[1] The genus divides phylogenetically into two branches, one that contains many founder members of the family, such as MVM, CPV and PPV, which have been studied in considerable detail, and a second branch occupied exclusively by predicted viruses whose coding sequences were identified recently in the wild using virus discovery approaches, but whose biology remains minimally explored.

[8] It is simply an abstract taxonomic concept that clusters a selected range of genetic variants, helping to distinguish branches in a phylogenetic lineage, but it is not a physical entity like a virus that can infect an animal or be isolated.

[10] Three genotypes of bufaviruses have so far been detected, circulating in Tunisia, Finland[11] and Bhutan[12] A second virus in this genus that infects humans —cutavirus— was initially isolated from the feces of children with diarrhea.

[14] Viruses in genus Protoparvovirus have non-enveloped protein capsids around 18–26 nm in diameter, which show T=1 icosahedral symmetry.

Genomes are single-stranded linear DNA between 4–6kb in length, with small (100–500b) imperfect palindromic sequences at each terminus that fold to form distinctive duplex hairpin telomeres.

In 1978 a virus from the same species as FPV emerged that was able to infect dogs (called canine parvovirus or CPV), which rapidly spread globally, causing pandemics of severe intestinal and coronary disease.