ABSTRACT
Assessing the duration of humoral and cellular immunity remains key to overcome the current SARS-CoV-2 pandemic, especially in understudied populations in least developed countries. Sixty-four Cambodian individuals with laboratory-confirmed infection with asymptomatic or mild/moderate clinical presentation were evaluated for humoral immune response to the viral spike protein and antibody effector functions during acute phase of infection and at 6-9 months follow-up. Antigen-specific B cells, CD4+ and CD8+ T cells were characterized, and T cells were interrogated for functionality at late convalescence. Anti-spike (S) antibody titers decreased over time, but effector functions mediated by S-specific antibodies remained stable. S- and nucleocapsid (N)-specific B cells could be detected in late convalescence in the activated memory B cell compartment and are mostly IgG+. CD4+ and CD8+ T cell immunity was maintained to S and membrane (M) protein. Asymptomatic infection resulted in decreased ADCC and frequency of SARS-CoV-2-specific CD4+ T cells at late convalescence. Whereas anti-S antibodies correlated with S-specific B cells, there was no correlation between T cell response and humoral immunity. Hence, all aspects of a protective immune response are maintained up to nine months after SARS-CoV-2 infection in the absence of re-infection. One sentence summaryFunctional immune memory to SARS-CoV-2, consisting of polyfunctional antibodies, memory B cells and memory T cells are maintained up to nine months in a South-East Asian cohort in the absence of re-infection.
Subject(s)
Laboratory Infection , COVID-19ABSTRACT
Most human infectious viral diseases – including COVID-19 and Ebola – originated in animals. As the largest group of mammalian species, rodents are natural reservoirs for many diverse zoonotic viruses. Better understanding the core rodent virome will reduce the risk of future emergence or re-emergence of rodent-borne pathogens. A recent study focused on viruses found in the lungs of rodents in Mainland Southeast Asia, a hotspot for zoonotic emerging infectious diseases. Lung samples were collected from 3,284 rodents and insectivores throughout Thailand, Lao PDR, and Cambodia. Using metatranscriptomics, researchers outlined unique characteristics of the rodent viruses identified. Many mammalian- or arthropod-related viruses from distinct evolutionary lineages were reported for the first time, and viruses related to known pathogens were found. These results expand our understanding of the core virome in rodent species in Mainland Southeast Asia and suggest that a highly diverse array of viruses remains to be found in these species. Viral surveillance in wildlife hosts will minimize the impact of potential wildlife-originating infectious diseases.
Subject(s)
COVID-19 , ZoonosesABSTRACT
Knowledge of the origin and reservoir of the coronavirus responsible for the ongoing COVID-19 pandemic is still fragmentary. To date, the closest relatives to SARS-CoV-2 have been detected in Rhinolophus bats sampled in the Yunnan province, China. Here we describe the identification of SARS-CoV-2 related coronaviruses in two Rhinolophus shameli bats sampled in Cambodia in 2010. Metagenomic sequencing identified nearly identical viruses sharing 92.6% nucleotide identity with SARS-CoV-2. Most genomic regions are closely related to SARS-CoV-2, with the exception of a small region corresponding to the spike N terminal domain. The discovery of these viruses in a bat species not found in China indicates that SARS-CoV-2 related viruses have a much wider geographic distribution than previously understood, and suggests that Southeast Asia represents a key area to consider in the ongoing search for the origins of SARS-CoV-2, and in future surveillance for coronaviruses.
Subject(s)
COVID-19ABSTRACT
The challenges imposed by the ongoing outbreak of severe acute respiratory syndrome coronavirus-2 affects every aspect of our modern world, ranging from our health to our socio-economic needs. Our existence highly depends on the vaccine's availability, which demands in-depth research of the available strains and their mutations. In this work, we have analyzed all the available SERS-CoV2 genomes isolated from the Kingdom of Bahrain in terms of their variance and origin analysis. We have predicted various known and unique mutations in the SERS-CoV2 isolated from Bahrain. The complexity of the phylogenetic tree and dot plot representation of the strains mentioned above with other isolates of Asia indicates the versatility and multiple origins of Bahrain's SERS-CoV2 isolates. Our research could have a high impact on vaccine development and distinguishes the source of SERS-CoV2 in the Kingdom of Bahrain.
Subject(s)
Coronavirus InfectionsABSTRACT
Coronaviruses can become zoonotic as in the case of COVID-19, and hunting, sale, and consumption of wild animals in Southeast Asia facilitates an increased risk for such incidents. We sampled and tested rodents (851) and other mammals, and found Betacoronavirus RNA in 12 rodents. The sequences belong to two separate genetic clusters, and relate closely to known rodent coronaviruses detected in the region, and distantly to human coronaviruses OC43 and HKU1. Considering close human-wildlife contact with many species in and beyond the region, a better understanding of virus diversity is urgently needed for the mitigation of future risks.
Subject(s)
COVID-19ABSTRACT
Rapid production and publication of pathogen genome sequences during emerging disease outbreaks provide crucial public health information. In resource-limited settings, especially near an outbreak epicenter, conventional deep sequencing or bioinformatics are often challenging. Here we successfully used metagenomic next generation sequencing on an iSeq100 Illumina platform paired with an open-source bioinformatics pipeline to quickly characterize Cambodias first case of COVID-2019.