* 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
(Adds expert comment on drug costs, vaccines)
By Kate Kelland
LONDON, Aug 30 Scientists have found an alarming
number of cases of the lung disease tuberculosis in Africa,
Asia, Europe and Latin America that are resistant to up to four
powerful antibiotic drugs.
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 infected 8.8
million people and killed 1.4 million in 2010.
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 complete their treatment
correctly, a factor which has fuelled a rise in the
Researchers who studied rates of the disease in Estonia,
Latvia, Peru, the Philippines, Russia, South Africa, South Korea
and Thailand found almost 44 percent of cases of MDR TB were
also resistant to at least one second-line drug.
Tom Evans, chief scientific officer at Aeras, a non-profit
group working to develop new TB vaccines, told Reuters treatment
options for XDR-TB patients were "limited, expensive and toxic".
Treatments for drug-resistant TB can cost 200 times more
than those for normal TB, he said in an emailed statement. They
can also cause severe side effects like deafness and psychosis,
and can take two years to complete, he added.
In the United States, MDR-TB treatment can cost $250,000 or
more per patient, and in many poorer countries costs can be
catastrophic to health systems and patients' families.
"Without a robust pipeline of new drugs to stay one step
ahead, it will be nearly impossible to treat our way out of this
epidemic," Evans said.
SPREADS THROUGH AIR
Tracy Dalton from the United States Centers for Disease
Control and Prevention, who led the Lancet 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 more than 2
million people will contract MDR TB by 2015.
A report by non-governmental organisations in March said a
$1.7 billion shortfall in 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 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 about 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
(Editing by Andrew Heavens)