If it is accompanied by fever likely it is typhoid fever
for which she may need a course of antibiotic course oral or IV.
Typhoid can cause loose stools.
E Histolytica cysts are usually asymptomatic only treatment is needed if stool has trophozoites of same.
Typhoid is transmitted by feco oral route. You need to dispose her stools properly and maintain good hygiene. Avoid eating outside and uncooked food. Hand washing is very important.
Hope this answers your query.
Please do reply in case of any further questions.
Wish her a speedy recovery.