New Rapid Diagnosis Test to Identify Tuberculosis Early

Tuberculosis (TB) is one of the most serious illnesses to afflict men, and is notorious for the way patients are ‘wasted’ away. The long history of this infection is believed to be associated with the death of more patients than any other bacterial infection. There are evidences of this infection, as early as in 8000 B.C, with estimates indicating that over a billion people have been killed by this infection. A research team from Arizona, Texas as well as Washington DC has joined hands to put together a rapid blood test for easy diagnosis and quantification of TB, the first of its kind. A researcher from Arizona State University's Biodesign Institute, Dr.Tony Hu, was the principal investigator and led this study along with 8 research groups from different institutions, including National Institutes of Health and Houston Methodist Research Institute.

The details of the study were published in the journal Proceedings of the National Academy of Sciences.

Limitations in the Current Testing Methods

According to Dr. Hu, the testing methods available currently for tuberculosis involve coughed-up-sputum,, lung and liver biopsies which are invasive, blood culture, or the use of spinal taps. The limitations of the current testing methods are:

• False negative results which could lead to misdiagnosis and worsen the condition.
• Time consuming results that take a few days to a week to come out, during which time the infection could increase in intensity.
• Tuberculosis testing centers that are present in public health centers, in relatively largely populated villages, are usually short staffed, and do not have the facilities to house people who come from remote regions to avail this test. After the samples are collected from these villagers, these villagers do not stay back to collect the test result and, therefore, do not find out if they are afflicted with TB. Further, these public health centers cannot send information about an individual’s health status, across the village.

Tuberculosis continues to be a major health hazard for individuals, and a lot of research is being carried out in this regard. $6.6 billion has been provided for international TB care and prevention efforts, particularly in the developing nations and among HIV infected individuals.

Dormant Tuberculosis:

The initial infection by Mycobacterium tuberculosis, leads to an active response by the immune system of the host, with the bacterium then lying dormant in the individual’s lung tissue. According to the World Heath Organization or WHO, dormant TB is present in over one-third of the world’s population. When the immune system of the host is compromised due to a secondary infection like HIV/AIDS, then this dormant state becomes active again.

Advertisement

Facts About Tuberculosis

According to the WHO

• Every year, approximately 10 million people across the world develop TB
• Nearly 2 million TB deaths occur every year
• Between the years 2000 and 2015, 50 million deaths have been averted through TB treatment
• TB continues to be an epidemic due to the absence of an effective TB vaccine
• There is an increasing incidence of drug resistant strains as well as insufficient methods of diagnosis which compound the ability to control the spread of this infection

Rapid Test for TB Recognized by WHO

Advertisement

The diagnosis procedure has now been simplified to easily screen for the infection. This new method that has been designed by the research team and recognized by WHO, helps to surpass a significant hurdle in diagnosing the disease.

Advantages of the New Diagnostic Test:

The new diagnostic test

• Is found to be more effective than other available tests
• Requires only a couple of hours to provide the results
• Allows for earlier detection that ensures early start of treatment for TB patients
• Also tracks the progress of treatment rapidly, so doctors can identify the right medication needed earlier

NanoDisk-MS Assay

The research team developed the NanoDisk-MS assay which can be used to provide faster results. This is the first test developed to clearly measure how severe the active TB infection is. The test involves detecting the presence of small quantities of two proteins that are present during the active phase of the disease

• CFP-10
• ESAT-6

Dr. Hu said that the development of this rapid assay is an exciting step towards better ways of monitoring TB. This will allow physicians to better treat TB infections worldwide, as the procedure requires that routine instruments be available in most hospitals worldwide.

This is a major step towards better TB care, especially among HIV infected populations, as the diagnosis equipment currently available shows reduced performance among

• HIV-positive TB patients
• Non-lung tissue TB patients

These patients, under the current diagnostic practices, would have to be tested by taking a biopsy of lung tissue. The new NanoDisk-MS assay can be used to detect lung- and non-lung- TB with a sensitivity of 92%, even among HIV infected patients. The new test can detect patients with good specificity

• 87% specificity among patients with latent TB
• 91% specificity among patients with nontuberculous mycobacterial conditions
• 100% differentiation of healthy subjects

The principle of detection of TB utilized in this test can also be used for other infectious diseases. Dr. Hu and his team is developed the test for clinical approval, paving the way for a new method of diagnosis.

History and Significance of Diagnosing Tuberculosis

Dr. Robert Koch discovered Mycobacterium tuberculosis in the year 1882 and announced this wonderful discovery to his small group of scientists at the Institute of Hygiene at the University of Berlin. At the time of discovery, TB was a rapidly spreading disease, with 1 out of 7 people with TB dying due to the infection. Dr. Robert Koch’s discovery played a pivotal role in diagnosis of the infection and the subsequent treatment which lowered the fatality rate.

The 100^th anniversary of the discovery of Mycobacterium tuberculosis as the causative agent for TB was celebrated as World TB Day, March 24^th, 1982. Since then, every March 24^th is regarded as World TB day to raise awareness about the infectious disease. The method of diagnosis and treatment has improved for patients with tuberculosis since then, and this latest rapid test will facilitate faster and better diagnosis.

References:

1. Tuberculosis - (http://www.who.int/mediacentre/factsheets/fs104/en/)

Source-Medindia