Israel develops an easier and cheaper way to diagnose tuberculosis 

Israel develops an easier and cheaper way to diagnose tuberculosis 

Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis bacteria that generally affects the lungs but can also wreak havoc on other parts of the body. 

Most infections are not symptomatic, but about 10% of latent infections progress to active disease which – if left untreated – kills about half of those who were infected. 

Typical symptoms of active TB are a chronic cough with bloody  mucus, fever, night sweats and weight loss. It was historically called “consumption” due to the victim’s weight loss. 

It is not often seen in Western societies – 95% of cases occur in the developing world. Cases most frequently occur in South-East Asia (44%), Africa (24%) and the Western Pacific (18%), with more than 50% of cases being diagnosed in eight countries – India (27%), China (9%), Indonesia (8%), the Philippines (6%), Pakistan (6%), Nigeria (4%) and Bangladesh (4%). 

About 10 million people get TB in an average year, with 1.4 million dying of the disease. Some one-third of the world population is estimated to be infected by tuberculosis bacteria. Since 1993, the World Health Organisation (WHO) has defined tuberculosis as a “global health emergency.” Effective treatment for tuberculosis is available, but diagnosis remains a roadblock, with around three million cases missed annually.

The disease is transmitted from one person to the next through the air when people who have active TB in their lungs cough, spit, speak or sneeze. People with latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke. Diagnosis of active TB is based on chest X-rays, as well as microscopic examination and culture of body fluids. Diagnosis of latent TB relies on the tuberculin skin test or blood tests. 

WHO regards a fast, cheap, and efficient tuberculosis test as crucial to fighting the disease The spread of TB requires screening those at high risk, early detection and treatment of cases and vaccination with the bacillus Calmette-Guérin (BCG) vaccine. 

 

Since early symptoms are not specific, diagnosis is complicated and currently existing diagnostic methods are slow and at times too expensive or complicated for poor countries. It is particularly difficult to diagnose in children and in people infected with HIV. 

 

For example, a sputum smear ($2.60 to $10.50 per examination) is too expensive in places where people live on a dollar a day, while a mycobacterial culture test takes four to eight weeks and at least three visits by the patient to finalize the diagnosis and begin treatment.

 

Now, scientists at the Technion-Israel Institute of Technology in Haifa are making it much easier to identify TB patients – and it will save lives. They developed a novel means of diagnosing the disease by means of a sticker patch that catches compounds released by the skin. Using an artificial intelligence (AI) analysis of these compounds, the scientists were able to provide a quick, non-invasive diagnosis. The research was recently published in the Advanced Science under the title “Profiles of Volatile Biomarkers Detect Tuberculosis from Skin.”  In the future, the Haifa team plan to integrate the sensors into the patch and use a smartphone to read its results.

 

The team in Prof. Hossam Haick of the Chemical Engineering Faculty conducted the ground-breaking research, creating a sticker patch that is attached to the patient’s arm, Led by Dr. Rotem Vishinkin, the group created the patch that includes a pouch of absorbing material. 

 

A device based on this proof-of-concept study, called A-patch, is already undergoing clinical trials. “Our initial studies, done on a large number of subjects in India and in South Africa, showed high effectiveness in diagnosing TB,” Vishinkin explained, with over 90% sensitivity and over 70% specificity. Sensitivity (a true-positive rate) measures the proportion of positives that are correctly identified, meaning the proportion of those who have some condition who are correctly identified as having it. Specificity (true-negative rate) measures the proportion of negatives that are correctly identified (i.e. the proportion of those who do not have the condition (unaffected) who are correctly identified as not having the condition).

 

The approach relies on TB-specific volatile organic compounds (VOCs) that are detected and quantified from the skin. A specifically designed nanomaterial-based sensors array translates these findings into a point-of-care diagnosis by discriminating between active pulmonary TB patients and controls who are not infected. 

“We showed that tuberculosis can be diagnosed through the compounds released by the skin. Our current challenge is minimizing the size of the sensor array and fitting it into the sticker patch,” she continued. 

 

The platform the group is developing is cheap, fast and simple in its use and requires no specially trained personnel. They hope the same technique and platform could in the future be used to diagnose other diseases and conditions, making effective diagnosis accessible to remote areas in the world.

 

The clinical studies were conducted in the University of Cape Town and Groote Schuur Hospital, South Africa, the All-India Institute of Medical Sciences, India, and the University of Latvia and Riga East University Hospital, Latvia.