Hi, Welcome to Healthcaremagic.com. I had gone through your question I can understand your concern about your mother. As per your history she is having the gastritis, and also you think this may be communicable disease. There are certain gastrointestinal diseases which may transfer from one to another by oro fecal route and this is not possible in a closed drainage system. Your father and the neighborhood friends may be having food poisoning, if they have eaten last time in same place and same food. I don t think they are having any relationship with the disease of your mother. May be they must have fallen to same cause as your mother did. Like same water which may be Contaminated. You need to visit a general physician for the medication of your mother, ciprofloxin plus tenidazole is mostly prescribed by doctors for infective gastritis. Hope my answer will help you and visit us back if you have any further queries. Regards Dr Muzaffer Hussain Parray.