Human parainfluenza virus in patients with influenza-like illness from Central and South America during 2006-2010

Abstract

Background: Human parainfluenza viruses (HPIVs) are common viral causes of community-acquired pneumonia, particularly in children. The four types of HPIV have world-wide distribution; however, limited information exists about the epidemiological profile of HPIV in Latin-America.

Objective: Provide epidemiologic and phylogenetic information about HPIVs that circulated in Latin America between 2006 and 2010 to better characterize the extent and variability of this respiratory virus in the region.

Methods: Oropharyngeal swabs, demographic data and clinical characteristics were obtained from individuals with influenza-like illness in 10 Latin-American countries between 2006-2010. Specimens were analyzed with culture and molecular methods.

Results: A total of 30 561 individuals were enrolled; 991 (3·2%) were HPIV positive. Most infected participants were male (53·7%) and under 5 years of age (68·7%). The HPIV type most frequently isolated was HPIV-3 (403, 40·7%). In 66/2007 (3·3%) hospitalized individuals, HPIV was identified. The most frequent symptoms at enrollment were cough and rhinorrhea. We identified certain patterns for HPIV-1, -2 and -3 in specific cities. Phylogenetic analysis revealed a homogeneous distribution in the region.

Conclusions: In the current scenario, no vaccine or treatment is available for this pathogen. Our results contribute to the scarce epidemiologic and phylogenetic information of HPIV in the region that could support the development of specific management.

Keywords: Epidemiology; Latin America; parainfluenza virus; phylogenetics.

Figure 1

Country distribution of HPIV, June 2006 – November 2010. (A) Participating cities in Central America; (B) Participating cities in the northern area of South America; (C) Participating cities in the southern area of South America.

Figure 2

Annual HPIV activity.

Figure 3

Phylogenetic analysis. Nucleotides of the HN protein gene of HPIV-1, -2, and -3 and of the P protein gene of HPIV-4 were amplified, sequenced, and compared to published sequences from GenBank. We labeled the samples according to the following format: “Country of collection - Sample code - Month - Year of collection.” The comparison sequences were labeled according to the following format: “Human parainfluenza virus – Country of collection – Year of collection – Accession Number”. Nucleotide sequences were aligned using Clustal X. Phylogenetic analyses were performed using the Kimura two-parameter model as a model of nucleotide substitution and using the neighbor-joining method to reconstruct phylogenetic trees (MEGA version 2.1). *Strain V98's country and year of collection was not available in GenBank. ** Strain 04-13's country of collection was not available in GenBank.