In a major breakthrough, Indian researchers have identified a crucial protein that plays a vital role in regulating the survival, infectivity and drug response of the parasite that causes visceral leishmaniasis - better known as 'kala-azar'.

It may be noted that kala-azar is the harshest form of leishmaniasis, and is caused by a parasite called Leishmania donovani that spreads to people through the bite of an infected female sandfly.

Reports said that Jitesh P. Iyer and co-workers from the National Institute of Immunology found that higher levels of an enzyme called cTXNPx made the L. donovani parasite more dangerous at certain times in its life cycle. Laboratory tests also showed a higher parasite burden in resistant cells.

cTXNPx belongs to the group of enzymes that detoxify peroxides, chemicals that are toxic to L. donovani. When humans are infected by L. donovani, their immune cells release hydrogen peroxide to destroy the parasite. Parasites with higher levels of cTXNPx were more able to endure high levels of hydrogren peroxide and were also resistant to an anti-leishmanial medicine.

A white paper published by the researchers in the April issue of the medical journal journal Molecular Microbiology says,"This study provides a link between cTXNPx expression to survival, virulence and drug response in L. donovani."

According to Swapan Jana of the Society for Social Pharmacology, "This study invites further studies to explore the plausibility of any new drug molecule targeting this enzyme. He adds, "The study is impressive - given the emerging drug resistance of Leishmania donovani, it's important to work on the ways to combat the parasite through newer drugs."