Medical

The race to revolutionize the diagnosis of tuberculosis

Part of the blame that Koch’s bacillus causes the infection that lives the most in the world is the difficulty to detect it. A sputum culture is necessary for the patient, which has to be analyzed by specialized laboratory technicians to find the bacillus. To simplify its detection have been tried imaginative ideas that range from using rats to capture it with the sense of smell to video games on the mobile phone. But they were still based on sputum, something that complicates and slows down the whole process.

Several investigations are trying to solve this. Two of them have been presented at the 48th Conference of the International Union Against Tuberculosis and Lung Diseases (The Union), held last week in Guadalajara, Mexico. The methods are very different: one is to take samples of cells from the mouth with what is called a buccal smear, a painless scraping with a small spatula of the tongue, cheeks and gums. It is a very simple thing, but one that has not been tried until now. The other, analyzing the blood, a process well studied, but that has not yielded satisfactory results.

The first would be especially useful for children since in them the collection of samples is much more complicated than in adults. Among the smaller ones, the characteristic cough of tuberculosis is less frequent because they have a less bacterial load in the lungs, so invasive methods, such as sucking fasting gastric juice or inducing cough with sera, are necessary to extract the mucus with a nasal aspirator.

The study is being developed in South Africa, with the same team looking for a vaccine to prevent the disease. One of its researchers, Angelique Luabeya, explained in Guadalajara that the first experiments are giving “very hopeful” results. 92% of the patients who underwent this test tested positive. In the first phase of this trial they have tested 49 patients, so to determine their suitability, they would still have to progress and increase the study cohort. If the effectiveness is confirmed, the calculations would have to be made to verify the cost-effectiveness of the procedure and implant it, although Luabeya said that the idea is to be “very economical”. He did not dare, however, to set deadlines in which the first results could be endorsed.

Such a test could revolutionize the way tuberculosis is diagnosed. Especially in children, whose magnitude is unknown precisely because of the difficulties in detecting it, although the World Health Organization estimates that around 6% of the more than 10 million cases per year. But not only, it could also be a paradigm shift for adults, especially for those living in areas where there is no trained personnel to extract and analyze samples. “Anyone can collect one sample with this technique”, said the researcher. The surprising thing about the method is that it had not been tested before. “It had been experimented with saliva, with blood, but never scraping the mouth. Sometimes you have the simplest thing in front of you and you do not realize it”, he reflected.

The other test that was presented at the conference of The Union consists of blood tests. This was an explored territory, but its lack of reliability had made the WHO specifically recommend that it should not be used. The company Omunis, however, continued to investigate and found a biomarker for the lipid molecule that allows it to be detected in a blood test. In the first experiment, performed with 20 people, there has been a 100% success, according to Pierre-Alain Rubbo, one of the researchers. It was tested with 15 infected and five healthy patients; in all cases this new test was right. Of course, it is only capable of identifying active tuberculosis, not latent tuberculosis (it is estimated that almost a quarter of the population has the disease in this state, of the infected, one in 10 will develop).

“If the first results were confirmed, it would be a much faster test than the current one, in 10 minutes the result could be known”, said Rubbo. This would also be revolutionary since crops take between two and four weeks to provide a verdict, at which time the patient can continue to spread the disease.

Again, it will be necessary to wait to continue experimenting and confirm its effectiveness, to have the necessary evidence and to expand the test, something that, in the opinion of the investigator, could arrive in 2020. Also, they would have to analyze its cost-effectiveness, since the tuberculosis is a disease that mainly affects very economically depressed areas and any added cost can disable the usefulness of a breakthrough.

What is clear, according to Paula Fujiwara, scientific director of The Union, is that progress such as these are absolutely essential if humanity wants to get rid of a burden that each year takes almost two million lives in the world, and so with the Sustainable Development Goals.

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