Pre-activated antiviral innate immunity in the upper airways controls early SARS-CoV-2 infection in children.

Children have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and a substantially lower risk for developing severe coronavirus disease 2019 compared with adults. However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n = 18) and age-matched SARS-CoV-2-positive (n = 24) children and corresponding samples from adults (n = 44), covering an age range of 4 weeks to 77 years. Children displayed higher basal expression of relevant pattern recognition receptors such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than in adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)+ cytotoxic T cells and a CD8+ T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral response to SARS-CoV-2 infection than in adults.

Rabies is still a fatal but neglected disease: a case report.

BACKGROUND: Rabies, caused by a lyssavirus, is a viral zoonosis that affects people in many parts of the world, especially those in low income countries. Contact with domestic animals, especially dogs, is the main source of human infections. Humans may present with the disease only after a long period of exposure. Nearly half of rabies cases occur in children <15 years old. We report on a fatal case of rabies in a Ghanaian school child 5 years after the exposure incident, and the vital role of molecular tools in the confirmation of the diagnosis. CASE PRESENTATION: The patient, an 11-year-old junior high school Ghanaian student from the Obuasi Municipality in Ghana, presented with aggressive behavior, which rapidly progressed to confusion and loss of consciousness within a day of onset. Her parents reported that the patient had experienced a bite from a stray dog on her right leg 5 years prior to presentation, for which no antirabies prophylaxis was given. The patient died within minutes of arrival in hospital (within 24 hours of symptom onset). Real-time polymerase chain reaction testing of cerebrospinal fluid obtained after her death confirmed the diagnosis of rabies. Subsequent phylogenetic analysis showed the virus to belong to the Africa 2 lineage of rabies viruses, which is one of the predominant circulating lineages in Ghana. CONCLUSION: The incubation period of rabies is highly variable so patients may only present with symptoms long after the exposure incident. Appropriate molecular testing tools, when available as part of rabies control programmes, are vital in confirming cases of rabies.

Molecular detection of cosaviruses in a patient with acute flaccid paralysis and in sewage samples in Germany.

Cosaviruses (CoSV) were first identified in stool samples collected from non-polio acute flaccid paralysis (AFP) cases and their healthy contacts in Pakistan in 2003. The clinical importance of CoSV remains unclear as data on epidemiology are scarce and no routine diagnostic testing is done. In this study, we characterized human CoSV (HCoSV) in a child with non-polio AFP and in sewage samples collected in Berlin, Germany. Using unbiased high-throughput sequencing and specific PCR, we characterized a HCoSV-D in stool samples of a three-year-old child hospitalized in Germany with non-polio AFP and travel history to Pakistan. The shedding pattern and absence of other relevant pathogens suggests that HCoSV-D may have been involved in the genesis of AFP. The HCoSV-RNA concentration was high, with 2.57 × 106 copies per mL fecal/suspension, decreasing in follow-up samples. To investigate the possibility of local circulation of HCoSV, we screened Berlin sewage samples collected between 2013 and 2018. Molecular testing of sewage samples has shown the presence of CoSV in several parts of the world, but until now not in Germany. Of our sewage samples, 54.3 % were positive for CoSV, with up to three viral species identified in samples. Phylogenetically, the German sequences clustered intermixed with sequences obtained globally. Together, these findings emphasize the need for further clinical, epidemiological, environmental, pathogenicity and phylogenetic studies of HCoSV.

[Coronaviruses as the cause of respiratory infections]. / Coronaviren als Ursache respiratorischer Infektionen.

BACKGROUND: There are six human pathogenic coronaviruses (CoV), which mainly cause infections of the respiratory system. In everyday clinical practice, it is helpful to know the relevance and characteristics of these pathogens. OBJECTIVE: To present the epidemiology, clinical picture and differences of human pathogenic CoV and to provide information on the diagnostics and treatment of patients suspected of having CoV infections. MATERIAL AND METHODS: Selective literature search, presentation of results and discussion of fundamental works and expert recommendations, including publications by the World Health Organization (WHO), the European Centre for Disease Prevention and Control (ECDC) and the Robert Koch Institute. RESULTS: The four endemic human CoVs (HCoV-NL63, HCoV-229E, HCoV-OC43 and HCoV-HKU1) mainly cause mild respiratory tract infections. In addition to these four endemic HCoV, the two epidemic CoV, severe acute respiratory syndrome (SARS)-CoV and Middle East respiratory syndrome (MERS)-CoV can cause severe pneumonia. The SARS-CoV has not been detected in humans in the last 15 years and MERS-CoV has been circulating mainly on the Arabian Peninsula since 2012; however, neither a specific treatment nor approved vaccines exist for any of the six human pathogenic CoVs. CONCLUSION: All six human CoVs can be diagnosed using RT-PCR on respiratory specimens but this is rarely necessary for the four endemic strains. In current clinical practice SARS-CoV has no importance as it has not been detected in humans for 15 years; however, a possible MERS-CoV infection should be taken into account in patients with typical symptoms and travel history to endemic regions. In this case, rapid diagnostic and general hygiene practices are important to prevent further transmission.

Similar virus spectra and seasonality in paediatric patients with acute respiratory disease, Ghana and Germany.

Epidemiological differences between tropical and temperate regions regarding viruses causing acute respiratory infection are poorly understood. This is in part because methodological differences limit the comparability of data from these two regions. Using identical molecular detection methods, we tested 1174 Ghanaian and 539 German children with acute respiratory infections sampled over 12 months for the 15 most common respiratory viruses by PCR. A total 43.2% of the Ghanaian and 56.6% of the German children tested positive for at least one respiratory virus. The pneumoviruses respiratory syncytial virus and human metapneumovirus were most frequently detected, in 13.1% and 25.1% within the Ghanaian and German children, respectively. At both study sites, pneumoviruses were more often observed at younger ages (p <0.001). In the Ghanaian rainy season, enveloped viruses were detected twice as often as non-enveloped viruses (prevalence rate ratio (PR) 2.0, 95% CI 1.7-2.4). In contrast, non-enveloped viruses were more frequent during the Ghanaian dry season (PR 0.6, 95% CI 0.4-0.8). In Germany, enveloped viruses were also more frequently detected during the relatively colder winter season (PR 1.6, 95% CI 1.2-2.1) and non-enveloped viruses during summer (PR 0.7, 95% CI 0.5-0.9). Despite a distance of about 5000 km and a difference of 44° latitude separating Germany and Ghana, virus spectra, age associations and seasonal fluctuation showed similarities between sites. Neither respiratory viruses overall, nor environmentally stable (non-enveloped) viruses in particular were more frequent in tropical Ghana. The standardization of our sampling and laboratory testing revealed similarities in acute respiratory infection virus patterns in tropical and temperate climates.

Unusual serological response to hepatitis E virus in plasma donors consistent with re-infection.

Hepatitis E virus (HEV)-positive plasma donations, identified by a plasma mini-pool screening approach, were analysed using serological methods for the presence of anti-HEV IgM and IgG. Avidity testing was performed on the IgG-reactive donations. Anti-HEV IgG with high avidity was observed in two donors together with high viral loads, but with the absence of anti-HEV IgM. These data are suggestive of re-infection in a small proportion of plasma donors, which has not previously been reported.

Specific detection by real-time reverse-transcription PCR assays of a novel avian influenza A(H7N9) strain associated with human spillover infections in China.

In response to a recent outbreak in China, detection assays for a novel avian influenza A(H7N9) virus need to be implemented in a large number of public health laboratories. Here we present real-time reverse-transcription polymerase chain reaction (RT-PCR) assays for specific detection of this virus, along with clinical validation data and biologically-safe positive controls.

Assays for laboratory confirmation of novel human coronavirus (hCoV-EMC) infections.

We present a rigorously validated and highly sensitive confirmatory real-time RT-PCR assay (1A assay) that can be used in combination with the previously reported upE assay. Two additional RT-PCR assays for sequencing are described, targeting the RdRp gene (RdRpSeq assay) and N gene (NSeq assay), where an insertion/deletion polymorphism might exist among different hCoV-EMC strains. Finally, a simplified and biologically safe protocol for detection of antibody response by immunofluorescence microscopy was developed using convalescent patient serum.

Detection of a novel human coronavirus by real-time reverse-transcription polymerase chain reaction.

We present two real-time reverse-transcription polymerase chain reaction assays for a novel human coronavirus (CoV), targeting regions upstream of the E gene (upE) or within open reading frame (ORF)1b, respectively. Sensitivity for upE is 3.4 copies per reaction (95% confidence interval (CI): 2.5­6.9 copies) or 291 copies/mL of sample. No cross-reactivity was observed with coronaviruses OC43, NL63, 229E, SARS-CoV, nor with 92 clinical specimens containing common human respiratory viruses. We recommend using upE for screening and ORF1b for confirmation.