the root (no rank)
Viruses (domain)
retroid viruses (subkingdom)
Retroviridae (family)
Orthoretrovirinae (subfamily)
Lentivirus (genus)
Visna virus (species)
[hide inferior taxa]
Maedi-Visna virus (subspecies)
neurovirulent visna virus (subspecies)
South African ovine Maedi-Visna virus (subspecies)