Some common equine diseases are colic, navicular disease, rain rot, founder and worms (bots). People often call colic a twisted gut and founder is often caused by feed problems.
Common equine diseases include such conditions as parasites and eye infections, colics and thrush, influenza (flu) and paralysis, arthritis and botulism, degenerative joint disease and anemia, skin cancer and hypothyroidism, laminitis hoof condition and mare reproductive loss syndrome, moonblindness and rhinovirus, ring bone and strangles, vesicular stomatitis and west Nile virus.
One common equine disease is Navicular which is when the cannon bone rotates causing laminitis. Laminitis is a sort of inflammation or irritation such as abscesses on the hoof area.