PRSV is a microparasite, meaning that it uses a vector to transmit infection from host to host. While some microparasites spread through abiotic (nonliving) vectors such as the air when people cough or sneeze, PRSV relies on biotic, or living, vectors--one of two insects scientifically known as Myzus persicae and Aphis gossypii. These insects transfer the virus from an infected plant to a healthy plant. PRSV causes premature molting and malformation of existing leaves. It may also result in ring spots and other markings on plant organs such as the fruit, stems, and petioles. Papaya plants infected with PRSV are generally smaller, less productive, and less likely to survive than uninfected plants.