Tuberculosis
What is this?
Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis. Many may know tuberculosis by several names: simply TB, consumption, pulmonary phthisis or tubercle bacilli.
Latent TB Infection occurs when an individual is infected by the bacterium but does not have symptoms and does not feel sick. If tested for TB, their results would be positive. However, they do not have active TB disease. Therefore, they cannot spread TB infection to other people(Roberts and Buikstra 2003).
Active TB disease occurs when an individual's immune system cannot defeat the bacterium, and latent TB infection progresses to active TB disease. This individual will show symtptoms and is infectious, meaning they can spread the bacteria to others (Roberts and Buikstra 2003).
What are the symptoms?
Symptoms include chronic coughing, blood in phlegm, fever, fatigue, extreme weight loss and even skin lesions called tubercles. Symptoms may differ depending on the part of the body affected.
What causes this?
Tuberculosis is spread by inhaling airborne microbes found in the particles exhaled by infected individuals through coughing or sneezing (Larsen 2015; 103). TB generally causes infection in the lungs, but can affect any part of the body and even result in the destruction of skeletal tissues, such as ribs and vertebrae.
How do bioarchaeologists study this?
We can observe tuberculosis in the archaeological record by looking at bony lesions, or abnormal growth, on ribs and vertebrae. Severe cases may lead to deterioration of disks between vertebrae, causing the spinal column to collapse. If this happens, we can observe compression of vertebrae in the skeleton.
Following the scoring methods of the Global History of Health, we focused first on scoring vertebrae: 0 (no vertebrae present), 1 (no lesions observable), 2 (lesions are present on at least one vertebrae). Next, we looked at ribs to identify how many and whether or not the head of the rib is present. We used a score of 0 (no lesions present) or 1-24 (number of ribs with lesions) (Steckel et al. 2005).
