|Year : 2017 | Volume
| Issue : 1 | Page : 134-136
Trends of respiratory syncytial virus sub-types in children hospitalised at a tertiary care centre in Jaipur during 2012–2014
M Anjaneya Swamy1, Bharti Malhotra1, P V. Janardhan Reddy1, Jitendra Kumar Tiwari1, Neeraj Kumar1, Manohar Lal Gupta2
1 Department of Microbiology and Immunology, Advanced Basic Sciences and Clinical Research Laboratory (ICMR Grade-I Viral Diagnostics and Research Laboratory), Sawai ManSingh Medical College, Jaipur, Rajasthan, India
2 Department of Paediatrics Medicine, JK Lone Hospital, Sawai Man Singh Medical College, Jaipur, Rajasthan, India
|Date of Web Publication||16-Mar-2017|
Department of Microbiology and Immunology, Advanced Basic Sciences and Clinical Research Laboratory (ICMR Grade-I Viral Diagnostics and Research Laboratory), Sawai ManSingh Medical College, Jawaharlal Nehru Marg, Jaipur - 302 004, Rajasthan
Source of Support: None, Conflict of Interest: None
Respiratory syncytial virus (RSV) causes high mortality and morbidity in infants. The study was planned to determine the trends of RSV sub-types in hospitalised children. Nasopharyngeal aspirate and throat swabs were collected from the hospitalised children up to 5 years of age. Viral nucleic acid was extracted using easyMAG automated extraction system, and real-time reverse transcription polymerase chain reaction was performed. Total positivity for RSV was found to be 25.40%, predominantly for RSV B (20.03%), followed by RSV A (2.90%) and RSV AB mixed infections (2.47%). Palivizumab prophylaxis can be planned to be given to infants from post-monsoon to end of winter.
Keywords: Palivizumab, real-time reverse transcription polymerase chain reaction, Respiratory syncytial virus A, respiratory syncytial virus B
|How to cite this article:|
Swamy M A, Malhotra B, Reddy P V, Tiwari JK, Kumar N, Gupta ML. Trends of respiratory syncytial virus sub-types in children hospitalised at a tertiary care centre in Jaipur during 2012–2014. Indian J Med Microbiol 2017;35:134-6
|How to cite this URL:|
Swamy M A, Malhotra B, Reddy P V, Tiwari JK, Kumar N, Gupta ML. Trends of respiratory syncytial virus sub-types in children hospitalised at a tertiary care centre in Jaipur during 2012–2014. Indian J Med Microbiol [serial online] 2017 [cited 2018 Jan 21];35:134-6. Available from: http://www.ijmm.org/text.asp?2017/35/1/134/202323
| ~ Introduction|| |
Respiratory syncytial virus (RSV) is an important cause of acute respiratory infections (ARIs) in children; about 60% of children get infected with RSV by the 1st year and 100% by the 2nd year of life. As per the World Health Organization, RSV is responsible for 4 million deaths around the world annually in children <5 years of age. The virus is mostly seen in children with bronchiolitis and pneumonia. Repeated infections and yearly outbreaks of RSV possibly occur due to the antigenic variability of the virus which is a challenge for designing and development of vaccine. To optimise the prophylaxis, it is important to forecast the trends of RSV infection in a given area for better prevention and control.
| ~ Materials and Methods|| |
The study was conducted over a period of 28 months, i.e., between September 2012 and December 2014.
The study was carried out subsequent to clearance from the Institutional Ethics Committee vide letter no MC/EC/2011/227.
Sample collection and transportation
A total of 689 nasopharyngeal aspirates and throat swab samples were collected from patients of ARI by a trained technician, using sterile nylon flocked swabs, and placed in viral transport medium, labelled and transported on ice at the earliest to advanced research laboratory (ICMR Grade-I Virology Lab) of Sawai ManSingh Medical College, Jaipur, for further processing and storage of the samples.
Nucleic acid extraction
One hundred and ten microlitres of viral nucleic acid was extracted from 400 µl of sample using NucliSENS easyMAG automated nucleic acid extractor (BioMerieux) as per the manufacturer's instructions.
Real-time reverse transcription polymerase chain reaction
Initial screening for the presence of RSV was done using previously published primer probes for RSV by real-time reverse transcription polymerase chain reaction amplification  (synthesised by Applied Biosystems Inc., USA). Samples positive for RSV were retested separately for RSV A and RSV B on ABI 7500 fast (Applied Biosystems Inc., USA). The primer probe for sub-typing of RSV A and RSV B was synthesised (TIB MOL, from TIB MOLBIOL, Berlin, Germany) as per the published literature.
| ~ Results|| |
Six hundred and eighty-nine samples from hospitalised children of age ≤ 5 years were screened for possible RSV infection. The total positivity for RSV was found to be 175/689 (25.40%), 133/490 (27.14%) in males and 42/199 (21.10%) in females. RSV B was found positive in 20.03% (138/689) patients, RSV A in 2.90% (20/689) patients and RSV AB in 2.47% (17/689) patients. Correlation of RSVsub-types in relation to signs, symptoms and clinical syndromes is mentioned in [Table 1].
|Table 1: Correlation of Respiratory syncytial virus sub-types in relation to signs, symptoms and clinical syndromes|
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Age-wise distribution of Respiratory syncytial virus A, Respiratory syncytial virus B and Respiratory syncytial virus AB
The occurrence of RSV infections varied in different age groups. Maximum positivity was observed in age group 1–12 months (36.13%), which was statistically significant (P < 0.001) (Chi-square test), followed by 13–24 months age group (18.34%); very low positivity was found in other age groups (2.33%–8.82%).
Seasonal distribution of Respiratory syncytial virus A, Respiratory syncytial virus B and Respiratory syncytial virus AB
In the 1st year of the study from September 2012 to August 2013, the only circulating type of RSV was the RSV A with its peak in March 2013, at the end of winter season. In the 2nd year of study from September 2013 to August 2014, both the types and mixed infections, i.e., RSV A, RSV B and RSV AB, were found to be circulating. All the RSV types were found to be circulating mainly during winter months and post-monsoon season [Figure 1].
|Figure 1: Seasonal variations in Respiratory syncytial virus A and Respiratory syncytial virus B along with Respiratory syncytial virus AB mixed infection.|
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| ~ Discussion|| |
RSV is an important cause of mortality and morbidity requiring hospitalisation in the first few years of life. The present study was first to report the trends of RSV A and RSV B from Jaipur and Rajasthan in the hospitalised children ≤5 years of age. During the study period of 27 months, total positivity of RSV was found to be 25.40%. This is in correlation with an earlier study which reported a positivity of 26%. On RSV typing of positive samples in the present study, predominance of RSV B (78.85%) was observed as compared to RSV A and RSV AB mixed infections. This is consistent with an earlier Indian study from Delhi (64.44%) and other studies globally, from Malaysia (73.36%), Zagreb (83.60%) and Brazil (92.07%). A study from Kolkata (India) reported predominance of RSV B (95%) in the 1st year, which was replaced by RSV A (94.84%) in the consequent years of the study.
In the present study, RSV was positive predominantly (36.13%) in the hospitalised children <12 months of age. RSV is known to be an important cause of hospitalisation in children younger than 1 year of age. This may be due to low levels of immunity in infants.
In the present study, pneumonia was observed in 51.42% and bronchiolitis in 12.57% of RSV-positive patients. Earlier studies reported bronchiolitis in 47.1% to 82%, and pneumonia in 36.2%–76%, in RSV-positive patients. RSV B was the predominant RSV type detected in the present study in the hospitalised children of ≤5 years of age. RSV B was reported to be a more common cause of bronchiolitis and pneumonia than sub-type A.
During the 1st year of our study, only RSV A was the type of RSV circulating whereas, during the 2nd and 3rd year of the study, all the two types and mixed infections, i.e., RSV A, RSV B and RSV AB, were found to be co circulating. The exact reason for this variation in the circulation patterns of RSV during different years of the study is not known. Similarly co-circulation of RSV A and RSV B has been found in other studies from India and Germany with the predominance of RSV A sub-group.,
| ~ Conclusion|| |
RSV B was the most predominant type circulating in our area with co-circulation of RSV A and RSVAB. Peak positivity was seen in winters and lower positivity in post-monsoon season. Palivizumab can be planned to be given post-monsoon till winters are over. Only hospitalised patients were studied in present study which is a limitation but provides information on trends in serious patients and can provide guidance to plan prevention and control policies.
We acknowledge the financial support from the Indian Council of Medical Research to BM for setting up ICMR Grade-I Viral Research and Diagnostic Laboratory and Senior Research Fellowship to MAS.
Financial support and sponsorship
Financial support was provided by the Indian Council of Medical Research to BM for setting up ICMR Grade-I Viral Research and Diagnostic Laboratory and Senior Research Fellowship to MAS.
Conflicts of interest
There are no conflicts of interest.
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