Patients suffering with skin condition known as post-Kala-Azar dermal leishmaniasis (PKDL) should be detected at the earliest and treated promptly as they can act as a reservoir for the parasite that causes Kala Azar (KA) or Visceral leishmaniasis (VL), a new study has said.
The observation holds importance given that India has set 2020 as a deadline to root out KA. But neglecting PKDL may put the poor people, who are the most affected, in a vicious cycle, as has been indicated in the study published the journal Clinical Infectious Disease.
Caused by parasite infected sandfly, while KA is potentially life threatening, PKDL is a neglected form of KA that manifests into skin disease. The PKDL patient suffers no fever, or even itching for that matter. Since the problem is by and large cosmetic-begining with skin discoloration and later to nodules in the body, the patients either remain neglected to their condition or do not feel need to access the healthcare.
However, this is where the threat lies. PKDL lesions contain the same parasite that causes KA, said the researchers of the study who had conducted xenodiagnosis test, that is, exposing sandflies to individuals with different stages of disease and infection.
In other words, PKDL patients were allowed themselves to be bitten by laboratory-reared sandflies (which were free from infection) by plunging their hands into a cage for 15 minutes containing male and female sandflies. The sandflies were then analysed for the parasites that cause KA.
The results showed that nearly 60 per cent of the 47 PKDL patients in the study passed on the parasites to sandflies. This means the insects could then go on to infect someone else, said the study conducted by the Drugs for Neglected Diseases initiative (DNDi) and the International Centre for Diarrhoeal Disease Research, Bangladesh (ICCDR, B). It aimed to access whether parasites in the skin of PKDL patients could be transmitted to the sandflies that transmit KA.
“This is the largest study of its type to date. Until now, information on the role of PKDL was scarce and scattered across decades of different research initiatives,” said Dr Jorge Alvar, senior leishmaniasis advisor at DNDi and co-principal investigator of the study. “The results unequivocally show that PKDL is of pivotal importance for maintaining transmission of the disease in-between epidemics.”
“Because PKDL is not fatal it has largely been ignored by public health efforts, and many scientific questions around its role have remained unaddressed,” said Dr Dinesh Mondal, senior scientist at the ICDDR, B and principal investigator of the study. “While these new findings don’t answer all our questions, they do show that early treatment of PKDL patients will be a critical element of any leishmaniasis public health and elimination strategy.”
‘’Great strides have been made in the control of KA in South Asia, but this study shows that now we must engage in active PKDL case detection and provide prompt treatment as an integral part of KA control and elimination,” said Dr Suman Rijal, Director of the DNDi Regional Office in India. “PKDL must be addressed in order to sustain elimination or we risk jeopardizing our earlier successes.”