Age-related susceptibility of ferrets to SARS-CoV-2 infection

Susceptibility to SARS-CoV-2 and the outcome of COVID-19 have been linked to underlying health conditions and the age of affected individuals. Here we assessed the effect of age on SARS-CoV-2 infection using a ferret model. For this, young (6-month-old) and aged (18-to-39-month-old) ferrets were inoculated intranasally with various doses of SARS-CoV-2. By using infectious virus shedding in respiratory secretions and seroconversion, we estimated that the infectious dose of SARS-CoV-2 in aged animals is ∼32 plaque forming units (PFU) per animal while in young animals it was estimated to be ∼100 PFU. We showed that viral replication in the upper respiratory tract and shedding in respiratory secretions is enhanced in aged ferrets when compared to young animals. Similar to observations in humans, this was associated with higher transcription levels of two key viral entry factors - ACE2 and TMPRSS2 - in the upper respiratory tract of aged ferrets. Importance In humans, ACE2 and TMPRSS2 are expressed in various cells and tissues, and a differential expression have been described in young and old people, with a higher level of expressing cells being detected in the nasal brushing of older people when compared to young individuals. We described the same pattern occurring in ferrets and we demonstrated that age affects susceptibility of ferrets to SARS-CoV-2. Aged animals were more likely to get infected when exposed to lower infectious dose of the virus when compared to young animals and the viral replication in the URT and shedding is enhanced in aged ferrets. Together these results suggest that the higher infectivity and enhanced ability of SARS-CoV-2 to replicate in aged individuals is associated – at least in part – with transcription levels of ACE2 and TMPRSS2 at the sites of virus entry. The young and aged ferret model developed here may represent a great platform to assess age-related differences in SARS-CoV-2 infection dynamics and replication.

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Effect of prophylactic use of intra-nasal oil formulations in the hamster model of Covid-19

10.1101/2021.06.25.449990 ◽

2021 ◽

Author(s):

Zaigham Abbas Rizvi ◽

Manas Ranjan Tripathy ◽

Nishant Sharma ◽

Sandeep Goswami ◽

N Srikanth ◽

...

Keyword(s):

Viral Load ◽

Respiratory Tract ◽

Viral Entry ◽

Body Weight Loss ◽

Lung Pathology ◽

Upper Respiratory Tract ◽

Hamster Model ◽

Reduced Body ◽

Upper Respiratory ◽

Prophylactic Use

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection initiates with viral entry in upper respiratory tract leading to coronavirus disease 2019 (Covid-19). Severe Covid-19 is characterized by pulmonary pathologies associated with respiratory failure. Thus, therapeutics aimed at inhibiting entry of the virus or its internalization in the upper respiratory tract, are of interest. Herein, we report the prophylactic application of two intra-nasal formulations provided by the National Medicinal Plant Board (NMPB), Anu oil and Til tailya in SARS-CoV2 infection hamster model. Prophylactic nasal instillation of these oil formulations exhibited reduced viral load in lungs, and resulted in reduced body weight loss and pneumonitis. In line with reduced viral load, histopathlogical analysis revealed a reduction in lung pathology in Anu oil group as compared to the control infected group. However, Til tailya group did not show a significant reduction in lung pathology. Furthermore, molecular analysis using mRNA expression profiling indicated reduced expression of pro-inflammatory cytokines genes, including Th1 and Th17 cytokines for both the intra-nasal formulations as a result of decreased viral load. Together, the prophylactic intra-nasal application of Annu oil seems to be useful in limiting both the viral load and disease severity disease in SARS-CoV2 infection in hamster model.

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Viremia and Nasal and Rectal Shedding of Rotavirus in Gnotobiotic Pigs Inoculated with Wa Human Rotavirus

Journal of Virology ◽

10.1128/jvi.79.9.5428-5436.2005 ◽

2005 ◽

Vol 79 (9) ◽

pp. 5428-5436 ◽

Cited By ~ 69

Author(s):

M. S. Azevedo ◽

L. Yuan ◽

K.-I. Jeong ◽

A. Gonzalez ◽

T. V. Nguyen ◽

...

Keyword(s):

Respiratory Tract ◽

Gastrointestinal Symptoms ◽

Upper Respiratory Tract ◽

Virus Shedding ◽

Diarrhea Virus ◽

Human Rotavirus ◽

Basolateral Side ◽

Gnotobiotic Pigs ◽

Upper Respiratory ◽

Tract Infections

ABSTRACT Respiratory symptoms with rotavirus shedding in nasopharyngeal secretions have been reported in children with and without gastrointestinal symptoms (Zheng et al., 1991, J. Med. Virol. 34:29-37). To investigate if attenuated and virulent human rotavirus (HRV) strains cause upper respiratory tract infections or viremia in gnotobiotic pigs, we inoculated them with attenuated or virulent HRV intranasally, intravenously, or orally or via feeding tube (gavage) and assayed virus shedding. After oral or intranasal inoculation with attenuated HRV, the pigs remained asymptomatic, but 79 to 95% shed virus nasally and 5 to 17% shed virus rectally. After inoculation by gavage, no pigs shed virus nasally or rectally, but all pigs seroconverted with antibodies to HRV. No viremia was detected through postinoculation day 10. Controls inoculated intranasally with nonreplicating rotavirus-like particles or mock inoculated did not shed virus. In contrast, 100% of pigs inoculated with virulent HRV (oral, intranasal, or gavage) developed diarrhea, shed virus nasally and rectally, and had viremia. The infectivity of sera from the viremic virulent HRV-inoculated pigs was confirmed by inoculating gnotobiotic pigs orally with pooled HRV-positive serum. Serum-inoculated pigs developed diarrhea and fecal and nasal virus shedding and seroconverted with serum and intestinal HRV antibodies. Pigs inoculated intravenously with serum or intestinal contents from the viremic virulent HRV-inoculated pigs developed diarrhea, virus shedding, and viremia, similar to the orally inoculated pigs. This study provides new evidence that virulent HRV causes transient viremia and upper respiratory tract infection in addition to gastrointestinal infection in gnotobiotic pigs, confirming previous reports of rotavirus antigenemia (Blutt et al., Lancet 362:1445-1449, 2003). Our data also suggest that intestinal infection might be initiated from the basolateral side of the epithelial cells via viremia. Additionally, virus shedding patterns indicate a different pathogenesis for attenuated versus virulent HRV.

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Virological assessment of hospitalized cases of coronavirus disease 2019

10.1101/2020.03.05.20030502 ◽

2020 ◽

Cited By ~ 100

Author(s):

Roman Wölfel ◽

Victor M. Corman ◽

Wolfgang Guggemos ◽

Michael Seilmaier ◽

Sabine Zange ◽

...

Keyword(s):

Respiratory Tract ◽

Virus Replication ◽

Acute Respiratory Tract Infection ◽

Rapid Decline ◽

Upper Respiratory Tract ◽

Virus Shedding ◽

Active Virus ◽

Virus Rna ◽

Upper Respiratory ◽

High Virus

Coronavirus disease 2019 (COVID-19) is an acute respiratory tract infection that emerged in late 20191,2. Initial outbreaks in China involved 13.8% cases with severe-, and 6.1% with critical courses3. This severe presentation corresponds to the usage of a virus receptor that is expressed predominantly in the lung2,4. By causing an early onset of severe symptoms, this same receptor tropism is thought to have determined pathogenicity but also aided the control of severe acute respiratory syndrome (SARS) in 20035. However, there are reports of COVID-19 cases with mild upper respiratory tract symptoms, suggesting a potential for pre- or oligosymptomatic transmission6-8. There is an urgent need for information on body site - specific virus replication, immunity, and infectivity. Here we provide a detailed virological analysis of nine cases, providing proof of active virus replication in upper respiratory tract tissues. Pharyngeal virus shedding was very high during the first week of symptoms (peak at 7.11 × 108 RNA copies per throat swab, day 4). Infectious virus was readily isolated from throat- and lung-derived samples, but not from stool samples in spite of high virus RNA concentration. Blood and urine never yielded virus. Active replication in the throat was confirmed by viral replicative RNA intermediates in throat samples. Sequence-distinct virus populations were consistently detected in throat- and lung samples of one same patient. Shedding of viral RNA from sputum outlasted the end of symptoms. Seroconversion occurred after 6-12 days, but was not followed by a rapid decline of viral loads. COVID-19 can present as a mild upper respiratory tract illness. Active virus replication in the upper respiratory tract puts prospects of COVID-19 containment in perspective.

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Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces viral shedding after SARS-CoV-2 D614G challenge in preclinical models

Science Translational Medicine ◽

10.1126/scitranslmed.abh0755 ◽

2021 ◽

pp. eabh0755

Author(s):

Neeltje van Doremalen ◽

Jyothi N. Purushotham ◽

Jonathan E. Schulz ◽

Myndi G. Holbrook ◽

Trenton Bushmaker ◽

...

Keyword(s):

Respiratory Tract ◽

Direct Contact ◽

Infectious Virus ◽

Rhesus Macaques ◽

Upper Respiratory Tract ◽

Preclinical Models ◽

Viral Loads ◽

Viral Shedding ◽

Nasal Swabs ◽

Upper Respiratory

ChAdOx1 nCoV-19/AZD1222 is an approved adenovirus-based vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently being deployed globally. Previous studies in rhesus macaques revealed that intramuscular vaccination with ChAdOx1 nCoV-19/AZD1222 provided protection against pneumonia but did not reduce shedding of SARS-CoV-2 from the upper respiratory tract. Here, we investigated whether intranasally administered ChAdOx1 nCoV-19 reduces detection of virus in nasal swabs after challenging vaccinated macaques and hamsters with SARS-CoV-2 carrying a D614G mutation in the spike protein. Viral loads in swabs obtained from intranasally vaccinated hamsters were decreased compared to control hamsters, and no viral RNA or infectious virus was found in lung tissue after a direct challenge or after direct contact with infected hamsters. Intranasal vaccination of rhesus macaques resulted in reduced virus concentrations in nasal swabs and a reduction in viral loads in bronchoalveolar lavage and lower respiratory tract tissue. Intranasal vaccination with ChAdOx1 nCoV-19/AZD1222 reduced virus concentrations in nasal swabs in two different SARS-CoV-2 animal models, warranting further investigation as a potential vaccination route for COVID-19 vaccines.

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Dynamic innate immune response determines susceptibility to SARS-CoV-2 infection and early replication kinetics

Journal of Experimental Medicine ◽

10.1084/jem.20210583 ◽

2021 ◽

Vol 218 (8) ◽

Author(s):

Nagarjuna R. Cheemarla ◽

Timothy A. Watkins ◽

Valia T. Mihaylova ◽

Bao Wang ◽

Dejian Zhao ◽

...

Keyword(s):

Respiratory Tract ◽

Viral Replication ◽

Innate Immune ◽

Airway Epithelial ◽

Upper Respiratory Tract ◽

Infectious Dose ◽

Interferon Stimulated Genes ◽

Upper Respiratory ◽

Early Replication

Initial replication of SARS-CoV-2 in the upper respiratory tract is required to establish infection, and the replication level correlates with the likelihood of viral transmission. Here, we examined the role of host innate immune defenses in restricting early SARS-CoV-2 infection using transcriptomics and biomarker-based tracking in serial patient nasopharyngeal samples and experiments with airway epithelial organoids. SARS-CoV-2 initially replicated exponentially, with a doubling time of ∼6 h, and induced interferon-stimulated genes (ISGs) in the upper respiratory tract, which rose with viral replication and peaked just as viral load began to decline. Rhinovirus infection before SARS-CoV-2 exposure accelerated ISG responses and prevented SARS-CoV-2 replication. Conversely, blocking ISG induction during SARS-CoV-2 infection enhanced viral replication from a low infectious dose. These results show that the activity of ISG-mediated defenses at the time of SARS-CoV-2 exposure impacts infection progression and that the heterologous antiviral response induced by a different virus can protect against SARS-CoV-2.

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SARS-CoV-2 Infections in mRNA Vaccinated Individuals are Biased for Viruses Encoding Spike E484K and Associated with Reduced Infectious Virus Loads that Correlate with Respiratory Antiviral IgG levels.

10.1101/2021.07.05.21259105 ◽

2021 ◽

Author(s):

Heba H Mostafa ◽

chun Huai Luo ◽

C. Paul Morris ◽

Maggie Li ◽

Nicholas J Swanson ◽

...

Keyword(s):

Cell Culture ◽

Respiratory Tract ◽

Large Scale ◽

Infectious Virus ◽

Time Frame ◽

Molecular Testing ◽

Upper Respiratory Tract ◽

Symptomatic Infection ◽

Viral Loads ◽

Upper Respiratory

Abstract Introduction COVID-19 large scale immunization in the US has been associated with infrequent breakthrough positive molecular testing. Whether a positive test is associated with a high viral RNA load, specific viral variant, recovery of infectious virus, or symptomatic infection is largely not known. Methods In this study, we identified 133 SARS-CoV-2 positive patients who had received two doses of either Pfizer-BioNTech (BNT162b2) or Moderna (mRNA-1273) vaccines, the 2nd of which was received between January and April of 2021. The positive samples were collected between January and May of 2021 with a time that extended from 2 to 100 days after the second dose. Samples were sequenced to characterize the whole genome and Spike protein changes and cycle thresholds that reflect viral loads were determined using a single molecular assay. Local SARS-CoV-2 IgG antibodies were examined using ELISA and specimens were grown on cell culture to assess the recovery of infectious virus as compared to a control unvaccinated cohort from a matched time frame. Results Of 133 specimens, 24 failed sequencing and yielded a negative or very low viral load on the repeat PCR. Of 109 specimens that were used for further genome analysis, 68 (62.4%) were from symptomatic infections, 11 (10.1%) were admitted for COVID-19, and 2 (1.8%) required ICU admission with no associated mortality. The predominant virus variant was the alpha (B.1.1.7), however a significant association between lineage B.1.526 and amino acid change S: E484K with positives after vaccination was noted when genomes were compared to a large control cohort from a matched time frame. A significant reduction of the recovery of infectious virus on cell culture as well as delayed time to the first appearance of cytopathic effect was accompanied by an increase in local IgG levels in respiratory samples of vaccinated individuals but upper respiratory tract IgG levels were not different between symptomatic or asymptomatic infections. Conclusions Vaccination reduces the recovery of infectious virus in breakthrough infections accompanied by an increase in upper respiratory tract local immune responses.

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Duration of infectiousness and correlation with RT-PCR cycle threshold values in cases of COVID-19, England, January to May 2020

Eurosurveillance ◽

10.2807/1560-7917.es.2020.25.32.2001483 ◽

2020 ◽

Vol 25 (32) ◽

Cited By ~ 43

Author(s):

Anika Singanayagam ◽

Monika Patel ◽

Andre Charlett ◽

Jamie Lopez Bernal ◽

Vanessa Saliba ◽

...

Keyword(s):

Viral Load ◽

Severe Acute Respiratory Syndrome ◽

Respiratory Tract ◽

Symptom Onset ◽

Infectious Virus ◽

Upper Respiratory Tract ◽

Threshold Values ◽

Rt Pcr ◽

Cycle Threshold ◽

Upper Respiratory

Severe acute respiratory syndrome coronavirus 2 viral load in the upper respiratory tract peaks around symptom onset and infectious virus persists for 10 days in mild-to-moderate coronavirus disease (n = 324 samples analysed). RT-PCR cycle threshold (Ct) values correlate strongly with cultivable virus. Probability of culturing virus declines to 8% in samples with Ct > 35 and to 6% 10 days after onset; it is similar in asymptomatic and symptomatic persons. Asymptomatic persons represent a source of transmissible virus.

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Effect of Prophylactic Use of Intranasal Oil Formulations in the Hamster Model of COVID-19

Frontiers in Pharmacology ◽

10.3389/fphar.2021.746729 ◽

2021 ◽

Vol 12 ◽

Author(s):

Zaigham Abbas Rizvi ◽

Manas Ranjan Tripathy ◽

Nishant Sharma ◽

Sandeep Goswami ◽

N Srikanth ◽

...

Keyword(s):

Viral Load ◽

Respiratory Tract ◽

Viral Entry ◽

Body Weight Loss ◽

Histopathological Analysis ◽

Lung Pathology ◽

Upper Respiratory Tract ◽

Hamster Model ◽

Reduced Body ◽

Upper Respiratory

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection initiates with viral entry in the upper respiratory tract, leading to coronavirus disease 2019 (COVID-19). Severe COVID-19 is characterized by pulmonary pathologies associated with respiratory failure. Thus, therapeutics aimed at inhibiting the entry of the virus or its internalization in the upper respiratory tract are of interest. Herein, we report the prophylactic application of two intranasal formulations provided by the National Medicinal Plant Board (NMPB), Anu oil and til tailya, in the hamster model of SARS-CoV-2 infection. Prophylactic intra-nasal instillation of these oil formulations exhibited reduced viral load in lungs and resulted in reduced body weight loss and lung-pneumonitis. In line with reduced viral load, histopathological analysis revealed a reduction in lung pathology in the Anu oil group as compared to the control infected group. However, the til tailya group did not show a significant reduction in lung pathology. Furthermore, molecular analysis using mRNA expression profiling indicated reduced expression of pro-inflammatory cytokine genes, including Th1 and Th17 cytokines for both the intranasal formulations as a result of decreased viral load. Together, the prophylactic intranasal application of Anu oil seems to be useful in limiting both viral load and severity in SARS-CoV2 infection in the hamster model.

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Shedding of infectious SARS-CoV-2 in symptomatic neonates, children and adolescents

10.1101/2020.04.27.20076778 ◽

2020 ◽

Cited By ~ 4

Author(s):

Arnaud G L’Huillier ◽

G Torriani ◽

F Pigny ◽

L Kaiser ◽

I Eckerle

Keyword(s):

Respiratory Tract ◽

Infectious Virus ◽

Virus Isolation ◽

Age Groups ◽

Low Frequency ◽

Nasopharyngeal Swab ◽

Upper Respiratory Tract ◽

Median Viral Load ◽

Acute Respiratory Diseases ◽

Upper Respiratory

AbstractChildren are underrepresented in COVID-19 case numbers, with most pediatric cases exhibiting limited severity, and do not seem to be major drivers of transmission, unlike for other respiratory viruses. That said, SARS-CoV-2 infects children across all age groups, and despite the high proportion of mild or asymptomatic infections, it would be naïve not to consider them as transmitters. To address this point we used cell culture to systematically assess the presence of cultivable SARS-CoV-2 in the upper respiratory tract in a cohort of our institution’s first 23 symptomatic neonates, children and teenagers with COVID-19 diagnosed by RT-PCR.Median age was 12.0 years (interquartile range [IQR 3.8–14.5], range 7 days-15.9 yrs). Most patients had an upper respiratory tract infection (n=13), followed by fever without source and pneumonia (each, n=2). Samples were collected at a median of 2 days (IQR 1–3) after symptom onset. Median viral load (VL) at time of diagnosis was 3.0×106 copies/ml (mean 4,4×108, IQR 6.9×103–4.4×108) from a nasopharyngeal swab (NPS).SARS-CoV-2 virus isolation was successful in 12/23 (52%) children after inoculating VeroE6 cells with a NPS specimen. SARS-CoV-2 isolation was determined by the presence of a typical cytopathic effect (CPE) and increased viral RNA in the supernatant. SARS-CoV-2 replication in all positive isolates (12/12) was confirmed by a second passage using new VeroE6 cells.Virus isolation was successful from NPS from all age groups, with a median initial VL of 1.7×108 copies/ml (mean 7.9×108, IQR 4.7×106–1.0×109) (Figure 1). The youngest patient that SARS-CoV-2 was isolated from was a 7-day old neonate. No correlation between disease presentation and success of virus isolation was observed.Our data show that initial VLs at diagnosis in symptomatic children is comparable to those in adults, and that symptomatic children of all ages shed infectious virus in early acute illness. Infectious virus isolation success was largely comparable to that of adults, although two specimens yielded an isolate at a lower VL (1.2×104 and 1.4×105 copies/ml) than what was observed in adults.SARS-CoV-2 shedding patterns of culture competent virus in symptomatic children resemble those observed in adults. Therefore, transmission of SARS-CoV-2 from children is plausible. Considering the relatively low frequency of infected children at this time, biological or other unknown factors could reduce transmission in this population. Both large serological investigations and systematic surveillance of acute respiratory diseases are needed to understand the role of children in this new pandemic.

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