The virus is a non-enveloped, flexous rod-shaped particle that is between 760–800 nm long and 12 nm in diameter. It is transmitted between plants by mechanical activities like pruning and by numerous aphid species such as Myzus persicae. No seed transmission has been detected.[2]
There are two major types of this virus that are serologically indistinguishable and are so closely genetically related that they are now considered the same virus species. The type that gave the virus its name are the Type P isolates (PRSV-P). This type infects papaya and several members of the melon family (Cucurbitaceae). The other type, Type W isolates (PRSV-W), does not infect papaya. Isolates of PRSV-W do infect cucurbits such as watermelon, cucumber, and squash and were originally known as Watermelon mosaic virus 1