Mekong schistosomiasis is more widespread than previously thought

Mar 19, 2008

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.

Citation: Attwood SW, Fatih FA, Upatham ES (2008) DNA-Sequence Variation Among Schistosoma mekongi Populations and Related Taxa; Phylogeography and the Current Distribution of Asian Schistosomiasis. PLoS Negl Trop Dis 2(3): e200. doi:10.1371/journal.pntd.0000200

Source: Public Library of Science

Explore further: New drug formulations to boost fight against respiratory illnesses and antibiotic-resistant superbugs

add to favorites email to friend print save as pdf

Related Stories

Netflix sets sights on European screens

7 minutes ago

US online streaming giant Netflix will launch the second phase of its European expansion plan on Monday as it sets about seducing French viewers with a "House of Cards"-style drama set in Marseille.

Prosecutors target credit card thieves overseas

13 hours ago

Criminals from around the world buy and sell stolen credit card information with ease in today's digital age. But if they commit their crime entirely outside the United States, they may be hard to prosecute.

SpaceX's next cargo launch set for Sept 20

13 hours ago

SpaceX's next unmanned cargo trip to restock supplies at the International Space Station is scheduled for September 20, the US space agency said Friday.

'Grand Theft Auto V' to hit PS4 and Xbox One

16 hours ago

Rockstar Games on Friday announced that the latest installment of its crime-themed blockbuster video game "Grand Theft Auto" will hit PlayStation 4 and Xbox One consoles in November.

Recommended for you

Obama to announce major Ebola effort

1 hour ago

US President Barack Obama will Tuesday seek to "turn the tide" in the Ebola epidemic by ordering 3,000 US military personnel to West Africa and launching a major health care training and hygiene program.

Sierra Leone: WHO too slow to help doc with Ebola

10 hours ago

Sierra Leone accused the World Health Organization on Monday of being "sluggish" in facilitating an evacuation of a doctor who died from Ebola before she could be sent out of the country for medical care.

Dutch doctors feared to have Ebola leave hospital

10 hours ago

Two Dutch doctors flown home from west Africa after fears they might have been contaminated with the killer Ebola virus have left hospital "in good health," their employer, the Lion Heart Medical Centre, said Monday.

Strategic self-sabotage? MRSA inhibits its own growth

15 hours ago

Scientists at the University of Western Ontario have uncovered a bacterial mystery. Against all logic, the most predominant strain of methicillin-resistant Staphylococcus aureus (MRSA) in North American produces an enzyme ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

COCO
not rated yet Mar 25, 2008
commies