Common and Rare Emerging and Re-Emerging Infectious Diseases in Pediatric Transplant Recipients: A Comprehensive...

The established pathogens, including cytomegalovirus, Epstein-Barr virus, and bacterial bloodstream infections, remain leading causes of morbidity and mortality in pediatric transplant recipients (PTR). However, over the past two decades, the landscape of infectious diseases in this population has evolved substantially, marked by an increasing burden of emerging and re-emerging pathogens. The global rise in multidrug-resistant bacteria and fungi has complicated antimicrobial management and limited therapeutic options. Concurrently, novel and re-emerging viral threats, most notably severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and other opportunistic viruses have been associated with severe disease, graft dysfunction, and prolonged hospitalization in immunocompromised children. Declining vaccination coverage has further contributed to the resurgence of vaccine-preventable infections such as measles and pertussis, which often present a more aggressive clinical course in PTR. Rare but consequential emerging pathogens, including arboviruses, hepatitis E virus, polyomaviruses, lymphocytic choriomeningitis virus, Enterovirus D68, Mpox (monkeypox virus), avian influenza A(H5N1), and emerging fungi, pose additional risks through both donor-derived transmission and community exposure, particularly in endemic and resource-limited settings. Broader global factors, including climate change, increased travel, and population displacement, have expanded pathogen distribution and exposure risk. Simultaneously, advances in molecular and syndromic diagnostics have improved pathogen detection, identifying infections previously under-recognized in transplant populations. These evolving epidemiological trends highlight the importance of ongoing surveillance, improved vaccination strategies, antimicrobial stewardship, and individualized prevention and treatment approaches. This comprehensive review synthesizes current evidence on most encountered and rare emerging and re-emerging bacterial, viral, and fungal infectious diseases affecting PTR.