- (Note - There are three types of XDR TB...the worst of
which is the South African SA1 strain which kills in 2-3 weeks, or less.
- JR)
-
- (Reuters) -- A new, untreatable form of tuberculosis
is striking up to 30 000 people a year, the World Health Organisation (WHO)
said on Friday [22 Jun 2007], and warned it could spark an "apocalyptic
scenario" if unchecked.
-
- The United Nations agency appealed for USD 2.15 billion
to combat drug-resistant TB under a programme which it said could save
up to 134 000 lives over 2 years.
-
- Extensively drug resistant TB (XDR-TB), a form virtually
immune to antibiotics, has been reported in 37 countries in all regions
since emerging in 2006, according to the WHO. "There are somewhere
between 25 000 and 30 000, we roughly estimate, cases of extensive drug
resistant TB each year," Paul Nunn, coordinator of WHO's Stop TB Department,
told a briefing. "Ultimately, to face down this epidemic, we need
new tools -- we need new drugs, we need new diagnostics," he added.
-
- The recent case of an American man with XDR-TB who travelled
abroad triggered an international health scare, highlighting the potential
risks of rapid spread.
-
- XDR-TB cases are particularly difficult to treat, and
a patient could infect other people for years, according to Mario Raviglione,
director of the WHO's Stop TB Department. "That is the big threat
here. If you have more and more of these cases, you will automatically
magnify the problem by having transmission going on to other individuals
... Once they become infected they are sort of a time bomb," Raviglione
said.
-
- "If this is kept unchecked and goes on, then you
may also see an apocalyptic scenario where the present epidemic of TB is
replaced by an epidemic of TB which is now fully resistant to everything,"
he added.
-
- "Pre-antibiotic era"
-
- Some 8.8 million people each year develop normal TB,
a bacterial infection that usually attacks the lungs and which kills 1.6
million people a year, according to the WHO.
-
- About 450 000 get a multidrug-resistant form (MDR-TB)
each year, which resists the main 1st-line drugs, but XDR-TB occurs when
there is resistance to even 2nd-line drugs. "The possibility is that
you could replace that epidemic with a drug-resistant epidemic, in other
words you could have 8 million cases of drug-resistant TB wandering around.
And then you will be back to the pre-antibiotic era," said Nunn.
-
- An outbreak in KwaZulu-Natal province of South Africa
last year [2006] confirmed the WHO's fears about XDR-TB, which killed 52
of the 53 patients, mainly carriers of the HIV virus, he said.
-
- "We really now have to focus on problems of infection
control. We can't allow drug-resistant MDR or XDR to get into populations
of HIV-infected people," he added.
-
- Regular TB can be diagnosed with a microscope, but drug-resistant
forms require laboratories that can do more sophisticated tests -- a capacity
lacking in many poor countries, especially in sub-Saharan Africa, he said.
-
- "The reality of the situation right now is that
we only have the drugs that we have and very likely we will not have new
drugs for at least another 5 to 10 years," Nunn said.
-
-
- ________
-
-
- Communicated by
- ProMED-mail Rapporteur Mary Marshall
-
- The XDR strains of _Mycobacterium tuberculosis_ are resistant
to the 2 most important 1st-line drugs (INH (isoniazid) and RIF (rifampin),
any of the fluoroquinolones, and at least one of the following injectable
antibiotics, amikacin (AK), kanamycin (KM), or capreomycin (CM). Use of
other antibiotics to which the XDR may be susceptible, such as ethionamide,
cycloserine (CS), viomycin (VM), or para-aminosalicylic acid (PAS), to
treat XDR tuberculosis is associated with poorer outcomes. Outcomes depend
on the extent of drug resistance, severity of disease, and the status of
the patient's immune system. Surgery may be curative if the area of involved
lung is small enough to be removed without causing deterioration in pulmonary
function.
-
- If patients with uncontrolled XDR tuberculosis who produce
sputum with a high _M. tuberculosis_ density -- as reflected by positive
acid-fast smears of sputum -- are not adequately isolated, they will likely
disseminate the disease to close contacts. Rapid tests that determine drug
resistance and new potent drugs that do not have severe side effects are
urgently needed. - Mod.ML]
-
-
- 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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