•The SARS epidemic drew attention to bats as major coronavirus hosts.•The known coronavirus genetic diversity is much higher in bats than in any other mammalian host.•Lack of bat coronavirus isolates ...and full genomes challenge taxonomic classification.•Viruses closely related to SARS-CoV, MERS-CoV and HCoV-229E exist in bats.•Mechanisms of putative host switches from bats into humans are unknown.
In 2002/2003, a novel coronavirus (CoV) caused a pandemic, infecting more than 8000 people, of whom nearly 10% died. This virus, termed severe acute respiratory syndrome-CoV was linked to a zoonotic origin from rhinolophid bats in 2005. Since then, numerous studies have described novel bat CoVs, including close relatives of the newly emerging Middle East respiratory syndrome (MERS)-CoV. In this paper we discuss CoV genomic properties and compare different taxonomic approaches in light of the technical difficulties of obtaining full genomic sequences directly from bat specimens. We first present an overview of the available studies on bat CoVs, with details on their chiropteran hosts, then comparatively analyze the increase in bat CoV studies and novel genomic sequences obtained since the SARS pandemic. We then conduct a comprehensive phylogenetic analysis of the genera Alpha- and Betacoronavirus, to show that bats harbour more CoV diversity than other mammalian hosts and are widely represented in most, but not all parts of the tree of mammalian CoVs. We next discuss preliminary evidence for phylogenetic co-segregation of CoVs and bat hosts encompassing the Betacoronavirus clades b and d, with an emphasis on the sampling bias that exists among bat species and other mammals, then present examples of CoVs infecting different hosts on the one hand and viruses apparently confined to host genera on the other. We also demonstrate a geographic bias within available studies on bat CoVs, and identify a critical lack of information from biodiversity hotspots in Africa, Asia and Latin America. We then present evidence for a zoonotic origin of four of the six known human CoVs (HCoV), three of which likely involved bats, namely SARS-CoV, MERS-CoV and HCoV-229E; compare the available data on CoV pathogenesis in bats to that in other mammalian hosts; and discuss hypotheses on the putative insect origins of CoV ancestors. Finally, we suggest caution with conclusions on the zoonotic potential of bat viruses, based only on genomic sequence data, and emphasize the need to preserve these ecologically highly relevant animals. This paper forms part of a symposium in Antiviral Research on “from SARS to MERS: 10years of research on highly pathogenic human coronaviruses”.
Potential zoonotic sources of SARS‐CoV‐2 infections Jo, Wendy K.; Oliveira‐Filho, Edmilson Ferreira; Rasche, Andrea ...
Transboundary and emerging diseases,
July 2021, Volume:
68, Issue:
4
Journal Article
Peer reviewed
Open access
The severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) causing coronavirus disease‐2019 (COVID‐19) likely has evolutionary origins in other animals than humans based on genetically related ...viruses existing in rhinolophid bats and pangolins. Similar to other animal coronaviruses, SARS‐CoV‐2 contains a functional furin cleavage site in its spike protein, which may broaden the SARS‐CoV‐2 host range and affect pathogenesis. Whether ongoing zoonotic infections are possible in addition to efficient human‐to‐human transmission remains unclear. In contrast, human‐to‐animal transmission can occur based on evidence provided from natural and experimental settings. Carnivores, including domestic cats, ferrets and minks, appear to be particularly susceptible to SARS‐CoV‐2 in contrast to poultry and other animals reared as livestock such as cattle and swine. Epidemiologic evidence supported by genomic sequencing corroborated mink‐to‐human transmission events in farm settings. Airborne transmission of SARS‐CoV‐2 between experimentally infected cats additionally substantiates the possibility of cat‐to‐human transmission. To evaluate the COVID‐19 risk represented by domestic and farmed carnivores, experimental assessments should include surveillance and health assessment of domestic and farmed carnivores, characterization of the immune interplay between SARS‐CoV‐2 and carnivore coronaviruses, determination of the SARS‐CoV‐2 host range beyond carnivores and identification of human risk groups such as veterinarians and farm workers. Strategies to mitigate the risk of zoonotic SARS‐CoV‐2 infections may have to be developed in a One Health framework and non‐pharmaceutical interventions may have to consider free‐roaming animals and the animal farming industry.
During 2015 to 2016, Brazil reported more Zika virus (ZIKV) cases than any other country, yet population exposure remains unknown. Serological studies of ZIKV are hampered by cross-reactive immune ...responses against heterologous viruses. We conducted serosurveys for ZIKV, dengue virus (DENV), and Chikungunya virus (CHIKV) in 633 individuals prospectively sampled during 2015 to 2016, including microcephaly and non-microcephaly pregnancies, HIV-infected patients, tuberculosis patients, and university staff in Salvador in northeastern Brazil using enzyme-linked immunosorbent assays (ELISAs) and plaque reduction neutralization tests. Sera sampled retrospectively during 2013 to 2015 from 277 HIV-infected patients were used to assess the spread of ZIKV over time. Individuals were georeferenced, and sociodemographic indicators were compared between ZIKV-positive and -negative areas and areas with and without microcephaly cases. Epidemiological key parameters were modeled in a Bayesian framework. ZIKV seroprevalence increased rapidly during 2015 to 2016, reaching 63.3% by 2016 (95% confidence interval CI, 59.4 to 66.8%), comparable to the seroprevalence of DENV (75.7%; CI, 69.4 to 81.1%) and higher than that of CHIKV (7.4%; CI, 5.6 to 9.8%). Of 19 microcephaly pregnancies, 94.7% showed ZIKV IgG antibodies, compared to 69.3% of 257 non-microcephaly pregnancies (
= 0.017). Analyses of sociodemographic data revealed a higher ZIKV burden in low socioeconomic status (SES) areas. High seroprevalence, combined with case data dynamics allowed estimates of the basic reproduction number
of 2.1 (CI, 1.8 to 2.5) at the onset of the outbreak and an effective reproductive number
of <1 in subsequent years. Our data corroborate ZIKV-associated congenital disease and an association of low SES and ZIKV infection and suggest that population immunity caused cessation of the outbreak. Similar studies from other areas will be required to determine the fate of the American ZIKV outbreak.
The ongoing American Zika virus (ZIKV) outbreak involves millions of cases and has a major impact on maternal and child health. Knowledge of infection rates is crucial to project future epidemic patterns and determine the absolute risk of microcephaly upon maternal ZIKV infection during pregnancy. For unknown reasons, the vast majority of ZIKV-associated microcephaly cases are concentrated in northeastern Brazil. We analyzed different subpopulations from Salvador, a Brazilian metropolis representing one of the most affected areas during the American ZIKV outbreak. We demonstrate rapid spread of ZIKV in Salvador, Brazil, and infection rates exceeding 60%. We provide evidence for the link between ZIKV and microcephaly, report that ZIKV predominantly affects geographic areas with low socioeconomic status, and show that population immunity likely caused cessation of the outbreak. Our results enable stakeholders to identify target populations for vaccination and for trials on vaccine efficacy and allow refocusing of research efforts and intervention strategies.
Dromedary camels are a putative source for human infections with Middle East respiratory syndrome coronavirus. We showed that camels sampled in different regions in Kenya during 1992-2013 have ...antibodies against this virus. High densities of camel populations correlated with increased seropositivity and might be a factor in predicting long-term virus maintenance.
Summary Background A new betacoronavirus—Middle East respiratory syndrome coronavirus (MERS-CoV)—has been identified in patients with severe acute respiratory infection. Although related viruses ...infect bats, molecular clock analyses have been unable to identify direct ancestors of MERS-CoV. Anecdotal exposure histories suggest that patients had been in contact with dromedary camels or goats. We investigated possible animal reservoirs of MERS-CoV by assessing specific serum antibodies in livestock. Methods We took sera from animals in the Middle East (Oman) and from elsewhere (Spain, Netherlands, Chile). Cattle (n=80), sheep (n=40), goats (n=40), dromedary camels (n=155), and various other camelid species (n=34) were tested for specific serum IgG by protein microarray using the receptor-binding S1 subunits of spike proteins of MERS-CoV, severe acute respiratory syndrome coronavirus, and human coronavirus OC43. Results were confirmed by virus neutralisation tests for MERS-CoV and bovine coronavirus. Findings 50 of 50 (100%) sera from Omani camels and 15 of 105 (14%) from Spanish camels had protein-specific antibodies against MERS-CoV spike. Sera from European sheep, goats, cattle, and other camelids had no such antibodies. MERS-CoV neutralising antibody titres varied between 1/320 and 1/2560 for the Omani camel sera and between 1/20 and 1/320 for the Spanish camel sera. There was no evidence for cross-neutralisation by bovine coronavirus antibodies. Interpretation MERS-CoV or a related virus has infected camel populations. Both titres and seroprevalences in sera from different locations in Oman suggest widespread infection. Funding European Union, European Centre For Disease Prevention and Control, Deutsche Forschungsgemeinschaft.
Here we propose a strategy allowing implementing efficient and practicable large-scale seroepidemiological studies for Zika Virus (ZIKV). It combines screening by a commercial NS1 protein-based Zika ...IgG ELISA, and confirmation by a cytopathic effect-based virus neutralization test (CPE-based VNT). In post-epidemic samples from Martinique Island blood donors (a population with a dengue seroprevalence above 90%), this strategy allowed reaching specificity and sensitivity values over 98%. The CPE-based VNT consists of recording CPE directly under the optical microscope, which is easy to identify with ZIKV strain H/PF/2013 at day 5 pi. Overall, considered that CPE-based VNT is cost effective and widely automatable, the NS1 protein-based Zika IgG ELISA+CPE-based VNT combination strategy represents a convenient tool to expedite ZIKV seroprevalence studies.
Viral emergence and immune interplay in flavivirus vaccines Fischer, Carlo; de Oliveira-Filho, Edmilson F; Drexler, Jan Felix
The Lancet infectious diseases,
January 2020, 2020-Jan, 2020-01-00, 20200101, Volume:
20, Issue:
1
Journal Article
Peer reviewed
Low titres might favour ADE, whereas high titres might provide cross-protection.7 Similarly, moderate titres of pre-existing antibodies against Japanese encephalitis virus were shown to prolong and ...increase viraemia in yellow fever vaccinees.5 Vaccination of individuals with CYD-TDV who have not been exposed to dengue virus before can increase their risk of severe disease when they are first exposed to dengue virus infection naturally.8 As a result, the WHO Strategic Advisory Group of Experts on Immunization recommended use of the vaccine only in individuals with pre-existing dengue virus immunity. In parallel, 23 million Brazilians are being vaccinated against yellow fever virus.1 The experiences from CYD-TDV trials and the magnitude of multitypic flavivirus infections in settings such as Brazil, suggest that determination of vaccine efficacy and safety in hyperendemic areas will be increasingly challenging.8 It seems likely that increasingly large numbers of individuals will have to be enrolled in vaccine trials, and long-term follow-ups will become necessary to identify severe adverse events and potential vaccination-related enhancement of subsequent flavivirus infections. ...new tests are urgently needed to determine flavivirus serological status, ideally suitable for point-of-care testing to allow approaches that pair screening with vaccination.12 However, the complexity of flaviviral immune interplay might require determination of other flaviviruses besides dengue, and at the very least semi-quantitative techniques including innovative tools for test interpretation that are currently entirely unavailable for point-of-care testing.
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