Emerging Respiratory Pathogens: Insights into Human Metapneumovirus (hMPV) and Bocavirus in Acute Respiratory Tract Infections

Acute respiratory tract infections caused by various viral pathogens remain a dominant cause of global morbidity and mortality, profoundly affecting healthcare systems and vulnerable populations. Human metapneumovirus and human bocavirus have emerged as critical agents implicated in both endemic and epidemic settings, often presenting with overlapping clinical features and significant burdens in paediatric, elderly, and immune compromised groups. Their virological diversity, capacity for coinfections, and potential for severe outcomes have led to intensified research aimed at unravelling their molecular mechanisms and clinical impact. Diagnostic modalities for these pathogens have advanced considerably, incorporating sensitive molecular assays and metagenomics-based approaches. Despite noteworthy progress in understanding their biology and epidemiology, therapeutic measures remain primarily supportive, and vaccine development continues to face challenges stemming from viral diversity and immune evasion strategies. This chapter provides a detailed and integrative review of human metapneumovirus and human bocavirus, beginning with their global epidemiological trends and delving into their virology, pathogenesis, clinical spectrum, and diagnostic complexities. It further examines emerging therapeutic and preventive paradigms, including the promise of novel antivirals and vaccine candidates. By highlighting gaps in current knowledge and exploring future research directions, this chapter underscores the necessity for comprehensive surveillance, innovative technologies, and collaborative efforts to reduce the burden of these pathogens on public health worldwide.