Moreover, the recently identified Merkel Cell Polyomavirus, a human oncovirus, likely uses the trisialylated ganglioside GT1b as a receptor [10, 11] , and other mammalian polyomaviruses such as Simian Virus 40 (SV40) and murine Polyomavirus (Polyoma) also bind glycans terminating in sialic acid [12] [13] [14] .