TB is a notifiable disease in India, and TB notification has been made mandatory at the point of diagnosis since May 2012. This means that when a case of TB is diagnosed and/or put on treatment it is to be reported to the NTEP.
Drug resistance in Mycobacterium tuberculosis occurs when there is acquisition of mutations in genes that code for anti-TB drug targets or drug-activating enzymes.
Drug resistance in Tuberculosis (TB) occurs through two main mechanisms shown in the figure below.
Figure: Mechanisms or Types of Drug Resistance in TB
The mechanism of transmission of drug-resistant (DR) and drug-sensitive (DS) TB is the same i.e., via infectious aerosols.
Tuberculosis (TB) is an infectious, chronic, granulomatous disease caused by Mycobacterium tuberculosis. It usually involves the lungs but may affect any organ or tissue in the body.
The pathogenesis of TB in a previously unexposed immunocompetent individual is centred on the development of cell-mediated immunity. This confers resistance to the organism and results in the development of tissue hypersensitivity to tubercular antigens.
TB is one of the top burdensome infectious diseases in India. It is estimated that, around 1/4th (26%) of the world's TB cases are in India, translating to about 30 Lakhs new TB cases emerging each year (TB incidence). Against this estimated incidence the National TB Elimination program reported around 19 lakh new and relapse cases in the year 2021.
Tuberculosis is transmitted mainly through the air via droplet nuclei generated when a TB patient coughs or sneezes.
It is estimated that every sputum smear-positive patient spreads the infection to 10 – 15 persons annually, if untreated..
Figure: Transmission of TB bacteria through air via droplet
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Environmental conditions have a huge role in the development of TB disease and are an important component of the epidemiological triad for TB disease.
The various environmental factors influencing TB are:
Host factors in TB disease are various factors/attributes of the host(person who is developing TB disease/infection).
The various host factors are as follows:
Mycobacterium tuberculosis (M. tuberculosis) belonging to the family Mycobacteriaceae cause Tuberculosis (TB).
These are rod shaped bacilli and require oxygen to survive (aerobic bacteria).
The following characteristics of these bacilli help them to survive in human body for a long time and resist the action of drugs:
TB notification rate is the number of TB cases notified over a specified time period for a specified population, usually per lakh. It indicates how many cases have been diagnosed and informed to the National TB Elimination Program.
It is mostly calculated annually, and the calculation formula is as follows: