A worrying increase in drug-resistant tuberculosis (TB) cases is a major cause for concern for all medical systems of the world due to the highly deadly nature of TB. Previously, this has been attributed to inadequate treatment by doctors and researchers alike.

A new study seeks to dispute that notion. The research was made possible with a tripartite alliance of researchers from the US Centres for Disease Control and Prevention, the Albert Einstein College of Medicine in New York, and the University of KwaZulu-Natal in South Africa.

Extensively drug-resistant TB is particularly troubling because of the way the disease is spread. The bacteria expelled from infected patients can float for hours under the right conditions, infecting others who inhale them.

Person-to-person transmission of drug resistant TB cause for concern

The research involved the analysis of hundreds of cases that took place in South Africa, and have concluded that about seven in ten cases of drug-resistant TB can be linked to human-to-human transmission.

This new research has important implications pertaining to how medical systems around the world treat TB.

Amongst 400 patients with drug resistant TB, 69% had never received any prior treatment for TB, suggesting that their TB infection was acquired from other individuals, via human to human contact, who are carriers of drug-resistant TB.

The past consensus as to how drug-resistant TB develops is when the TB virus is treated with sub-par or incomplete therapy, thereby allowing the slow-growing bacterium to establish immunity towards other well-established therapies.

Co-author Dr. Neel R. Gandhi, at Emory University's Rollins School of Public Health in Atlanta, said, “For many years, there was this thought that maybe drug-resistant TB strains might not be able to be transmitted as efficiently a regular TB strains (sic).”

A researcher who specialises in infectious disease at the Vanderbilt University Medical Center, who is unaffiliated to the research team, professor William Schaffner, added that this new research has “turn[ed] this idea on its head.”

A global phenomenon with no signs of abating

Multi-drug resistance TB - defined to be resistant to at least four drugs - is a growing phenomenon that affects 105 countries globally.

Even in a country with a highly developed healthcare system such as Singapore, TB remains a cause for concern, although not of the resistant kind. Despite the low prevalence, there was a prominent case of drug-resistant TB just before the end of last year that has spread in a densely populated housing estate. In a sign that the epidemiological data surrounding drug resistant TB remains elusive, that prominent case confounded health experts, months after its outbreak.

In Singapore, incidences of drug-resistant TB remain low, accounting for less than 1% of all cases since 2013. In 2015, all forms of TB affect 38.4 per 100,000 population, according the latest available data furnished by the Health Ministry as of this month.

In Malaysia, drug resistant TB (new and recurrent cases) affects 4.6% of all TB cases, with an incidence of 89 per 100,000 population for all forms of TB.

This week in India, the Supreme Court ordered the government to administer daily medications to millions of TB patients who were only receiving the dose thrice a week. The order came amid activist claims of lives being endangered should daily doses not be administered.

An activist, Raman Kakkar said, “The government’s reluctance to shift to the new dosage was causing a relapse of the disease in many patients and was even responsible for the development of drug-resistant infections.”

The Indian government said it would switch to the new dosage after the depletion of the stock of medicine, which is estimated to be nine months later.

Risk of regressing back to the thirties

Dr Gandhi stressed that the figures was “mostly (sic) likely a minimum estimate,” and added that TB was an known epidemic for a decade, but breakthrough in breakthrough in treatments and efforts to combat TB remains scarce.

He delivered a grim outlook, saying that should there be no improvements in the effort to contain the spread of TB, even with recent breakthroughs, humanity is at risk of going “back to the 1930s and 1940s”. That era was cited explicitly, as due to a lack of medical knowledge surrounding the transmission and cures of TB then, those infected with TB was sent to sanatoriums to prevent further transmissions.

Mortality rates for those diagnosed with drug resistant strains are bleak, and lie between 50% to 80%. Compounding the challenge of control is that individuals can be highly infectious before knowing that they are carriers of drug-resistant TB, and some might try to evade containment efforts by health authorities, such as the Singapore case of a man found to be guilty of evading quarantine thrice. MIMS

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