Hi
Diarrhea of 5 months duration with
weight loss, needs to be addressed seriously.
She has to be investigated for the cause. Malabsorption/ celiac disease/ immunodeficiency/
food allergy etc have to be ruled out. Few blood tests and Stool examination have to be done to rule out these.
If already done, do get back with all reports.
You can give her Flagyl syrup as your doctor would have thought of
amoebiasis.
Black worm like thing may be due to the fibre in the diet- as in banana- that is not digested well.
Based on the diagnosis, her diet has to be modified. If she has
lactose intolerance, milk has to be avoided. If celiac disease, gluten has to avoided.
If secretory diarrhea, medications like Racegadotril will help.
Probiotics may be of use. Discuss these things with your doctor.
Give her plenty of fluids- like ORS, plain water, vegetable soups, rice based food, curd etc.
Have her investigated and treated accordingly.
Hope my answer helps you
Wish a speedy recovery for your kid.