OBJECTIVES: To characterize FAdV isolates based on phylogenetic analysis, and to study the pathogenicity of FAdV-8b in specific-pathogen-free (SPF) chickens following virus inoculation via oral and intramuscular (IM) routes.
METHODS: Suspected organ samples were subjected to virus isolation and polymerase chain reaction (PCR) for FAdV detection. Hexon gene sequencing and phylogenetic analysis were performed on FAdV-positive samples for serotype identification. One FAdV-8b isolate, UPM/FAdV/420/2017, was selected for fiber gene characterization and pathogenicity study and was inoculated in SPF chickens via oral and IM routes.
RESULTS: The hexon gene phylogenetic analysis revealed that all isolates belonged to FAdV-8b. The fiber gene-based phylogenetic analysis of isolate UPM/FAdV/420/2017 supported the grouping of that isolate into FAdV species E. Pathogenicity study revealed that, chickens infected with UPM/FAdV/420/2017 via the IM route had higher clinical score values, higher percent mortality, higher degree of the liver lesions, higher antibody response (p < 0.05), and higher virus shedding amounts (p < 0.05) than those infected via the oral route. The highest virus copy numbers were detected in liver and gizzard.
CONCLUSIONS: FAdV-8b is the dominant FAdV serotype in Malaysia, and pathogenicity study of the FAdV-8b isolate UPM/FAdV/420/2017 indicated its ability to induce IBH in young SPF chickens when infected via oral or IM routes.
METHODOLOGY: Retrospective review of children under 12 years of age, admitted with HAdV pneumonia, between January 2011 and July 2013, in a single centre in Malaysia. HAdV isolated from nasopharyngeal secretions were typed by sequencing hypervariable regions 1-6 of the hexon gene. Patients were reviewed for respiratory complications.
RESULTS: HAdV was detected in 131 children of whom 92 fulfilled inclusion criteria. Median (range) age was 1.1 (0.1-8.0) years with 80% under 2 years. Twenty percent had severe disease with a case-fatality rate of 5.4%. Duration of admission (p = 0.02) was independently associated with severe illness. Twenty-two percent developed respiratory complications, the commonest being bronchiolitis obliterans (15.2%) and recurrent wheeze (5.4%). The predominant type shifted from HAdV1 and HAdV3 in 2011 to HAdV7 in 2013. The commonest types identified were types 7 (54.4%), 1(17.7%) and 3 (12.6%). Four out of the five patients who died were positive for HAdV7. Infection with type 7 (OR 8.90, 95% CI 1.32, 59.89), family history of asthma (OR 14.80, 95% CI 2.12-103.21) and need for invasive or non-invasive ventilation (OR 151.84, 95% CI 9.93-2.32E) were independent predictors of respiratory complications.
CONCLUSIONS: One in five children admitted with HAdV pneumonia had severe disease and 22% developed respiratory complications. Type 7 was commonly isolated in children with severe disease. Family history of asthma need for invasive or non-invasive ventilation and HAdV 7 were independent predictors of respiratory complications.
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.