User:Ktwest/Paleopathology

Infectious diseases in the archaeological record
Several diseases are present in the archaeological record. Through archaeological evaluation these diseases can be identified and sometimes can explain the cause of death for certain individuals. Aside from looking at sex, age, etc. of a skeleton, a paleopathologist may analyize the condition of the bones to determine what sort of diseases the individual may have. The goal of a forensic anthropologist looking at the Paleopathology of certain diseases is to determine if the disease they are researching are still present over time, with the occurance of certain events, or if this disease still exists today and why this disease may not exist today. Some disease that are found based on changes in bone include, These diseases are all infectious diseases. Other diseases include:
 * Tuberculosis
 * Leprosy
 * Syphilis
 * Joint disease
 * Vitamin deficiencies
 * Tumors on the bone

Tuberculosis
Some diseases are difficult to evaluate in the archaeology, however, tuberculosis can be found and dates as far back as the Neolithic period. Tuberculosis is presumed to have been transmitted from domesticated cattle to humans through ingestion of contaminated meats and the drinking of contaminated milk. It is also possible to contract syphilis through contact with infected persons. When an infected person coughs, they eject infected mucus from their body which can possibly infect those close by. There are several types of tuberculosis, the kind that effect cold-blooded animals, the kind that effects birds and the bovine type that causes disease in humans. Because bovine tuberculosis is often found in children, it May be that the disease is spread through the consumption of contaminated milk.

Tuberculosis manifests itself in the archaeological record through DNA extraction from the skeletal remains of people. Tuberculosis rarely manifests itself in the skeleton of individuals and when it does, it is usually only in advanced stages of the disease. The tuberculosis bacteria stays in the the growth centers and spongy areas of the bone. This disease has a very long period of maturation, or the time it takes the disease to reach it's full destructive potential. Because of the long period of development in the body, tuberculosis damages the body and then the body has time to repair itself. The evidence of the disease in bones can be seen in the destruction and healing of the bone structures especially in joints. Tuberculosis therefore appears in the archaeology record in the knee and hip joints and also the spine.

It was thought that there was no tuberculosis infection in North America before the arrival of Europeans but recent findings from the 80's and 90's have overturned that idea. Through extraction of DNA within the bone tuberculosis was not only found, but also dated to have been present in the Americas since 800 BC. Tuberculosis is a disease that thrives in dense populations. So the implications of finding tuberculosis in pre-Columbian society indicates that there was a large thriving community at the time. . The earliest evidence of tuberculosis has been found in Italy dating to the 4th millennium BC. Evidence of tuberculosis has also been found in mummies from ancient Egypt dating to the same period. There is however, a lack of medical texts from ancient European and Mediterranean regions describing diseases that are identifiable as Tuberculosis but the bones show that there was a disease of this type.

Syphilis
Syphilis is a disease classified in a category of Treponemal disease. This group includes diseases like pinta, yaws, endemic syphilis and venereal syphilis. These disease have symptoms that include inflammatory changes in tissues through out the body. Initially the infected person may notice an area of inflamation at the site where the bacteria entered the body. Then the individual can expect more widespread soft tissue changes and lastly the diseases start to affect the bones. However, Only 10-20 percent of people infected with venerial syphilis show bone changes. Venereal syphilis has more severe symptoms than the other types of treponemal disease. Nervous system and circulatory disruption are unique to venereal syphilis and are not seen in yaws, endemic syphilis or pinta.

Bone changes can be seen in the archaeological record through lesions on the surface on the bone. In venereal syphilis the bone change is characterized by damage to the knees and joints. The damaged joints could be the source of infection or they could be damaged because of disruption in the nervous systems and ability to feel. In the beginning stages of the disease, the bone forms small lesions on the skull and tibiae. These lesions are caused mostly by inflammation of the marrow. In the final stages of the disease the bones start to be destroyed. Lesions that are formed tend to look similar to "worm holes" in the bone and are seen in the skull as well as large bones in the body. Most of the bone that is destroyed is due to secondary infections.

Syphilis has been seen in the Americas and Europe alike but there is debate as to what the origin of the disease is. Columbus and his sailors were said to have brought it to the Americas, however, Europeans blame Columbus for bringing the disease to Europe. There have not been any evidence of bone lesions associated with the disease that Columbus and the Europeans describe. The debate on the origins of venereal syphilis has been the subject of scientific discussions for hundreds of year and has recently been discussed and debated. At the first International Congress on the Evolution and Paleoepidemiology the subject was examined and debated by scholars from all over the world. There was no conclusive decision made as to the origin of venereal syphilis. There is however, more archaeological evidence for the disease in the Americas than there is for the disease in Europe at the time of Columbus's expeditions.

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