NEWARK, N.J.?The creator of the “Melissa” computer virus was sentenced Wednesday to 20 months in federal prison for causing millions of dollars of damage by disrupting email systems worldwide in 1999.

David L. Smith pleaded guilty to a federal charge of sending a damaging computer program. A court plea said the damage was greater than $80 million.

Smith is believed to be among the first people ever prosecuted for creating a computer virus. In court Wednesday, he called the act a “colossal mistake.”

The Melissa virus, which struck in March 1999, was disguised as an email marked “important message” from a friend or colleague. It automatically caused each infected computer to send 50 additional infected messages.

Smith could have faced up to five years in prison, but prosecutors suggested a term of two years, saying he had given authorities extensive assistance in thwarting other virus creators.