Getting to know the mouse papillomavirus

New insights into the mouse papillomavirus show that it could be a good model to study the papillomaviruses that cause cancers in humans.

Cross-sections of the reproductive tract of a female mouse carrying MmuPV1 after being mated to an infected male. In brown (right image) are areas where the virus is present in the surface layer of the vagina. Image credit: Spurgeon and Lambert (CC BY 4.0)

Human papillomaviruses are responsible for about 5% of all cancers: infections with high-risk strains of the virus lead to the vast majority of cervical cancers, other cancers of the anus and genital area, as well as a growing fraction of head and neck cancers. In humans, these viruses are transmitted through sexual contact.

Other animals do not get infected by human papillomaviruses, and this makes it difficult to study in the laboratory how these viruses pass from one individual to another. However, a mouse papillomavirus has recently been identified: known as MmuPV1, it also causes cervical cancer in rodents, but it was unknown whether it was transmitted sexually.

To investigate this question, Spurgeon and Lambert experimentally infected female mice with MmuPV1 and allowed them to have intercourse with healthy males. When the males then were mated to healthy females, approximately a third of these female mice became infected with MmuPV1. Males that transmitted the virus were also found to have penile infections. These results show that, like the human papillomavirus, MmuPV1 spreads through sexual interactions.

Knowledge gathered by studying MmuPV1 could help to understand sexually transmitted human papillomaviruses that cause cancer. Additional work could look into how the virus leads to cancer and investigate the viral and host factors that contribute to sexual transmission. Further studies may also focus on testing drugs that prevent transmission or eliminate the persistent infections that can lead to cancer.