they start by loss of appetite, then they won't eat at all. then they lay around and get yellow drainage out of thier eyes, then they start throwing up, then they die of dehydration if not treated. Doxycycline is the treatment, 100 mg every day for 21 days strait. Sometimes I will double dosage at first if the dog is bad off. Hope this helps, also its seems alot easier to treat if you can catch it early.