Alpacas are very tough animals when it comes to diseases and parasites, but that doesnt mean they can never get them. The below diseases/parasites are rare and also depends on your area. Do regular worming on your alpacas and other parasites should not affect them badly.
Rabies
Depending on your area, rabies can be a big deal when it comes to your alpaca being healthy. Rabies affects the brain and is caused by a bite from another animal infected with it, from squirrels to possibly your own dog. Research to see if your area has an issue with rabies.
Meningeal Worm
This Parasite is only an issue or a worry to people that are living in the same areas as White Tail Deer. It is a very sad way for your alpaca to die because it is a slow, horrible and painful death.