16-08-2012, 04:56 PM
Tuberculosis (TB)
INTRODUCTION:
Tuberculosis (TB) has emerged as one of the leading causes of human deaths world wide. An increase of incidence of the disease has been observed since the early 1980s (20). It has been estimated that about one third of the human population is infected with Mycobacterium tuberculosis with a huge mortality rate of 1.6 million deaths per annum worldwide (25).
Pakistan ranks sixth in the world in terms of tuberculosis (TB) burden among the top 22 high-burden tuberculosis countries (26). One of the fundamental problems in TB control is a high defaulter rate among the registered TB cases in the public sector (14). According to World Health Organization the estimated incidence is 181 per 100,000 or 286000 new cases annually. This alarming figure is higher than that found in Taiwan population where the last seven years data suggests that new TB cases per 100,000 populations were from 62.0 to 74.6. Our assumption is that Pakistani population has similar exposure to Mycobacterium tuberculosis as the modes of its transmission are mainly through large droplets and small particle droplet nuclei.
Fortunately the transition from infection to active disease is quite low thus only 5-15% of infected individuals develop symptomatic TB during their lifetime (8, 20). Role of Innate immunity is obvious in the development of active disease since a good percentage of the individuals remain healthy following infection while the others don’t,
Mtb is an intracellular pathogen and infects APCs primarily the lung APCs. These include lung macrophages and lung dendritic cells (DCs) in the lung parenchyma, as well as alveolar macrophages (13). Mtb is harbored within alveolar macrophages early in infection and within lung macrophages and lung DCs later in infection (12;14;18).
INTRODUCTION:
Tuberculosis (TB) has emerged as one of the leading causes of human deaths world wide. An increase of incidence of the disease has been observed since the early 1980s (20). It has been estimated that about one third of the human population is infected with Mycobacterium tuberculosis with a huge mortality rate of 1.6 million deaths per annum worldwide (25).
Pakistan ranks sixth in the world in terms of tuberculosis (TB) burden among the top 22 high-burden tuberculosis countries (26). One of the fundamental problems in TB control is a high defaulter rate among the registered TB cases in the public sector (14). According to World Health Organization the estimated incidence is 181 per 100,000 or 286000 new cases annually. This alarming figure is higher than that found in Taiwan population where the last seven years data suggests that new TB cases per 100,000 populations were from 62.0 to 74.6. Our assumption is that Pakistani population has similar exposure to Mycobacterium tuberculosis as the modes of its transmission are mainly through large droplets and small particle droplet nuclei.
Fortunately the transition from infection to active disease is quite low thus only 5-15% of infected individuals develop symptomatic TB during their lifetime (8, 20). Role of Innate immunity is obvious in the development of active disease since a good percentage of the individuals remain healthy following infection while the others don’t,
Mtb is an intracellular pathogen and infects APCs primarily the lung APCs. These include lung macrophages and lung dendritic cells (DCs) in the lung parenchyma, as well as alveolar macrophages (13). Mtb is harbored within alveolar macrophages early in infection and within lung macrophages and lung DCs later in infection (12;14;18).