Scientists reveal possible leishmaniasis-arsenic link

Visceral leishmaniasis infects around half a million people across the world every year. Picture: TSPL

Visceral leishmaniasis infects around half a million people across the world every year. Picture: TSPL

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SCOTTISH scientists believe they have finally solved of the riddle of why so many Indian victims of one of the world’s most devastating tropical diseases still die from leishmaniasis, despite advances in drug treatments.

Visceral leishmaniasis infects around half a million people across the world every year. The tropical infection leads to illnesses including Black Fever, which results in horrific facial deformities, and kills around 50,000 people, mostly in India, each year.

The highest death rate is in the Bihar region of India, which houses 90 per cent of India’s leishmaniasis victims and where there is widespread resistance to antimony compounds, one of the main treatments for the disease.

But it was revealed today that researchers at the universities of Dundee and Aberdeen believe that arsenic contamination of water supplies in the region of the Indian subcontinent may have played a “significant role” in the development of the resistance of antimonial preparations in successfully treating leishmaniasis throughout Bihar.

And the researchers say their findings point to the desperate need for alternative domestic water supply sources to be urgently identified.

Professor Alan Fairlamb, one of the leading researchers from Dundee University, said that the success of antimonial preparations in treating the disease was so low in Bihar that, by the end of the 20th century the use of the drugs was no longer recommended.

He explained: “The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs which are used to treat visceral leishmaniasis.”

Prof Fairlamb continued: “The water supply in Bihar has been found to be affected by contamination from naturally occurring arsenic in the ground water. What we have been able to show through experiments is that arsenic contamination of water can build resistance in Leishmania parasites to antimonial treatments.

“This is important as we need to be sure of why resistance to drugs develops. Leishmaniasis is a neglected disease that has a devastating effect across the developing world and there is a desperate need for better drugs to treat it. What we cannot afford is for the existing treatments to be compromised while we search for new ones.”

Research

Meghan Perry, a Wellcome Trust-funded clinical PhD student who was a member of the research team, carried out field studies in Bihar as part of the research.

She said: “Arsenic contamination of the groundwater is a serious issue in Bihar. Many villagers continue to drink arsenic contaminated water as they have no alternative. Knowledge of the dangers of arsenic pollution is low and mitigation projects are not reaching all of those in need.”

Ms Perry added:”Arsenic can lead to a myriad of health issues and our research adds to this long list. Community education and alternative drinking water sources are desperately needed.”

Professor Jörg Feldmann, the Head of Chemistry at Aberdeen University, said: “As an environmental chemist I have always been interested in arsenic exposure through drinking water and food, but to show the influence of arsenic on an the efficacy of a drug based on antimony, an element chemically similar to arsenic, is fascinating. This only adds to the many detrimental effects arsenic has on the human being and shows how complex the arsenic biochemistry can be.”

Visceral leishmaniasis

Visceral leishmaniasis is the most serious form of the disease which is caused by a parasite transmitted by the sandfly. The parasite responsible for the disease, then known as “dum-dum fever,” was first identified in 1900 by Sir William Leishman a graduate of Glasgow University and the distinguished bacteriologist who became the first Director of Pathology at the War Office and later Medical Director of the army medical services.

The Dundee and Aberdeen University research is published in the latest edition of the journal Proceedings of the National Academy of Sciences of the United States of America.

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