fort morgan virus fort morgan virus fort morgan virus is an rna virus in the genus alphavirus. it is an alphavirus isolated from nesting cliff swallows, house sparrows and from cimicid bugs in eastern colorado for which the name fort morgan virus was proposed. fort morgan virus virus classification (unranked): virus realm: riboviria kingdom: orthornavirae phylum: kitrinoviricota class: alsuviricetes order: martellivirales family: togaviridae genus: alphavirus species: fort morgan virus