While South Africans have so far been spared an outbreak of the severe acute respiratory syndrome (Sars) that has spread across developing nations in Asia in particular, there is no room for complacency.
Researchers in Singapore have suggested that patients with Sars may run a higher-than-average risk of developing tuberculosis, which is widespread throughout South Africa.
According to the Science and Development Network, during the outbreak of Sars last year, doctors at the country’s Tan Tock Seng hospital found that two out of 236 individuals diagnosed with ”probable” Sars were also infected with tuberculosis. Although small, this represents a far higher incidence rate than is commonly found in the general population.
”We think the patients developed tuberculosis after acquiring Sars,” says CC Lee, one of the members of the research team, which has reported its findings in the medical journal Clinical Infectious Diseases. ”To the best of our knowledge, this is the first documented case of its kind.”
Tuberculosis is a bacterial infection that spreads through droplets in the air. When a person’s immune system is working normally, the infection can remain inactive in the body for a long time without causing any symptoms to appear. The researchers suggest that the reduced immunity in patients with Sars increases their susceptibility to tuberculosis.
According to their paper, the two patients found to be suffering from tuberculosis had previously been discharged from hospital, after having fully recovered from Sars.
One then developed a dry cough and showed worsening lung conditions in follow-up chest X-rays; the other was recalled for treatment when he tested positive for the tuberculosis bacterium.
”When the result came back, we recalled the patient so that therapy could be started immediately,” says Lee.
He points out that World Health Organisation guidelines for hospital discharge and follow-up for patients with Sars stipulate that they should be given repeated chest X-rays until their health returns to normal.
Following this guideline, he says, should allow doctors to diagnose tuberculosis infections, as the disease will be revealed by chest X-rays if left untreated.
But Lee says health services should be made aware that any physiological signs revealed by X-rays of patients recovering from Sars could actually be caused by tuberculosis, rather then the original infection. — SciDev.Net