caenorhabditis elegans cer13 virus caenorhabditis elegans cer13 virus caenorhabditis elegans cer13 virus is a species of virus in the genus semotivirus and the family belpaoviridae. it exists as retrotransposons in the caenorhabditis elegans genome. caenorhabditis elegans cer13 virus virus classification (unranked): virus realm: riboviria kingdom: pararnavirae phylum: artverviricota class: revtraviricetes order: ortervirales family: belpaoviridae genus: semotivirus species: caenorhabditis elegans cer13 virus