Abstract :
Human metapneumovirus is one of the respiratory viruses with increasing importance in clinical field. The present study does focus on the incidence of human metapneumovirus (HMPV) among hospitalized pediatric patients suffering from respiratory tract infection. The patients were recruited from inpatients of Al zahraa hospital, Najaf City, Iraq. Studies conducted in various countries all over the world has verified that the human metapneumovirus (HPMV) is the most etiological agent of respiratory infections among children. In this context, this study encompassed 156 children suffered from respiratory infections with clinical manifestations like cough, wheezing, shortness of breath, fever, rhinorrhea, and nasal congestion. The recruited patients were those routinely do visit the external clinics of Al zahraa hospital, Najaf City from September 2020 to April 2021. The presumptive diagnosis by the physician was viral respiratory infection with human metapneumovirus (HPMV). Data of participants including clinical symptoms, age and family history were collected by using a questionnaire specially designed for this purpose. Molecular detection and genotyping of HMPV from patient with respiratory tract infections in AL-zahraa hospital, Najaf city, Iraq. One hundred fifty six nasopharyngeal swabs samples were suspected of having respiratory tract infections of different ages were enrolled, Real-time PCR assay was used for molecular detection of HMPV, and one PCR primer set for Fusion (F)gene of HMPV has been used in order to get PCR products used in the sequencing method for genotyping of the virus and phylogenetic tree analysis. Statistical analysis for all data was done using Statistical Package of Social Sciences (SPSS), version 27, (Inc., Chicago, IL, USA) computer software. Statistical comparison between study groups analyzed using chi-square test and T test. P<0.05 was regarded as statistically significant (Al-Ukaelii and Al-Shaeb, 1998). Molecularly, the results revealed that out of 156 specimens, 44(28.20%) specimens were positive for HMPV, with higher in ages less than 1 year 24 (54.5%). clinically, Dyspnea 40(90.9%) and cough 30(68.1%) were associated with HMPV. Genotypically, 9 HMPV positive samples were showed good (F) gene sequences that submitted to NCBI. A phylogenetic tree was constructed to portray the genetic relatedness among the nucleotides sequences of fusion protein F isolated from the nine strains of human metapneumovirus (HPMV). The constructed Neighbor joining tree reflected the speciation of the nine strains of human metapneumovirus (HPMV) into five groups namely 1-5. Group1 included human metapneumovirus (HPMV) –HW-4 and human metapneumovirus (HPMV)-HW-8. Group 2 encompassed human metapneumovirus (HPMV)-HW-2 and human metapneumovirus (HPMV)-HW-7. Group 3 included human metapneumovirus (HPMV)-HW-1 and human metapneumovirus (HPMV)-HW-3. However, group 4 included human metapneumovirus (HPMV)-HW-6 and human metapneumovirus (HPMV)-9. The group 5 included human metapneumovirus (HPMV)-HW-5. Only HW-4 could be genotyped as genotype A2, whilst, the other four remaining strains HW-1, HW-2, HW-7, and HW-9 could not be genotyped. Despite the potential of fusion protein F in the infection process of human metapneumovirus (HMPV) as reported by several studies, four strains namely HW-3, HW-5, HW-6, and HW-8 proved to harbor non-functional fusion protein. These results would necessitate further confirmation by repeated sequencing through at least three runs to verify the non-functionality of fusion protein in these human metapneumovirus (HMPV) strains. Otherwise, a conclusion addressing the presence of other proteins or factors contributes greatly in the infectivity and attachment-entry of the virus inside host cells might be outlined. Another approach to unveil the mystery of the presence of non-functional fusion proteins among virulent Human metapneumovirus (HMPV) strains isolated from cases with acute symptoms is monitoring the expression of the fusion protein in these strains on both transcriptional and translational level in further studies.
