Poxviruses: Slipping and sliding through transcription and translation

Poxviruses are truly remarkable pathogens. The most notorious, variola virus (VarV), is thought to have emerged in Africa around 3,000-4,000 years ago. From there, VarV swept across the world causing smallpox, a disease that killed more people than all other infectious agents in recorded history combined Noticing apparent immunity in milkmaids, Edward Jenner inoculated nave children with cowpox, resulting in protection against smallpox and ushering in the era of vaccines ("vacca" being Latin for "cow"). Intriguingly, we now use a close relative of VarV, vaccinia virus (VacV), both as a vaccine and laboratory prototype for poxvirus infection. Mysteriously, we don't know the true origin or natural host of VacV because of the lack of records and way in which vaccines were generated and shared across the globe in the earliest attempts to control smallpox Despite its mysterious origins, VacV was instrumental in making VarV the only human pathogen to have been successfully eradicated. This medical milestone was possible in part because of the fortunate fact that VarV only infects humans, leaving it with no reservoir in which to hide. Serious threats remain from the potential reintroduction of VarV as well as the ongoing emergence and adaptation of new or zoonotic poxviruses. However, these viruses have also become invaluable tools in oncolytic gene therapy and as vaccine vectors in modern medicine.