Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dartmouth study reveals flaws in screening for TB; Cases in 3rd world HIV patients may go undetected

17.06.2005


New findings from a Dartmouth Medical School collaboration in Tanzania may alter assumptions about the diagnosis of tuberculosis in HIV-infected people, and prompt a major change in way TB testing is routinely done in the developing world.



Writing in the journal, "Clinical Infectious Diseases," researchers found that while the co-existence of HIV and TB is well-known, traditional screening methods for TB are allowing significant number of cases of subclinical, active tuberculosis to go undetected. In apparent response to the these findings, the international physicians’ group, Médecins Sans Frontières (Doctors Without Borders), has recommended that all HIV/AIDS patients receive the more sensitive and accurate TB culture test used in the Tanzania research project.

This latest research was reported by investigators in the DARDAR Health Study, a collaboration between Dartmouth Medical School and the Muhimbili University College of Health Sciences in Dar Es Salaam, Tanzania. C. Fordham von Reyn, MD, Chief of the Section of Infectious Disease and International Health at Dartmouth-Hitchcock Medical Center, is the leader of the DARDAR project and author of the new study with Lillian Mtei MD, and other colleagues in Tanzania.


"Our study team found that when we used the same comprehensive diagnostic approach to tuberculosis available in industrialized countries 15% of HIV-infected patients in Tanzania had previously unrecognized active tuberculosis," von Reyn said. "These findings emphasize the importance of improving the availability of TB diagnostic tests in the developing world."

In the developing world, TB is the leading cause of death among people with HIV infection. Thus, diagnosis and proper treatment of TB is a critical component of HIV treatment in these regions. Unfortunately, HIV infection can actually make TB more difficult to diagnose, creating additional challenges for health workers.

The DARDAR team, working from their clinic in Tanzania, tested HIV-positive subjects with traditional skin testing for TB and physical exams, followed by chest x-rays and microscopic examination of sputum samples. They then preformed cultures of these samples, incubating them in a controlled lab environment a procedure used widely in the industrialized countries, but typically not available or recommended in resource poor countries . In 10 cases sputum culture was the only positive test. These patients with "subclinical" tuberculosis denied symptoms when they were first examined and had normal chest x-rays.

"…Previously undiagnosed tuberculosis was common, often asymptomatic, and difficult to detect on the basis of a single evaluation," the authors reported. In addition the authors noted that the HIV-infected patients with subclinical tuberculosis had a much better prognosis than previously observed, perhaps due to earlier diagnosis and treatment. Failure to diagnose an subclinical case of active TB and treat with standard multiple drug treatment could result in improper single drug treatment for latent TB, which has the potential to induce TB drug resistance.

The findings are important because existing standards for detection of TB rely on using cough as the indication for screening, with chest x-ray as the screening method. "Our study demonstrates that neither cough nor chest radiography would have identified the 10 subjects (in the study) with subclinical tuberculosis," write the authors.

In an accompanying editorial in the same issue, Dr. David L. Cohn said the findings serve "as a reminder of the complexity of tuberculosis in HIV-infected patients in high-burden countries. This study … presents a potential new challenge for the diagnosis of subtle tuberculosis in asymptomatic patients and it may have implications with regard to treatment decisions."

In the wake of the study, Médecins Sans Frontières issued an advisory from its South Africa office, urging patients to insist on the sputum culture test if traditional TB skin and X-ray tests come back negative.

Deborah Kimbell | EurekAlert!
Further information:
http://dms.dartmouth.edu/dardar/index.shtml
http://www.dartmouth.edu

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>