the VOA Special English Development Report.
An estimated one-third of all people are
infected with tuberculosis. Most have latent, or inactive, cases. They do not
suffer coughing, increased body temperature or other signs of active TB.
year, about nine million people develop active cases and two million die. TB is
an ancient bacterial disease. It can be cured with antibiotics, if patients
take all their medicine. The victims, though, are mostly poor and live in
scientists have reported two new developments in tuberculosis research.
past century, a skin test has been the traditional way to identify latent TB.
When cases are found, treatment can prevent many from becoming active. But the
preventive drugs have a risk of side effects.
test depends on the body's reaction to an injection of specially prepared TB
protein. But the test often falsely identifies people as having latent TB if
they have been vaccinated against the disease.
needless treatment, scientists have developed a blood test. This test is
designed to identify patients with a high risk of developing the active form of
Lalvani from Imperial College London led an international team in developing
the blood test, called ELISpot (EL-ee spot). A study showed that the ELISpot
blood test identifies latent TB while giving fewer false positive results.
researchers say the ELISpot test has been recommended for use in about twenty
countries worldwide. A report on the
new blood test appeared last week in the Annals of Internal Medicine.
another development, scientists have reported a step toward a better vaccine
against TB. One currently used is seventy-five years old.
experimental vaccine contains a weakened TB bacterium from a strain of the
current vaccine. The scientists say that in their study, the experimental
vaccine created stronger responses against TB than the traditional one.
new vaccine contains an antibiotic-resistant gene that the scientists do not
want released into the environment. So the vaccine will not be tested further.
But research will continue on a similar one that does not contain the gene.
Hoft of the Saint Louis University School of Medicine in Missouri was lead
author of a report in the Journal of Infectious Diseases.
that's the VOA Special English Development Report. It was written by Jerilyn