Sunday, October 30, 2011

Beijing strains: New strain of tuberculosis linked to travel

By Syed Akbar
Hyderabad:  It may sound strange, but rapid growth in
information technology and frequent travel by software experts is
affecting the tuberculosis/HIV control programme in the country.
Individuals, particularly youngsters, who travel frequently across cities
are in a way helping the spread of a new strain of tuberculosis which is
more dangerous than the native ancient Indian strains, according to a
research study by the city-based Centre for DNA Fingerprinting and
Diagnostics and Ondokuz Mayis University Medical School of Turkey.
Transmission of "Beijing strains" of TB is facilitated with "recent
economic activity due to a boom in the information technology  and
communication sectors, where affordable air-travel has facilitated
frequent movement of especially younger population, across cities," the
study pointed out.
The spread of Beijing strains is slow but gradual and health planners
and experts fear that they will "out-compete" the ancestral types found
in India for over 10,000 years. The Indian native strains are less
virulent and docile as compared with the Beijing strains. And this is a
troubling news for health planners.
"The outcome could be hastened as India is witnessing a steep rise in
the number of human immunodeficiency virus cases," said Dr Niyaz
Ahmad of the CDFD and Hakan Leblebicioglue of OMUM School in
the study published in BMC Genetics, a prestigious international
scientific journal.
The study warned that synergy of TB, lead predominantly by the
Beijing strains, with HIV, threatens a series of outbreaks in several
years to come. "With fast spreading HIV, local advantages due to
ancestral bacilli, in terms of adaptation, and possibly `reduced
virulence' might be ruined. HIV through depleting the host immune
cells disregards any such advantages".
India is long known to harbour reservoirs of the ancestral TB strains,
which continue to predominate throughout the population. The TB
bacteria, M. tuberculosis is a millennia old pestilence that continues to
trouble people in the country. India also has TB bacteria diversity.
Stating that the ancestral strains bear seemingly important benefits for
the TB control programs in India, the study noted that "more
importantly, as a result of their adaptive evolution, the pathology
triggered by them may not be lethal. The Indian strains disseminate less
rapidly than the modern types like Beijing strains.
"Although Beijing strains are not an immediate threat, there is a danger
that they might predominate in due course if their dissemination
dynamics change with enhanced HIV transmission," the scientists said.
Of late the Beijing strains have been reported in different parts of the
country with Mumbai reporting as high as 30 per cent of the total TB
"It has been widely believed that India with its vast human resource in
healthcare, with DOTS coverage penetrating almost countrywide, and a
large national TB control program, is all set to tackle the pestilence. We
caution, to prepare for the threat of institutionalised outbreaks
perpetuated by newly emerging and expanding strains in synergy with
HIV, that is probably looming large," they cautioned.

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