Maclawrence Famuyiwa | Although prevalent, TB can be beaten

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Many who are infected with the TB bacteria would never develop the TB disease if their immune system is not already compromised. Photo: Supplied
Many who are infected with the TB bacteria would never develop the TB disease if their immune system is not already compromised. Photo: Supplied

Tuberculosis is more complicated than many of us realise and it is easy to spread, but there are ways to control and finally beat it, writes Maclawrence Famuyiwa

In climes such as ours where tuberculosis (TB) is highly prevalent, many people breathe in TB bacteria daily without getting sick or having any TB symptoms. This is when they have latent TB infection. Such people would not be sick because the body would fight off the bacteria, thereby, stopping them from growing.

But, when the body’s immune system cannot stop their growth, the TB bacteria become active by multiplying in the body and eventually making infected people become sick and show TB signs and symptoms. Such people can spread the TB bacteria to those they come in contact with.

To put this in a clear perspective, TB bacteria have the capacity of going through three stages in the humans' body.

The stages are primary TB infection, latent TB infection and active TB disease.

Frankly, many who are infected with the TB bacteria would never develop the TB disease if their immune system is not already compromised. Most active cases of TB are often in people who are newly infected, but only about five to 10% of those with latent TB would eventually develop active TB in their lifetime. This number is much higher in people co-infected with HIV.

READ: Over 110 000 South Africans died from TB between 2020 and 2021

Some symptoms of TB include cough lasting over three weeks, chest pain, coughing up blood or sputum, weakness, weight loss, loss of appetite, chills, fever and night sweats.

For those in whom the TB infection would progress to a TB disease, such progression may be within a few weeks of the TB infection or it may take several years, by which time their immune system would have become weakened by other causes. 

Tuberculosis is an ancient disease that researchers have been able to trace back to 5 000 years ago in ancient Egypt.

It is even mentioned in the Bible as the Hebrew word ‘schachepheth’ in Deuteronomy and Leviticus. Hippocrates also described it as “phthisis” in his writing.

It is believed that TB might have killed more people than any microorganism ever known. It was recorded as an epidemic during the 18th and 19th centuries, when it was known as “consumption”.  

TB mainly affects the lungs. It is caused by Mycobacterium tuberculosis. About two-thirds of total cases of TB disease are found in just eight countries: India, China, Indonesia, the Philippines, Pakistan, Nigeria, Bangladesh and South Africa.

TB is spread through the air from person to person when people with lungs infected with TB cough, sneeze or spit. Only a few of these germs need to be inhaled before a previously uninfected person becomes infected.

It was the discovery of streptomycin in the 1940s that dramatically lowered the spread of tuberculosis in developed countries and many parts of the world.

However, the advent of HIV  dramatically made TB of public health importance in some countries.

In most people, all inhaled TB bacteria are killed instantaneously by the body’s immune system while in some others, the TB bacteria are first surrounded by macrophages, a type of white blood cell, following which the TB bacteria become dormant to form latent TB infection.

This latency stage may be for many years and may remain so till old age when the person rather dies of natural death.

However, recently acquired TB tends to progress faster from primary infection to active TB disease than latent TB infection. Such progression is usually within two weeks of infection in infants, the elderly and people with weakened immune systems.

When people with latent TB infection are tested for TB using a tuberculin skin test or blood test such as the interferon-gamma release assay, they will test positive.

So, such tests are not relied upon for diagnostic purposes in countries with a high prevalence of TB; rather, sputum smear microscopy and GeneXpert are used.

In countries where TB is rampant, people with latent TB infection are not treated with preventive drugs as in developed countries where active TB diseases are rare. Only people with TB disease are treated as a precautionary measure to prevent resistance to TB drugs.

READ: Watch | Organ donor gives Gauteng man a second chance at life

In conclusion, children in countries with high TB burden must have BCG vaccination. Anyone with a cough of over two weeks should be tested for TB. Coughs should be covered by wearing face masks or using disposable towels, not handkerchiefs or hands.

People on TB treatment should always complete their treatment. With these and other precautionary measures, we will surely eradicate TB.

* Famuyiwa is a medical doctor with a specialisation in public health with a PhD in the field and an MSc in infectious diseases from the London School of Hygiene and Tropical Medicine.

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