The virus attacks compromised skin through direct contact,  possibly entering through tiny cuts and abrasions in the stratum corneum (outermost layer of skin). After infection, warts may not become visible for several weeks or months. Because of pressure on the sole of the foot or finger, the wart is pushed inward and a layer of hard skin may form over the wart. A plantar wart can be painful if left untreated.Warts may spread through autoinoculation, by infecting nearby skin, or by contaminated walking surfaces. They may fuse or develop into clusters called mosaic warts. Diagnosis
A plantar wart is a small lesion that appears on the surface of the skin and typically resembles a cauliflower, with tiny black petechiae (tiny hemorrhages under the skin) in the center. Pinpoint bleeding may occur when these are scratched. Plantar warts occur on the soles of feet and toes. They may be painful when standing or walking.Plantar warts are often similar to calluses or corns, but can be differentiated by close observation of skin striations. Feet are covered in friction ridges, which are akin to fingerprints of the feet. Friction ridges are disrupted by plantar warts; if the lesion is not a plantar wart, the striations continue across the top layer of the skin. Plantar warts tend to be painful on application of pressure from either side of the lesion rather than direct pressure, unlike calluses (which tend to be painful on direct pressure, instead). Prevention
HPV is spread by direct and indirect contact from an infected host.
These duplications allow for the pancreatic amylase AMY2 to re-target to the salivary glands, allowing animals to detect starch by taste and to digest starch more efficiently and in higher quantities. This has happened independently in mice, rats, dogs, pigs, and most importantly, humans after the agricultural revolution.Following the agricultural revolution 12,000 years ago, human diet began to shift more to plant and animal domestication in place of hunting and gathering. Starch has become a staple of the human diet. Despite the obvious benefits, early humans did not possess salivary amylase, a trend that is also seen in evolutionary relatives of the human, such as chimpanzees and bonobos, who possess either one or no copies of the gene responsible for producing salivary amylase.Like in other mammals, the pancreatic alpha-amylase AMY2 was duplicated multiple times. One event allowed it to evolve salivary specificity, leading to the production of amylase in the saliva (named in humans as AMY1). The 1p21.1 region of human chromosome 1 contains many copies of these genes, variously named AMY1A, AMY1B, AMY1C, AMY2A, AMY2B, and so on.However, not all humans possess the same number of copies of the AMY1 gene. Populations known to rely more on saccharides have a higher number of AMY1 copies than human populations that, by comparison, consume little starch.