Identification and characterization of nonpolio enterovirus associated with nonpolio-acute flaccid paralysis in polio endemic state of Uttar Pradesh, Northern India.

Harjeet Singh Maan,Tapan N Dhole,Rashmi Chowdhary,Shamala Devi Sekaran

doi:10.1371/journal.pone.0208902

Harjeet Singh Maan, Tapan N Dhole + Show 2 more

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https://doi.org/10.1371/journal.pone.0208902

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Abstract

Despite polio eradication, nonpolio enterovirus (NPEV) detection amid polio surveillance, which is considered to have implications in paralysis, requires attention. The attributes of NPEV infections in nonpolio-AFP (NPAFP) cases from Uttar Pradesh (UP), India, remain undetermined and are thus investigated. A total of 1839 stool samples collected from patients with acute flaccid paralysis (AFP) from UP, India, between January 2010 and October 2011 were analyzed as per the WHO algorithm. A total of 359 NPAFP cases yielded NPEVs, which were subjected to microneutralization assay, partial VP1 gene-based molecular serotyping and phylogenetic analysis. Demographic and clinical-epidemiological features were also ascertained. Echoviruses (29%) and Coxsackievirus (CV)-B (17%) were the most common viruses identified by the microneutralization assay. The molecular genotyping characterized the NPEVs into 34 different serotypes, corresponding to Enterovirus (EV)-A (1.6%), EV-B (94%) and EV-C (5.3%) species. The rarely described EV serotypes, such as EV-C95, CV-A20, EV-C105, EV-B75, EV-B101, and EV-B107, were also identified. NPEV-associated AFP was more prevalent in younger male children, peaked in the monsoon months and was predominantly found in the central part of the state. The NPEV strains isolated in the study exhibited genetic diversity from those isolated in other countries. These form part of a different cluster or subcluster existing in cocirculation, limited to India only. This study augments the understanding of epidemiological features and demonstrates the extensive diversity exhibited by the NPEV strains in NPAFP cases from the polio-endemic region. It also underscores the need or effective long-term strategies to monitor NPEV circulation and its associated health risks in the post-polio eradication era.

Highlights

Since 1988, global efforts led by the World Health Organization (WHO) have interrupted the transmission of indigenous wild poliovirus (WPV) and reduced the global incidence of poliomyelitis [1, 2]
Numbers in bold face represent the total number of nonpolio enterovirus (NPEV) isolate detected in EV-A, EV-C and EV species-B (EV-B) species #Coxsackievirus B (CV-B) typed by VP1 PCR and sequencing as CV-B1 (n = 4), CV-B2 (n = 6), CV-B3 (n = 8), CV-B4 (n = 10), CV-B5 (n = 9) and CV-B6 (n = 3); n, represent the number of isolates. †EV isolates typed by microneutralization ‡ untypable enteroviruses (UT-EVs) isolates characterized by molecular typing excludes isolates with mixed infections
During the post-polio eradication era, the rate of isolation of NPEVs remains a clinical yardstick for the surveillance of acute flaccid paralysis (AFP) cases in the field

Summary

Introduction

Since 1988, global efforts led by the World Health Organization (WHO) have interrupted the transmission of indigenous wild poliovirus (WPV) and reduced the global incidence of poliomyelitis [1, 2]. With the success of the eradication program, wild polio virus (WPV), the most common cause of acute flaccid paralysis (AFP), has been eliminated from India. Nonpolio enteroviruses (NPEVs; family Picornaviridae) could potentially be the causative agents of many NP-AFP cases, as they are frequently detected and isolated during laboratory surveillance for poliomyelitis [5, 6]. NPEVs are associated with neurological illnesses and have been identified in AFP children [7,8,9]. Only few reports of the isolation and epidemiology of AFP-associated NPEVs are available from India [10,11,12,13]

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