Spumaviridae

Spumaviridae is a family of retroviruses that infect a wide range of vertebrate hosts. These viruses are characterized by their distinctive, bubble-like virions, which give them their name. Spumaviruses are known for their persistent, often asymptomatic infections in their hosts. Unlike many other retroviruses, spumaviruses do not typically cause disease, although exceptions have been noted in certain experimental conditions or in severely immunocompromised individuals.

The genetic material of spumaviruses consists of a diploid RNA genome. Their replication cycle involves reverse transcription, a hallmark of retroviruses, but with some unique features. For instance, spumaviruses encode a specific protease that is essential for their maturation. Their genomes are relatively large compared to other retroviruses, containing multiple open reading frames.

Spumaviruses are found in mammals, birds, and reptiles. Examples include Simian foamy virus (SFV) in primates, Bovine foamy virus (BFV) in cattle, and Feline foamy virus (FFV) in cats. Transmission of spumaviruses typically occurs through direct contact, such as bites or saliva, and they are often acquired early in life. Despite their widespread presence and long-term persistence, their pathogenicity remains low, making them a subject of interest for understanding viral latency and host-virus interactions without overt disease. Research continues to explore their potential as tools in gene therapy due to their ability to integrate into the host genome without causing significant harm.