Panspecies molecular assays detect viral pathogens missed by real-time PCR/reverse-transcriptase PCR among pneumonia patients, Sarawak, Malaysia.

BACKGROUND: In a year-long pneumonia etiology study conducted June 2017 to May 2018 in Sarawak, Malaysia, 599 patients' nasopharyngeal swab specimens were studied with real-time polymerase chain reaction (rPCR)/ reverse-transcription (rRT-PCR) assays for respiratory pathogens known to contribute to the high burden of lower respiratory tract infections. The study team sought to compare real-time assay results with panspecies conventional molecular diagnostics to compare sensitivities and learn if novel viruses had been missed. METHODS: Specimens were studied for evidence of adenovirus (AdV), enterovirus (EV) and coronavirus (CoV) with panspecies gel-based nested PCR/RT-PCR assays. Gene sequences of specimens positive by panspecies assays were sequenced and studied with the NCBI Basic Local Alignment Search Tool software. RESULTS: There was considerable discordance between real-time and conventional molecular methods. The real-time AdV assay found a positivity of 10.4%; however, the AdV panspecies assay detected a positivity of 12.4% and the conventional AdV-Hexon assay detected a positivity of 19.6%. The CoV and EV panspecies assays similarly detected more positive specimens than the real-time assays, with a positivity of 7.8% by the CoV panspecies assay versus 4.2% by rRT-PCR, and 8.0% by the EV panspecies assay versus 1.0% by rRT-PCR. We were not able to ascertain virus viability in this setting. While most discordance was likely due to assay sensitivity for previously described human viruses, two novel, possible zoonotic AdV were detected. CONCLUSIONS: The observed differences in the two modes of amplification suggest that where a problem with sensitivity is suspected, real-time assay results might be supplemented with panspecies conventional PCR/RT-PCR assays.

High Prevalence of Viral Infections Among Hospitalized Pneumonia Patients in Equatorial Sarawak, Malaysia.

BACKGROUND: Although pneumonia is a known cause of morbidity and mortality in Sarawak, Malaysia, the etiology and epidemiology of pneumonia are not well described in this equatorial region. Routine clinical diagnostics for pneumonia etiology at government hospitals in Sarawak had historically involved only bacterial diagnostics. Viral diagnostics were only obtained through outside consultations. METHODS: From June 15, 2017 to May 14, 2018, we collected nasopharyngeal swabs from 600 patients of all ages older than 1 month hospitalized with pneumonia at Sibu and Kapit Hospitals. Specimens were examined at our collaborating institutions with a panel of molecular assays for viral pathogens including influenza A (IAV), IBV, ICV, and IDV, human adenovirus (AdV), human enterovirus (EV), human coronavirus (CoV), respiratory syncytial virus subtype A (RSV-A) or RSV-B, and parainfluenza virus (PIV) types 1-4. RESULTS: Of 599 samples examined, 288 (48%) had molecular evidence of 1 or more respiratory viruses. Overall, the most prevalent virus detected was RSV-A (14.2%) followed by AdV (10.4%) and IAV (10.4%), then RSV-B (6.2%), EV (4.2%), IBV (2.2%), PIV-3 (1.7%), CoV (1.0%), PIV-1 (1.0%), PIV-4 (0.7%), and PIV-2 (0.2%). No specimens were confirmed positive for ICV or IDV. CONCLUSIONS: The high prevalence of viruses detected in this study suggest that respiratory viruses may be responsible for considerable morbidity in equatorial regions such as Sarawak. Access to viral diagnostics are very necessary for medical staff to determine appropriate pneumonia treatments.

Human enterovirus 71 disease in Sarawak, Malaysia: a prospective clinical, virological, and molecular epidemiological study.

BACKGROUND: Human enterovirus (HEV)-71 causes large outbreaks of hand-foot-and-mouth disease with central nervous system (CNS) complications, but the role of HEV-71 genogroups or dual infection with other viruses in causing severe disease is unclear. METHODS: We prospectively studied children with suspected HEV-71 (i.e., hand-foot-and-mouth disease, CNS disease, or both) over 3.5 years, using detailed virological investigation and genogroup analysis of all isolates. RESULTS: Seven hundred seventy-three children were recruited, 277 of whom were infected with HEV-71, including 28 who were coinfected with other viruses. Risk factors for CNS disease in HEV-71 included young age, fever, vomiting, mouth ulcers, breathlessness, cold limbs, and poor urine output. Genogroup analysis for the HEV-71-infected patients revealed that 168 were infected with genogroup B4, 68 with C1, and 41 with a newly emerged genogroup, B5. Children with HEV-71 genogroup B4 were less likely to have CNS complications than those with other genogroups (26 [15%] of 168 vs. 30 [28%] of 109; odds ratio [OR], 0.48; 95% confidence interval [CI], 0.26-0.91; P=.0223) and less likely to be part of a family cluster (12 [7%] of 168 vs. 29 [27%] of 109; OR, 0.21; 95% CI, 0.10-0.46; P<.0001); children with HEV-71 genogroup B5 were more likely to be part of a family cluster (OR, 6.26; 95% CI, 2.77-14.18; P<.0001). Children with HEV-71 and coinfected with another enterovirus or adenovirus were no more likely to have CNS disease. CONCLUSIONS: Genogroups of HEV-71 may differ with regard to the risk of causing CNS disease and the association with family clusters. Dual infections are common, and all possible causes should be excluded before accepting that the first virus identified is the causal agent.

Adenovirus type 21-associated acute flaccid paralysis during an outbreak of hand-foot-and-mouth disease in Sarawak, Malaysia.

We report the virological and clinical features of 8 children who presented with adenovirus-associated acute flaccid paralysis (AFP) during an epidemic of enterovirus type 71 (EV71)-associated hand-foot-and-mouth disease (HFMD) in Sarawak, Malaysia, in 1997. Neutralization tests and phylogenetic analysis revealed adenovirus type 21 (Ad21), although DNA restriction digests suggested that this virus was different from the prototype Ad21. Four children had upper-limb monoparesis, 2 had lower-limb monoparesis (one of whom had changes in the anterior spinal cord noted on magnetic resonance imaging), and 2 had flaccid paraparesis. At follow-up, 4 children were noted to have made full recoveries and 3 had residual flaccid weakness and wasting. Neurophysiological investigation revealed a mixture of axonal and demyelinating features in motor and sensory nerves, with denervation. These findings suggest that Ad21 might cause AFP by anterior horn cell damage or neuropathy of the brachial or lumbosacral plexus. The occurrence of these unusual adenovirus infections during an outbreak of EV71-associated HFMD suggests that an interaction between the 2 viruses may have occurred.