hello and welcome.
your sister is having persistent high fever
with high ESR
, high ESR suggests infection in the body.
since all the investigation done are not giving any diagnosis,
it can be diagnosed as pyrexia of unknown origin = PUO.
she needs to take the symptomatic treatment. in the mean time get investigated for malaria
, get a blood culture
and sensisitivity done.hoping we come to know from the culture report , the microorganism causing the symptom and the antibiotic it will respond to.
hope your friend get well soon, take care.