「Illness of presuming upon another, or of being naive」is RICKETS, caused in part by a lack of sufficient exposure to sunshine and the subsequent synthesis of vitamin D as a result of「being too sweet」and over-caring for children:
「Rickets is a softening of bones in immature mammals due to deficiency or impaired metabolism of vitamin D, phosphorus or calcium, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a vitamin D deficiency,…the majority of cases occur in children suffering from severe malnutrition, usually resulting from famine or starvation during the early stages of childhood. …Cases have been reported in Britain in recent years of rickets in children of many social backgrounds caused by insufficient production in the body of vitamin D because the sun's ultraviolet light was not reaching the skin due to use of strong sunblock, too much 'covering up' in sunlight, or not getting out into the sun. Other cases have been reported among the children of some ethnic groups in which mothers avoid exposure to the sun for religious or cultural reasons, leading to a maternal shortage of vitamin D. And people with darker skins need more sunlight to maintain vitamin D levels. …Rickets had been a significant malaise in London, especially during the Industrial Revolution. Persistent thick fog and heavy industrial smog permeating the city blocked out significant amounts of sunlight so much so that up to 80 percent of children at one time had varying degrees of rickets in one form or the other.」
[ https://en.wikipedia.org/wiki/Rickets 2013-10-17 ]
「Illness of sweetness」to children was at one time referred to as 'spoiling' the child, but may lead in Japan to neurosis in children, or so the experts tell us, characterized by crying at night and convulsions, temper, nerves, and so on that are characteristic of any child at various ages anywhere.
「Illness of presuming upon another, or of being naive, sweetness and smiles」may refer to a child contracting oral gonorrhea from performing oral services, or a case contracted congenitally at birth from the mother…semen contains significant amounts of fructose, and sometimes also significant amounts of the bacterium Neisseria gonorrhoeae. Childhood neurosis (or, 'neurotic disorder') is the occurrence of a broad range of neurotic conditions in children, characterized by anxiety, fears, obsessive thoughts, compulsions, dissociation and depression that is caused in many cases by stress and anxiety from which the child cannot escape (sound familiar: no-longer-integrated feet leaving no escape? parents and elder siblings, adult relatives…) inconsolable crying at night, twitching, convulsions, temper tantrums, nervousness and so on. Perhaps neuroses caused by being forced to perform fellatio in dynastic China, or anywhere anytime for that matter.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: rickets
Japanese EDRDG: children's diseases
Unihan extended: childhood diseases