convulsions in a child; nervousness; short-temperedness
Traditional expression for a child's irritability, fretfulness, or convulsions, often attributed to an imaginary 'bug' in old folk belief. In modern usage, it refers to a child's bad mood or tantrums.
The baby won't stop crying; maybe it's because the 'kan no mushi' is strong.
My child has a bad case of 'kan no mushi' and often throws tantrums.
bug thought to cause children's diseases
Historical folk belief: an imaginary insect or worm in a child's stomach thought to cause convulsions and irritability. Now only used when explaining the origin of the expression.
In the past, it was believed that a child's tantrums were caused by a bug called 'kan no mushi'.
夜泣き means night crying of a baby, a symptom often associated with 疳の虫 in folk belief.
Standard kanji spelling for this traditional expression.
Mixed kana-kanji spelling; common in everyday writing.
Irregular kanji usage; 癇 is not standard for this word.
Literally 'the bug of kan (a traditional Chinese medicine concept of infantile convulsions)'. The word reflects an old folk belief that a worm or insect in a child's body caused irritability and convulsions. The exact origin is uncertain, but it has been used in Japanese since at least the Edo period.