OBJECTIVES: We investigated the molecular epidemiology, demographic and clinical characteristics of HRVs among hospitalized children with ALRIs.
STUDY DESIGN: One hundred and sixty-five nasopharangeal aspirates taken from children <5 years hospitalized with ALRTIs in Serdang Hospital, Malaysia, were subject to reverse transcriptase-PCR for HRV. Phylogenetic analysis on VP4/VP2 and 5'-NCR regions was used to further characterize HRV. Other respiratory viruses were also investigated using semi-nested multiplex RT-PCR assay. Clinical parameters were analyzed between HRV, RSV and IFV-A mono-infections and between HRV species.
RESULTS: HRV was detected in 54 (33%) patients for both single (36 samples) and multiple (18 samples) infections, 61.1% (22/36) represents HRV-A strains while the remaining 14 HRV-C. Strain P51 was the first reported representative of HRV98. The majority of the single HRV cases were in the second half of infancy; HRV-C occurred among older children compared with HRV-A. HRV children were admitted significantly earlier and less febrile than RSV and IFV-A infection. HRV-C infected children were more likely to have rhonchi and vomiting as compared to HRV-A. Pneumonia was the most common discharge diagnosis followed by bronchiolitis and post-viral wheeze in HRV patients.
CONCLUSION: Our study showed high prevalence of HRVs and detection of HRV-C among hospitalized children with ALRTIs in Malaysia. Analysis of clinical parameters suggested specific features associated with HRVs infections and specific HRV groups.
METHODS: We collected a total of 125 bat flies from three Pteropus species (Pteropus vampyrus, P. hypomelanus, and P. lylei) from eight localities in Malaysia, Cambodia, and Vietnam. We identified specimens morphologically and then sequenced three mitochondrial DNA gene fragments (CoI, CoII, cytB; 1744 basepairs total) from a subset of 45 bat flies. We measured genetic diversity, molecular variance, and population genetic subdivision (FST), and used phylogenetic and haplotype network analyses to quantify parasite genetic structure across host species and localities.
RESULTS: All flies were identified as Cyclopodia horsfieldi with the exception of two individuals of Eucampsipoda sundaica. Low levels of population genetic structure were detected between populations of Cyclopodia horsfieldi from across a wide geographic range (~1000 km), and tests for isolation by distance were rejected. AMOVA results support a lack of geographic and host-specific population structure, with molecular variance primarily partitioned within populations. Pairwise FST values from flies collected from island populations of Pteropus hypomelanus in East and West Peninsular Malaysia supported predictions based on previous studies of host genetic structure.
CONCLUSIONS: The lack of population genetic structure and morphological variation observed in Cyclopodia horsfieldi is most likely due to frequent contact between flying fox species and subsequent high levels of parasite gene flow. Specifically, we suggest that Pteropus vampyrus may facilitate movement of bat flies between the three Pteropus species in the region. We demonstrate the utility of parasite genetics as an additional layer of information to measure host movement and interspecific host contact. These approaches may have wide implications for understanding zoonotic, epizootic, and enzootic disease dynamics. Bat flies may play a role as vectors of disease in bats, and their competence as vectors of bacterial and/or viral pathogens is in need of further investigation.