Susceptibility varies among individuals. Some person may have more chance of catching a disease compared to some other person. That means that person who has more chance of catching the disease is "susceptible" to that disease. Immune system has an important role in determining the susceptibility of an individual.
Like we saw tuberculosis is an infectious disease. When a Tuberculosis patient sneezes or coughs droplets are sprayed into the air which makes anyone exposed to it in danger of catching infection. Sometimes there are conditions where the immune system is weakened like for example: when a person has AIDS their immune system is severely compromised thus they are highly susceptible.
Susceptibility of the individuals to a particular disease increases if the person has some disorders or disease that may weaken his/her immunity. Also some therapies depresses the immune system.
Down here is the list of conditions wherein immunity of the person is compromised, thus making them susceptible to Tuberculosis.
- Age : Elderly people & infants are more susceptible. this is because, Elderly people may have weakened immune system & infants do not have fully developed immune system "to fight of infections like tuberculosis"[1].
- AIDS : HIV(Human Immunodeficiency Virus) severely compromises the immune system of the individual making that person easily susceptible. These people have the highest risk of catching the disease. Most of the people with AIDS die because of tuberculosis.
- Cancer : Chemotherapy drugs helps in cancer treatment by killing the fast dividing cells. But cancerous cells are not the only fast dividing cells, in human body, the hematopoietic stem cells , hair follicles, epithelial cells, are also rapidly dividing cells. Chemotherapy ends up killing these cells too. Hematopoietic stem cells are the ones which give rise to the cells responsible for our immunity, thus making cancer patients more vulnerable to catching tuberculosis infection.
- Diabetic patients : Diabetes is another disease that weakens the immune system of the person
- Organ Transplant recipient : Immune system of the person, who has received an organ from a donor, is suppressed by drugs so that the body doesn't reject the newly transplanted organ. Thus their immunity is lower.
- People with kidney disease : This illness can weaken the body including the immune system, making a person more susceptible to illness
[1].
- Autoimmune diseases : People suffering from autoimmune diseases like Crohn's disease, Rheumatoid Arthritis have major chance of contracting this disease as autoimmune diseases affect immune system.
- Malnourished individual : Poor diet means weaker immune system. Body can thus, not defend itself against this disease.
- People surrounded by potential cases of Tuberculosis : People who work in close contact with people having Tuberculosis like that of doctors, nurses have greater chance of getting this disease as they are constantly in exposure to this bacterium. Or say a person studying Mycobacterium tuberculosis is using live bacterium culture to carry out some experiments, then if proper precautions are not taken there are chances that the person might get the disease.
- People in crowded places : In a crowded place like train, bus or any social gathering, if a healthy individual is close to a person with Tuberculosis disease, there are chances of contracting the disease. This is because if the diseased individual coughs, sneezes he spreads the bacteria into air which can be inhaled by the healthy individual and thus he can become infected.
Reference:
[1] Everyday Health n.d., Risk Factors for Tuberculosis Infection, viewed 12 August 2012,
http://www.everydayhealth.com/tuberculosis/risk-factors.aspx
