What we have to know about TB

The National Weekender
HEALTH

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UNFORTUNATELY here in Papua New Guinea we have a very high incidence of tuberculosis (TB), one of the highest in the world. Every day more than 100 new patients catch this dangerous disease in our country, and according to the World Health Organisation (WHO), about 10 per cent of infected patients unfortunately die, and about 5 per cent are infections with drug-resistant bacteria, and therefore very difficult to treat.
TB bacteria typically spread through the air. One person infected by TB can infect others around him or her via droplets carrying the TB bacteria which are sprayed into the surrounding space when speaking, shouting, singing, sneezing or coughing.
TB bacteria attack the body, multiply in the body and destroy tissue. They typically attack the lungs and can create holes in the lung tissue.
Tuberculosis (TB) can be deadly if left untreated. In fact, TB is one of the top 10 causes of death worldwide, and a very serious health problem in our country. The rising prevalence of drug-resistant TB is a “public health crisis and a health security threat,” according to the World Health Organization (WHO).

Symptoms of TB
Once a person is infected, usually by inhaling droplets from other sick people, it takes some time for symptoms to develop. This period of time, the incubation period, can be between several weeks and even years.
However, not everyone infected with the TB bacterium becomes sick. This is called a latent infection; a person with latent TB does not experience symptoms and cannot spread the disease to others.
Common symptoms of an active TB infection include coughing – and coughing up blood or sputum, chest pain, fatigue and night sweats. TB can damage the lungs during an infection, causing inflammation making breathing difficult. A patient with an active TB infection may also show an abnormal chest X-ray.
Although TB could be mistaken for pneumonia, (pneumonia is an infection of the lung) the specific symptoms and diagnostic testing make TB a straightforward diagnosis, said late Dr Paul Mondia, the former specialist at the Pacific International Hospital in Port Moresby.
A latent infection of TB, on the other hand, does not cause any symptoms, and only diagnostic testing can reveal if an otherwise healthy person has latent TB. Latent infections can take years to turn into active disease, and some people with latent TB infections never develop the active disease. It’s unclear what causes a latent TB infection to become active and why some people never develop the active form, Dr Mondia said.

Diagnosing TB
There are two types of tests commonly used to diagnose TB: a skin test and blood tests.
The TB skin test is commonly used in PNG, however in areas where TB is endemic, blood tests are more successful at diagnosing TB. That’s because a person who has received the Bacillus Calmette-Guérin (BCG) vaccine against TB may give a false positive result after a skin test.
A blood test requires blood samples to be sent to a laboratory, where they’re exposed to TB bacteria. White blood cells will produce a certain chemical if they’ve encountered TB before.

How is TB treated?
Active tuberculosis infections are treated with multidrug cocktails. The first-line antibiotics prescribed are Isoniazid, Rifampin, Ethambutol and Pyrazinamide. This regimen may last six to nine months, according to the PIH specialists.
Patients who do not complete the full regimen may develop multidrug-resistant or extensively drug-resistant TB infections, which are very hard to heal – therefore we recommend you to carefully follow the explanations of the doctors who treat you. The WHO estimates that 5 per cent of new TB cases and 20 per cent of previously treated TB cases were drug-resistant tuberculosis infections. Drug resistant TB patients who became drug resistance because they did not take their medicaments and did not finish their treatment prescribed by their doctors, will themselves have big health problems – not only that, they are also a huge problem for the whole community, for everyone.
Drug-resistant tuberculosis infections are a result of the antibiotics not wiping out all the TB bacteria. If bacteria are left at the end of a treatment cycle (which is likely when the treatment is not completed), then those bacteria have a higher chance of becoming resistant to the drugs made to combat them.

How to prevent TB?
A century ago, Albert Calmette and Camille Guérin, both researchers at the Pasteur Institute in France, developed a vaccine for TB from weakened strains of the bacterium. Called the BCG vaccine, forms of it are produced today by different manufacturers around the world, but there is controversy around its efficacy.
According to the UK’s National Health Service, the BCG vaccine is 70 to 80 per cent effective against the most severe forms of TB including TB meningitis in children, but it’s less effective in preventing respiratory TB in adults.
One of the WHO’s approaches to the prevention of TB is to manage latent TB infections to stop them from progressing to active disease. The updated recommendations for the treatment of latent TB recommend that once a case of latent TB is diagnosed, a patient may be put on a treatment regimen of Isoniazid, Rifampin or a combination of Isoniazid and Rifapentine. The recommended duration for this treatment depends on the drug used and whether the patient is an adult or a child, but it can last from three to nine months.

Could the current Covid crisis help to prevent TB?
The recent global spread of coronavirus originating in Wuhan, China, has led world leaders to invoke an ancient tradition to control the spread of illness: Quarantine.
The practice is first recorded in the Old Testament where several verses mandate isolation for those with leprosy. Ancient civilisations relied on isolating the sick, well before the actual microbial causes of disease were known. In times when treatments for illnesses were rare and public health measures few, physicians and lay leaders, beginning as early as the ancient Greeks, turned to quarantine to contain a scourge.
The word quarantine comes from “quarantena” meaning “forty days” in 14th-15th century in Venice, Italy. Passengers and crews on arriving ships were required to insulate for forty days to prevent the import of plague and other epidemics.
Now these days, promoting widespread awareness of effective preventive measures like wearing a face mask, may help (as a side effect) to prevent or limit the spread of tuberculosis infections.
Why is it a good idea to wear a face mask to prevent the spread of the new coronavirus or the tuberculosis bacterial infections? Without a mask, droplets produced during coughing can travel up to 12 feet (3.7 meters), but with a mask, this distance is reduced to just a few inches in the best cases.
Also, if everyone uses face masks, bacteria and viruses in droplets have to pass two filter barriers to be transmitted from one person to another, greatly reducing the probability of infections.
Next week: Our circulation system – what keeps us up and running!

  • Dr Fasol is an academic surgeon from the University of Vienna in Austria, and has worked, built and managed hospitals in Europe, Africa and China operating and treating thousands of patients.