Dogs catch this disease by inhaling or eating the virus that is present in the urine, nasal and eye secretions of other infected dogs. (2ndchance.info)
As the fly feasts on cattle tears and other eye secretions, it spreads the nematode larvae. (sciencenewsforstudents.org)
However, if bacterial conjunctivitis is suspected, a doctor may collect a sample of eye secretions for laboratory testing to determine the type of bacteria and the best treatment. (health.com)