All vets are not the same. Consider that as human doctors go, we have general practitioners, and then specialists that cover everything from eyesight, to having babies and more. Yet there is only one line of study to become a vet and that needs to encompass all animals as well as their individual problems and age related illnesses.
For that reason, all vets are not the same. The greater majority of vets excel in the care of cats and dogs as these are the most common domesticated animals. However as guinea pigs go – you will need to find a vet that is a small animal expert. Most of these vets are called Exotic vets or Cavy Savvy Vets.
If you are in remote areas then you may have some distance to cover in order to find the right vet for the care of guinea pigs. Luckily, there is a great deal of information about their care that you have access to on-line. But it does not remove you from situations where you may require the help of a good guinea pig vet.
In most instances they can do a “faecal float” where they take a sample of the poop onto a glass slide and then looking at it under a microscope they will be able to tell if a particular parasite or organism (such as Giardia) is to blame. The treatment of this may then be a course of antibiotics.