Human metapneumovirus in Pediatric Patients with Acute Respiratory Tract Infections in the Aseer Region of Saudi Arabia

Alsuheel, Ali Mohammed; Ali, Abdelwahid Saeed; Al-Hakami, Ahmed Musa; Shati, Ayed Abdullah; Chandramoorthy, Harish C.; Al-Qahtani, Saleh Mohammed

Human metapneumovirus (hMPV) is a single-stranded RNA-enveloped virus, recently classified in the order Mononegavirales, family Pneumoviridae, genus Metapneumovirus and species hMPV. It was first isolated in the Netherlands by van den Hoogen et al., [1, 2] and is now a known causative agent of upper and lower respiratory tract infections in children and adults. hMPV infections have been reported in Australia, [3] Canada, [4] the United States, [5] the United Kingdom, [6] Hong Kong, [7] South Africa, [8] Mexico, [9] Spain [10] and Peru. [11] However, in the Middle East, there have only been few reports of hMPV infections, mainly as sporadic infections in Egypt, [12] Jordan, [13] Kuwait [14] and Saudi Arabia. [15] Along with respiratory syncytial virus (RSV) infections, hMPV is now recognized as a primary etiologic agent for acute upper and lower respiratory tract infections in pediatrics. [16, 17] In a study from Mexico, it was found that the number of hMPV infections increased in children aged 24-36 months as compared with those in younger age groups, whereas RSV infections were inversely proportional to increase in age. [9] Co-infection with both viruses can also occur, resulting in a more complicated and serious clinical disease. [3, 18] In addition to the pediatric population, studies have also found hMPV to infect adults [19] and elderly people. [20] In terms of transmission, hMPV spreads through contact with contaminated secretions, i.e., droplet, aerosol or fomites. Hospital-acquired hMPV infections have also been reported. [5] In young children, infections are usually not asymptomatic, and bronchiolitis, with or without pneumonia, is the most common associated presentation. [18, 20, 21] Other reported conditions include bronchial asthma exacerbation, otitis media, pneumonitis, flu-like illness and community-acquired pneumonia. [9] In adults, hMPV has been associated with bronchitis, pneumonia and exacerbations of both bronchial asthma and chronic obstructive pulmonary disease. [22, 23] In terms of detection, reverse transcriptase-polymerase chain reaction (RT-PCR) is a sensitive and commonly used method to detect hMPV. [5] Real-time RT-PCR is also commonly used for detecting hMPV in clinical specimens with many genomic target sequences. [24, 25] A touch-down genomic amplification protocol for the diagnosis of acute viral respiratory tract infections has also been used previously. [26] The enzyme-linked immunosorbent assay for hMPV diagnosis is a simple and specific serological test for anti-hMPV antibodies detection. [27] Immunofluorescence using specific antibodies is routinely used for detecting hMPV antigens, particularly in epidemiological studies. [28] However, cell culturing techniques have a low sensitivity in detecting hMPV from respiratory tract secretions, as the virus exhibits extremely limited types of cell tropism. [2, 10, 29, 30] In Saudi Arabia, there is a paucity of data regarding the occurrence of hMPV and its role in complicated clinical cases of commonly reported respiratory infections. Therefore, the current study aimed to determine the role of hMPV in the respiratory tract infections' severity and complications among hospitalized children in the Aseer region, where no such study has previously been conducted.