Editorial [Hot Topic: Cytomegalovirus Infection in the Fetus, Infant, Child, and Adolescent: An Overview of Virus Genetics and Pathogenesis, Disease Burden, Prevention, Diagnosis, Treatment, Antiviral Resistance, and Drug Targets (Guest Editor: Robert W. Tolan)]

This special issue of Infectious Disorders-Drug Targets focuses on human cytomegalovirus (CMV) infection from a pediatric standpoint, presenting state-of-the-art reviews by experts in the field, with whom I have been privileged to collaborate. This issue will cover congenital infections in general, congenital CMV infection specifically, infection in the compromised host, CMV genetics and pathogenesis, diagnostic approaches, antiviral treatment and resistance, and CMV vaccine development. Many of these authors participate in the National Institute on Deafness and Other Communication Disorders CMV and Hearing Multicenter Screening (CHIMES) Study, which is providing invaluable information on the incidence, detection, and sequelae of congenital CMV infection by screening more than 100,000 newborns for congenital CMV infection and following those infected for hearing outcomes [1, 2]. While this issue was in preparation, Andrei, De Clercq, and Snoeck published an extraordinary overview of drug targets in CMV infection in this journal [3]. This special issue both expands on that foundation and emphasizes the importance of CMV infection in the pediatric population. CMV is the most common intrauterine infection in the United States and, likely, the rest of the world [4-6] in addition to being the leading infectious cause of psychomotor impairment and sensorineural hearing loss in infants and children [7, 8]. In fact, in 1999, the Institute of Medicine assigned CMV the highest priority in its assessment of targets for vaccine development based upon “the cost and human suffering that would be alleviated by reducing the disease burden of congenital CMV infection” [4]. More than 50 years after discovery of the virus, progress toward a vaccine is being made [9-11], but much remains to be done [6]. CMV infection has been reviewed frequently [6, 12, 13] and the state-of-the-art reviews in this issue supplement and update previous work. To review CMV disease burden and contextualize congenital CMV, Joseph Cantey and Pablo Sánchez have provided a broad overview of congenital infections [14]. Focusing on CMV specifically, Sean Elliott has narrowed the purview, thoughtfully describing congenital infection [15]. Finally, Marsha Russell, April Palmer, and Marian Michaels have cogently reviewed non-congenital CMV infection in the compromised host, including post-natally acquired CMV in the premature baby, oncology patient, solid organ and hematopoietic stem cell transplant recipient, and human immunodeficiency virus-infected individual [16]. In an excellent review of CMV-host interactions, Mark Schleiss has covered the pathogenesis of infection, including mechanisms for evasion of the immune response and suggesting possible targets for therapeutic intervention [17]. Current methods for diagnosing CMV infection in a variety of populations are thoroughly elucidated by Shannon Ross, Zdenek Novak, Sunil Kumar Pati, and Suresh Boppana [18]. Amina Ahmed has provided an encyclopedic assessment of treatment issues [19] which is complemented by a thorough overview of the genetic basis and current evaluation of antiviral resistance by Scott James and Mark Prichard [20]. Finally, David Bernstein has written a superior treatise on the status of vaccines to prevent CMV infection [21]. Space limitations do not allow inclusion of many important and interesting aspects of CMV biology and disease, such as the increasingly described, severe manifestations of CMV infection in apparently immunocompetent children [22] or the role of passive immunoprophylaxis for infected pregnant women [23-25]. The interplay between the immune system and CMV latency and reactivation is another topic worthy of further study and review [26, 27]. Finally, the role of CMV infection in cancer [28] (among many other diseases and conditions) is fascinating, but addressing these interactions is just beginning. Any of these areas (and many others) could have been included in this issue. In addition to the remarkable proficiency and expertise of the authors of these reviews, the following colleagues generously contributed to this issue's quality and success by serving as peer reviewers of the articles: Doctors Janet Chen, Jeffrey Cies, Irini Daskalaki, Gail Demmler-Harrison, Kristina Feja, Lawrence Frenkel, Jane Gould, Paul Griffiths, Hemant Kesarwala, David Kimberlin, Sarah Long, Robert Pass, Swetha Pinninti, Mobeen Rathore, Judy Scala, Sunil Sood, Greg Storch, and Jennifer Vodzak. The opportunity to interact with colleagues of this caliber is extraordinarily gratifying and the results of their hard work and dedication are reflected in the reviews comprising this special issue of Infectious Disorders-Drug Targets.....