Printer Friendly

Respiratory Viruses in Young Children.

Respiratory illnesses are the most common causes of hospitalizations of preschool children in the U.S. (1) Many of the respiratory ailments that afflict children under 5 years of age are caused by viruses with a wide range of severity and a variety of genomes. Understanding the uniquenesses of each virus can aid in diagnosis and treatment, reducing patient suffering and easing anxiety in many parents.

The "common cold" is the most common cause of all respiratory illnesses. The various strains of rhinovirus usually cause runny nose, sneezing, watery eyes, head and body aches, and are most often self-limiting, disappearing after about a week. Although the mortality rate is very low, rhinoviruses do contribute to about 0.5% of hospitalizations in young children, most of whom are asthmatics. (2) These non-enveloped single-stranded RNA viruses belong to the Picornaviridae family and have a high RNA polymerase error rate. The high mutation rate of rhinoviruses causes them to evolve rapidly. (3) Therefore, while they are extremely common infectious agents worthy of a vaccine, this has proven difficult given the diverse antigenic variability among the many rhinoviruses. (4)

Pathogens for which vaccines are formulated annually, the influenza viruses are enveloped, segmented single-stranded RNA viruses of the Orthomyxoviridae family. (5) Symptoms generally include cold-like symptoms with the addition of cough, fever and chills, sore throat, and fatigue, with the possible addition of vomiting and diarrhea. (6) The number of deaths due to influenza varies from one year to another in the U.S. because of changes in the epidemic strain. (7) Generally, about half of all child deaths from influenza occur in previously healthy children, while others suffer from some type of acute or chronic condition. (8) In the 2003-2004 influenza season, 63% of child deaths resulting from influenza were among children less than 5 years of age. However, the percentage of patients in this age group being hospitalized is relatively small at about 0.1%. That is, only about 108 children in 100,000 under 5 years of age were hospitalized with influenza between the years 1979 and 2001. (9)

When children are sick, many parents may initially assume the problem is the "common cold" or "the flu". But this assumption may be erroneous. There are a few other viruses that commonly affect children other than rhinovirus and influenza. Similar to the rhinoviruses, enterovirus D68 (EV68) is a naked single-stranded RNA virus in the Picornaviridae family. Though most cases are mild and self-limiting and it has rarely been reported since 1962, EV68 was recently in the news from August to October of 2014. Outbreaks from EV68 occurred in the Midwestern, Northeastern, and Southern U.S, including several deaths. (10,11) Children were having difficulties breathing and most of the cases occurred in patients aged 4 and 5. (12) As with other respiratory viruses, the situation is usually worse in patients with underlying respiratory illnesses. There is no vaccine for enteroviruses.

Mastadenoviruses of the Adenoviridae family are common naked double-stranded DNA viruses with over 50 serotypes divided into 7 subgroups, each with varying symptoms. (13-15) Some serotypes cause mostly respiratory symptoms similar to rhinovirus and influenza, but others may cause bladder inflammation, pink eye, and gastrointestinal illnesses as well. (16) Although rarely severe, an individual can be sick multiple times in his life from the various mastadenovirus strains. Most children under the age of 10 have had at least one illness from this group of viruses. Serotypes most often associated with respiratory problems are types 3, 4, 7, and 14, and there is a vaccine that covers serotypes 4 and 7. (13,17,18) Although lower respiratory infections from this virus may last several weeks, most last only several days.

Respiratory syncytial virus (RSV) has more specific symptoms than the mastadenoviruses and is more commonly associated with severe problems than either mastadenoviruses or enteroviruses. Around 95% of all children are exposed to RSV before the age of 2. (19) This highly contagious enveloped single-stranded RNA virus belongs to the Paramyxoviridae family and has a major impact on hospitalizations of preschool aged children. (20,21) Accounting for about 20% of hospitalizations in children under age 5, it is one of the leading causes of mortality in preschool children in the U.S. (22) Most children experience runny nose and decreased appetite, followed by coughing, sneezing, fever, and possibly wheezing and difficulty breathing, with the majority recovering after a few days even if hospitalized. (23) Those with preexisting diseases are at greatest risk of fatality from RSV, including cardiac lesions, chromosomal abnormalities, chronic lung disease, neuromuscular disorders, and immunodeficiencies. (24) Some young patients with these underlying disorders actually contract RSV nosocomially.

Another member of the Paramyxoviridae family with the same type of genome as RSV is parainfluenza virus (PIV). This pathogen also causes similar symptoms as RSV, including fever, runny nose, cough, and possibly bronchitis, pneumonia, croup, and ear infection. (25,26) PIV accounts for about 7% of all hospitalizations of children under 5 years of age. (27) While deaths in the developed world from PIV are uncommon, it does contribute to a greater extent to the mortality rate in young children in developing countries. (28)

A relatively new member among children's respiratory illness of the Paramyxoviridae family is Metapneumovirus (MPV). (29) Genetically related to RSV and in the same family as both RSV and PIV, it has greatly contributed to hospitalizations for respiratory illnesses in children across the U.S. since its discovery in the Netherlands just over a decade ago. While the total number of cases varies from one year to another, children less than 1 year of age have presented with severe cases of the disease more often than children between 1 and 5 years of age. (29,30) Studies suggest that RSV and MPV sometimes work synergistically to cause severe respiratory problems in young children. (29,31,32) One study that involved testing children under 5 years of age in several counties across the U.S. found that MPV was present in 6% of children that were hospitalized and 7% of children in outpatient settings compared to 1% in asymptomatic controls. (30) This virus has a relatively common occurrence and, as of now, there are no vaccines for either RSV, PIV, or MPV.

In general, these respiratory viruses can present with the same symptoms. For epidemiological purposes and to aid in treatment, it may be important to identify the causes of individual cases. Fortunately, methods of identification have improved over the years, especially due to molecular testing. Nucleic acid amplification technologies have aided in greater sensitivity and specificity of testing for respiratory diseases, which cause significant morbidity and even mortality in industrialized countries. (33) Some biotechnology companies offer respiratory virus panel testing, so that the presence of several major viruses can be determined in one physician order. (34)

Case Study

A two year old boy who attends daycare was brought to the emergency room after 2 days of symptoms including fever, nasal congestion, wheezing and barking cough, with an onset of agitation and struggling to breathe within the last few hours. The physician observed the patient's breathing, examined the child's throat, and listened to the chest with a stethoscope. Laboratory orders initially included complete blood count (CBC) and nucleic acid testing for respiratory viruses. Pulse oximetry testing was also performed. The CBC indicated an increased percentage of lymphocytes and the oxygen saturation was 92%. Respiratory virus molecular testing was negative for influenza, RSV, and MPV, but positive for PIV. The child was hospitalized for 2 days and received oxygen and oral corticosteroids before being discharged.


(1.) U.S. Department of Health and Human Services, Health Resources and Services Administration. Maternal and Child Health Bureau. Hospitalization. Child Health USA. 2011. Available online from hstat/hsc/pages/211h.html

(2.) Miller K, Lu X, Erdman D, Poehling K, Zhu Y, Griffin M, Hartert T, Anderson L, Weinberg G, Hall C, Iwane M, Edwards K. Rhinovirus-Associated Hospitalizations in Young Children. J Infect Dis. 2007;195(6):773-781.

(3.) Cordey S, Junier T, Gerlach D, Gobbini F, Farinelli L, Zdobnov D, Winther B, Tapparel C, Kaiser L. 2010. http://www.ncbi. Rhinovirus Genome Evolution during Experimental Human Infection. PloS One. 2010; 5(5): e10588.

(4.) Papi A, Contoli M. Rhinovirus vaccination: the case against. Eur Respir J. 2011;37(1):5-7.

Quest Diagnostics. Respiratory Virus PCR Panel I. 2015. Available online from

(5.) Tsai K, Chen G. Influenza genome diversity and evolution. Mi crobes Infect. 2011;13(5):479-488.

(6.) Center for Disease Control. Influenza: Key Facts about influ enza and flu vaccine. 2014. Available online from http://www.

(7.) Center for Disease Control and Prevention. Influenza: Season al influenza-associated hospitalizations in the U.S. 2011. Online available from htm

(8.) Bhat N, Wright J, Broder K, Murray E, Greenberg M, Glover M, Likos A, Posey D, Klimov A, Lindstrom S, Balish A, Medina M, Wallis T, Guarner J, Paddock C, Shieh W, Zaki S, Sejvar J, Shay D, Harper S, Cox N, Fukuda K, Uyeki T. Influenza-associated deaths among children in the United States, 20032004. New Engl J Med. 2005;353:2559-2567.

(9.) Thompson W, Shay D, Weintraub E, Brammer L, Bridges C, Cox N, Fukuda K. Influenza-Associated Hospitalizations in the United States. J Amer Med Assoc. 2004;292(11):13331340.

(10.) Malone, S. Rhode Island child with Enterovirus dies after infection: officials. Yahoo News. Available online from http://

(11.) Children's Hospitals and Clinics of Minnesota. Emergency and trauma: Facts about enterovirus D68. 2014. Available online from

(12.) Moisse K. What you need to know about the enterovirus outbreak. ABC News. 2014. Available online from http:// story?id=25345098

(13.) Center for Disease Control. Vaccine Information Statements: Adenovirus. 2014. Available online from vaccines/hcp/vis/vis-statements/adenovirus.html

(14.) Robinson C, Seto D, Jones M, Dyer D, Chodosh J. Molecular evolution of human species D adenoviruses. Infect Genet Evol. 2011;11(6):1208-1217.

(15.) Gompf S, Kelkar D, Oehler R. Adenoviruses. Medscape. 2015. Available online from

(16.) Durani Y. Adenovirus. Wake Forest Baptist Health, Brenner's Children's Hospital. 2012. Available online from https://www. Lung-and-Respiratory-Infections/Adenovirus.htm

(17.) Center for Disease Control and Prevention. Adenoviruses: Symptoms. 2011. Online available from adenovirus/about/symptoms.html

(18.) Louie J, Kajon A, Holodniy M, Guardia-LaBar L, Lee B, Petru A, Hacker J, Schnurr D. Severe pneumonia due to adenovirus serotype 14: a new respiratory threat? Clin Infect Dis. 2008;46(3):421-425.

(19.) Polkinghorne B, Mellis C, Kesson A. Respiratory syncytial virus. New South Wales Public Health Bulletin. 2011;22(78):159.

(20.) Jumaah S. Respiratory Syncytial Virus. Textbook of Clinical Pediatrics. 2012;1245-1248. Available online from http:// 978-3-642-02202-9_119

(21.) McCarthy A, Goodman S. Reassessing conflicting evolutionary histories of the Paramyxoviridae and the origins of respiroviruses with Bayesian multigene phylogenies. Infect Genet Evol. 2010;10(1):97-107.

(22.) Hall C, Weinberg G, Iwane M, Blumkin A, Edwards K, Staat M, Auinger P, Griffin M, Poehling K, Erdman D, Grijalva C, Zhu Y, Szilagyi P. The Burden of Respiratory Syncytial Virus Infection in Young Children. New Engl J Med. 2009;360:588598.

(23.) Center for Disease Control. Respiratory Syncytial Virus Infection: Symptoms and Care. 2014. Available online from

(24.) Thorburn K. Pre-existing disease is associated with a significantly higher risk of death in severe respiratory syncytial virus infection. Arch Dis Child. 2009;94:99-103.

(25.) Skiadopoulos M, Vogel L, Riggs J, Surman S, Collins P, Murphy B. The genome length of human parainfluenza virus type 2 follows the rule of six, and recombinant viruses recovered from non-polyhexameric-length antigenomic cDNAs contain a biased distribution of correcting mutations. J Virol. 2003;77(1):270-279.

(26.) Center for Disease Control and Prevention. Human Parainfluenza Viruses: Symptoms and Illness. 2012. Online available from html

(27.) Weinberg G, Hall C, Iwane M, Poehling K, Edwards K, Griffin M, Staat M, Curns A, Erdman D, Szilagyi P. Parainfluenza Virus Infection of Young Children: Estimates of the Population-Based Burden of Hospitalization. J Pediatr. 2009;154(5):694-699.

(28.) Parija S, Marrie T. Parainfluenza virus. Medscape. 2015. Available online from

(29.) Caracciolo S, Minini C, Colombrita D, Rossi D, Miglietti N, Vettore E, Caruso A, Fiorentini S. Human metapneumovirus infection in young children hospitalized With acute respiratory tract disease: virologic and clinical features. Pediatr Infect Dis J. 2008;27(5):406-412.

(30.) Edwards K, Zhu Y, Griffin M, Weinberg G, Hall C, Szilagyi P, Staat M, Iwane M, Prill M, Williams J. Burden of Human Metapneumovirus Infection in Young Children. New Engl J Med. 2013;368:633-643.

(31.) Foulongne V, Guyon G, Rodiere M, Segondy M. Human metapneumovirus infection in young children hospitalized with respiratory tract disease. Pediatr Infect Dis J. 2006; 25(4):354-359.

(32.) Williams J, Harris P, Tollefson S, Halburnt-Rush L, Pingsterhaus J, Edwards K, Wright P, Crowe J. Human Metapneumovirus and Lower Respiratory Tract Disease in Otherwise Healthy Infants and Children. New Engl J Med. 2004;350:443450.

(33.) Mahony J. Detection of respiratory viruses by molecular methods. Clin Microbiol Rev. 2008;21(4):716-747.

(34.) Quest Diagnostics. Respiratory Virus PCR Panel I. Available online from testguide.action?dc=TS_RespVirusPanel

Lisa Maness, PhD, MT(ASCP), is Assistant Professor at Winston-Salem State University, North Carolina. She teaches Microbiology, UA/ Body Fluids, and Medical Biochemistry in the Clinical Laboratory Science Dept.
COPYRIGHT 2016 American Medical Technologists
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2016 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Article 426 .5 Clock Hour
Author:Maness, Lisa
Publication:Journal of Continuing Education Topics & Issues
Article Type:Report
Geographic Code:1USA
Date:Jan 1, 2016
Previous Article:Questions for STEP Participants.
Next Article:Questions for STEP Participants.

Terms of use | Privacy policy | Copyright © 2022 Farlex, Inc. | Feedback | For webmasters |