Identification and characterisation of SARS-CoV-2 and Human alphaherpesvirus 1 from a productive coinfection in a fatal COVID-19 case

BACKGROUND During routine Coronavirus disease 2019 (COVID-19) diagnosis, an unusually high viral load was detected by reverse transcription real-time polymerase chain reaction (RT-qPCR) in a nasopharyngeal swab sample collected from a patient with respiratory and neurological symptoms who rapidly succumbed to the disease. Therefore we sought to characterise the infection. OBJECTIVES We aimed to determine and characterise the etiological agent responsible for the poor outcome. METHODS Classical virological methods, such as plaque assay and plaque reduction neutralisation test combined with amplicon-based sequencing, as well as a viral metagenomic approach, were performed to characterise the etiological agents of the infection. FINDINGS Plaque assay revealed two distinct plaque phenotypes, suggesting either the presence of two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains or a productive coinfection of two different species of virus. Amplicon-based sequencing did not support the presence of any SARS-CoV-2 genetic variants that would explain the high viral load and suggested the presence of a single SARS-CoV-2 strain. Nonetheless, the viral metagenomic analysis revealed that Coronaviridae and Herpesviridae were the predominant virus families within the sample. This finding was confirmed by a plaque reduction neutralisation test and PCR. MAIN CONCLUSIONS We characterised a productive coinfection of SARS-CoV-2 and Herpes simplex virus 1 (HSV-1) in a patient with severe symptoms that succumbed to the disease. Although we cannot establish the causal relationship between the coinfection and the severity of the clinical case, this work serves as a warning for future studies focused on the interplay between SARS-CoV-2 and HSV-1 coinfection and COVID-19 severity.

A novel Betacoronavirus characterised in collared peccaries from the Rio de Janeiro Zoo (Brazil) killed by unknown disease

In an enclosure with nine collared peccaries (Pecari tajacu) from the Rio de Janeiro city Zoo, Brazil, one specimen was found dead and two others developed prostration, apathy and dehydration, resulting on its death. Necropsy of two animals pointed to pulmonary and renal damage. Histological examination revealed vasculitis in spleen from both P. tajacu, suggesting a systemic viral infection. Lungs from one specimen showed fibrinoid vasculitis, alveolar damage with hyaline membrane, and interstitial lymphocytes infiltration. Virome analysis in anal wash samples from the latter two animals revealed a new type of Betacoronavirus, lineage A, provisionally named Ptajacu-CoV.

Conservation of the α4ß7 lymphocyte homing receptor in HIV-infected patients with distinct transmission routes and disease progression profiles.

The α4ß7 is a lymphocyte homing receptor to the gut-associated lymphoid tissue (GALT). HIV-1 gp120 binds to α4ß7 integrin through a mimetic tripeptide in V2 and ensures successful infection of GALT. In the present report, we investigated the presence of polymorphisms in the α4ß7 cytoplasmic and α4 N-terminal binding domains and their potential association with susceptibility to HIV infection or disease progression. Subjects displaying distinct categories of disease progression or transmission routes (HIV-positive adults, vertically infected infants, and seronegative subjects) had their ITGA4 and ITGB7 gene segments corresponding to virus binding sites and C-terminal domains PCR amplified and sequenced. An absolute conservation of the studied regions was observed in all patients and controls. Albeit polymorphisms in α4ß7 may exist in other regions not tracked in this study, α4ß7 activation and binding domains do not seem to be polymorphic and are not correlated with distinct patterns of HIV transmission or disease progression.

Molecular evolution of α4 integrin binding site to lentiviral envelope proteins in new world primates.

Integrin epitopes encoded by ITGA4 exons 5 and 6 encompass the α4ß7 binding site to natural ligands and HIV-1 gp120. Functional assays of α4 variants of new world primates (NWP) showed reduced binding of several ligands, including the HIV-1 envelope, probably accounting for restriction phenotypes conferring resistance to lentiviral infection (Darc et al., 2011). In this paper, we have analyzed, by cloning and sequencing, the α4 domain polymorphisms present in 10 NWP species and four old world primates (including human). Analyses of differential selection at codon sites and along evolutionary lineages were carried out. We identified codons under positive selection, including polymorphic variations at codon 201, presumably convergent during NWP radiation and significant positive selection leading to a single allele (SagVar2).

Polymorphisms in the α4 integrin of neotropical primates: insights for binding of natural ligands and HIV-1 gp120 to the human α4ß7.

The α4 integrin subunit associates with ß7 and ß1 and plays important roles in immune function and cell trafficking. The gut-homing receptor α4ß7 has been recently described as a new receptor for HIV. Here, we describe polymorphisms of ITGA4 gene in New World primates (NWP), and tested their impact on the binding to monoclonal antibodies, natural ligands (MAdCAM and VCAM), and several gp120 HIV-1 envelope proteins. Genomic DNA of NWP specimens comprising all genera of the group had their exons 5 and 6 (encoding the region of binding to the ligands studied) analyzed. The polymorphisms found were introduced into an ITGA4 cDNA clone encoding the human α4 subunit. Mutant α4 proteins were co-expressed with ß7 and were tested for binding of mAbs, MAdCAM, VCAM and gp120 of HIV-1, which was compared to the wild-type (human) α4. Mutant α4 proteins harboring the K201E/I/N substitution had reduced binding of all ligands tested, including HIV-1 gp120 envelopes. The mAbs found with reduced biding included one from which a clinically-approved drug for the treatment of neurological disorders has been derived. α4 polymorphisms in other primate species may influence outcomes in the development and treatment of infectious and autoimmune diseases in humans and in non-human primates.