a total of 897 clinical specimens were collected from february 2007 to january 2008 and transported to the national influenza center .
two hundred and two samples belonged to children under the age of six from 897 specimens , described above , were selected .
then they were tested for influenza virus types and subtypes by real time pcr assay subsequently , the specimens were tested for rsv and hmpv by hemi - nested multiplex pcr and parainfluenza viruses type 14 by hemi - nested multiplex pcr and adenovirus by hemi - nested pcr .
the throat swab was taken from the kawasaki case with the history of chicken s contact .
the specimen was tested for all influenza subtypes especially h5n1 and the results were negative .
meanwhile pcr was done for screening of other respiratory viruses that results came out positive for rsv and hmpv .
in the present study , we demonstrated the possibility to detect dual infection caused by rsv and hmpv , but because of the extravagant pattern of this case , more investigation is suggested specially on kawasaki patients .
due to worldwide occurrence , substantial morbidity and mortality rates , respiratory viral infection which swiftly and easily spread , pose a serious public health problem ( 1 ) .
human metapneumovirus ( hmpv ) is one of the etiological agents of acute respiratory tract infections ( artis ) which can infect people in all age groups ( 2 ) .
it induces clinical symptoms ranging from upper to lower respiratory tract illnesses such as bronchiolitis , bronchitis and pneumonia ( 35 ) . in 2001 , hmpv was identified in samples from children with respiratory tract disease for the first time ( 6 ) .
in addition , it is a new member of the family paramyxoviridae , subfamily pneumovirus , genus metapneumovirus ( 7 ) .
rsv is one of the most important respiratory pathogens of childhood , with detection rates reaching 7085% in hospitalized infants during seasonal winter epidemics worldwide ( 1 , 8) .
rsv causes severe lower respiratory infections like bronchiolitis or pneumonia in infants and young children ( 9 ) .
coinfection of hmpv with rsv in infants has been suggested to be a factor that influences the severity of bronchiolitis ( 9 ) .
phylogenetically , rsv is the closest human virus related to hmpv , and the clinical manifestations of hmpv may share an overlapping spectrum with rsv , so that these two viruses can not be distinguished by clinical manifestations ( 4 , 7 , 9 , 10 ) . rsv and hmpv might have similar seasonal patterns , so co - infection is possible ( 6 , 9 ) .
this report describes a case who did not have the respiratory sign and symptoms , while was actually infected with rsv and hmpv simultaneously .
a 24 mo old girl , who was originally from tehran , capital of iran , was admitted to a pediatric hospital in tehran on 29 jan 2007 with a 2 wk history of fever and erythema of cheeks , lips , throat , and mouth since 4 d ago . in spite of treating with antipyretics ,
fever still was persistent . on physical examination , the vital signs were as follow : respiration , 22 breath / min ; pulse , 104 beats / min and temperature , 38 c. cardiac , abdominal , neurological and respiratory findings were normal .
laboratory findings were as follows : wbc count , 9.910/l ; rbc , 3.7710/l ; hb , 10.6 g / dl ; hct , 34.5% ; plt , 44310/l ; esr , 90 ; crp , + 1 ; wright / widal and salmonella para a / b , typhi d were negative .
, there was no problem and chest x ray was also normal . according to the findings , possible diagnosis was kawasaki syndrome and treatment with ivig , aspirin and acetaminophen was started .
after one day , fever was resolved but dry cough started at the day four of the admission . because of the history of contact with chickens and possibility of h5n1 , throat swab specimen of the patient was collected and sent to the national influenza center in tehran university of medical sciences for influenza surveillance .
the specimen was tested for influenza virus types and subtypes by real time pcr assay using cdc procedure , cdc real - time rt - pcr ( r.rt-pcr ) protocol for detection and characterization of influenza virus ( version.2007 ) , but the result was negative .
subsequently , as a part of a project , the specimen was tested for rsv and hmpv by hemi - nested multiplex pcr and parainfluenza viruses type 14 by hemi - nested multiplex pcr ( 11 ) , and adenovirus by hemi - nested pcr ( 12 ) . in our surprise positive results for rsv and hmpv were observed without any special respiratory sign and symptoms .
the test was repeated and the results were confirmed again . the nucleotide sequence of the pcr product of the detected hmpv ( the m gene fragment ) was submitted to genbank ( accession no .
in the present study , we demonstrated the possibility to detect dual infection which caused by rsv and hmpv . due to the lack of sensitivity of conventional methods detection of co - infections with
severe rsv bronchiolitis in small patient series had been recognized because of co - infection with other viral pathogens ( 14 ) .
some previous studies have lighted up increased clinical severity in case of dual infection caused by rsv and hmpv ( 8 , 9 ) .
greensill et al . observed a 70% co - infection rate with hmpv and rsv and a 90% co - infection rate among intubated infants with hmpv and rsv admitted to their picu ( 8) .
although greensill et al . did not include an appropriate control group in their study , these findings suggest that co - infection with both hmpv and rsv is common and that together the two viruses may contribute to increase the severity of disease ( 9 , 14 ) . whereas in other reports hmpv did not contribute to the severity of rsv infection ( 15 , 16 ) .
since severe rsv disease may develop in apparently healthy children , known host risk factors can not completely account for instances of severe illness .
preexisting or maternally acquired immunity , innate immunity , viral factors and genotypes and environment all likely contribute to disease pathogenesis .
we detected co - infection of hmpv and rsv in kawasaki patient without special respiratory sign and symptoms , we could not find the patient to follow up her and study more about the immunity status and other possibilities of this scenario .
all ethical issues including plagiarism , informed consent , misconduct , data fabrication and/or falsification , double publication and/or submission , redundancy , etc have been completely observed by the authors .
 background : respiratory virus infections in children are a leading cause of morbidity and mortality worldwide.methods:a total of 897 clinical specimens were collected from february 2007 to january 2008 and transported to the national influenza center . 
 two hundred and two samples belonged to children under the age of six from 897 specimens , described above , were selected . 
 then they were tested for influenza virus types and subtypes by real time pcr assay subsequently , the specimens were tested for rsv and hmpv by hemi - nested multiplex pcr and parainfluenza viruses type 14 by hemi - nested multiplex pcr and adenovirus by hemi - nested pcr.results:the throat swab was taken from the kawasaki case with the history of chicken s contact . 
 the specimen was tested for all influenza subtypes especially h5n1 and the results were negative . 
 meanwhile pcr was done for screening of other respiratory viruses that results came out positive for rsv and hmpv.conclusion:in the present study , we demonstrated the possibility to detect dual infection caused by rsv and hmpv , but because of the extravagant pattern of this case , more investigation is suggested specially on kawasaki patients . 
Background:
Methods:
Results:
Conclusion:
Introduction
Case report
Discussion
Ethical Considerations