Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India

Anthroponotic VL caused by Leishmania donovani in the Indian subcontinent accounts for 70% of the world burden of VL. Among the estimated 100,000 cases of VL acquired annually in India, 90% occur in the state of Bihar. Leishmania infection can result in either symptomatic or asymptomatic infection....

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Main Authors:	Sudarshan, Medhavi, Singh, Toolika, Singh, Abhishek Kumar, Chourasia, Ankita, Singh, Bhawana, Wilson, Mary E., Chakravarty, Jaya, Sundar, Shyam
Format:	Online
Language:	English
Published:	Public Library of Science 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4263468/

id	pubmed-4263468
recordtype	oai_dc
spelling	pubmed-42634682014-12-19 Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India Sudarshan, Medhavi Singh, Toolika Singh, Abhishek Kumar Chourasia, Ankita Singh, Bhawana Wilson, Mary E. Chakravarty, Jaya Sundar, Shyam Research Article Anthroponotic VL caused by Leishmania donovani in the Indian subcontinent accounts for 70% of the world burden of VL. Among the estimated 100,000 cases of VL acquired annually in India, 90% occur in the state of Bihar. Leishmania infection can result in either symptomatic or asymptomatic infection. L. donovani infection can also manifest as post-kala azar dermal leishmaniasis, a chronic cutaneous form thought to provide the reservoir for anthroponotic transmission of VL in regions endemic for this parasite species. We hypothesized that, in areas endemic for L. donovani, asymptomatic infections might also play a crucial role in disease transmission. This study describes use of quantitative PCR (qPCR) to determine the infection status in individuals living in an endemic region of India. We hypothesized that parasite load estimation by qPCR of peripheral blood cells among healthy individuals living in the endemic region might reveal the true frequency of infections through direct evidence of parasitemia. We reasoned this test would detect both asymptomatic non-progressors as well as asymptomatic individuals who will progress to fully symptomatic VL. Serologic testing by ELISA or DAT showed poor agreement with molecular detection of parasite DNA by qPCR, suggesting the tests differentiate between infection and immune response. Amongst ten healthy individuals who progressed to VL, only six were serologically positive whereas eight were initially qPCR positive, among whom five had high parasite loads in their blood. Thus, deployment of qPCR technique to estimate the presence and level of parasitemia in healthy individuals from Leishmania endemic regions may contribute to early case detection, thereby reducing morbidity and mortality. Consistent with the goals of the VL control and elimination program, this early intervention approach could help interrupt disease transmission. Public Library of Science 2014-12-11 /pmc/articles/PMC4263468/ /pubmed/25503103 http://dx.doi.org/10.1371/journal.pntd.0003366 Text en https://creativecommons.org/publicdomain/zero/1.0/ This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Sudarshan, Medhavi Singh, Toolika Singh, Abhishek Kumar Chourasia, Ankita Singh, Bhawana Wilson, Mary E. Chakravarty, Jaya Sundar, Shyam
spellingShingle	Sudarshan, Medhavi Singh, Toolika Singh, Abhishek Kumar Chourasia, Ankita Singh, Bhawana Wilson, Mary E. Chakravarty, Jaya Sundar, Shyam Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
author_facet	Sudarshan, Medhavi Singh, Toolika Singh, Abhishek Kumar Chourasia, Ankita Singh, Bhawana Wilson, Mary E. Chakravarty, Jaya Sundar, Shyam
author_sort	Sudarshan, Medhavi
title	Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
title_short	Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
title_full	Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
title_fullStr	Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
title_full_unstemmed	Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India
title_sort	quantitative pcr in epidemiology for early detection of visceral leishmaniasis cases in india
description	Anthroponotic VL caused by Leishmania donovani in the Indian subcontinent accounts for 70% of the world burden of VL. Among the estimated 100,000 cases of VL acquired annually in India, 90% occur in the state of Bihar. Leishmania infection can result in either symptomatic or asymptomatic infection. L. donovani infection can also manifest as post-kala azar dermal leishmaniasis, a chronic cutaneous form thought to provide the reservoir for anthroponotic transmission of VL in regions endemic for this parasite species. We hypothesized that, in areas endemic for L. donovani, asymptomatic infections might also play a crucial role in disease transmission. This study describes use of quantitative PCR (qPCR) to determine the infection status in individuals living in an endemic region of India. We hypothesized that parasite load estimation by qPCR of peripheral blood cells among healthy individuals living in the endemic region might reveal the true frequency of infections through direct evidence of parasitemia. We reasoned this test would detect both asymptomatic non-progressors as well as asymptomatic individuals who will progress to fully symptomatic VL. Serologic testing by ELISA or DAT showed poor agreement with molecular detection of parasite DNA by qPCR, suggesting the tests differentiate between infection and immune response. Amongst ten healthy individuals who progressed to VL, only six were serologically positive whereas eight were initially qPCR positive, among whom five had high parasite loads in their blood. Thus, deployment of qPCR technique to estimate the presence and level of parasitemia in healthy individuals from Leishmania endemic regions may contribute to early case detection, thereby reducing morbidity and mortality. Consistent with the goals of the VL control and elimination program, this early intervention approach could help interrupt disease transmission.
publisher	Public Library of Science
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4263468/
_version_	1613166577707909120

Quantitative PCR in Epidemiology for Early Detection of Visceral Leishmaniasis Cases in India

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