Modifiers matching std:

• serious,
• bacterial,
• common,
• ulcerative,
• prevalent,
• protozoal,
• chronic,
• inflammatory,
• infectious,
• viral,
• nasty,
• major,

Simple categories matching infectious:

• disease,
• complication,
• agent,
• diarrhea,
• residue,
• microorganism,
• diarrhoea,
• cyst,
• fluid,
• microbe,
• organism,
• illness,
• waste,
• virus,
• std,
• change,
• pathology,
• process,
• entity,
• germ,
• material,
• state,
• dermatosis,
• symptom,
• condition,
• software,
• cause,
• substance,
• particle,
• secretion,
• pathogen,
• program,
• parasite,
• bacteria,
• disorder,
• antigen,
• nature,