 |
|
|
 Health & Beauty | September 2007 
TB Still a Leading Cause of Death in Many Countries
 InfoChange
go to original
| | A tuberculosis (TB) patient eats outside a ward at Moroto hospital. Tuberculosis, which is spread through close personal contact, has long been a problem in Africa, where hundreds of millions are latent carriers of the disease. But the growing relationship between TB and HIV has made treatment of both diseases more difficult in vulnerable populations. (Reuters/Xavier Toya) |
In a review of the epidemiology of TB worldwide, researchers from the University of Cape Town in South Africa point out that research has provided new diagnostic, treatment and preventive measures but that we need to make them available to populations most at risk.
With 8.9 million new cases and 1.7 million deaths (the most recent figures are from 2004), tuberculosis is still a leading cause of death in low-income and middle-income countries. Yet, diagnostic methods in many parts of the world are similar to those used 100 years ago, say researchers from the University of Cape Town in South Africa, in a paper published early online and in an upcoming edition of The Lancet.
In a review of the epidemiology of TB worldwide, and technological advances in prevention, diagnosis and treatment, Gary Maartens and Robert J Wilkinson point out that research has provided new diagnostic, treatment and preventive measures, but we need to make them available to populations most at risk.
One of the biggest threats to TB control is the HIV epidemic. Ten per cent of HIV-infected people in high-burden communities develop TB every year. An HIV-positive person’s risk of getting TB increases as the disease progresses. The annual incidence is as high as 30% in South African patients with clinically advanced HIV.
Another fear is the widespread emergence of Multi-Drug-Resistant (MDR) and Extensively Drug-Resistant (XDR) tuberculosis. More than 4% of patients with tuberculosis worldwide have MDR TB; more than 40% of these patients have previously been treated for tuberculosis and stopped treatment before it was completed, causing drug resistance to develop.
Treatment of MDR TB is long, less effective, costly, and difficult to tolerate. XDR TB is resistant to most drugs, is essentially untreatable and is a swift killer. In one study, 52 of 53 patients died after an average of 16 days. A genetic analysis suggests that MDR and XDR TB may be transmitted speedily through inadequate healthcare practices.
The internationally recommended tuberculosis control strategy ‘Directly Observed Treatment Short Course (DOTS)’ is highly cost-effective in developing countries. It includes case-detection, standardised observed therapy (to ensure that patients complete treatment) and an effective drug supply. However, completion rates under programme conditions are variable. Many patients discontinue treatment when their symptoms improve. The result is increasing infection transmission, relapses and drug resistance.
The BCG vaccine seems to provide limited protection, and only to children. Vaccinologists are developing new vaccines which animal trials suggest are as effective as BCG, or better, and some of these are in Phase I or II clinical trials. However, trials need to enrol many people and to follow them for a long time because the disease can manifest years after infection, and only in a minority of those infected.
There are limited ways to cope with the HIV/TB epidemic, and poor health infrastructure restricts their implementation. Both anti-TB and antiretroviral drugs, and giving them together, can provoke severe drug reactions. They can also make it difficult to diagnose reactions such as immune reconstitution inflammatory syndrome for which treatment causes additional problems.
Still, basic and applied research activity is more intense than ever, and there is clear progress towards better preventive measures, diagnostic tests, and drug treatment options. Increased political will within the international health community is essential to ensure that these are made available to poor countries. |
| |
|
Vallarta Weddings
Tell a Friend
Site Map
Print this Page
Email Us