[Tlc] TLC-Mekong

[justinm at ucr.edu]

FYI.
Thanks,
justin

2008-0319 - EurekAlert - Mekong schistosomiasis is more
widespread than previously thought

http://www.eurekalert.org/pub_releases/2008-03/plos-msi031408.php

Public release date: 18-Mar-2008

Contact: Mary Kohut
Press at plos.org
415-568-3457
Public Library of Science

Mekong schistosomiasis is more widespread than previously thought

A new genetic analysis, published March 19th in the
open-access journal PLoS Neglected Tropical Diseases, suggests
that the parasitic worm Schistosoma mekongi is more widespread
than previously thought. According to the study, the human
population at risk of infection could be up to 10 times
greater than previously estimated. Furthermore, it posits an
increased possibility of the spread of the parasite across
Laos and Vietnam.

Schistosomiasis, a parasitic disease which affects over 200
million people worldwide, is caused by several flatworm
species of the genus Schistosoma. In the Mekong River basin in
South-East Asia, the disease is transmitted by the species
Schistosoma mekongi. A mass treatment program in the mid-1990s
greatly reduced the prevalence of the disease and encouraged
optimism regarding the control of S. mekongi infection.
However, based on the implications of this new study, the
control of Mekong schistosomiasis could be problematic.

Researchers Stephen W. Attwood of China’s Sichuan University,
Farrah A. Fatih of London’s Natural History Museum, and E.
Suchart Upatham of Thailand’s Mahidol University analyzed DNA
sequences of sample organisms collected from the Mekong river
and its tributaries in Cambodia, Laos and Malaysia. They
found, contrary to the previously held belief that S. mekongi
is confined to a small section of the lower Mekong River, that
organisms collected in its tributaries across Cambodia were
also of the species S. mekongi. The range of the snail
intermediate host and the ecological conditions for potential
transmission were also shown to be much broader than once thought.

Prior to this study it was also assumed that S. mekongi
originated in Yunnan, China, migrated southwards across Laos
and into Cambodia, and later became extinct in Laos due to
conditions unsuitable for transmission. However, Attwood and
colleagues’ analysis suggested a more recent, and ongoing,
migration northwards from Vietnam, towards Cambodia and Laos.

According to the authors, further work is required into this
problem, as, if we have no reason to assume that ecological
conditions in Laos are unsuitable for transmission, we may
expect the future spread of this disease northwards into Laos.

###

______________
Dr. Justin McDaniel
Dept. of Religious Studies
2617 Humanities Building
University of California, Riverside
Riverside, CA 92521
951-827-4530
justinm at ucr.edu