I've had a low-grade fever (around 100; my normal temps is 97.5-98.5) for almost three months now. It started while I was living in sub-Saharan Africa. The country where I was living (Burundi) has poor medical care. I was put on two courses of antibiotics and an anti-parasitic medicine, but I did not get better. I was evacuated to Nairobi, where the doctor found giardia (I had no gastrointestinal symptoms). I was treated for that, but no change in the fever (although before the treatment for that, I had had a poor appetite and had lost about 13 pounds - a lot, since I'm about 115 normally - and the giardia treatment seemed to fix that problem). When I returned to the US, I had many more tests done. They found that the giardia had indeed cleared up. I had an abdominal ultrasound, which was normal. So far, all of the blood work has been normal. They have done a stool culture, blood cultures, CBC, and urine sample - everything normal. HIV, mono, dengue, typhoid, and malaria were all negative.
My housemate from Burundi fell sick at about the same time I did, with the same symptoms, so we figure it has to either be contagious or a common source, with the latter being more probably because none of our respective family members has fallen sick in the month we've been back. She still has a low-grade fever, as well. She also has had many tests done, at different places from where my tests were done, all negative/normal.
Besides the low-grade fever, I feel weak and have some fatigue, but I wouldn't say it's extreme.
I'm going to be seeing an infectious disease specialist, but the waiting list is long. With all of these tests being negative/normal, are there any serious illnesses left that could be causing the fever, or is it more likely that it's something less serious?