Written by the Healthline Medical Network. In humans the P antigen (also known as globoside) is the cellular receptor for parvovirus B19 virus that causes erythema infectiosum (fifth disease) in children. Parvovirus B19 is known to be pathogenic to humans, the only one among all parvoviruses.  |  Three of the four women who exhibited serologic evidence of recent exposure to the parvovirus had hydropic fetuses who died, one of whom was anencephalic. Pregnant women who are not immune usually have only mild illness if they are exposed to fifth disease. How Is Parvovirus B19 Diagnosed in the Mother? Parvovirus affects people of all ages and ethnic groups. A pandemic is an epidemic that reaches worldwide. Eur J Obstet Gynecol Reprod Biol. Parvovirus B19 can also spread through blood or blood products. 109 (5):311-323. .