Piroplasmosis is a tick-borne parasitic disease of horses. Most infected horses do not develop symptoms of piroplasmosis.
Pigeon fever is a common bacterial infection of horses caused by Corynebacterium pseudotuberculosis. Even though most affected horses don’t get a fever, it takes its name from the way the associated abscesses shape the horse’s chest to resemble a pigeon breast
Pyrrolizidine Alkaloid (PA) toxicosis occurs when horses ingest a toxic dose of pyrrolizidine alkaloids, a group of organic compounds produced by a wide variety of plants as a natural insecticide.
Prepubic tendon (PPT) rupture in horses is a serious condition in which there is a tear in the tendon that runs between the pubic bone and the abdominal wall.
Premature placental separation (also known as Red Bag Delivery) in horses occurs when the outer layer of the placenta does not burst as delivery begins and instead travels down the birth canal.
Potomac horse fever (PHF) is an intestinal infection caused by Neorickettsia risticii, a bacteria that is transmitted from a parasite affecting snails, to aquatic insects, and then ingested by the horse.
Pleuropneumonia is an infection in horses of the lungs and the space around the lungs, usually caused by one or more types of bacteria.
Paspalum staggers in horses is a rare neurological condition caused by the ingestion of dallis grass (*Paspalum dilatatum*) that is infested by parasitic fungi.
Amyloidosis in horses is when amyloids, incorrectly formed proteins, deposit in the tissues due to chronic inflammation or cancers.
Leishmaniasis in horses is a disease caused by infection by the protozoa *Leishmania,* which is transmitted to horses through a sandfly bite.