82K / 166 – Surveillance for viral pathogens causing acute respiratory infections in remote Indigenous communities in Australia: a comparison of sample transport methods.

KFOGrady1, PJTorzillo2, TSloots3, RRockett3, SBLambert3.

1Menzies School of Health Research Child Health Division – Casuarina, Australia

2Royal Prince Alfred Hospital Department of Respiratory Medicine - Sydney, Australia

3Royal Childrens Hospital Queensland Paediatric Infectious Diseases Laboratory - Brisbane, Australia

Background

Acute respiratory infection rates in Aboriginal children in remote areas of Australia are amongst the highest reported worldwide. Surveillance programs and research are complicated by difficulties in the storage and transport of frozen samples to urban laboratories for testing. This study assessed the sensitivity of a simple method for transporting respiratory samples from a remote setting for viral PCR compared with frozen specimens.

Methods

We convenience sampled every individual who presented for any reason to a remote community (population ~ 580) clinic over a three week period in a non-epidemic respiratory season. Demographic data, reason for presentation, clinical signs and symptoms were obtained. Two anterior nasal swabs were collected from each participant using the Virocult® system. The L nare specimen was stored refrigerated and mailed to the laboratory via routine postal services (once a week by plane). The R nare specimen was stored and transported frozen. Testing for adenovirus, RSV, influenza virus, PIVs types 1,2 3, hMPV, RVs, hCoV (OC43, 229E,NL63 + HKU1), bocavirus, and KI and WUPyV was undertaken using real-time multiplex PCR methods.

Results

140 participants were enrolled who contributed 153 study visits; 82% percent were Aboriginal, 60% were female and 21% were aged less than five years. Respiratory illnesses accounted for 15% of the overall reported reasons for presentation, but a respiratory symptom was present in 74 (48.4%) of all visits. The prevalences of viruses tested to date in the 153 paired nasal specimens are presented in Table 1. With the exception of adenovirus (detected more frequently in mailed specimens, p=0.03), there were no differences in the proportion of other viruses detected in mailed specimens compared to frozen specimens (sensitivity L nare = 52.3%; R nare=45.5%, p=0.234). No respiratory illness was reported in 15 (62.5%) of the 24 episodes in which viruses were detected although a runny nose was present in 9 (60%) of these non-respiratory episodes.

Conclusions

Results to date suggest that mailing of unfrozen nasal specimens from remote communities does not compromise the viability of the specimen for viral studies.

Proposals for action

Aetiological studies and surveillance of respiratory viruses in remote regions can be conducted using simple collection, storage and transport methods. As acute respiratory illnesses are the major causes of childhood morbidity worldwide, more accurate assessment of disease at the community level is now feasible.

Table 1. Respiratory viruses detected in 153 paired nasal swabs by transport method

Virus / L nare only
(mailed)
n(%) / R nare only
(frozen)
n(%) / Both nares
n(%)
Rhinovirus / 4 (2.61) / 6 (3.92) / 10 (6.53)
Influenza A / 1 (0.01) / 0 / 0
Adenovirus / 5 (3.27) / 1 (0.01) / 0
WUPyV / 2 (1.31) / 2 (1.31) / 0
Total / 12 (7.84) / 9 (5.88) / 10 (6.53)