St. Louis Encephalitis
Elizabeth Salas &
Humans and Viruses
Human Biology 115A
Date completed: 3/6/00
"Sapporo-like viruses," or SLV, is the informal name given to the new genus of Caliciviridae. SLVs are also referred to as "typical" caliciviruses and/or enteric human caliciviruses (HuCVs). Sapporo refers to an outbreak of gastroenteritis that occurred in an orphanage in Sapporo, Japan.
This genus has the expected appearance of a typical calicivirus. When viewed along the 3-fold axes of symmetry, the virus possess a central "calyx" surrounded by 6 peripheral cups. SLVs have icosahedral symmetry with 32 surface depressions at the 5-fold and 3-fold axes of symmetry. Viruses included in the genus SLVs have a ragged edge outline. This makes accurate measurements of the virus difficult. In general, SLVs are 30nm in diameter, though estimates range from 31-38nm.
Recent advances in technology have helped genetically distinguished SLVs from NLVs (Norwalk-Like Viruses). In fact, recent research involving sequence analyses have indicated that SLVs maybe more closely related to animal caliciviruses than to NLVs. Sapporo-like viruses have smaller genomes than SRSVs. However, the major difference between SLVs and NLVs are the arrangement of open reading frames. These frames are distinct from those found in NLVs, but share similarities with animal caliciviruses.