* Eight country study finds high rates of drug resistance
* Resistant strains more costly to treat, often more fatal
* Almost 9 million people a year get TB, 1.4 million die
By Kate Kelland
LONDON, Aug 30 Scientists have found alarming
levels of the lung disease tuberculosis in Africa, Asia, Europe
and Latin America that are resistant to up to four powerful
In a large international study published in the Lancet
medical journal on Thursday, researchers found rates of both
multi drug-resistant TB (MDR-TB) and extensively drug-resistant
TB (XDR-TB) were higher than previously thought and were
threatening global efforts to curb the spread of the disease.
"Most international recommendations for TB control have been
developed for MDR-TB prevalence of up to around 5 percent. Yet
now we face prevalence up to 10 times higher in some places,
where almost half of the patients ... are transmitting MDR
strains," Sven Hoffner of the Swedish Institute for Communicable
Disease Control, said in a commentary on the study.
TB is already a worldwide pandemic that in 2010 infected 8.8
million people and killed 1.4 million of them.
Drug-resistant TB is more difficult and costly than normal
TB to treat, and is more often fatal.
MDR-TB is resistant to at least two first-line drugs -
isoniazid and rifampicin - while XDR-TB is resistant to those
two drugs as well as a powerful antibiotic type called a
fluoroquinolone and a second-line injectable antibiotic.
Treating even normal TB is a long process, with patients
needing to take a cocktail of powerful antibiotics for six
months. Many patients fail to correctly complete treatment, a
factor which has fuelled a rise in the drug-resistant forms.
Researchers who studied rates of the disease in Estonia,
Latvia, Peru, the Philippines, Russia, South Africa, South
Korea, and Thailand found that almost 44 percent of cases of MDR
TB were also resistant to at least one second-line drug.
SPREADS THROUGH AIR
Tracy Dalton from the United States Centers for Disease
Control and Prevention, who led the study, said that so far,
XDR-TB has been reported in 77 countries worldwide.
"As more individuals are diagnosed with, and treated for,
drug-resistant TB, more resistance to second-line drugs is
expected to emerge," she said.
The spread of these drug-resistant strains was "particularly
worrisome" in areas with poor healthcare resources and limited
access to effective drugs, she added.
TB is a bacterial infection that destroys patients' lung
tissue, making them cough and sneeze and spread germs through
the air. Experts say anyone with active TB can easily infect
another 10 to 15 people a year.
The World Health Organisation (WHO) predicts that more than
2 million people will contract MDR TB by 2015.
A report by non-governmental organisations in March warned
that $1.7 billion shortfall in global funds to fight TB over the
next five years meant 3.4 million patients would go untreated
and gains made against the disease will be reversed.
In their research, Dalton and colleagues found that rates of
resistance varied widely between countries.
Overall, resistance to any second-line drug was detected in
nearly 44 percent of patients, ranging from 33 percent in
Thailand to 62 percent in Latvia.
In around a fifth of cases, they found resistance to at
least one second-line injectable drug. This ranged from 2
percent in the Philippines to 47 percent in Latvia.
XDR-TB was found in 6.7 percent of patients overall. Rates
in South Korea, at 15.2 percent, and Russia at 11.3 percent,
were more than twice the WHO's global estimate of 5.4 percent at
"These results show that XDR-TB is increasingly a cause for
concern, especially in areas where prevalence of MDR-TB is
high," said Hoffner.
(Editing by Alison Williams)