Tuberculosis highly infectious disease

What Is Tuberculosis?

Tuberculosis is commonly known as TB. As we known tuberculosis is an  infectious disease and caused by Mycobacterium tuberculosis and it is the ‘world’s largest killer’ amongst infectious diseases overtaking HIV in 2014. One-quarter of the world population is infected with tuberculosis with 1% newly infected population annually. The prevalence of active tuberculosis comprises 1,000,000 patients worldwide with 1.3 million deaths. The emergence of drug-resistant tuberculosis has enhanced tuberculosis-associated mortality worldwide.

India is the country which cover approx 20 percent of world tuberculosis patients with annual mortality of 4 lac. As we discuss Tuberculosis is highly infectious even one bacteria can cause tuberculosis.

Structure of Mycobacterium tuberculosis:

M.tuberculosis is straight and curved bacilli(rod),occur in single or in pair or as small clumps. Interesting point about tuberculosis bacilli is presence of Mycolic acid in cell wall which resist decolourisation by 20 percent sulphuric acid and therefore also known as ACID FAST BACILLUS 

How tuberculosis occur?

Well its quietly common because as we know its a type of infectious disease so it can be spread through inhale aerosol from infected person and its a most common transmission mode.

other mode of transmission can be Ingestion sputum in open case of pulmonary tuberculosis and also from the un pasteurized milk in which M. bovine is present.

Other mode of transmission could be Inoculation of organism into the skin from infected postmortem tissue but its occur rarely.

Classification of tuberculosis:

Now, we are going to talk about classification of tuberculosis so, basically its divided into LATENT TB and ACTIVE TB.

Active TB further classified as PULMONARY TB and EXTRAPULMONARY TB. Now Pulmonary TB can be divided into PRIMARY TUBERCULOSIS and SECONDARY TUBERCULOSIS.

What is Latent TB?

Its a basically a period or state in which immune response is stimulated by M. tuberculosis antigen without any clinical manifestation. Person with latent TB CANNOT SPREAD TB Infection.

What is Primary TB?

Its the initial infection by mycobacterium in a host usually young children are more susceptible.

Primary tuberculosis is characterized by presence of GHON FOCUS which is usually located on upper part of the lower lobe and lower part of the upper lobe of lung. when hilar lymph node are involved with Ghon Focus and its known as GHONE COMPLEX or Primary Complex.

What is Secondary TB?

Also called Post Primary TB and Adult TB due to reactivation of Latent infection or exogenous re-infecion.

Its affect mainly upper lobe of the lung because oxygen is present in much concentration in upper part of the lung and mycobacteria is a type of aerobic bacteria.

The characteristic of secondary TB is presence of Cavitation in Lung which is Known as ASSMANN FOCUS.

What is Extrapulmonary tuberculosis?

TB occur in different parts of body other than lung. It will occur in less than 20 percent of the cases. some common sites are;

-pleura

-lymphnodes

-genitourinary tract

-skin

-joints

-bones

-intestine etc

Sign and Symptoms:

Symptoms will be depends on which are of the body is affected means where the tuberculosis bacteria is growing but most commonly lungs is affected so symptoms which is seen in case of pulmonary tuberculosis will be:

-cough that lasts 2-3 weeks

-low to mild grade fever 

-weight loss

-night sweating

-blood in sputum

-weakness

-chill

-fatigue

TB occur in mostly immunocompromised people so in HIV patient have high risk for developing tuberculosis.

Other type of tuberculosis:

Nowadays tuberculosis develops resistance against first line of drugs called as MULTIDRUG RESISTANT TUBERCULOSIS(MTB)

and other is EXTENSIVELY RESISTANT TUBERCULOSIS(XDR-TB) where resistance develops against second line of drug. if you wants to know about these type of TB in detail than comment us we will provide you more details about MTB and XDR-TB.