A computer virus is responsible for paralysing the networks of several Dutch municipalities, along with other business and research organizations, the country’s Justice Ministry announced Thursday. The ministry’s computer security division says 22 cases have been reported since Tuesday. Communities affected include Venlo, Den Bosch, Almere and Tilburg. The malicious software, a variant of the Trojan.Sasfis virus, spreads through documents created with Microsoft Office. Anti-virus software has been updated to catch the threat, a spokesman for the ministry said.