Sarcoids are wart-like growths that can be found on the skin of horses. It is unknown what exactly causes them but it is thought to be either yeast infecitons or the actual papilloma virus. They are relatively common, particularly on white skinned horses (sun thought to have an influence) where the small ones are literally warts. These aren't usually anything to worry about. They can however grow quite considerably (like cancer) and depending on the location can be very serious in deed - around the anus and nose particularly where it can actaully effectively 'seal' up the passages causing the horse to not be able to breathe or pass faeces.
Apart from the typical signs of an ill horse (temp. Change, sweating) the characteristic signs are the swelling of the lymph nodes in the neck. These can abscess and if they do not burst can crush the airpipe, causing strangulation. Lets hope that vaccine comes soon.
The gestation period is around 11 months.
Tetanus; Equine Encophalomyelitis (W, E or V); influenza and Herpesvirus (Rhinopneumonitis).
If applicable - West Nile Virus; Potomac Horse Fever and Rabies.
Admittedly I did have to check up the spellings of these vaccines!