[3] The most common are vaccinia (seen on the Indian subcontinent)[citation needed] and molluscum contagiosum, but Mpox infections are rising (seen in west and central African rainforest countries).

The name of the family, Poxviridae, is a legacy of the original grouping of viruses associated with diseases that produced poxes on the skin.

One of the earliest suspected cases is that of Egyptian pharaoh Ramses V who is thought to have died from smallpox circa 1150 years BCE.

This death toll can be attributed to the indigenous population's complete lack of exposure to the virus over millennia.

Extensive searches over two years detected no further cases, and in 1979 the World Health Organization (WHO) declared the disease officially eradicated.

[citation needed] In 1986, all virus samples were destroyed or transferred to two approved WHO reference labs: at the headquarters of the federal Centers for Disease Control and Prevention (the C.D.C.)

[6] After the September 11 attacks in 2001, the American and UK governments have had increased concern over the use of smallpox, or a smallpox-like disease, in bioterrorism.

[citation needed] The late genes are expressed after the genome has been replicated and encode the structural proteins to make the virus particle.

[citation needed] The assembly of the virus particle occurs in five stages of maturation that lead to the final exocytosis of the new enveloped virion.

[citation needed] The assembly of the virus particle occurs in the cytoplasm of the cell and is a complex process that is currently being researched to understand each stage in more depth.

[16] Poxvirus encodes its own machinery for genome transcription, a DNA dependent RNA polymerase,[17] which makes replication in the cytoplasm possible.

Most double-stranded DNA viruses require the host cell's DNA-dependent RNA polymerase to perform transcription.

[citation needed] The intermediate phase of replication is critical because, on that stage, the virus affects the host's normal function and modifies it more optimally to itself.

[citation needed] An isolate from a fish – salmon gill poxvirus – appears to be the earliest branch in the Chordopoxvirinae.

One clade was the variola major strains (the more clinically severe form of smallpox) which spread from Asia between 400 and 1,600 years ago.

A second clade included both alastrim minor (a phenotypically mild smallpox) described from the American continents and isolates from West Africa which diverged from an ancestral strain between 1,400 and 6,300 years before present.

[22] This is consistent with archaeological and historical evidence regarding the appearance of smallpox as a human disease which suggests a relatively recent origin.

However, if the mutation rate is assumed to be similar to that of the herpesviruses the divergence date between variola from Taterapox has been estimated to be 50,000 years ago.

The vaccinia virus is an effective tool for foreign protein expression, as it elicits a strong host immune-response.

This is transported along cytoskeletal microtubules to reach the cell periphery, where it fuses with the plasma membrane to become the cell-associated enveloped virus.