Etiologic Involvement of Enterovirus and Human Bocavirus in Acute Flaccid Paralysis Cases in India

Abstract

BackgroundAcute flaccid paralysis (AFP), characterized by the rapid onset of asymmetric paralysis, can be caused by a variety of viral infections or coinfections. Besides wild-type and revertant vaccine strains of polioviruses, several nonpolio enteroviruses, have also been associated with AFP. Enteroviruses (EVs) are RNA viruses in the family Picornaviridae comprising more than 100 serotypes that are divided into four species, human enteroviruses A to D. The clinical manifestations of EVs range from conjunctivitis, respiratory tract infection, myocarditis, meningitis, encephalitis, and neonatal sepsis, like illness. Human Bocavirus (HBoV), a newly classified member of the Parvoviridae family, has been detected frequently in feces of diarrhoeic children suggesting its possible etiological involvement in the disease.MethodsTotal 586 stool specimens were collected in 2016 from children suspected for AFP. Molecular method for targeting 5’ untranslated region (UTR) and VP1 capsid region was used for detection of human enteroviruses (HEV), human boca viruses (HBoV) and saffold viruses in direct clinical specimen.ResultsEV RNA was detected in 103 (17.6%) of 586 stool specimens by real-time RT-PCR targeting the highly conserved 5’ UTR region. Out of them, 71 (12.11%) were NPEV, partially sequenced by VP1 which revealed the prevalence of echovirus (ECV) 19 (n = 6), ECV 11 (n = 7), ECV 18 (n = 4), ECV 33 (n = 5), ECV 29 (n = 1), ECV 25 (n = 2), ECV 24 (n = 3), ECV 3 (n = 3), ECV 14 (n = 2), ECV 13 (n = 1), ECV 2 (n = 1), ECV 20 (n = 2), ECV 27 (n = 4), ECV 6 (n = 2), CV A10 (n = 2), CV A9 (n = 1), CV A6 (n = 2), CV B4 (n = 1), CV B5 (n = 3), CV B6 (n = 3), EV 80 (n = 1), EV 83 (n = 1), EV 97 (n = 2).Total 63 (10.75%) HBoVs were detected by real-time PCR which were further sequenced by VP1, consists of HBoV-1 (n = 8), HBoV-2 (n = 15), HBoV-3 (n = 9) and HBoV-4 (n = 5). Out of them 9 (1.5%) were detected as co infection with NPEVs. Phylogenetic analysis showed 0.9 - 5.6% divergence at nucleotide level among HBoVs.Total 9 (1.5%) saffold viruses was detected and characterized by VP1 sequencing.ConclusionECV and HBoV were found the main etiologic agent in children suspected with AFP. Molecular typing of these viruses is useful for characterizing emerging serotypes and their epidemiological investigation.Disclosures All authors: No reported disclosures.