Respiratory syncytial and influenza viruses in children under 2 years old with severe acute respiratory infection (SARI) in Maputo, 2015

<div><p>Introduction</p><p>Although respiratory syncytial virus (RSV) and influenza virus (influenza) infections are one of the leading causes of Severe Acute Respiratory Infections (SARI) and death in young children worldwide, little is known about the burden of these pathogens in Mozambique.</p><p>Material and methods</p><p>From January 2015 to January 2016, nasopharyngeal swabs from 450 children, aged ≤2 years, who had been admitted to the Pediatric Department of the Maputo Central Hospital (HCM) in Mozambique, suffering with SARI were enrolled and tested for influenza and RSV using a real-time PCR assay.</p><p>Results</p><p>Influenza and RSV were detected in 2.4% (11/450) and 26.7% (113/424) of the participants. Children with influenza were slightly older than those infected with RSV (10 months in influenza-infected children compared to 3 months in RSV-infected children); male children were predominant in both groups (63.6% versus 54.9% in children with influenza and RSV, respectively). There was a trend towards a higher frequency of influenza (72.7%) and RSV (93.8%) cases in the dry season. Bronchopneumonia, bronchitis and respiratory distress were the most common diagnoses at admission. Antibiotics were administered to 27,3% and 15,9% of the children with influenza and RSV, respectively. Two children, of whom, one was positive for RSV (aged 6 months) and another was positive for Influenza (aged 3 months) died; both were children of HIV seropositive mothers and had bronchopneumonia.</p><p>Conclusions</p><p>Our data demonstrated that RSV, and less frequently influenza, occurs in children with SARI in urban/sub-urban settings from southern Mozambique. The occurrence of deaths in small children suspected of being HIV-infected, suggests that particular attention should be given to this vulnerable population. Our data also provide evidence of antibiotics prescription in children with respiratory viral infection, which represents an important public health problem and calls for urgent interventions.</p></div

Monthly and seasonal variation of cases of influenza and RSV.

<p>The graph depicts the monthly and seasonal variation of cases of influenza (right axis) and RSV (left axis).</p

Flowchart of recruitment of study participants and sample testing.

<p>Of the 439 negative samples for influenza, 424 were tested for RSV; 15 samples were not tested due to lack of reagents.</p

Clinical and demographic characteristics of participants.

<p>Clinical and demographic characteristics of participants.</p

General characteristics of the participants analyzed in this study.

<p>General characteristics of the participants analyzed in this study.</p

Antigenic (HI) analyses of A(H3N2) viruses (guinea pig RBCs in the presence of 20 nM oseltamivir).

<p>Antigenic (HI) analyses of A(H3N2) viruses (guinea pig RBCs in the presence of 20 nM oseltamivir).</p

Phylogenetic comparison of influenza A(H3N2) HA genes.

<p>The month of clinical specimen collection is indicated by colour (March to July 2015) after each virus name. Specific viruses are highlighted: vaccine virus (bold red), reference viruses to which post-infection ferret antisera were raised (bold black) and Mozambican viruses (boxed). Amino acid substitutions defining specific genetic clusters are indicated at nodes and virus-specific substitutions are shown after the virus name (* indicates polymorphism). Genetic clades and subclades are indicated at the right of the tree and the scale bar indicates the distance between isolates.</p

Antigenic (HI) analyses of A(H1N1)pdm09 viruses.

<p>Antigenic (HI) analyses of A(H1N1)pdm09 viruses.</p

Phylogenetic comparison of influenza A(H1N1)pdm09 HA genes.

<p>The month of clinical specimen collection is indicated by colour (April to July 2015) and after each virus name. Specific viruses are highlighted: vaccine virus (bold red), reference viruses to which post-infection ferret antisera were raised (bold black) and Mozambican viruses (boxed). Amino acid substitutions defining specific genetic clusters are indicated at nodes and virus-specific substitutions are shown after the virus name (* indicates polymorphism). Genetic group 6B, defined by HA1 amino acid substitutions K163Q and A256T, is indicated and the scale bar indicates the distance between isolates.</p

Antigenic (HI) analyses of influenza B viruses.

<p>Antigenic (HI) analyses of influenza B viruses.</p