In light of several recent and unrelated strangles outbreaks around the state, Abby Sage, VMD, DACVIM with VDACS has provided the following links for reference and dispersal to your clients. She has also drawn up a handout for your clients of guidelines for quarantine and prevention of spread of disease between farms.
http://www.thehorse.com/articles/34919/strangles-dispelling-the-myths
https://www.aphis.usda.gov/publications/animal_health/2014/fsc_equine_biosecurity.pdf
http://onlinelibrary.wiley.com/doi/10.1111/j.1939-1676.2005.tb02671.x/pdf
http://www.equinediseasecc.org/biosecurity.aspx
Biosecurity Guidelines for Horse Owners-3(1).docx