Translation guide
The English word 'epidemic' can refer to a widespread disease outbreak or, metaphorically, to something spreading rapidly in society. Japanese uses different words for medical vs. figurative contexts, and the most common equivalent depends on the nuance.
To refer to a widespread occurrence of an infectious disease in a community at a particular time.
The most common and general term for an epidemic. It can be used for diseases, trends, fashions, etc. Often used in compounds like インフルエンザの流行 (influenza epidemic).
An influenza epidemic has started.
This year's hay fever epidemic is severe.
Literally 'epidemic disease'. More specific to diseases than 流行, but less common in everyday speech. Often used in medical or historical contexts.
Cholera was a terrifying epidemic disease.
A more formal or literary term for epidemic or plague. Often used in historical or dramatic contexts.
In medieval Europe, epidemics broke out many times.
To describe something undesirable that spreads quickly through a population, like crime, panic, or a trend.
Also used for figurative epidemics, such as a craze or fad. Can be neutral or negative depending on context.
Taking selfies is an epidemic among young people.
Means 'spread' or 'proliferation', often used for negative things like crime, disease, or harmful ideas. Can be used as a noun or verb (蔓延する).
Means 'being rampant' or 'widespread', typically for negative behaviors like corruption or crime. Stronger than 蔓延.
To use 'epidemic' as an adjective meaning 'widespread and affecting many people'.
流行 (りゅうこう) is the most general and neutral term for something spreading, including positive trends. 蔓延 (まんえん) implies an undesirable, pervasive spread, often used for diseases or social problems. 横行 (おうこう) is stronger, suggesting something bad is rampant and unchecked, like crime or corruption.
The katakana word エピデミック exists but is rarely used outside technical medical contexts. It sounds unnatural in everyday Japanese. Use 流行 or 蔓延 instead.
フェイクニュースの蔓延が問題になっている。
The epidemic of fake news has become a problem.
Violent behavior is epidemic in schools.
汚職が横行している。
Corruption is epidemic.
Drug abuse is epidemic.