New York Times
February 27, 2008
Drug-Resistant TB Rates Soar in Former Soviet Regions
By LAWRENCE K. ALTMAN
Drug-resistant tuberculosis cases in parts of the former Soviet Union
have reached the highest rates ever recorded globally, the World
Health Organization said Tuesday. The rates could soar even higher,
spreading the potentially fatal disease elsewhere, a top W.H.O.
official said, releasing findings from the largest global survey of
the problem.
The highest rate was in Baku, Azerbaijan, where 22.3 percent of new
tuberculosis cases were resistant to the standard anti-TB drug regimen
during the survey period, from 2002 to 2006. That exceeded the
previous high of 14.2 percent, in Kazakhstan.
Drug-resistant TB is widespread in the Inner Mongolia and Heilongjiang
regions of China, where the rates are about 7.25 percent, the W.H.O.
said.
The survey, the first in four years, shows that earlier predictions
were correct and that governments have lost control of tuberculosis in
many areas. The reason, health officials say, is that countries have
not invested enough to build, equip and staff laboratories to detect
the disease. The countries also have not made sure there are enough
standard drugs and have not monitored patients to ensure they complete
a full course of therapy.
Inadequate therapy can lead to the development of strains of the
tuberculosis bacterium that are resistant to two or more drugs, a
condition known as MDR-TB.
Drug-resistant TB, like drug-sensitive TB, can be transmitted from an
infected individual to a noninfected person in droplets through
coughing, sneezing and other activities. Patients can continue to
suffer fevers; coughing, often bringing up blood-tinged sputum; weight
loss; and other chronic health problems and they can die if the
resistant bacteria are not identified.
If the resistant form is detected, two years may be needed to treat
with drugs that are 100 times as expensive as the first-line regimen,
said the health agency, a unit of the United Nations. Technically
difficult surgery may also be required.
The survey also found alarmingly high rates in Moldova (19.4 percent),
Donetsk in Ukraine (16 percent), Tomsk, an oblast in Russia (15
percent), and Tashkent in Uzbekistan (14.8 percent).
Those levels surpassed the highest levels that nearly all experts had
once thought were possible, Dr. Mario C. Raviglione, who directs the
health organization’s tuberculosis program, said in an interview.
"We are seeing levels of multidrug-resistant TB that we never expected
– 20 percent is a very high level," Dr. Raviglione said. His program,
the Global Plan to Stop TB, is a road map for reducing by half TB
prevalence and deaths by 2015 compared with 1990 levels.
When the W.H.O. started a drug surveillance project in 1994, he said,
"the general thinking was that multidrug-resistant TB would never be a
real problem, since it was felt to be confined to immunosuppressed
patients."
A decade ago when the W.H.O. first received reports of 9 to 10 percent
rates of multidrug-resistant tuberculosis in some areas, many
scientists thought the figure was inaccurate.
Experts also said that higher rates were impossible, Dr. Raviglione
said, but "it is possible; it tells you they are really doing
something wrong in places where this form of TB is spreading."
About one in 20 new cases of tuberculosis in the world is resistant to
first-line drugs, or 450,000 of the nine million new tuberculosis
cases that are detected each year, according to the W.H.O. survey,
which involved 90,000 patients in 81 countries.
In the United States, the prevalence of drug-resistant TB fell to 1
percent between 1997 and 2006, from 2.4 percent in 1993, according to
the Centers for Disease Control and Prevention. Since 1995, the
prevalence of drug-resistant tuberculosis among foreign-born cases has
been about 1.5 percent, about three times as high as in American-born
patients with TB.
"In sub-Saharan Africa, H.I.V. and AIDS are dramatically fueling the
spread of TB," the W.H.O. said. TB patients in Latvia and Donetsk who
were H.I.V.-infected were almost twice as likely to have a
drug-resistant strain of TB as TB patients who were not
H.I.V.-infected.
The W.H.O. says there is a shortfall of $2.5 billion of the estimated
$4.8 billion needed this year for overall TB control in low- and
middle-income countries.
For the first time, the survey included analysis of extensively
drug-resistant tuberculosis, or XDR-TB, a form of the respiratory
disease that is virtually untreatable because the causative bacteria
are resistant to virtually all the most effective anti-TB drugs.
XDR-TB has been reported in 45 countries, but because few countries
have the laboratories to detect it, the data were limited.
The true extent of the problem remains unknown in some pockets of the
world because only six countries in Africa, the region with the
world’s highest incidence of TB, could provide drug-resistance data
for the report, Dr. Raviglione said. Other countries in the region
could not conduct surveys because they lack the laboratory equipment
and trained personnel needed to identify drug-resistant TB.
Outbreaks of drug resistance are probably going undetected, said
Abigail Wright, the principal author of the W.H.O. report.
Although the report highlights the extent of drug resistance, Dr.
Raviglione said there were successes in which governments invested in
control measures. He cited the Baltic countries of Estonia and Latvia
as "the model" because they were the "hot spots" 13 years ago for
drug-resistant tuberculosis. Today, he said, after a sustained
investment and assault on multidrug-resistant TB, rates in these two
countries are stabilizing and rates of new tuberculosis are falling.