Abstract of Thesis Approved for the PhD Degree at the Faculty of Medicine, Health Sciences Center, Kuwait University, Kuwait

of Thesis Approved for the PhD Degree at the Faculty of Medicine, Health Sciences Center, Kuwait University, Kuwait types and the severity of respiratory tract disease was analyzed. In addition, the association between RNA load of different hMPV genotypes and its effect on the outcome and prognosis of hMPV disease was also investigated. Our results show that the prevalence of hMPV infection in Kuwait among patients with RTIs was almost 5%; both genotypes A and B were detected in Kuwait with no predominance of one over the other. Furthermore, there was no evidence for a direct correlation between hMPV genotypes and the severity of the clinical outcome. Moreover, hMPV infection was seasonal, and peaks occurred during winter and spring. hMPV infection was detected in all age groups, but mostly in young children and the elderly. Most of hMPV-positive patients presented with lower RTIs such as pneumonia and bronchopneumonia. The major cause of lower RTIs in our study population was human rhinovirus (hRV; 30%), followed by hMPV (22%), and then human respiratory syncytial virus (13%). The proportion of hMPV coinfection with other respiratory viruses was almost 19% among hMPV-positive cases (mainly hRV, 13%). This coinfection was associated with severer disease and prolonged hospital stay. High viral RNA load in hMPV-positive patients with lower RTIs correlated well with the severity of clinical symptoms and virus replication rate. Our results highlight the importance of hMPV infection as an important cause of severe lower RTI, especially among children and elderly subjects in Kuwait. Prof. Widad Al Nakib (Supervisor) Prof. Fahd Al Mulla (Co-supervisor) Dr. Wassim Chehadeh (Co-supervisor) Supported by a fellowship from the College of Graduate Studies and Kuwait University Research Administration grant No. YM05/09. PhD Degree