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1.
J Infect Public Health ; 15(6): 628-630, 2022 Apr 28.
Article in English | MEDLINE | ID: covidwho-1873160

ABSTRACT

In the era of SARS-CoV-2 variants and COVID-19 vaccination, the duration of infectious viral shedding and isolation in post vaccine breakthrough infections is challenging and depends on disease severity. The current study described a case of SARS-CoV-2 Delta variant pneumonia requiring hospitalization. The patient received two doses of BNT162b2 COVID-19 vaccines, and he had positive SARS-CoV-2 viral cultures 12 days post symptom onset. The time between the second dose of vaccine and the breakthrough infection was 6 months. While immunosuppression is a known risk factor for prolonged infectious viral shedding, age and time between vaccination and breakthrough infection are important risk factors that warrant further studies.

2.
Journal of infection and public health ; 2022.
Article in English | EuropePMC | ID: covidwho-1842616

ABSTRACT

Background Rheumatic diseases patients receiving Rituximab had severe COVID-19 disease. Although they had impaired humoral immune responses following COVID-19 vaccine, they had preserved cellular immune responses. Waning of COVID-19 antibody responses was observed within six months post vaccination among immunocompromised patients. Recent reports showed fatal outcome of breakthrough SARS-CoV-2 infections among vaccinated high-risk rheumatic diseases patients receiving Rituximab. SAR-CoV-2 serological tests were not performed. Objective Evaluation of COVID-19 vaccine humoral responses and breakthrough infections among low risk fully vaccinated rheumatic patients during the Delta Variant Era. Methods A case series of 19 fully vaccinated patients with rheumatic diseases were followed to determine post vaccine SARS-CoV-2 neutralizing antibody titers and to monitor the development of breakthrough infections up to eight months post vaccine at our tertiary care center in Jeddah, Saudi Arabia from 1st April until 30th November 2021. Results The mean age of patients was 49 years old. 10% of patients were receiving Rituximab. 73% of patients had positive SARS-CoV-2 serological testing post second vaccine. Two mild breakthrough COVID-19 infections were diagnosed six months post second dose of vaccine. Patients were less than 65 years, did not receive Rituximab, did not have interstitial lung diseases and had positive post vaccine serological testing. Conclusions We demonstrated high SARS-CoV-2 neutralizing antibodies seroprevalence and self-limiting breakthrough infections in low risk rheumatic diseases patients during the Delta Era. Future studies are needed to study the outcome of rheumatic diseases patients in the Era of Omicron in view of viral immune escape responses.

3.
Sci Rep ; 12(1): 7005, 2022 04 29.
Article in English | MEDLINE | ID: covidwho-1830097

ABSTRACT

Camels gained attention since the discovery of MERS-CoV as intermediary hosts for potentially epidemic zoonotic viruses. DcHEV is a novel zoonotic pathogen associated with camel contact. This study aimed to genetically characterize DcHEV in domestic and imported camels in Saudi Arabia. DcHEV was detected by RT-PCR in serum samples, PCR-positive samples were subjected to sequencing and phylogenetic analyses. DcHEV was detected in 1.77% of samples with higher positivity in domestic DCs. All positive imported dromedaries were from Sudan with age declining prevalence. Domestic DcHEV sequences clustered with sequences from Kenya, Somalia, and UAE while imported sequences clustered with one DcHEV isolate from UAE and both sequences clustered away from isolates reported from Pakistan. Full-genome sequences showed 24 amino acid difference with reference sequences. Our results confirm the detection of DcHEV in domestic and imported DCs. Further investigations are needed in human and camel populations to identify DcHEV potential zoonosis threat.


Subject(s)
Coronavirus Infections , Hepatitis E virus , Animals , Camelus , Coronavirus Infections/epidemiology , Coronavirus Infections/veterinary , Genetic Variation , Hepatitis E virus/genetics , Phylogeny , Saudi Arabia/epidemiology
4.
Diagnostics ; 12(4):828, 2022.
Article in English | MDPI | ID: covidwho-1762241

ABSTRACT

Background: The global pandemic coronavirus SARS-CoV-2 has a healthcare, social and economic burden. To limit the spread of the virus, the World Health Organization (WHO) urgently called for extensive screening of suspected individuals;thus, a quick, simple, and sensitive diagnostic assay is always in need. Methods: We applied reverse transcription-loop-mediated isothermal amplification (RT-LAMP) for the detection of SARS-CoV-2. The RT-LAMP method was optimized by evaluating two fluorescence amplification mixes and several reaction times, and results were compared to the standard real-time RT-PCR (rtRT-PCR). The assay was validated using 200 nasopharyngeal swabs collected in viral transport media (62 positive for SARS-CoV-2, and 138 negative for SARS-CoV-2 detected by the rtRT-PCR method). The samples were diluted 1:4 in diethylpyrocarbonate (DEPC)-treated water, utilized for RT-LAMP using different singleplex and multiplex sets of LAMP primers (N gene, S gene, and orf1ab gene), and incubated at 65 °C using real-time PCR 7500. Results: Our direct detection with the RT-LAMP protocol showed 100% concordance (sensitivity and specificity) with the standard protocol used for the detection of SARS-CoV-2 nucleic acid. Conclusions: In this study, we set up a rapid, simple, and sensitive RT-LAMP assay for the detection of SARS-CoV-2 in clinical samples. The assay is suitable for point of care detection in public hospitals, medical centers in rural areas, and in transportation hubs.

5.
IEEE Trans Nanobioscience ; PP2022 Mar 02.
Article in English | MEDLINE | ID: covidwho-1722945

ABSTRACT

Traditional molecular techniques for SARS-CoV-2 viral detection are time-consuming and can exhibit a high probability of false negatives. In this work, we present a computational study of SARS-CoV-2 detection using plasmonic gold nanoparticles. The resonance wavelength of a SARS-CoV-2 virus was recently estimated to be in the near-infrared region. By engineering gold nanospheres to specifically bind with the outer surface of the SARS-CoV-2 virus, the resonance frequency can be shifted to the visible range (380 nm - 700 nm). Moreover, we show that broadband absorption will emerge in the visible spectrum when the virus is partially covered with gold nanoparticles at a specific coverage percentage. This broadband absorption can be used to guide the development of an efficient and accurate colorimetric plasmon sensor for COVID-19 detection. Our observation also suggests that this technique is unaffected by the number of protein spikes present on the virus outer surface, hence can pave a potential path for a label-free COVID-19 diagnostic tool independent of the number of protein spikes.

6.
Int J Infect Dis ; 108: 112-115, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1351691

ABSTRACT

BACKGROUND: Immunocompromised patients with coronavirus disease 2019 (COVID-19) have prolonged infectious viral shedding for more than 20 days. A test-based approach is suggested for de-isolation of these patients. METHODS: The strategy was evaluated by comparing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load (cycle threshold (Ct) values) and viral culture at the time of hospital discharge in a series of 13 COVID-19 patients: six immunocompetent and seven immunocompromised (five solid organ transplant patients, one lymphoma patient, and one hepatocellular carcinoma patient). RESULTS: Three of the 13 (23%) patients had positive viral cultures: one patient with lymphoma (on day 16) and two immunocompetent patients (on day 7 and day 11). Eighty percent of the patients had negative viral cultures and had a mean Ct value of 20.5. None of the solid organ transplant recipients had positive viral cultures. CONCLUSIONS: The mean Ct value for negative viral cultures was 20.5 in this case series of immunocompromised patients. Unlike those with hematological malignancies, none of the solid organ transplant patients had positive viral cultures. Adopting the test-based approach for all immunocompromised patients may lead to prolonged quarantine. Large-scale studies in disease-specific populations are needed to determine whether a test-based approach versus a symptom-based approach or a combination is applicable for the de-isolation of various immunocompromised patients.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Immunocompromised Host , Quarantine , Virus Shedding
7.
Vox Sang ; 116(6): 673-681, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1319364

ABSTRACT

BACKGROUND AND OBJECTIVES: During the ongoing pandemic of COVID-19, SARS-CoV-2 RNA was detected in plasma and platelet products from asymptomatic blood donors, raising concerns about potential risk of transfusion transmission, also in the context of the current therapeutic approach utilizing plasma from convalescent donors. The objective of this study was to assess the efficacy of amotosalen/UVA light treatment to inactivate SARS-CoV-2 in human plasma to reduce the risk of potential transmission through blood transfusion. METHODS: Pools of three whole-blood-derived human plasma units (630-650 ml) were inoculated with a clinical SARS-CoV-2 isolate. Spiked units were treated with amotosalen/UVA light (INTERCEPT Blood System™) to inactivate SARS-CoV-2. Infectious titres and genomic viral load were assessed by plaque assay and real-time quantitative PCR. Inactivated samples were subject to three successive passages on permissive tissue culture to exclude the presence of replication-competent viral particles. RESULTS: Inactivation of infectious viral particles in spiked plasma units below the limit of detection was achieved by amotosalen/UVA light treatment with a mean log reduction of >3·32 ± 0·2. Passaging of inactivated samples on permissive tissue showed no viral replication even after 9 days of incubation and three passages, confirming complete inactivation. The treatment also inhibited NAT detection by nucleic acid modification with a mean log reduction of 2·92 ± 0·87 PFU genomic equivalents. CONCLUSION: Amotosalen/UVA light treatment of SARS-CoV-2 spiked human plasma units efficiently and completely inactivated >3·32 ± 0·2 log of SARS-CoV-2 infectivity, showing that such treatment could minimize the risk of transfusion-related SARS-CoV-2 transmission.


Subject(s)
Furocoumarins/pharmacology , Plasma/virology , SARS-CoV-2/drug effects , SARS-CoV-2/radiation effects , Ultraviolet Therapy , Virus Inactivation , COVID-19/prevention & control , COVID-19/transmission , Humans , Transfusion Reaction/prevention & control , Treatment Outcome
8.
Int J Infect Dis ; 110: 267-271, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1313161

ABSTRACT

Immunocompromised patients who have a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection pose many clinical and public health challenges. We describe the case of a hematopoietic stem cell transplantation patient with lymphoma who had a protracted illness requiring three consecutive hospital admissions. Whole genome sequencing confirmed two different SARS-CoV-2 clades. Clinical management issues and the unanswered questions arising from this case are discussed.


Subject(s)
COVID-19 , Hematopoietic Stem Cell Transplantation , Humans , Reinfection , SARS-CoV-2 , Virus Shedding
9.
Diagnostics (Basel) ; 11(6)2021 May 30.
Article in English | MEDLINE | ID: covidwho-1256438

ABSTRACT

The unusual cases of pneumonia outbreak were reported from Wuhan city in late December 2019. Serological testing provides a powerful tool for the identification of prior infection and for epidemiological studies. Pseudotype virus neutralization assays are widely used for many viruses and applications in the fields of serology. The accuracy of pseudotype neutralizing assay allows for its use in low biosafety lab and provides a safe and effective alternative to the use of wild-type viruses. In this study, we evaluated the performance of this assay compared to the standard microneutralization assay as a reference. The lentiviral pseudotype particles were generated harboring the Spike gene of SARS-CoV-2. The generated pseudotype particles assay was used to evaluate the activity of neutralizing antibodies in 300 human serum samples from a COVID-19 sero-epidemiological study. Testing of these samples resulted in 55 positive samples and 245 negative samples by pseudotype viral particles assay while microneutralization assay resulted in 64 positive and 236 negative by MN assay. Compared to the MN, the pseudotyped viral particles assay showed a sensitivity of 85.94% and a specificity of 100%. Based on the data generated from this study, the pseudotype-based neutralization assay showed a reliable performance for the detection of neutralizing antibodies against SARS-CoV-2 and can be used safely and efficiently as a diagnostic tool in a biosafety level 2 laboratory.

10.
Diagnostics (Basel) ; 11(5)2021 May 02.
Article in English | MEDLINE | ID: covidwho-1223965

ABSTRACT

A few months ago, the availability of a reliable and cost-effective testing capacity for COVID-19 was a concern for many countries. With the emergence and circulation of new SARS-CoV-2 variants, another layer of challenge can be added for COVID-19 testing at both molecular and serological levels. This is particularly important for the available tests principally designed to target the S gene/protein where multiple mutations have been reported. Herein, the SARS-CoV-2 NP recombinant protein was utilized to develop a simple and reliable COVID-19 NP human IgG ELISA. The optimized protocol was validated against a micro-neutralization (MN) assay, in-house S-based ELISA, and commercial chemiluminescence immunoassay (CLIA). The developed assay provides 100% sensitivity, 98.9% specificity, 98.9% agreement, and high overall accuracy with an area under curve equal to 0.9998 ± 0.0002 with a 95% confidence interval of 0.99 to 1.00. The optical density values of positive samples significantly correlated with their corresponding MN titers. The assay specifically detects IgG antibodies to the SARS-CoV-2 NP protein and does not cross-detect IgG to the viral S protein. Moreover, it does not cross-react with antibodies related to other coronaviruses (e.g., the Middle East respiratory syndrome coronavirus or human coronavirus HKU1). The availability of this reliable COVID-19 NP IgG ELISA protocol is highly valuable for its diagnostic and epidemiological applications.

11.
Emerg Infect Dis ; 27(5)2021 05.
Article in English | MEDLINE | ID: covidwho-1200875

ABSTRACT

Understanding the immune response to Middle East respiratory syndrome coronavirus (MERS-CoV) is crucial for disease prevention and vaccine development. We studied the antibody responses in 48 human MERS-CoV infection survivors who had variable disease severity in Saudi Arabia. MERS-CoV-specific neutralizing antibodies were detected for 6 years postinfection.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Animals , Antibody Formation , Camelus , Coronavirus Infections/epidemiology , Humans , Saudi Arabia/epidemiology
12.
Mikrochim Acta ; 188(4): 137, 2021 03 25.
Article in English | MEDLINE | ID: covidwho-1148895

ABSTRACT

The novel corona (SARS-CoV-2) virus causes a global pandemic, which motivates researchers to develop reliable and effective methods for screening and detection of SARS-CoV-2. Though there are several methods available for the diagnosis of SARS-CoV-2 such as RT-PCR and ELSIA, nevertheless, these methods are time-consuming and may not apply at the point of care. In this study, we have developed a specific, sensitive, quantitative and fast detection method for SARS-CoV-2 by fluorescence resonance energy transfer (FRET) assay. The total extracellular protease proteolytic activity from the virus has been used as the biomarker. The specific peptide sequences from the library of 115 dipeptides were identified via changes in the fluorescence signal. The fluorogenic dipeptide substrates have the fluorophore and a quencher at the N- and the C- terminals, respectively. When the protease hydrolyzes the peptide bond between the two specific amino acids, it leads to a significant increase in the fluorescence signals. The specific fluorogenic peptide (H-d) produces a high fluorescence signal. A calibration plot was obtained from the changes in the fluorescence intensity against the different concentrations of the viral protease. The lowest limit of detection of this method was 9.7 ± 3 pfu/mL. The cross-reactivity of the SARS-CoV-2-specific peptide was tested against the MERS-CoV which does not affect the fluorescence signal. A significant change in the fluorescence signal with patient samples indicates that this FRET-based assay might be applied for the diagnosis of SARS-CoV-2 patients. Graphical abstract.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Coronavirus 3C Proteases/metabolism , Fluorescent Dyes/metabolism , Peptides/metabolism , SARS-CoV-2 , Viral Proteins/metabolism , Animals , Biological Assay , COVID-19/microbiology , Chlorocebus aethiops , Fluorescence Resonance Energy Transfer , Humans , Peptide Library , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Vero Cells , Viral Plaque Assay
13.
Pathogens ; 10(3)2021 Mar 08.
Article in English | MEDLINE | ID: covidwho-1143550

ABSTRACT

The aim of our study was to define the spectrum of viral infections in pilgrims with acute respiratory tract illnesses presenting to healthcare facilities around the holy places in Makkah, Saudi Arabia during the 2019 Hajj pilgrimage. During the five days of Hajj, a total of 185 pilgrims were enrolled in the study. Nasopharyngeal swabs (NPSs) of 126/185 patients (68.11%) tested positive for one or more respiratory viruses by PCR. Among the 126 pilgrims whose NPS were PCR positive: (a) there were 93/126 (74%) with a single virus infection, (b) 33/126 (26%) with coinfection with more than one virus (up to four viruses): of these, 25/33 cases had coinfection with two viruses; 6/33 were infected with three viruses, while the remaining 2/33 patients had infection with four viruses. Human rhinovirus (HRV) was the most common detected viruses with 53 cases (42.06%), followed by 27 (21.43%) cases of influenza A (H1N1), and 23 (18.25%) cases of influenza A other than H1N1. Twenty-five cases of CoV-229E (19.84%) were detected more than other coronavirus members (5 CoV-OC43 (3.97%), 4 CoV-HKU1 (3.17%), and 1 CoV-NL63 (0.79%)). PIV-3 was detected in 8 cases (6.35%). A single case (0.79%) of PIV-1 and PIV-4 were found. HMPV represented 5 (3.97%), RSV and influenza B 4 (3.17%) for each, and Parechovirus 1 (0.79%). Enterovirus, Bocavirus, and M. pneumoniae were not detected. Whether identification of viral nucleic acid represents nasopharyngeal carriage or specific causal etiology of RTI remains to be defined. Large controlled cohort studies (pre-Hajj, during Hajj, and post-Hajj) are required to define the carriage rates and the specific etiology and causal roles of specific individual viruses or combination of viruses in the pathogenesis of respiratory tract infections in pilgrims participating in the annual Hajj. Studies of the specific microbial etiology of respiratory track infections (RTIs) at mass gathering religious events remain a priority, especially in light of the novel SARS-CoV-2 pandemic.

14.
Open Heart ; 8(1)2021 03.
Article in English | MEDLINE | ID: covidwho-1136107

ABSTRACT

OBJECTIVES: The clinical impact of SARS-CoV-2 has varied across countries with varying cardiovascular manifestations. We review the cardiac presentations, in-hospital outcomes and development of cardiovascular complications in the initial cohort of SARS-CoV-2 positive patients at Imperial College Healthcare National Health Service Trust, UK. METHODS: We retrospectively analysed 498 COVID-19 positive adult admissions to our institute from 7 March to 7 April 2020. Patient data were collected for baseline demographics, comorbidities and in-hospital outcomes, especially relating to cardiovascular intervention. RESULTS: Mean age was 67.4±16.1 years and 62.2% (n=310) were male. 64.1% (n=319) of our cohort had underlying cardiovascular disease (CVD) with 53.4% (n=266) having hypertension. 43.2%(n=215) developed acute myocardial injury. Mortality was significantly increased in those patients with myocardial injury (47.4% vs 18.4%, p<0.001). Only four COVID-19 patients had invasive coronary angiography, two underwent percutaneous coronary intervention and one required a permanent pacemaker implantation. 7.0% (n=35) of patients had an inpatient echocardiogram. Acute myocardial injury (OR 2.39, 95% CI 1.31 to 4.40, p=0.005) and history of hypertension (OR 1.88, 95% CI 1.01 to 3.55, p=0.049) approximately doubled the odds of in-hospital mortality in patients admitted with COVID-19 after other variables had been controlled for. CONCLUSION: Hypertension, pre-existing CVD and acute myocardial injury were associated with increased in-hospital mortality in our cohort of COVID-19 patients. However, only a low number of patients required invasive cardiac intervention.


Subject(s)
COVID-19/epidemiology , Cardiovascular Diseases/epidemiology , Pandemics , Aged , Comorbidity , Female , Hospital Mortality/trends , Humans , Incidence , London , Male , RNA, Viral/analysis , Retrospective Studies , SARS-CoV-2/genetics , Survival Rate/trends
15.
Healthcare (Basel) ; 9(1)2021 Jan 05.
Article in English | MEDLINE | ID: covidwho-1011456

ABSTRACT

In response to the coronavirus disease 2019 (COVID-19), Saudi Arabia have imposed timely restrictions to minimize the infection spread, lower the risk for vulnerable groups, and reduce the pressure on healthcare services. The effectiveness of these measures has not been assessed comprehensively and, thereby, remains uncertain. Besides monitoring the number of COVID-19 cases diagnosed by molecular assays, the seroprevalence can serve as an indicator for the incidence rate among the general population. This study aimed to evaluate seroprevalence status of all healthy blood donors who attended one of the main largest hospital located in the western region of Saudi Arabia from 1 January to 31 May 2020. The study period covered two months prior to reporting the first COVID-19 case in the country on 2 March 2020. Importantly, it covered the period when "lock-down type" measures have been enforced. Samples were subjected to in-house enzyme-linked immunosorbent assay (ELISA), chemiluminescence immunoassay (CLIA), and microneutralization (MN). The sero statuses of all samples were confirmed negative, demonstrating the lack of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among blood donors during COVID-19 lockdown period. This study supports the hypothesis that COVID-19 restrictions have potential for limiting the extent of the infection.

16.
Healthcare (Basel) ; 9(1)2021 Jan 04.
Article in English | MEDLINE | ID: covidwho-1011452

ABSTRACT

INTRODUCTION: the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of acute respiratory disease (COVID-19). SARS-CoV-2 is a positive-strand RNA virus and its genomic characterization has played a vital role in the design of appropriate diagnostics tests. The current RT-PCR protocol for SARS-CoV-2 detects two regions of the viral genome, requiring RNA extraction and several hours. There is a need for fast, simple, and cost-effective detection strategies. METHODS: we optimized a protocol for direct RT-PCR detection of SARS-CoV-2 without the need for nucleic acid extraction. Nasopharyngeal samples were diluted to 1:3 using diethyl pyrocarbonate (DEPC)-treated water. The diluted samples were incubated at 95 °C for 5 min in a thermal cycler, followed by a cooling step at 4 °C for 5 min. Samples then underwent reverse transcription real-time RT-PCR in the E and RdRp genes. RESULTS: our direct detection protocol showed 100% concordance with the standard protocol with an average Ct value difference of 4.38 for the E region and 3.85 for the RdRp region. CONCLUSION: the direct PCR technique was found to be a reliable and sensitive method that can be used to reduce the time and cost of the assay by removing the need for RNA extraction. It enables the use of the assay in research, diagnostics, and screening for COVID-19 in regions with fewer economic resources, where supplies are more limited allowing for wider use for screening.

17.
Pathogens ; 9(10)2020 Sep 28.
Article in English | MEDLINE | ID: covidwho-904941

ABSTRACT

The ongoing coronavirus disease 19 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a threat to human health. Despite this, many affected countries are now in the process of gradual lifting of COVID-19 restrictions that were initially implemented in response to the pandemic. The success of the so-called "exit strategy" requires continued surveillance of virus circulation in the community and evaluation of the prevalence of protective immunity among population. Serology tests are valuable tools for these purposes. Herein, SARS-CoV-2 full-length spike (S) recombinant protein was utilized to develop and optimize an indirect enzyme-linked immunoassay (ELISA) that enables a reliable detection of virus-specific IgG antibody in human sera. Importantly, the performance of this assay was evaluated utilizing micro-neutralization (MN) assay as a reference test. Our developed ELISA offers 100% sensitivity, 98.4% specificity, 98.8% agreement, and high overall accuracy. Moreover, the optical density (OD) values of positive samples significantly correlated with their MN titers. The assay specifically detects human IgG antibodies directed against SARS-CoV-2, but not those to Middle East respiratory syndrome coronavirus (MERS-CoV) or human coronavirus HKU1 (HCoV-HKU1). The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications.

18.
Vaccines (Basel) ; 8(4)2020 Nov 01.
Article in English | MEDLINE | ID: covidwho-902683

ABSTRACT

The Middle East respiratory syndrome coronavirus (MERS-CoV) was identified in 2012 and causes severe and often fatal acute respiratory illness in humans. No approved prophylactic and therapeutic interventions are currently available. In this study, we have developed egg yolk antibodies (immunoglobulin Y (IgY)) specific for MERS-CoV spike protein (S1) in order to evaluate their neutralizing efficiency against MERS-CoV infection. S1-specific immunoglobulins were produced by injecting chickens with purified recombinant S1 protein of MERS-CoV at a high titer (5.7 mg/mL egg yolk) at week 7 post immunization. Western blotting and immune-dot blot assays demonstrated that the IgY antibody specifically bound to the MERS-CoV S1 protein. Anti-S1 antibodies were also able to recognize MERS-COV inside cells, as demonstrated by an immunofluorescence assay. Plaque reduction and microneutralization assays showed the neutralization of MERS-COV in Vero cells by anti-S1 IgY antibodies and non-significantly reduced virus titers in the lungs of MERS-CoV-infected mice during early infection, with a nonsignificant decrease in weight loss. However, a statistically significant (p = 0.0196) quantitative reduction in viral antigen expression and marked reduction in inflammation were observed in lung tissue. Collectively, our data suggest that the anti-MERS-CoV S1 IgY could serve as a potential candidate for the passive treatment of MERS-CoV infection.

19.
Pathogens ; 9(10):803, 2020.
Article | MDPI | ID: covidwho-798869

ABSTRACT

The ongoing coronavirus disease 19 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses a threat to human health. Despite this, many affected countries are now in the process of gradual lifting of COVID-19 restrictions that were initially implemented in response to the pandemic. The success of the so-called "exit strategy"requires continued surveillance of virus circulation in the community and evaluation of the prevalence of protective immunity among population. Serology tests are valuable tools for these purposes. Herein, SARS-CoV-2 full-length spike (S) recombinant protein was utilized to develop and optimize an indirect enzyme-linked immunoassay (ELISA) that enables a reliable detection of virus-specific IgG antibody in human sera. Importantly, the performance of this assay was evaluated utilizing micro-neutralization (MN) assay as a reference test. Our developed ELISA offers 100% sensitivity, 98.4% specificity, 98.8% agreement, and high overall accuracy. Moreover, the optical density (OD) values of positive samples significantly correlated with their MN titers. The assay specifically detects human IgG antibodies directed against SARS-CoV-2, but not those to Middle East respiratory syndrome coronavirus (MERS-CoV) or human coronavirus HKU1 (HCoV-HKU1). The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications.

20.
PLoS One ; 15(5): e0232790, 2020.
Article in English | MEDLINE | ID: covidwho-616862

ABSTRACT

The Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) is an endemic virus in dromedaries. Annually, Saudi Arabia imports thousands of camels from the Horn of Africa, yet the epidemiology of MERS-CoV in these animals is largely unknown. Here, MERS-CoV prevalence was compared in imported African camels and their local counterparts. A total of 1399 paired sera and nasal swabs were collected from camels between 2016 and 2018. Imported animals from Sudan (n = 829) and Djibouti (n = 328) were sampled on incoming ships at Jeddah Islamic seaport before unloading, and local camels were sampled from Jeddah (n = 242). Samples were screened for neutralizing antibodies (nAbs) and MERS-CoV viral RNA. The overall seroprevalence was 92.7% and RNA detection rate was 17.2%. Imported camels had higher seroprevalence compared to resident herds (93.8% vs 87.6%, p <0.01) in contrast to RNA detection (13.3% vs 35.5%, p <0.0001). Seroprevalence significantly increased with age (p<0.0001) and viral RNA detection rate was ~2-folds higher in camels <2-year-old compared to older animals. RNA detection was higher in males verses females (24.3% vs 12.6%, p<0.0001) but seroprevalence was similar. Concurrent positivity for viral RNA and nAbs was found in >87% of the RNA positive animals, increased with age and was sex-dependent. Importantly, reduced viral RNA load was positively correlated with nAb titers. Our data confirm the widespread of MERS-CoV in imported and domestic camels in Saudi Arabia and highlight the need for continuous active surveillance and better prevention measures. Further studies are also warranted to understand camels correlates of protection for proper vaccine development.


Subject(s)
Antibodies, Viral/blood , Camelus/virology , Coronavirus Infections/epidemiology , Middle East Respiratory Syndrome Coronavirus/isolation & purification , RNA, Viral/blood , Animals , Antibodies, Neutralizing/blood , Coronavirus Infections/virology , Cross-Sectional Studies , Disease Reservoirs/virology , Djibouti/epidemiology , Female , Male , Middle East Respiratory Syndrome Coronavirus/genetics , Prevalence , Saudi Arabia/epidemiology , Seroepidemiologic Studies , Sudan/epidemiology
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