Short answers, pulled from the story.
The World Health Organization defines hygiene as conditions and practices that help to maintain health and prevent the spread of diseases. Hygiene activities can be grouped into home and everyday hygiene, personal hygiene, medical hygiene, sleep hygiene, and food hygiene.
Research shows that if widely practiced, handwashing with soap could reduce diarrhea by almost fifty percent and respiratory infections by nearly twenty-five percent. It also reduces skin diseases, eye infections such as trachoma, and intestinal worms including ascariasis and trichuriasis.
The importance of handwashing was first recognized in the mid 19th century by the Hungarian physician Ignaz Semmelweis, who worked in Vienna, Austria, and by Florence Nightingale, the English founder of modern nursing. At that time most people still believed infections were caused by foul odors called miasmas.
Targeted hygiene identifies the routes of pathogen spread in the home and introduces hygiene practices at critical times to break the chain of infection. It uses a risk-based approach based on Hazard Analysis Critical Control Point, or HACCP.
The ear canals are sensitive and mostly self-cleaning, with a slow migration of skin that carries old earwax out to the opening where it dries and falls out. Attempts to remove earwax can push debris deeper into the ear and can result in infection or irritation.
The word hygiene was first attested in English in 1676 and comes from the French hygiene, a latinisation of the Greek hygieine techne, meaning art of health. In ancient Greek religion, Hygeia was the personification of health, cleanliness, and hygiene.
Bathing culture in China dates to the Shang dynasty, and the Abbasid capital of Baghdad had 65,000 baths along with a sewer system. Regular bathing was a hallmark of Roman civilization, served by aqueduct-fed baths and great sewers such as Rome's Cloaca Maxima.