New Delhi, October 28 (IANS). According to a study published in the journal The Lancet Global Health, commonly used chest X-rays based on symptoms are not sufficient to detect asymptomatic tuberculosis (TB) infection in relatives of infected patients.
Researchers at the University of Cape Town in South Africa conducted systematic screening with universal sputum microbiological testing of 979 close relatives of pulmonary tuberculosis patients in three South African communities.
They compared tuberculosis symptoms (of any duration) and chest radiograph (any abnormality indicating active tuberculosis) screening methods against a microbiological reference standard.
The team confirmed pulmonary tuberculosis in 5.2 percent of the relatives, and 82.4 percent of these had no symptoms. Of concern is that chest radiographs failed to detect 40 percent of cases.
“More than 80 percent of people confirmed with tuberculosis had no symptoms; chest radiograph screening missed more than 40 percent of these cases,” said lead author Dr. Simon C. Mendelsohn of the South African Tuberculosis Vaccine Initiative at the university.
According to the World Health Organization (WHO), of the estimated 10.8 million people with tuberculosis worldwide in 2023, about 2.7 million (25 percent) remain undiagnosed or treated.
While it is important to find and treat these so-called missing millions, the challenge is that most of them remain asymptomatic.
“More than half of all tuberculosis detected in community prevalence surveys (surveys conducted in a certain population) are classified as asymptomatic (showing no symptoms), which is in people who do not have the typical symptoms of tuberculosis, such as cough, fever, night sweats and weight loss, or do not recognize or report them,” the team said in the paper.
In this study, asymptomatic tuberculosis in relatives had a low bacterial load (very low amount of bacteria) and was also associated with a low serum C-reactive protein concentration that was no different from healthy people. However, these were different from symptomatic tuberculosis in a comparison group of people visiting the clinic.
The sensitivity of chest radiograph screening for asymptomatic tuberculosis was only 56.1 percent; The sensitivity of combined symptom and chest radiograph screening for all tuberculosis was slightly higher at 64.0 percent.
“Our results from household contacts show that methods based on symptoms and chest radiographs are not sufficient for community tuberculosis screening,” Mendelsohn said.
–IANS
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