instruction: From the passage identify the subtypes of Hepatovirus A. Display the results in comma separated format.
output: IA, IB, IIA, IIB, IIIA, IIIB
input: Hepatovirus A is a species of virus in the order Picornavirales, family Picornaviridae, genus Hepatovirus. Humans and other vertebrates serve as natural hosts.
  
  Nine members of Hepatovirus are recognized. These species infect bats, rodents, hedgehogs, and shrews. Phylogenetic analysis suggests a rodent origin for Hepatitis A.[citation needed]
  
  A member virus of hepatovirus B (Phopivirus) has been isolated from a seal. This virus shared a common ancestor with Hepatovirus A about 1800 years ago.[citation needed]
  
  Another hepatovirus – Marmota himalayana hepatovirus – has been isolated from the woodchuck Marmota himalayana. This virus appears to have had a common ancestor with the primate-infecting species around 1000 years ago.[citation needed]
  
  One serotype and seven different genetic groups (four human and three simian) have been described. The human genotypes are numbered I–III. Six subtypes have been described (IA, IB, IIA, IIB, IIIA, IIIB). The simian genotypes have been numbered IV–VI. A single isolate of genotype VII isolated from a human has also been described. Genotype III has been isolated from both humans and owl monkeys. Most human isolates are of genotype I. Of the type I isolates subtype IA accounts for the majority.
  
  The mutation rate in the genome has been estimated to be 1.73–9.76 × 10−4 nucleotide substitutions per site per year. The human strains appear to have diverged from the simian about 3600 years ago. The mean age of genotypes III and IIIA strains has been estimated to be 592 and 202 years, respectively.