Not related to any parasite, but an oppurtunistic infection e.g. when the body is weakened by another pathogen others are able to enter the body or proliferate and vice versa.
I suppose this is an antigen test? If it is then read about this testing. I believe that it is not necessarily a marker for a current infection it just shows that you have had an immune response (could be a past or present infection). But if you are having issues with fatigue this could be the culprit.
Cytomegelo is a nasty virus. Every time it flared on me I had massive fatigue. I would look into homeopathy for this one. Jessesmom was treated for this as well, check with her.