There are several questions relating to ATCV-1 exposure in humans that remain to be addressed. One concerns the source of the acquisition of ATCV-1 in the virome. ATCV-1–like viruses are common in inland waters such as those around Baltimore, so exposure to these water sources would be relatively common. The factors involved in the acquisition of ATCV-1 in
the oropharynx following exposure will be the subject of additional investigations. ATCV-1 is the reference genome for the SAG virus group, but we have previously sequenced 12 other SAG viruses and there are 2–3 distinct clades (29). Therefore, the exact nature of SAG viruses capable of colonizing the human oropharynx and other mucosal sites is also an important subject for future studies.