Hello Sir/madam My Grandmother Is Sick From Last Two Years

Hello sir/madam my grandmother is sick from last two years she is having a low grade fever, we have consulted more than 10 docters but no one could diagnose the infection, she has gone under various tests sevral times for once maleria came possitive
After the treatment there was no noticeable effect on her health same was with the vidal test.
She has blood pressure and asthma.
Please reply if any of you could help with this.