With accent marks:
Дурно́й приме́р зарази́телен.
A bad example is contagious.
Bad habits and wrong views of one person very often “stick” to other people.
The proverb is used to talk about a person who, without any thinking and hesitation, adopts bad habits of others.
Other Russian proverbs
Strike the iron while it's hot.
What you will sow, that you will reap.
Man does not live thanks to bread alone.
Hurry to much and you will make people laugh.
Do not spit in the well - you will need it when thirsty
The beauty of a debt is its payment
The quieter you go, the further you'll get.
Don't bring your set of rules in a foreign monastery