Tuberculosis (TB) infections and human health

Tuberculosis infections on human health is a global threat to life because of the severe symtoms it brings up when a person gets an active Infection from it. According to the World Health Organization (WHO), in the year 2018 a total number of 1.5 million people died from tuberculosis infection and it is one of the top 10 causes of death from an infection caused by a single pathogen. Today’s article will be focus on the meaning of tuberculosis, symptoms, diagnosis and treatment.

What is Tuberculosis?

Tuberculosis is an infection that affects the lungs and it is caused by the bacteria known as mycobacterium tuberculosis. This infection is spread when an infected person sneezes, sings, coughs or spits into the air and an healthy person inhales the droplet. About one-third of the word population is believed to have latent tuberculosis (inactive TB), however people that live with HIV have higher chances of developing active tuberculosis. Malnutrition, drug abuse, diabetes and liver problem are also factors that can increase the chances of developing active tuberculosis.

Types of tuberculosis

There are varieties of tuberculosis that affect humans which depend on the state of the infection and the site they affect in the body. The following are the different types of tuberculosis:
Latent Tuberculosis: it is a condition whereby mycobacterium tuberculosis remain dormant in the body and cannot be spread, a person with latent tuberculosis doesn’t exhibit the symptoms of tuberculosis and cannot spread it as well. It is of paramount importance to identify and treat people infected at early stage so as to prevent the infection from progressing into active tuberculosis.

Active Tuberculosis: this is a condition in which a person infected with mycobacterium tuberculosis falls sick and start exhibiting the symptoms of tuberculosis. At this stage the person can spread the disease.

Pulmonary Tuberculosis: this is the tuberculosis that affects the lungs alone and causes symptoms such as chest pain, difficulty in breathing, fatigue, rapid weight loss and cough with blood.

Extrapulmonary Tuberculosis: It is the tuberculosis that affects other part of the body except the lungs. Extrapulmonary tuberculosis is a chronic health condition whereby mycobacterium tuberculosis spread to other parts of the body through the bloodstream and cause health problems such as spinal pains, arthritis, kidney damage, liver problem and heart disorder.

Risk factors of Tuberculosis

People who inhale the droplet that contains mycobacterium tuberculosis will surely be infected with tuberculosis. Moreover, health care workers and care givers for tuberculosis patient , prisoners and crowded populations are more likely to be infected with TB. The following are other risk factors that can also increase the chance of developing active tuberculosis from latent TB :

  • HIV infections: People with HIV have higher chances of progressing to active tuberculosis and experiencing more damage because of their weak immune system and the infection can move out of the lungs and cause extrapulmonary tuberculosis.
  • Drug abuse: people who smoke cigarette, tobacco, Indian hemp and those that inject intravenous drug such as opiate, cocaine, heroine and amphetamines are more likely to develop active tuberculosis because of damage done by these drugs to reduce the eficiency of their immune system.
  • Age group: children and old people are also proned to develop active tuberculosis and experience more complications from the infection because their immune system is compromised.

Other is condition that can subject people to higher risk of developing active tuberculosis include diabetes, severe kidney disease, cancer and malnutrition.

Symptoms of Tuberculosis

Tuberculosis infection can spread to other parts of the body and cause serious damage if not treated at early stage. According to WHO in 2018 a total number of 10 million people fell sick from tuberculosis worldwide and this is a major threat to live if not controlled at latent state. Therefore the signs and symptoms exhibited by people with active tuberculosis include:

  • Difficulty in breathing
  • Chest pain
  • Cough with thick mucus and blood
  • Sweating especially at night
  • Lost of appetite
  • Fever
  • Rapid loss of weight
  • Fatigue

Diagnosis of Tuberculosis infection

Tuberculosis are usually detected clinically by the following test:

  • Tuberculin skin test (TST)
  • Culture test
  • Sputum smear microscopy examination
  • Chest X-ray

Tuberculin Skin Test

This is the standard test procedure for detecting immune response to mycobacterium tuberculosis in the body. It is carried out by mantoux test, this test is performed by injecting a fluid(contains tuberculin) into the arm . A positive result indicates reddish and swollen bump at the site of injection after 48 to 72 hours, however this does not specify if the person has latent or active tuberculosis and someone that has received BCG vaccine can also test positive to this test.

Culture Test

This is a comprehensive test to detect mycobacterium tuberculosis in patients but it’s usually take longer period of 8 to 12 weeks before the result comes out. The bacteria is grown in a suitable medium called lowensteen Jensen agar in a sterile environment and the colonies of the bacteria is seen physically growing on the agar plate after several weeks of inoculation. Thereafter the colonies of this bacteria can be picked and Stained with different dyes under sterile condition and then finally viewed under the microscope.

Sputum Smear Microscopy Examination

This test is usually carried out by Ziehl Neelsen staining technique. The sputum sample(Thick mucus) of the patient is collected in the morning when the concentration of mycobacterium tuberculosis is still very high and the sample is used for the purpose of this test. The following are the procedures for ziehl neelsen staining:

  • Make the smear of the sputum sample on a clean grease free slide and heat fix.
  • Flood the smear with carbol fuchsin and heat gently until fumes appears, then wash away with water
  • Flood the smear again with acid alcohol to decolorize and wash away with water after 2-3 minutes
  • Finally counterstain the smear with methylene blue for 2-3 minutes and wash away with water
  • Air-dry the smear and observe under oil immersion microscope

Result: Mycobacterium tuberculosis is seen as red rods in blue background while examining it under oil immersion microscope

Chest X-ray

This test is used to detect the complications that are linked to the damage caused by mycobacterium tuberculosis to the chest. Abnormal inflammations or shadow are seen on the chest and this indicates a positive result to tuberculosis infection.

Treatment of Tuberculosis infection

The factors that determine the period for completing the treatment for tuberculosis infection depend on the age, site of infection in the body, drug resistance by the bacteria and the health status of the patient. A person with active tuberculosis is required to take antibiotics for 6 to 9 month and first-line drug are usually prescribed for such patient. The first-line drugs for the treatment of tuberculosis infection include:

  • Isoniazid (INH)
  • Rifampicin or Rifampin (RIF)
  • Entabutol (EMB)

Multidrug-resistant TB

This is an adverse health condition whereby the causative agent of tuberculosis infection resist isoniazid and rifampicin which are the two most effective first-line anti-Tb drugs. This health complication is as a result of the misuse of anti-TB drugs due to wrong prescription by healthcare providers, self medications, stopping of treatment at early stage and fake drug usage. However multidrug-resistant TB can still be treated by the use of second-line drug but the implication is that it takes a longer period up to 3 years to complete the treatment and the drug could pose a toxic reaction to the body system.

Extensively Drug-resistant TB (XDR-TB)

This is a chronic health condition and it arises when the causative agent of tuberculosis becomes resistant to the second line anti-TB drug thereby subjecting the patient to more adverse health issues.
Therefore the use of high quality drugs, correct prescription of drugs by doctors, completion of drug usage must be ensured so as to prevent the resistance of mycobacterium tuberculosis
to anti-tb drugs.

Is there a Vaccine for Tuberculosis?

Yes, vaccines have been developed against tuberculosis infections and the name is BCG (Bacille Calmette-Guérin) vaccine. The vaccine is usually injected into the upper arm where it leaves a scar after administration. BCG Vaccines are usually given to children ,health care workers and the populace in many developing countries but the use of BCG Vaccines in United States is limited because it does not always protect against the infection and it also compromises the result of Tuberculin test by giving a false positive result.

About Adebayo Taiwo

Adebayo Taiwo hails from Africa. He's a Microbiologist , Health Safety and Environment Specialist and a Health Advisor who is concerned about the well-being and healthy lifestyle of people around the globe. The health of my people is my pride.

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