- GENEVA -- The World Health
Organization (WHO) has expressed concern over the emergence of virulent
drug-resistant strains of tuberculosis (TB) and is calling for measures
to be strengthened and implemented to prevent the global spread of the
deadly TB strains. This follows research showing the extent of XDR-TB,
a newly identified TB threat which leaves patients (including many people
living with HIV) virtually untreatable using currently available anti-TB
drugs.
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- Later this week, WHO will join other TB experts at a
two-day meeting in South Africa (7-8 September) to assess the response
required to critically address TB drug resistance, particularly in Africa,
and will take part in a news conference scheduled for Thursday, 7 September
in Johannesburg.
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- What is XDR-TB?
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- MDR-TB (Multidrug Resistant TB) describes strains of
tuberculosis that are resistant to at least the two main first-line TB
drugs - isoniazid and rifampicin. XDR-TB, or Extensive Drug Resistant TB
(also referred to as Extreme Drug Resistance) is MDR-TB that is also resistant
to three or more of the six classes of second-line drugs.
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- The description of XDR-TB was first used earlier in 2006,
following a joint survey by WHO and the US Centers for Disease Control
and Prevention (CDC).
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- Resistance to anti-TB drugs in populations is a phenomenon
that occurs primarily due to poorly managed TB care. Problems include incorrect
drug prescribing practices by providers, poor quality drugs or erratic
supply of drugs, and also patient non-adherence.
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- What is the current evidence of XDR-TB?
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- Recent findings from a survey conducted by WHO and CDC
on data from 2000-2004 found that XDR-TB has been identified in all regions
of the world but is most frequent in the countries of the former Soviet
Union and in Asia.
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- In the United States, 4% of MDR-TB cases met the criteria
for XDR-TB.
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- In Latvia, a country with one of the highest rates of
MDR-TB, 19% of MDR-TB cases met the XDR-TB criteria.
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- Separate data on a recent outbreak of XDR-TB in an HIV-positive
population in Kwazulu-Natal in South Africa was characterized by alarmingly
high mortality rates.
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- Of the 544 patients studied, 221 had MDR-TB. Of the 221
MDR-TB cases, 53 were defined as XDR-TB. Of the 53 patients, 44 had been
tested for HIV and all were HIV-positive.
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- 52 of 53 patients died, on average, within 25 days including
those benefiting from antiretroviral drugs.
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- Scarce drug resistance data available from Africa indicate
that while population prevalence of drug resistant TB appears to be low
compared to Eastern Europe and Asia, drug resistance in the region is on
the rise.
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- Given the underlying HIV epidemic, drug-resistant TB
could have a severe impact on mortality in Africa and requires urgent preventative
action.
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- What action is required to prevent XDR-TB?
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- XDR-TB poses a grave public health threat, especially
in populations with high rates of HIV and where there are few health care
resources. Recommendations outlined in the WHO Guidelines for the Programmatic
Management of Drug Resistant Tuberculosis include:
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- strengthen basic TB care to prevent the emergence of
drug-resistance
- ensure prompt diagnosis and treatment of drug resistant
cases to cure existing cases and prevent further transmission
- increase collaboration between HIV and TB control programmes
to provide necessary prevention and care to co-infected patients
- increase investment in laboratory infrastructures to
enable better detection and management of resistant cases.
- The Expert Consultation on Drug Resistant TB, hosted
by the South African Medical Research Council with support from WHO and
CDC, takes place in Johannesburg, 7-8 September.
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- A news conference will be held at 12.30pm, Thursday,
7 September, at the conference venue: Sunnyside Park Hotel, Parktown, Johannesburg.
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- For more information contact:
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- Glenn Thomas
- Stop TB Department
- WHO
- Mobile: +41 79 5 09 06 77
- E-mail: thomasg@who.int
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- Dr Karin Weyer
- Director, South African Medical Research Council
- Unit for TB Operational and Policy Research
- Tel: +27 12 3 39 85 50
- Mobile: +27 82 4 60 88 36
- E-mail: kweyer@mrc.ac.za
-
-
- Patricia A. Doyle DVM, PhD
- Bus Admin, Tropical Agricultural Economics
- Univ of West Indies
-
- Please visit my "Emerging Diseases" message
board at:
- http://www.emergingdisease.org/phpbb/index.php
- Also my new website:
- http://drpdoyle.tripod.com/
- Zhan le Devlesa tai sastimasa
- Go with God and in Good Health
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