Even as India sets its sights on elimination of kala azar by the end of this year, incidence of a little-known skin condition that is a red flag for transmission of the disease has been growing — in fact, it has more than doubled in the last year, and trebled in the last two.
Post kala-azar dermal leishmaniasis (PKDL) cases rose from 421 in 2014 to 1,487 in 2016, the spike being sharp from 648 cases in 2015. PKDL brings what looks like many other skin lesions but this lesion houses the kala-azar parasite, Leishmania donovani. The lesion, being the only symptom, is often ignored while the person afflicted continues to act as a reservoir for kala-azar infection. Kala-azar, which in India is spread by L donovani alone, infects the reticulo endothelial system — a network of cells and tissues found throughout the body, especially in the blood, general connective tissue, spleen, liver, lungs,bone marrow, and lymph nodes.
Currently endemic in 54 districts of the country, kala-azar affects 33 districts of Bihar – which reports more than 70% cases — 11 of West Bengal, four of Jharkhand and six of eastern UP. It is also sporadically found in other states. Cases have decreased significantly, from 80,000 in 1992 to under 9,000 in 2015 , as have deaths — 90 deaths in 2011, 5 in 2015 and none in 2016. However, PKDL is showing a reverse trend.
According to an article on PKDL, published in The Lancet in 2003, “It (PKDL) is mainly seen in Sudan and India where it follows treated VL in 50% and 5-10% of cases, respectively. Thus, it is largely restricted to areas where Leishmania donovani is the causative parasite. The interval at which PKDL follows VL is 0-6 months in Sudan and 2-3 years in India. PKDL probably has an important role in inter-epidemic periods of VL, acting as a reservoir for parasites.”
There is an increased urgency the world over to eliminate kala-azar, partly because of its association with HIV. Visceral leishmaniasis, as kala-azar is otherwise known, is an opportunistic infection (like TB) in HIV and other infections that cause suppression of the immune mechanism. However, it is not a very serious problem in India yet, according to the National Vector Borne Disease Control Programme.
A commitment to eliminate kala-azar by the end of the year is part of both the 2017 budget speech and the recent National Health Policy. However, the rising PKDL cases are a challenge though Health Ministry officials say the increased reporting of PKDL is proof of a robust surveillance mechanism. A senior health ministry official told The Indian Express the issue of PKDL did come up for discussion when the accelerated kala-azar elimination plan was launched in 2017 but it is not a matter of concern. “It shows we are on course for elimination and the surveillance system is getting better. We have a treatment protocol for PKDL and we are following it in all these cases. There is no cause for alarm,” the official said.