Molecular Investigations of an Outbreak of Parainfluenza Virus Type 3 and Respiratory Syncytial Virus Infections in a Hematology Unit

Abstract

A large simultaneous outbreak of respiratory syncytial virus (RSV) and parainfluenza type 3 (PIV-3) infections occurred on an adult hematology unit. Implementation of enhanced infection control was complicated by cocirculation of the two different viruses, with prolonged viral shedding from infected patients, and placed great pressure on health care staff; of 27 infected hematopoietic stem cell transplant patients, 9 died, and the unit was closed for 2 months. Retrospective molecular investigation of the virus strains involved in the outbreak was performed by analyzing part of the fusion gene of PIV-3 and part of the glycoprotein gene of RSV. Reverse transcription-PCR on nasopharyngeal aspirates from patients infected before and during the simultaneous outbreak generated amplicons for sequence analysis. A single strain of RSV and a single strain of PIV-3 had spread from person to person within the unit; 7 patients were infected with RSV, 22 were infected with PIV-3, and 4 were infected with both viruses. The PIV-3 outbreak had started at the beginning of August 3 months before the RSV outbreak; it had arisen when PIV-3 was introduced from the community by a patient and passed to another patient, who became chronically infected with the identical strain and, in spite of being nursed in isolation, was most likely the source from which widespread infection occurred in November. Had these early cases been linked to a common PIV-3 strain at the time of diagnosis, enhanced infection control precautions might have prevented the eventual extensive spread of PIV-3, making it much easier to deal with the later RSV outbreak.

Risk factors and containment of respiratory syncytial virus outbreak in a hematology and transplant unit

“…Several smaller outbreaks have been reported from adult hematology or transplant units 13,[21][22][23][24][25] as well as from pediatric wards and neonatal intensive care units. [18][19][20] A unique aspect of this retrospective analysis was the fact that all inpatients were repeatedly screened for the presence of RSV infection.…”

“…However, a recent pooled analysis suggests some efficacy. 17 Several nosocomial outbreaks of RSV infections on pediatric wards [18][19][20] as well as in adult hematology and transplantation units 13,[21][22][23][24][25] have been described in the literature.…”

Cross-immunity between strains explains the dynamical pattern of paramyxoviruses

“…paramyxoviruses | respiratory syncytial viruses | human parainfluenza | pathogen interactions | cross-immunity R espiratory Syncytial Virus (RSV) and Human Parainfluenza Virus (HPIV), two important closely related members in the Paramyxovirus family (1), are leading causes of hospitalization in young children with community-acquired respiratory disease (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Each year, they impose a huge burden on public health by demanding substantial healthcare system resources (14).…”

Diversidade genética dos Vírus Parainfluenza 1, 2 e 3, identificados em amostras colhidas no Hospital Universitário da Universidade de São Paulo, durante os anos de 1995 a 2005.

“…A transmissão do vírus é direta e ocorre pessoa a pessoa pelo contato direto das mãos com a mucosa, principalmente ocular e nasal, e por gotículas de aerossóis disseminadas durante tosses e espirros, que podem ser inaladas ou contaminar superfícies (ECHEVARRÍA et al, 2000;JALAL et al, 2007). HPIV-1, HPIV-2 e HPIV-3 podem sobreviver cerca de 10 horas em superfícies não porosas e 4 horas em superfícies porosas (BRADY; EVANS; CUARTAS, 1990).…”

“…Embora a ribavirina apresente atividade in vitro contra os HPIVs, sua eficácia in vivo não foi boa (NICHOLS et al, 2001 Os surtos do HPIV-1 ocorrem no outono sendo que a maioria das infecções ocorre entre sete e 36 meses de idade, com um pico de incidência entre o segundo e o terceiro ano de vida. As principais síndromes são traqueobronquite e pneumonia (CARBALLAL et al, 2001;ECHEVARRIA et al, 2000;HSIEH et al, 2010;MARX et al, 1997 Embora os HPIVs tenham sido isolados pela primeira vez há mais de quarenta anos, a verificação da heterogeneidade entre as cepas de cada gênero é relativamente recente (ECHEVARRÍA et al, 2000;JALAL et al, 2007;MIZUTA et al 2012;ZAMBON et al, 1998 …”