kindly proceeded with some aspects of the work, although more needs to be done. We have identified two transport mediums that inactivate FMDV in tissue samples within 2 hours of collection, at the same time preserving the genetic material sufficiently for further characterisation. This is a significant improvement on our previous experiments where at least 24 hours were required for inactivation. The methodology therefore allows confirmation that there is FMD virus in the sample by detecting the genetic material, determine the serotype and the genetic sequence that allows us to forensically trace the movement of viruses between premises that can help direct control options. It therefore increases the numbers of laboratories that can participate in the diagnostics and surveillance in an outbreak and helps the response. Without this methodology, diagnostics would be confined to a few BSL 3 laboratories.
FMDV inactivation kinetics – Temperature vs Relative Humidity
SP1 has been generating data on how FMD virus is inactivated at different temperatures and humidity. This information is important for virus dispersion modelling and to make predictions on virus transmission between farms more accurate. This work has also been delayed, but thanks to our collaborators at FLI, some progress has been made. Data analysis is progressing to model the impact of increasing temperature and humidity on virus survival using both linear and non-linear regression analysis to compare the differences between and within strains of viruses. The design and data from this study will provide a framework for similar studies on other viruses such as avian influenza where wind dispersion is thought to play a role, to obtain solid scientific data to support dispersion model development.
Systems Immunology – Pigs
Vaccination of susceptible animals is an option to reduce the risk of them becoming diseased and control the spread of FMD during an outbreak. It would be useful to be able to measure immune responses and predict correlates of protection in vaccinated animals/pigs. Intradermal Application of Liquids (IDAL) technology has shown that intradermal (ID) vaccine delivery is comparable to intramuscular (IM) vaccination, without causing local granulomatous reactions at the site of vaccination. We have used a novel Systems Immunology (SI) based approach to investigate the immune responses as a whole in pigs as proof of concept. Based on the outcomes of this study, we will apply the technology to other species as well.
In addition, we are measuring host responses to vaccination by investigating small RNAs (micro RNAs; miRNAs). These miRNAs provide additional important information on how pigs respond to vaccination and can potentially be used as diagnostic tests. We are currently analysing the miRNA sequence data.
These novel approaches will provide additional tools to measure the early immune responses in vaccinated pigs, before antibodies are detected. Expansion of this work is required to correlate the detection of these early responses to booster vaccination and downstream protection from challenge.
FMD antigen matching and epidemiology:
Building on the FMD Ready project, we have received funding from Agriculture Victoria, Cattle Compensation Fund to investigate novel methods to trace the genetic relationships between different FMDV isolates. The methodology being investigated is in addition to more classical ways of measuring genetic relationships between viruses and will add to our array of tools that can be used during an outbreak to trace the origin of the outbreak and provide links between infected premises.
A pipeline to better understand the genetic diversity of FMD serotype O viruses and explore how they evolved over time is being developed.
Impact of COVID-19
SP1 has made significant progress despite the impacts of the pandemic. However, due to the international travel bans, it is not possible to progress the investigations in South East Asia (SEA) using genomic sequencing to determine how virus variants are spreading throughout the region and determine if new emerging variants are arising. In addition, no new data were generated on FMD vaccine antigenic relationships with circulating strains since 2019. These data are essential for Australia to ensure the current strains in our FMD Vaccine Bank will protect against any new variants.
Members of SP1 have been closely involved with research on COVID-19 vaccines and the progress made with the novel method of Systems Immunology was applied to SARS-CoV-2. Similar work was done to look at vaccine responses in ferrets. This successful application of technology developed under the FMD Ready project to a different virus of such importance is crucial in Australia’s general response to disease incursions. The success of this transfer is evident from the publications listed here.
View publications and conference proceedings here.