Correct Answer: A
Explanation:
Researchers have stumbled upon evidence of an unknown virus that may be responsible for the persistence of kala-azar or visceral leishmaniasis, a parasite infection that has spawned epidemics and sickened thousands of Indians for over a century.
It's still early to pointedly blame the virus but its discovery portends a new kind of treatment regime and may aid attempts to eradicating the disease.
Historically, the parasite Leishmania donovani is believed to be responsible for the dreaded infection. People get infected when bitten by an insect called the sandfly, which harbours the disease-causing parasite.
Scientists from West Bengal and Uttar Pradesh said that another parasite may be involved. Another parasite called Leptomonas seymouri may also be present.
The researchers inferred this after they found the L seymouri and a virus called Lepsey NLV1 within it in 20 of 22 biological samples of patients who had a residual L donovani infection.
They reported their findings in an online version of the peer-reviewed Archives of Virology.
Kala Azar: Know More
Kala-azar is endemic to the Indian subcontinent in 119 districts in four countries (Bangladesh, Bhutan, India and Nepal). India itself accounts for half the global burden of the disease.
If untreated, kala-azar can kill within two years of the onset of the ailment, though the availability of a range of drugs has meant that less than one in 1,000 now succumbs to the disease.
However, scientists are still not clear how the parasites cause the infection and how they manage to hide within the body.