Middle East Respiratory Syndrome coronavirus (MERS-CoV) serology in major livestock species in an affected region in Jordan, June to September 2013

Molecular diagnosis and phylogenetic analysis of a Middle East respiratory syndrome coronavirus human case in Jordan

Middle East respiratory syndrome coronavirus (MERS-CoV) is an important zoonotic pathogen. The aim of this paper is to report one polymerase chain reaction (PCR)-positive case of MERS-CoV in a 27-year-old man who was involved in a nationwide longitudinal surveillance study of certain zoonotic diseases in Jordan including MERS-CoV. Whole-blood and nasal swab samples were collected from the man and five camels in the vicinity of his living area. The samples were subjected to enzyme-linked immunosorbent assay (ELISA) and real-time reverse-transcription PCR (RT-PCR) to detect MERS-CoV-specific antibodies and MERS-CoV genetic material, respectively. Genomic sequencing and phylogenetic analysis were also performed to detect similarities with known strains of the virus in the region. In January 2021, an ongoing surveillance study detected a MERS-CoV-positive nasal swab sample from an asymptomatic male and camels using RT-PCR. Phylogenetically, the MERS-CoV isolated in this case belonged to clade B and is clustered with other strains originating in the Arabian Peninsula. The case report represents the first PCR-positive case of MERS-CoV in an asymptomatic individual in Jordan, indicating active circulation of the virus within the population.

Acquisition of a multibasic cleavage site does not increase MERS-CoV entry into Calu-3 human lung cells

Human-to-human transmission of the highly pathogenic Middle East respiratory syndrome coronavirus (MERS-CoV) is currently inefficient. However, there is concern that the virus might mutate and thereby increase its transmissibility and thus pandemic potential. The pandemic SARS-CoV-2 depends on a highly cleavable furin motif at the S1/S2 site of the viral spike (S) protein for efficient lung cell entry, transmission, and pathogenicity. Here, by employing pseudotyped particles, we investigated whether augmented cleavage at the S1/S2 site also increases MERS-CoV entry into Calu-3 human lung cells. We report that polymorphism T746K at the S1/S2 cleavage site or optimization of the furin motif increases S protein cleavage but not lung cell entry. These findings suggest that, unlike what has been reported for SARS-CoV-2, a highly cleavable S1/S2 site might not augment MERS-CoV infectivity for human lung cells.IMPORTANCEThe highly cleavable furin motif in the spike protein is required for robust lung cell entry, transmission, and pathogenicity of SARS-CoV-2. In contrast, it is unknown whether optimization of the furin motif in the spike protein of the pre-pandemic MERS-CoV increases lung cell entry and allows for robust human-human transmission. The present study indicates that this might not be the case. Thus, neither a naturally occurring polymorphism that increased MERS-CoV spike protein cleavage nor artificial optimization of the cleavage site allowed for increased spike-protein-driven entry into Calu-3 human lung cells.

MERS-CoV exposure and risk factors for MERS-CoV ELISA seropositivity among members of livestock-owning households in southern Jordan: a population based cross-sectional study

BACKGROUND

Although dromedary camels (Camelus dromedarius) are known to be the host reservoir for MERS-CoV, the virus causing Middle East respiratory syndrome (MERS), zoonotic transmission pathways and camel subpopulations posing highest transmission risk are poorly understood. Extensively managed herds, ubiquitous across the Arabian Peninsula, present a major potential source of primary infection. In this study we aimed to address key knowledge gaps regarding MERS epidemiology among high-risk communities associated with such herds, which is essential information for effective control strategies.

METHODS

We did a cross-sectional study between Sept 27, 2017, and Oct 11, 2018, among members of livestock-owning households in southern Jordan (Aqaba East, Aqaba West, Ma'an East, and Ma'an West regions), with random selection of households (house and tent dwellings) from Ministry of Agriculture lists via computer-generated randomisation lists. Household visits were done, with questionnaires administered to household members regarding potential risk factors for MERS-CoV exposure in the past 6 months and blood samples and nasal and oral swabs collected, alongside physical examination data including blood pressure and blood glucose. Children younger than 5 years and individuals without capacity to provide informed consent were excluded. Serum was tested for IgG antibodies to MERS-CoV spike protein (S1 subunit) and nucleocapsid (N) protein with in-house indirect ELISAs, and viral RNA was detected in nasal and oral samples by RT-PCR. The primary outcome was evidence of MERS-CoV exposure (ascertained by seropositive status on S1 or N ELISAs, or a positive swab sample on RT-PCR); secondary outcomes were potential associations between possible risk factors and seropositive status. RT-PCR data were to be presented descriptively. Seroprevalence estimates were obtained at the individual and household levels, and associations between hypothetical risk factors and seropositive status were assessed with use of mixed-effects logistic regression.

FINDINGS

We sampled 879 household members (median age 27 years [IQR 16-44]; 471 [54%] males and 408 [46%] females) from 204 households. 72 (8%) household members were seropositive on S1 ELISA (n=25, 3%) or N ELISA (n=52, 6%). No positive nasal or oral swab samples were identified on RT-PCR. Within-household clustering was identified for seropositivity on S1 ELISA (intraclass correlation coefficient 0·88 [0·35-0·96]) but not N ELISA (0·00 [0·00-0·27]). On multivariable analysis, S1 ELISA seropositivity was associated with frequently (≥weekly) interacting with young (age <1 year) camels (adjusted odds ratio [ORadj] 3·85 [95% CI 1·41-11·61], p=0·011), with frequent kissing and petting (ORadj 4·56 [1·55-15·42], p=0·0074), and frequent feeding and watering (ORadj 4·97 [1·80-15·29], p=0·0027) of young camels identified as risk activities. Attending camel races (ORadj 3·73 [1·11-12·47], p=0·029), frequently feeding and watering camels of any age (ORadj 3·18 [1·12-10·84], p=0·040), and elevated blood glucose (>150 mg/dL; ORadj 4·59 [1·23-18·36], p=0·021) were also associated with S1 ELISA seropositivity. Among individuals without history of camel contact, S1 ELISA seropositivity was associated with sharing a household with an S1 ELISA-positive household member (ORadj 8·92 [1·06-92·99], p=0·044), and with sharing a household with an S1 ELISA-positive household member with history of camel contact (ORadj 24·74 [2·72-306·14], p=0·0050). N ELISA seropositivity was associated with age (categorical, p=0·0069), a household owning a young camel (age <18 months; ORadj 1·98 [1·02-4·09], p=0·043), and frequently feeding and watering camels of any age (ORadj 1·98 [1·09-3·69]; p=0·025).

INTERPRETATION

The study findings highlight the importance of effective MERS-CoV surveillance and control strategies among camel-owning communities in Jordan and the Arabian Peninsula. Juvenile dromedaries pose increased risk for zoonotic MERS-CoV transmission and should be prioritised for vaccination once such vaccines become available. Among high-risk communities, vaccination strategies should prioritise camel-owning households, particularly individuals engaged in camel husbandry or racing, and household members who are older or diabetic, with evidence to suggest secondary within-household transmission.

FUNDING

UK Medical Research Council and US National Institute of Allergy and Infectious Diseases.

Global patterns of Middle East respiratory syndrome coronavirus (MERS-CoV) prevalence and seroprevalence in camels: A systematic review and meta-analysis

The Middle East respiratory syndrome Coronavirus (MERS-CoV) is one of the human coronaviruses that causes severe respiratory infection. Bats are considered to be the natural reservoir, where dromedary camels (DC) are the intermediate hosts of the virus. The current study was undertaken to provide an update on global distribution of the virus in camels, and to investigate the pooled prevalence and camel-associated risk factors of infection. After registration of the review protocol in the Open Science Framework, data searches were conducted on 18 April 2023 through Embase, PubMed, Scopus, and Web of Science. Considering only natural MERS-CoV infection in camels, 94 articles were selected for data curation through blind screening by two authors. Meta-analysis was conducted to estimate the pooled prevalence and to evaluate camel-associated risk factors. Finally, the results were presented in forest plots. The reviewed articles tested 34 countries, of which camels of 24 countries were seropositive and in 15 countries they were positive by molecular method. Viral RNA was detected in DC. Non-DC, such as bactrian camels, alpaca, llama, and hybrid camels were only seropositive. The global estimated pooled seroprevalence and viral RNA prevalence in DC were 77.53% and 23.63%, respectively, with the highest prevalence in West Asia (86.04% and 32.37% respectively). In addition, 41.08% of non-DC were seropositive. The estimated pooled prevalence of MERS-CoV RNA significantly varied by sample types with the highest in oral (45.01%) and lowest in rectal (8.42%) samples; the estimated pooled prevalence in nasal (23.10%) and milk (21.21%) samples were comparable. The estimated pooled seroprevalence in <2 years, 2-5 years, and > 5 years age groups were 56.32%, 75.31%, and 86.31%, respectively, while viral RNA prevalence was 33.40%, 15.87%, and 13.74%, respectively. Seroprevalence and viral RNA prevalence were generally higher in females (75.28% and 19.70%, respectively) than in males (69.53% and 18.99%, respectively). Local camels had lower estimated pooled seroprevalence (63.34%) and viral RNA prevalence (17.78%) than those of imported camels (89.17% and 29.41%, respectively). The estimated pooled seroprevalence was higher in camels of free-herds (71.70%) than confined herds (47.77%). Furthermore, estimated pooled seroprevalence was higher in samples from livestock markets, followed by abattoirs, quarantine, and farms but viral RNA prevalence was the highest in samples from abattoirs, followed by livestock markets, quarantine, and farms. Risk factors, such as sample type, young age, female sex, imported camels, and camel management must be considered to control and prevent the spread and emergence of MERS-CoV.

A framework for measuring timeliness in the outbreak response path: lessons learned from the Middle East respiratory syndrome (MERS) epidemic, September 2012 to January 2019

BackgroundEpidemics are a constant threat in the 21st century, particularly disease outbreaks following spillover of an animal virus to humans. Timeliness, a key metric in epidemic response, can be examined to identify critical steps and delays in public health action.AimTo examine timeliness, we analysed the response to the Middle East respiratory syndrome (MERS) epidemic, with a focus on the international and One Health response efforts.MethodsWe performed a historical review of the MERS epidemic between September 2012 and January 2019 in three steps: (i) the construction of a timeline identifying critical events in the global response, (ii) the performance of a critical path analysis to define outbreak milestones and (iii) a time gap analysis to measure timeliness in the execution of these milestones.ResultsWe proposed 14 MERS-specific milestones at different phases of the epidemic, assessing timeliness of the public health response as well as at the animal-human interface, where we identified the most significant delays.ConclusionsWhen comparing timeliness across three coronavirus epidemics, i.e. MERS (2012), SARS (2002) and COVID-19 (2019), we identified clear improvements over time for certain milestones including laboratory confirmation and diagnostics development, while this was not as apparent for others, as the identification of zoonotic hosts. To more efficiently respond to emerging threats, the global health community should widely assess and tackle specific delays in implementing response interventions by addressing challenges in the sharing of information, data and resources, as well as efficiency, quality, transparency and reliability of reporting events.

Detection of Middle East Respiratory Syndrome Coronavirus-Specific RNA and Anti-MERS-Receptor-Binding Domain Antibodies in Camel Milk from Different Regions of Saudi Arabia

Middle East respiratory syndrome coronavirus (MERS-CoV) causes viral pneumonia disease in humans. The close contact with camels and drinking milk may cause MERS-CoV transfer to humans. This study was designed to detect the existence of MERS-CoV in camel milk samples collected from healthy animals of various barns located around Saudi Arabia. Camel milk samples were examined for MERS-CoV RNA by real time-quantitative polymerase chain reaction, also enzyme-linked immunosorbent assay was performed to detect IgG antibodies directed against Middle East respiratory syndrome receptor-binding domain. Among 83 camel milk samples tested, the result showed that seven samples (8.4%) were positive for MERS-CoV RNA, whereas 40.9% of camel milk samples had antibodies directed against MERS-CoV. The findings indicate that some regions (East and South part) are characterized by a high incidence of viral antibodies. The Southwestern region displayed the lowest infection rates. Among the camel breeds, the lowest positivity for detection of MERS-CoV RNA and IgG antibodies was found in Sahilia. This could be related to a higher resistance to viral infection of the breed Sahilia and/or to the geographical origin of the camels sampled in the study. This needs to be more explored to reduce spread of infection and also to understand the underlying reasons. The presence of viral RNA in camel milk samples warrants for measures to prevent possible foodborne transmission of MERS-CoV through milk consumption.

Evaluation of alpaca tracheal explants as an ex vivo model for the study of Middle East respiratory syndrome coronavirus (MERS-CoV) infection

Middle East respiratory syndrome coronavirus (MERS-CoV) poses a serious threat to public health. Here, we established an ex vivo alpaca tracheal explant (ATE) model using an air-liquid interface culture system to gain insights into MERS-CoV infection in the camelid lower respiratory tract. ATE can be infected by MERS-CoV, being 10³ TCID₅₀/mL the minimum viral dosage required to establish a productive infection. IFNs and antiviral ISGs were not induced in ATE cultures in response to MERS-CoV infection, strongly suggesting that ISGs expression observed in vivo is rather a consequence of the IFN induction occurring in the nasal mucosa of camelids.

Immunogenicity of High-Dose MVA-Based MERS Vaccine Candidate in Mice and Camels

The Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic pathogen that can transmit from dromedary camels to humans, causing severe pneumonia, with a 35% mortality rate. Vaccine candidates have been developed and tested in mice, camels, and humans. Previously, we developed a vaccine based on the modified vaccinia virus Ankara (MVA) viral vector, encoding a full-length spike protein of MERS-CoV, MVA-MERS. Here, we report the immunogenicity of high-dose MVA-MERS in prime–boost vaccinations in mice and camels. Methods: Three groups of mice were immunised with MVA wild-type (MVA-wt) and MVA-MERS (MVA-wt/MVA-MERS), MVA-MERS/MVA-wt, or MVA-MERS/MVA-MERS. Camels were immunised with two doses of PBS, MVA-wt, or MVA-MERS. Antibody (Ab) responses were evaluated using ELISA and MERS pseudovirus neutralisation assays. Results: Two high doses of MVA-MERS induced strong Ab responses in both mice and camels, including neutralising antibodies. Anti-MVA Ab responses did not affect the immune responses to the vaccine antigen (MERS-CoV spike). Conclusions: MVA-MERS vaccine, administered in a homologous prime–boost regimen, induced high levels of neutralising anti-MERS-CoV antibodies in mice and camels. This could be considered for further development and evaluation as a dromedary vaccine to reduce MERS-CoV transmission to humans.

Adaptive Evolution of the Fox Coronavirus Based on Genome-Wide Sequence Analysis

Purpose. To report the first complete fox coronavirus (CoV) genome sequence obtained through genome-wide amplifications and to understand the adaptive evolution of fox CoV. Methods. Anal swab samples were collected from 35 foxes to detect the presence of CoV and obtain the virus sequence. Phylogenetic analysis was conducted using MrBayes. The possibility of recombination within these sequences was assessed using GARD. Analysis of the levels of selection pressure experienced by these sequences was assessed using methods on both the PAML and Data Monkey platforms. Results. Of the 35 samples, two were positive, and complete genome sequences for the viruses were obtained. Phylogenetic analysis, using Bayesian methods, of these sequences, together with other CoV sequences, revealed that the fox CoV sequences clustered with canine coronavirus (CCoV) sequences, with sequences from other carnivores more distantly related. In contrast to the feline, ferret and mink CoV sequences that clustered into species-specific clades, the fox CoV fell within the CCoV clade. Minimal evidence for recombination was found among the sequences. A total of 7, 3, 14, and 2 positively selected sites were identified in the M, N, S, and 7B genes, respectively, with 99, 111, and 581 negatively selected sites identified in M, N, and S genes, respectively. Conclusion. The complete genome sequence of fox CoV has been obtained for the first time. The results suggest that the genome sequence of fox CoV may have experienced adaptive evolution in the genes replication, entry, and virulence. The number of sites in each gene that experienced negative selection is far greater than the number that underwent positive selection, suggesting that most of the sequence is highly conserved and important for viral survive. However, positive selection at a few sites likely aided these viruses to adapt to new environments.

Strategies for fighting pandemic virus infections: Integration of virology and drug delivery

Respiratory viruses have sometimes resulted in worldwide pandemics, with the influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) being major participants. Long-term efforts have made it possible to control the influenza virus, but seasonal influenza continues to take many lives each year, and a pandemic influenza virus sometimes emerges. Although vaccines for coronavirus disease 2019 (COVID-19) have been developed, we are not yet able to coexist with the SARS-CoV-2. To overcome such viruses, it is necessary to obtain knowledge about international surveillance systems, virology, ecology and to determine that immune responses are effective. The information must then be transferred to drugs. Delivery systems would be expected to contribute to the rational development of drugs. In this review, virologist and drug delivery system (DDS) researchers discuss drug delivery strategies, especially the use of lipid-based nanocarriers, for fighting to respiratory virus infections.

Middle East respiratory syndrome coronavirus infection in camelids

Middle East respiratory syndrome coronavirus (MERS-CoV) is the cause of a severe respiratory disease with a high case fatality rate in humans. Since its emergence in mid-2012, 2578 laboratory-confirmed cases in 27 countries have been reported by the World Health Organization, leading to 888 known deaths due to the disease and related complications. Dromedary camels are considered the major reservoir host for this virus leading to zoonotic infection in humans. Dromedary camels, llamas, and alpacas are susceptible to MERS-CoV, developing a mild-to-moderate upper respiratory tract infection characterized by epithelial hyperplasia as well as infiltration of neutrophils, lymphocytes, and some macrophages within epithelium, lamina propria, in association with abundant viral antigen. The very mild lesions in the lower respiratory tract of these camelids correlate with absence of overt illness following MERS-CoV infection. Unfortunately, there is no approved antiviral treatment or vaccine for MERS-CoV infection in humans. Thus, there is an urgent need to develop intervention strategies in camelids, such as vaccination, to minimize virus spillover to humans. Therefore, the development of camelid models of MERS-CoV infection is key not only to assess vaccine prototypes but also to understand the biologic mechanisms by which the infection can be naturally controlled in these reservoir species. This review summarizes information on virus-induced pathological changes, pathogenesis, viral epidemiology, and control strategies in camelids, as the intermediate hosts and primary source of MERS-CoV infection in humans.

Monitoring of the Middle East Respiratory Syndrome Coronavirus Activity in a Secluded Herd of Camels Kept Under Field Conditions

Background: Camel-to-human transmission of the Middle East Respiratory Syndrome coronavirus (MERS-CoV) was confirmed as a cause of primary infection in humans. There is a dearth of information regarding the behavior of the virus in camels and the mode of spread among them under natural conditions. The aim of this study was to monitor exposure of camels to the MERS-CoV under field conditions. Methods: From January 1 to November 30, 2015, a secluded herd of 20 pregnant female camels and their neonate calves was established. Nasal and rectal swabs were collected from calves daily for 90 days after birth, then weekly until the end of the study. Nasal and rectal samples were collected from the dams at outset and then weekly until the end of the study. The samples were tested with rtRT-PCR to detect the MERS-CoV RNA. Results: All purchased pregnant camels were MERS-CoV RNA negative at outset. Nineteen dams and 15 calves completed the study. Seven (46.7%) of the 15 calves developed a rise in rectal temperature (39-40°C), shivering, rhinitis, anorexia, and general weakness at a mean ± standard deviation of 18.9 ± 4.9 days of age and their MERS-CoV RNA test was positive on the first day of illness. Three of the seven infected calves died 14 ± 9.1 days postonset of illness at age 17, 14, and 46 days, respectively. The remaining four infected calves fully recovered and they were MERS-CoV RNA positive for 17.5 ± 8.8 days. Four (21.1%) of the 19 dams had positive tests; three dams had no clinical signs, whereas the fourth dam exhibited signs not compatible with MERS-CoV infection and died three days after the positive test, 33 days after parturition. All MERS-CoV infections occurred within 22 days. Conclusions: This study has expanded our understanding of the MERS-CoV epidemiology among camels, which is an important step forward to device effective preventive measures.

Middle East Respiratory Syndrome Coronavirus

The past two decades have witnessed the emergence of three zoonotic coronaviruses which have jumped species to cause lethal disease in humans: severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1), Middle East respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2. MERS-CoV emerged in Saudi Arabia in 2012 and the origins of MERS-CoV are not fully understood. Genomic analysis indicates it originated in bats and transmitted to camels. Human-to-human transmission occurs in varying frequency, being highest in healthcare environment and to a lesser degree in the community and among family members. Several nosocomial outbreaks of human-to-human transmission have occurred, the largest in Riyadh and Jeddah in 2014 and South Korea in 2015. MERS-CoV remains a high-threat pathogen identified by World Health Organization as a priority pathogen because it causes severe disease that has a high mortality rate, epidemic potential, and no medical countermeasures. MERS-CoV has been identified in dromedaries in several countries in the Middle East, Africa, and South Asia. MERS-CoV-2 causes a wide range of clinical presentations, although the respiratory system is predominantly affected. There are no specific antiviral treatments, although recent trials indicate that combination antivirals may be useful in severely ill patients. Diagnosing MERS-CoV early and implementation infection control measures are critical to preventing hospital-associated outbreaks. Preventing MERS relies on avoiding unpasteurized or uncooked animal products, practicing safe hygiene habits in health care settings and around dromedaries, community education and awareness training for health workers, as well as implementing effective control measures. Effective vaccines for MERS-COV are urgently needed but still under development.

Interspecies Jumping of Bat Coronaviruses

In the last two decades, several coronavirus (CoV) interspecies jumping events have occurred between bats and other animals/humans, leading to major epidemics/pandemics and high fatalities. The SARS epidemic in 2002/2003 had a ~10% fatality. The discovery of SARS-related CoVs in horseshoe bats and civets and genomic studies have confirmed bat-to-civet-to-human transmission. The MERS epidemic that emerged in 2012 had a ~35% mortality, with dromedaries as the reservoir. Although CoVs with the same genome organization (e.g., Tylonycteris BatCoV HKU4 and Pipistrellus BatCoV HKU5) were also detected in bats, there is still a phylogenetic gap between these bat CoVs and MERS-CoV. In 2016, 10 years after the discovery of Rhinolophus BatCoV HKU2 in Chinese horseshoe bats, fatal swine disease outbreaks caused by this virus were reported in southern China. In late 2019, an outbreak of pneumonia emerged in Wuhan, China, and rapidly spread globally, leading to >4,000,000 fatalities so far. Although the genome of SARS-CoV-2 is highly similar to that of SARS-CoV, patient zero and the original source of the pandemic are still unknown. To protect humans from future public health threats, measures should be taken to monitor and reduce the chance of interspecies jumping events, either occurring naturally or through recombineering experiments.

Longitudinal and abattoir-based surveillance of MERS-CoV in camels in Jordan, 2018-2020

To generate baseline information to help better understand the antibody kinetics and nasal shedding dynamics of MERS-CoV in camels in Jordan, a longitudinal surveillance study was conducted in two phases; phase 1 was between December, 2018 and January, 2019 and phase 2 between August and December 2020. In each phase, two camel herds were studied. These herds were located in Al-azraq and in Al-ramtha area and were named Al-azraq and Al-ramtha herds, respectively. The same camel herd of Al-zarqa area was sampled in both phases while two different camel herds, one in each phase, were sampled in Al-ramtha area. Blood and nasal swabs were collected from same selected animals in all visits to each herd in both phases. Additionally, nasal swabs and retropharyngeal lymph node tissue samples were collected from sixty-one camels slaughtered at Al-ramtha abattoir during phase 2 to enhance virus isolation opportunities and phylogenetic analysis. All sampled animals from Al-azraq camel herd were either borderline or seropositive on spike 1 based ELISA assay and negative on quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in both phases. In Al-ramtha camel herds, an unsteady pattern prevailed in animals' seropositivity in both phases and viral RNA was detected in all animals in the end of phase 1 and in one animal during phase 2. For the seroconversion, anti-MERS-CoV spike 1 antibodies were detected in two animals in phase 1 in the first collection only. While, in phase 2, intermittent seroconversion pattern was observed in several samples over time of collections that ended with all animals became seropositive in the last collection (after nineteen days from viral RNA detection). In addition, viral RNA was detected in nasal swabs of 3 slaughtered camels. Phylogenetic analysis of a partial fragment of spike 1 gene sequences of all MERS-CoV isolates clustered together with clade B of MERS-CoV. This cluster contains all MERS-CoV sequences obtained either from camels or human sources in the Arabian Peninsula indicating the continuous circulation of this clade also in Jordan.

Current diagnostic approaches to detect two important betacoronaviruses: Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are two common betacoronaviruses, which are still causing transmission among the human population worldwide. The major difference between the two coronaviruses is that MERS-CoV is now causing sporadic transmission worldwide, whereas SARS-CoV-2 is causing a pandemic outbreak globally. Currently, different guidelines and reports have highlighted several diagnostic methods and approaches which could be used to screen and confirm MERS-CoV and SARS-CoV-2 infections. These methods include clinical evaluation, laboratory diagnosis (nucleic acid-based test, protein-based test, or viral culture), and radiological diagnosis. With the presence of these different diagnostic approaches, it could cause a dilemma to the clinicians and diagnostic laboratories in selecting the best diagnostic strategies to confirm MERS-CoV and SARS-CoV-2 infections. Therefore, this review aims to provide an up-to-date comparison of the advantages and limitations of different diagnostic approaches in detecting MERS-CoV and SARS-CoV-2 infections. This review could provide insights for clinicians and scientists in detecting MERS-CoV and SARS-CoV-2 infections to help combat the transmission of these coronaviruses.

Risk Factors for Middle East Respiratory Syndrome Coronavirus Infection among Camel Populations, Southern Jordan, 2014-2018

After the first detection of Middle East respiratory syndrome coronavirus (MERS-CoV) in camels in Jordan in 2013, we conducted 2 consecutive surveys in 2014–2015 and 2017–2018 investigating risk factors for MERS-CoV infection among camel populations in southern Jordan. Multivariate analysis to control for confounding demonstrated that borrowing of camels, particularly males, for breeding purposes was associated with increased MERS-CoV seroprevalence among receiving herds, suggesting a potential route of viral transmission between herds. Increasing age, herd size, and use of water troughs within herds were also associated with increased seroprevalence. Closed herd management practices were found to be protective. Future vaccination strategies among camel populations in Jordan could potentially prioritize breeding males, which are likely to be shared between herds. In addition, targeted management interventions with the potential to reduce transmission between herds should be considered; voluntary closed herd schemes offer a possible route to achieving disease-free herds.

Evolutionary trajectory of SARS-CoV-2 and emerging variants

The emergence of a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and more recently, the independent evolution of multiple SARS-CoV-2 variants has generated renewed interest in virus evolution and cross-species transmission. While all known human coronaviruses (HCoVs) are speculated to have originated in animals, very little is known about their evolutionary history and factors that enable some CoVs to co-exist with humans as low pathogenic and endemic infections (HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1), while others, such as SARS-CoV, MERS-CoV and SARS-CoV-2 have evolved to cause severe disease. In this review, we highlight the origins of all known HCoVs and map positively selected for mutations within HCoV proteins to discuss the evolutionary trajectory of SARS-CoV-2. Furthermore, we discuss emerging mutations within SARS-CoV-2 and variants of concern (VOC), along with highlighting the demonstrated or speculated impact of these mutations on virus transmission, pathogenicity, and neutralization by natural or vaccine-mediated immunity.

Common Themes in Zoonotic Spillover and Disease Emergence: Lessons Learned from Bat- and Rodent-Borne RNA Viruses

Rodents (order Rodentia), followed by bats (order Chiroptera), comprise the largest percentage of living mammals on earth. Thus, it is not surprising that these two orders account for many of the reservoirs of the zoonotic RNA viruses discovered to date. The spillover of these viruses from wildlife to human do not typically result in pandemics but rather geographically confined outbreaks of human infection and disease. While limited geographically, these viruses cause thousands of cases of human disease each year. In this review, we focus on three questions regarding zoonotic viruses that originate in bats and rodents. First, what biological strategies have evolved that allow RNA viruses to reside in bats and rodents? Second, what are the environmental and ecological causes that drive viral spillover? Third, how does virus spillover occur from bats and rodents to humans?

Setting the Terms for Zoonotic Diseases: Effective Communication for Research, Conservation, and Public Policy

Many of the world's most pressing issues, such as the emergence of zoonotic diseases, can only be addressed through interdisciplinary research. However, the findings of interdisciplinary research are susceptible to miscommunication among both professional and non-professional audiences due to differences in training, language, experience, and understanding. Such miscommunication contributes to the misunderstanding of key concepts or processes and hinders the development of effective research agendas and public policy. These misunderstandings can also provoke unnecessary fear in the public and have devastating effects for wildlife conservation. For example, inaccurate communication and subsequent misunderstanding of the potential associations between certain bats and zoonoses has led to persecution of diverse bats worldwide and even government calls to cull them. Here, we identify four types of miscommunication driven by the use of terminology regarding bats and the emergence of zoonotic diseases that we have categorized based on their root causes: (1) incorrect or overly broad use of terms; (2) terms that have unstable usage within a discipline, or different usages among disciplines; (3) terms that are used correctly but spark incorrect inferences about biological processes or significance in the audience; (4) incorrect inference drawn from the evidence presented. We illustrate each type of miscommunication with commonly misused or misinterpreted terms, providing a definition, caveats and common misconceptions, and suggest alternatives as appropriate. While we focus on terms specific to bats and disease ecology, we present a more general framework for addressing miscommunication that can be applied to other topics and disciplines to facilitate more effective research, problem-solving, and public policy.

Middle East Respiratory Syndrome (MERS) Virus-Pathophysiological Axis and the Current Treatment Strategies

Middle East respiratory syndrome (MERS) is a lethal respiratory disease with its first case reported back in 2012 (Jeddah, Saudi Arabia). It is a novel, single-stranded, positive-sense RNA beta coronavirus (MERS-CoV) that was isolated from a patient who died from a severe respiratory illness. Later, it was found that this patient was infected with MERS. MERS is endemic to countries in the Middle East regions, such as Saudi Arabia, Jordan, Qatar, Oman, Kuwait and the United Arab Emirates. It has been reported that the MERS virus originated from bats and dromedary camels, the natural hosts of MERS-CoV. The transmission of the virus to humans has been thought to be either direct or indirect. Few camel-to-human transmissions were reported earlier. However, the mode of transmission of how the virus affects humans remains unanswered. Moreover, outbreaks in either family-based or hospital-based settings were observed with high mortality rates, especially in individuals who did not receive proper management or those with underlying comorbidities, such as diabetes and renal failure. Since then, there have been numerous reports hypothesising complications in fatal cases of MERS. Over the years, various diagnostic methods, treatment strategies and preventive measures have been strategised in containing the MERS infection. Evidence from multiple sources implicated that no treatment options and vaccines have been developed in specific, for the direct management of MERS-CoV infection. Nevertheless, there are supportive measures outlined in response to symptom-related management. Health authorities should stress more on infection and prevention control measures, to ensure that MERS remains as a low-level threat to public health.

Emergence of Bat-Related Betacoronaviruses: Hazard and Risks

The current Coronavirus Disease 2019 (COVID-19) pandemic, with more than 111 million reported cases and 2,500,000 deaths worldwide (mortality rate currently estimated at 2.2%), is a stark reminder that coronaviruses (CoV)-induced diseases remain a major threat to humanity. COVID-19 is only the latest case of betacoronavirus (β-CoV) epidemics/pandemics. In the last 20 years, two deadly CoV epidemics, Severe Acute Respiratory Syndrome (SARS; fatality rate 9.6%) and Middle East Respiratory Syndrome (MERS; fatality rate 34.7%), plus the emergence of HCoV-HKU1 which causes the winter common cold (fatality rate 0.5%), were already a source of public health concern. Betacoronaviruses can also be a threat for livestock, as evidenced by the Swine Acute Diarrhea Syndrome (SADS) epizootic in pigs. These repeated outbreaks of β-CoV-induced diseases raise the question of the dynamic of propagation of this group of viruses in wildlife and human ecosystems. SARS-CoV, SARS-CoV-2, and HCoV-HKU1 emerged in Asia, strongly suggesting the existence of a regional hot spot for emergence. However, there might be other regional hot spots, as seen with MERS-CoV, which emerged in the Arabian Peninsula. β-CoVs responsible for human respiratory infections are closely related to bat-borne viruses. Bats are present worldwide and their level of infection with CoVs is very high on all continents. However, there is as yet no evidence of direct bat-to-human coronavirus infection. Transmission of β-CoV to humans is considered to occur accidentally through contact with susceptible intermediate animal species. This zoonotic emergence is a complex process involving not only bats, wildlife and natural ecosystems, but also many anthropogenic and societal aspects. Here, we try to understand why only few hot spots of β-CoV emergence have been identified despite worldwide bats and bat-borne β-CoV distribution. In this work, we analyze and compare the natural and anthropogenic environments associated with the emergence of β-CoV and outline conserved features likely to create favorable conditions for a new epidemic. We suggest monitoring South and East Africa as well as South America as these regions bring together many of the conditions that could make them future hot spots.

Application of Nanotechnology in the COVID-19 Pandemic

COVID-19, caused by SARS-CoV-2 infection, has been prevalent worldwide for almost a year. In early 2000, there was an outbreak of SARS-CoV, and in early 2010, a similar dissemination of infection by MERS-CoV occurred. However, no clear explanation for the spread of SARS-CoV-2 and a massive increase in the number of infections has yet been proposed. The best solution to overcome this pandemic is the development of suitable and effective vaccines and therapeutics. Fortunately, for SARS-CoV-2, the genome sequence and protein structure have been published in a short period, making research and development for prevention and treatment relatively easy. In addition, intranasal drug delivery has proven to be an effective method of administration for treating viral lung diseases. In recent years, nanotechnology-based drug delivery systems have been applied to intranasal drug delivery to overcome various limitations that occur during mucosal administration, and advances have been made to the stage where effective drug delivery is possible. This review describes the accumulated knowledge of the previous SARS-CoV and MERS-CoV infections and aims to help understand the newly emerged SARS-CoV-2 infection. Furthermore, it elucidates the achievements in developing COVID-19 vaccines and therapeutics to date through existing approaches. Finally, the applicable nanotechnology approach is described in detail, and vaccines and therapeutic drugs developed based on nanomedicine, which are currently undergoing clinical trials, have presented the potential to become innovative alternatives for overcoming COVID-19.

Bat-Borne Coronaviruses in Jordan and Saudi Arabia: A Threat to Public Health?

Emerging infectious diseases are of great concern to public health, as highlighted by the ongoing coronavirus disease 2019 (COVID-19) pandemic. Such diseases are of particular danger during mass gathering and mass influx events, as large crowds of people in close proximity to each other creates optimal opportunities for disease transmission. The Hashemite Kingdom of Jordan and the Kingdom of Saudi Arabia are two countries that have witnessed mass gatherings due to the arrival of Syrian refugees and the annual Hajj season. The mass migration of people not only brings exotic diseases to these regions but also brings new diseases back to their own countries, e.g., the outbreak of MERS in South Korea. Many emerging pathogens originate in bats, and more than 30 bat species have been identified in these two countries. Some of those bat species are known to carry viruses that cause deadly diseases in other parts of the world, such as the rabies virus and coronaviruses. However, little is known about bats and the pathogens they carry in Jordan and Saudi Arabia. Here, the importance of enhanced surveillance of bat-borne infections in Jordan and Saudi Arabia is emphasized, promoting the awareness of bat-borne diseases among the general public and building up infrastructure and capability to fill the gaps in public health preparedness to prevent future pandemics.

Assessing the aggregated probability of entry of a novel prion disease agent into the United Kingdom

In 2018 prion disease was detected in camels at an abattoir in Algeria for the first time. The emergence of prion disease in this species made it prudent to assess the probability of entry of the pathogen into the United Kingdom (UK) from this region. Potentially contaminated products were identified as evidenced by other prion diseases. The aggregated probability of entry of the pathogen was estimated as very high and high for legal milk and cheese imports respectively and very high, high and high for illegal meat, milk and cheese products respectively. This aggregated probability represents a qualitative assessment of the probability of one or more entry events per year into the UK; it gives no indication of the number of entry events per year. The uncertainty associated with these estimates was high due to the unknown variation in prevalence of infection in camels and an uncertain number and type of illegal products entering the UK. Potential public health implications of this pathogen are unknown although there is currently no evidence of zoonotic transmission of prion diseases other than bovine spongiform encephalopathy to humans.

High MERS-CoV seropositivity associated with camel herd profile, husbandry practices and household socio-demographic characteristics in Northern Kenya

Despite high exposure to Middle East respiratory syndrome coronavirus (MERS-CoV), the predictors for seropositivity in the context of husbandry practices for camels in Eastern Africa are not well understood. We conducted a cross-sectional survey to describe the camel herd profile and determine the factors associated with MERS-CoV seropositivity in Northern Kenya. We enrolled 29 camel-owning households and administered questionnaires to collect herd and household data. Serum samples collected from 493 randomly selected camels were tested for anti-MERS-CoV antibodies using a microneutralisation assay, and regression analysis used to correlate herd and household characteristics with camel seropositivity. Households reared camels (median = 23 camels and IQR 16–56), and at least one other livestock species in two distinct herds; a home herd kept near homesteads, and a range/fora herd that resided far from the homestead. The overall MERS-CoV IgG seropositivity was 76.3%, with no statistically significant difference between home and fora herds. Significant predictors for seropositivity (P ⩽ 0.05) included camels 6–10 years old (aOR 2.3, 95% CI 1.0–5.2), herds with ⩾25 camels (aOR 2.0, 95% CI 1.2–3.4) and camels from Gabra community (aOR 2.3, 95% CI 1.2–4.2). These results suggest high levels of virus transmission among camels, with potential for human infection.

Camelid Inoculation With Middle East Respiratory Syndrome Coronavirus: Experimental Models of Reservoir Host Infection

Within the past two decades, three zoonotic betacoronaviruses have been associated with outbreaks causing severe respiratory disease in humans. Of these, Middle East respiratory s yndrome coronavirus (MERS-CoV) is the only zoonotic coronavirus that is known to consistently result in frequent zoonotic spillover events from the proximate reservoir host—the dromedary camel. A comprehensive understanding of infection in dromedaries is critical to informing public health recommendations and implementing intervention strategies to mitigate spillover events. Experimental models of reservoir disease are absolutely critical in understanding the pathogenesis and transmission, and are key to testing potential dromedary vaccines against MERS-CoV. In this review, we describe experimental infections of dromedary camels as well as additional camelid models used to further understand the camel’s role in MERS-CoV spillover to humans.

The recent challenges of highly contagious COVID-19, causing respiratory infections: Symptoms, diagnosis, transmission, possible vaccines, animal models, and immunotherapy

COVID-19 is highly contagious pathogenic viral infection initiated from Wuhan seafood wholesale market of China on December 2019 and spread rapidly around the whole world due to onward transmission. This recent outbreak of novel coronavirus (CoV) was believed to be originated from bats and causing respiratory infections such as common cold, dry cough, fever, headache, dyspnea, pneumonia, and finally Severe Acute Respiratory Syndrome (SARS) in humans. For this widespread zoonotic virus, human-to-human transmission has resulted in nearly 83 lakh cases in 213 countries and territories with 4,50,686 deaths as on 19 June 2020. This review presents a report on the origin, transmission, symptoms, diagnosis, possible vaccines, animal models, and immunotherapy for this novel virus and will provide ample references for the researchers toward the ongoing development of therapeutic agents and vaccines and also preventing the spread of this disease.

The recent challenges of highly contagious COVID-19, causing respiratory infections: Symptoms, diagnosis, transmission, possible vaccines, animal models, and immunotherapy

COVID-19 is highly contagious pathogenic viral infection initiated from Wuhan seafood wholesale market of China on December 2019 and spread rapidly around the whole world due to onward transmission. This recent outbreak of novel coronavirus (CoV) was believed to be originated from bats and causing respiratory infections such as common cold, dry cough, fever, headache, dyspnea, pneumonia, and finally Severe Acute Respiratory Syndrome (SARS) in humans. For this widespread zoonotic virus, human-to-human transmission has resulted in nearly 83 lakh cases in 213 countries and territories with 4,50,686 deaths as on 19 June 2020. This review presents a report on the origin, transmission, symptoms, diagnosis, possible vaccines, animal models, and immunotherapy for this novel virus and will provide ample references for the researchers toward the ongoing development of therapeutic agents and vaccines and also preventing the spread of this disease.

High Rate of Circulating MERS-CoV in Dromedary Camels at Slaughterhouses in Riyadh, 2019

MERS-CoV is a zoonotic virus that has emerged in humans in 2012 and caused severe respiratory illness with a mortality rate of 34.4%. Since its appearance, MERS-CoV has been reported in 27 countries and most of these cases were in Saudi Arabia. So far, dromedaries are considered to be the intermediate host and the only known source of human infection. This study was designed to determine the seroprevalence and the infection rate of MERS-CoV in slaughtered food-camels in Riyadh, Saudi Arabia. A total of 171 nasal swabs along with 161 serum samples were collected during the winter; from January to April 2019. Nasal swabs were examined by Rapid test and RT-PCR to detect MERS-CoV RNA, while serum samples were tested primarily using S1-based ELISA Kit to detect MERS-CoV (IgG) antibodies and subsequently by MERS pseudotyped viral particles (MERSpp) neutralization assay for confirmation. Genetic diversity of the positive isolates was determined based on the amplification and sequencing of the spike gene. Our results showed high prevalence (38.6%) of MERS-CoV infection in slaughtered camels and high seropositivity (70.8%) during the time of the study. These data indicate previous and ongoing MERS-CoV infection in camels. Phylogenic analysis revealed relatively low genetic variability among our isolated samples. When these isolates were aligned against published spike sequences of MERS-CoV, deposited in global databases, there was sequence similarity of 94%. High seroprevalence and high genetic stability of MERS-CoV in camels indicating that camels pose a public health threat. The widespread MERS-CoV infections in camels might lead to a risk of future zoonotic transmission into people with direct contact with these infected camels. This study confirms re-infections in camels, highlighting a challenge for vaccine development when it comes to protective immunity.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV): State of the Science

Coronaviruses belong to a large family of viruses that can cause disease outbreaks ranging from the common cold to acute respiratory syndrome. Since 2003, three zoonotic members of this family evolved to cross species barriers infecting humans and resulting in relatively high case fatality rates (CFR). Compared to Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV, CFR = 10%) and pandemic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, CFR = 6%), the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) has scored the highest CFR (approximately 35%). In this review, we systematically summarize the current state of scientific knowledge about MERS-CoV, including virology and origin, epidemiology, zoonotic mode of transmission, and potential therapeutic or prophylactic intervention modalities.

Cross-sectional prevalence study of MERS-CoV in local and imported dromedary camels in Saudi Arabia, 2016-2018

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.

Novel human coronavirus (SARS-CoV-2): A lesson from animal coronaviruses

The recent pandemic caused by the novel human coronavirus, referrred to as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), not only is having a great impact on the health care systems and economies in all continents but it is also causing radical changes of common habits and life styles. The novel coronavirus (CoV) recognises, with high probability, a zoonotic origin but the role of animals in the SARS-CoV-2 epidemiology is still largely unknown. However, CoVs have been known in animals since several decades, so that veterinary coronavirologists have a great expertise on how to face CoV infections in animals, which could represent a model for SARS-CoV-2 infection in humans. In the present paper, we provide an up-to-date review of the literature currently available on animal CoVs, focusing on the molecular mechanisms that are responsible for the emergence of novel CoV strains with different antigenic, biologic and/or pathogenetic features. A full comprehension of the mechanisms driving the evolution of animal CoVs will help better understand the emergence, spreading, and evolution of SARS-CoV-2.

Middle East Respiratory Syndrome Coronavirus and Severe Acute Respiratory Syndrome Coronavirus

Emerging infectious diseases continue to be of a significant importance worldwide with the potential to cause major outbreaks and global pandemics. In 2002, the world had witnessed the appearance of the severe acute respiratory syndrome coronavirus in China which disappeared abruptly within 6 months. About a decade later, a new and emerging novel coronavirus named the Middle East respiratory syndrome coronavirus (MERS-CoV) was described in a patient from Saudi Arabia. These two coronaviruses shared multiple similarities in the epidemiology, clinical presentations, and posed challenges in its prevention and management. Seven years since its discovery, MERS-CoV continues to be a lethal zoonotic pathogen capable of causing severe pneumonia with high case fatality rates and the ability to cause large health care-associated outbreaks.

Molecular Diagnosis of a Novel Coronavirus (2019-nCoV) Causing an Outbreak of Pneumonia

BACKGROUND

A novel coronavirus of zoonotic origin (2019-nCoV) has recently been identified in patients with acute respiratory disease. This virus is genetically similar to SARS coronavirus and bat SARS-like coronaviruses. The outbreak was initially detected in Wuhan, a major city of China, but has subsequently been detected in other provinces of China. Travel-associated cases have also been reported in a few other countries. Outbreaks in health care workers indicate human-to-human transmission. Molecular tests for rapid detection of this virus are urgently needed for early identification of infected patients.

METHODS

We developed two 1-step quantitative real-time reverse-transcription PCR assays to detect two different regions (ORF1b and N) of the viral genome. The primer and probe sets were designed to react with this novel coronavirus and its closely related viruses, such as SARS coronavirus. These assays were evaluated using a panel of positive and negative controls. In addition, respiratory specimens from two 2019-nCoV-infected patients were tested.

RESULTS

Using RNA extracted from cells infected by SARS coronavirus as a positive control, these assays were shown to have a dynamic range of at least seven orders of magnitude (2x10-4-2000 TCID50/reaction). Using DNA plasmids as positive standards, the detection limits of these assays were found to be below 10 copies per reaction. All negative control samples were negative in the assays. Samples from two 2019-nCoV-infected patients were positive in the tests.

CONCLUSIONS

The established assays can achieve a rapid detection of 2019n-CoV in human samples, thereby allowing early identification of patients.

Middle East respiratory syndrome

The Middle East respiratory syndrome coronavirus (MERS-CoV) is a lethal zoonotic pathogen that was first identified in humans in Saudi Arabia and Jordan in 2012. Intermittent sporadic cases, community clusters, and nosocomial outbreaks of MERS-CoV continue to occur. Between April 2012 and December 2019, 2499 laboratory-confirmed cases of MERS-CoV infection, including 858 deaths (34·3% mortality) were reported from 27 countries to WHO, the majority of which were reported by Saudi Arabia (2106 cases, 780 deaths). Large outbreaks of human-to-human transmission have occurred, the largest in Riyadh and Jeddah in 2014 and in South Korea in 2015. MERS-CoV remains a high-threat pathogen identified by WHO as a priority pathogen because it causes severe disease that has a high mortality rate, epidemic potential, and no medical countermeasures. This Seminar provides an update on the current knowledge and perspectives on MERS epidemiology, virology, mode of transmission, pathogenesis, diagnosis, clinical features, management, infection control, development of new therapeutics and vaccines, and highlights unanswered questions and priorities for research, improved management, and prevention.

Global status of Middle East respiratory syndrome coronavirus in dromedary camels: a systematic review

Dromedary camels have been shown to be the main reservoir for human Middle East respiratory syndrome (MERS) infections. This systematic review aims to compile and analyse all published data on MERS-coronavirus (CoV) in the global camel population to provide an overview of current knowledge on the distribution, spread and risk factors of infections in dromedary camels. We included original research articles containing laboratory evidence of MERS-CoV infections in dromedary camels in the field from 2013 to April 2018. In general, camels only show minor clinical signs of disease after being infected with MERS-CoV. Serological evidence of MERS-CoV in camels has been found in 20 countries, with molecular evidence for virus circulation in 13 countries. The seroprevalence of MERS-CoV antibodies increases with age in camels, while the prevalence of viral shedding as determined by MERS-CoV RNA detection in nasal swabs decreases. In several studies, camels that were sampled at animal markets or quarantine facilities were seropositive more often than camels at farms as well as imported camels vs. locally bred camels. Some studies show a relatively higher seroprevalence and viral detection during the cooler winter months. Knowledge of the animal reservoir of MERS-CoV is essential to develop intervention and control measures to prevent human infections.

Spatial association between primary Middle East respiratory syndrome coronavirus infection and exposure to dromedary camels in Saudi Arabia

Middle East respiratory syndrome coronavirus (MERS‐CoV) is an emerging zoonotic disease. Exposure to dromedary camels (Camelus dromedaries) has been consistently considered the main source of primary human infection. Although Saudi Arabia reports the highest rate of human MERS‐CoV infection and has one of the largest populations of dromedary camels worldwide, their spatial association has not yet been investigated. Thus, this study aimed to examine the correlation between the spatial distribution of primary MERS‐CoV cases with or without a history of camel exposure reported between 2012 and 2019 and dromedary camels at the provincial level in Saudi Arabia. In most provinces, a high proportion of older men develop infections after exposure to camels. Primary human infections during spring and winter were highest in provinces characterized by seasonal breeding and calving, increased camel mobilization and camel–human interactions. A strong and significant association was found between the total number of dromedary camels and the numbers of primary camel‐exposed and non‐exposed MERS‐CoV cases. Furthermore, spatial correlations between MERS‐CoV cases and camel sex, age and dairy status were significant. Via a cluster analysis, we identified Riyadh, Makkah and Eastern provinces as having the most primary MERS‐CoV cases and the highest number of camels. Transmission of MERS‐CoV from camels to humans occurs in most primary cases, but there is still a high proportion of primary infections with an ambiguous link to camels. The results from this study include significant correlations between primary MERS‐CoV cases and camel populations in all provinces, regardless of camel exposure history. This supports the hypothesis of the role of an asymptomatic human carrier or, less likely, an unknown animal host that has direct contact with both infected camels and humans. In this study, we performed a preliminary risk assessment of prioritization measures to control the transmission of infection from camels to humans.

Seroprevalence of MERS-CoV in healthy adults in western Saudi Arabia, 2011-2016

Background

The Middle East respiratory syndrome coronavirus (MERS-CoV) is a newly recognized zoonotic coronavirus. Current evidence confirms the role of dromedaries in primary human infections but does not explain the sporadic community cases. However, asymptomatic or subclinical cases could represent a possible source of infection in the community.

Methods

Archived human sera (7461) collected between 2011 and 2016 from healthy adult blood donors from 50 different nationalities in the western part of Saudi Arabia were obtained for MERS-CoV seroprevalence investigation. Samples were tested for MERS-CoV S1-specific antibodies (Abs) by ELISA and confirmed by testing for neutralizing Abs (nAbs) using both pseudotyped and live virus neutralization assays.

Results

Out of 7461 samples, 174 sera from individuals with 18 different nationalities were ELISA positive (2.3%, 95% CI 2.0–2.7). Presence of nAbs was confirmed in 17 samples (0.23%, 95% CI 0.1–0.4) of which one sample exhibited positivity in both neutralization assays. Confirmed seropositivity was identified in young (15–44 years) men and women from Saudi Arabia, Egypt, Yemen, Pakistan, Palestine, Sudan, and India without significant preference.

Conclusions

An increasing trend of MERS-CoV seroprevalence was observed in the general population in western Saudi Arabia, suggesting that asymptomatic or mild infections might exist and act as an unrecognized source of infection. Seropositivity of individuals from different nationalities underscores the potential MERS exportation outside of the Arabian Peninsula. Thus, enhanced and continuous surveillance is highly warranted.

Competitive ELISA for the Detection of Serum Antibodies Specific for Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

Middle East respiratory syndrome coronavirus (MERS-CoV) is the etiological agent of MERS, a severe respiratory disease first reported in the Middle East in 2012. Serological assays are used to diagnose MERS-CoV infection and to screen for serum antibodies in seroepidemiological studies. The conventional enzyme-linked immunosorbent assay (ELISA) is the preferred tool for detecting serum antibodies specific for pathogens; however, the utility of conventional ELISA with respect to detection of MERS-CoV antibodies is limited due to the number of false-positives caused by cross-reactivity of serum antibodies with antigens that are conserved among coronaviruses. The competitive ELISA (cELISA) uses a pathogen-specific monoclonal antibody (MAb) that competes with serum antibodies for binding to an antigen; therefore, it is used widely for serological surveillance of many pathogens. In this chapter, I describe detection of serum antibodies using cELISA based on MAbs specific for MERS-CoV.

A database of geopositioned Middle East Respiratory Syndrome Coronavirus occurrences

As a World Health Organization Research and Development Blueprint priority pathogen, there is a need to better understand the geographic distribution of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and its potential to infect mammals and humans. This database documents cases of MERS-CoV globally, with specific attention paid to zoonotic transmission. An initial literature search was conducted in PubMed, Web of Science, and Scopus; after screening articles according to the inclusion/exclusion criteria, a total of 208 sources were selected for extraction and geo-positioning. Each MERS-CoV occurrence was assigned one of the following classifications based upon published contextual information: index, unspecified, secondary, mammal, environmental, or imported. In total, this database is comprised of 861 unique geo-positioned MERS-CoV occurrences. The purpose of this article is to share a collated MERS-CoV database and extraction protocol that can be utilized in future mapping efforts for both MERS-CoV and other infectious diseases. More broadly, it may also provide useful data for the development of targeted MERS-CoV surveillance, which would prove invaluable in preventing future zoonotic spillover.

Measurement(s)	Middle East Respiratory Syndrome • geographic location
Technology Type(s)	digital curation
Factor Type(s)	geographic distribution of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) • year
Sample Characteristic - Organism	Middle East respiratory syndrome-related coronavirus
Sample Characteristic - Location	Earth (planet)

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.11108801

Sero-prevalence, cross-species infection and serological determinants of prevalence of Bovine Coronavirus in Cattle, Sheep and Goats in Ghana

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Bovine coronavirus has considerable seroprevalence in cattle across Ghana.

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Sheep and goats are kept without strict separation from cattle and show seropositivity against bovine coronavirus.

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Bovine coronavirus seroprevalence is positively correlated with large farm size.

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Highest bovine coronavirus seroprevalence was found in Ghana´s Northern Province with prevailing arid climate.

Cattle, goats and sheep are dominant livestock species in sub-Saharan Africa, with sometimes limited information on the prevalence of major infectious diseases. Restrictions due to notifiable epizootics complicate the exchange of samples in surveillance studies and suggest that laboratory capacities should be established domestically. Bovine Coronavirus (BCoV) causes mainly enteric disease in cattle. Spillover to small ruminants is possible. Here we established BCoV serology based on a recombinant immunofluorescence assay for cattle, goats and sheep, and studied the seroprevalence of BCoV in these species in four different locations in the Greater Accra, Volta, Upper East, and Northern provinces of Ghana. The whole sampling and testing was organized and conducted by a veterinary school in Kumasi, Ashanti Region of Ghana. Among sampled sheep (n = 102), goats (n = 66), and cattle (n = 1495), the seroprevalence rates were 25.8 %, 43.1 % and 55.8 %. For cattle, seroprevalence was significantly higher on larger farms (82.2 % vs 17.8 %, comparing farms with >50 or <50 animals; p = 0.027). Highest prevalence was seen in the Northern province with dry climate, but no significant trend following the north-south gradient of sampling sites was detected. Our study identifies a considerable seroprevalence for BCoV in Ghana and provides further support for the spillover of BCoV to small ruminants in settings with mixed husbandry and limited separation between species.

Evaluation of serological assays available in a biosafety level 2 laboratory and their application for survey of Middle East respiratory syndrome coronavirus among livestock in Ethiopia

A serological survey of Middle East respiratory syndrome coronavirus (MERS-CoV) was conducted among dromedary camels and herbivorous animals sharing the same pasturage in Ethiopia. The pseudotyped vesicular stomatitis virus coated with the spike protein of MERS-CoV was used in virus neutralization (VN) tests performed in a biosafety level (BSL)-2 laboratory. The results were similar to those obtained from the VN test using live MERS-CoV and were more sensitive than the ELISA performed using synthetic MERS S1 fragment as the antigen as well as the competitive ELISA performed using a monoclonal antibody against MERS-CoV. According to the comprehensive results of the four types of serodiagnosis methods, positive antibodies were detected only in dromedary camels and the remaining herbivorous animals were not infected with the virus. Moreover, using the present procedure, serological tests for MERS-CoV can be conducted even in BSL 2 laboratory.

Recombinant adenoviral vaccine encoding the spike 1 subunit of the Middle East Respiratory Syndrome Coronavirus elicits strong humoral and cellular immune responses in mice

Background and Aim

Middle East respiratory syndrome coronavirus (MERS-CoV) has rapidly spread throughout the Middle East since its discovery in 2012. The virus poses a significant global public health threat with potentially devastating effects. In this study, a recombinant adenoviral-based vaccine encoding the spike 1 (S1) subunit of the MERS-CoV genome was constructed, and its humoral, and cellular immune responses were evaluated in mice.

Materials and Methods

Mice were immunized initially by intramuscular injection and boosted 3 weeks later by intranasal application. Expression of the S1 protein in the lungs and kidneys was detected using conventional polymerase chain reaction (PCR) and immunohistochemistry (IHC) targeting specific regions within the S1 subunit at weeks 3, 4, 5, and 6 after the first vaccination. Antigen-specific humoral and cellular immune responses were evaluated in serum and in cell culture following in vitro stimulation with a specific 9-mer epitope within the S1 protein (CYSSLILDY).

Results

S1 protein expression was only detected by IHC in the kidneys of the Ad-MERS-S1 group at week 6 from first immunization, and in both lungs and kidneys of Ad-MERS-S1 group by conventional PCR at weeks 3 and 5 post-prime. The vaccine elicited a specific S1-immunoglobulin G antibody response, which was detected in the sera of the vaccinated mice at weeks 4 and 6 from the onset of the first immunization. There was a significant increase in the amount of Th1-related cytokines (interferon-γ and interleukin [IL] 12), and a significant decrease in the Th2-related cytokine IL-4 in splenocyte cell culture of the vaccinated group compared with the control groups.

Conclusion

The results of this study suggest that this recombinant adenovirus vaccine encoding the S1 subunit of MERS-CoV elicits potentially protective antigen-specific humoral and cellular immune responses in mice. This study demonstrates a promising vaccine for the control and/or prevention of MERS-CoV infection in humans.

Bovine-like coronaviruses in domestic and wild ruminants

Coronaviruses (CoVs) produce a wide spectrum of disease syndromes in different mammalian and avian host species. These viruses are well-recognized for their ability to change tissue tropism, to hurdle the interspecies barriers and to adapt ecological variations. It is predicted that the inherent genetic diversity of CoVs caused by accumulation of point mutations and high frequency of homologous recombination is the principal determinant of these competences. Several CoVs (e.g. Severe acute respiratory syndrome-CoV, Middle East respiratory syndrome-CoV) have been recorded to cross the interspecies barrier, inducing different disease conditions in variable animal hosts. Bovine CoV (BCoV) is a primary cause of gastroenteritis and respiratory disease in cattle calves, winter dysentery in lactating cows and shipping fever pneumonia in feedlot cattle. Although it has long been known as a restrictive cattle pathogen, CoVs that are closely related to BCoV have been recognized in dogs, humans and in other ruminant species. Biologic, antigenic and genetic analyses of the so-called ‘bovine-like CoVs’ proposed classification of these viruses as host-range variants rather than distinct virus species. In this review, the different bovine-like CoVs that have been identified in domesticated ruminants (water buffalo, sheep, goat, dromedary camel, llama and alpaca) and wild ruminants (deer, wild cattle, antelopes, giraffes and wild goats) are discussed in terms of epidemiology, transmission and virus characteristics. The presented data denote the importance of these viruses in the persistence of BCoV in nature, spread to new geographical zones, and continuous emergence of disease epidemics in cattle farms.

Detection of MERS-CoV antigen on formalin-fixed paraffin-embedded nasal tissue of alpacas by immunohistochemistry using human monoclonal antibodies directed against different epitopes of the spike protein

Middle East respiratory syndrome (MERS) represents an important respiratory disease accompanied by lethal outcome in one third of human patients. In recent years, several investigators developed protective antibodies which could be used as prophylaxis in prospective human epidemics. In the current study, eight human monoclonal antibodies (mAbs) with neutralizing and non-neutralizing capabilities, directed against different epitopes of the MERS-coronavirus (MERS-CoV) spike (MERS-S) protein, were investigated with regard to their ability to immunohistochemically detect respective epitopes on formalin-fixed paraffin-embedded (FFPE) nasal tissue sections of MERS-CoV experimentally infected alpacas. The most intense immunoreaction was detected using a neutralizing antibody directed against the receptor binding domain S1B of the MERS-S protein, which produced an immunosignal in the cytoplasm of ciliated respiratory epithelium and along the apical membranous region. A similar staining was obtained by two other mAbs which recognize the sialic acid-binding domain and the ectodomain of the membrane fusion subunit S2, respectively. Five mAbs lacked immunoreactivity for MERS-CoV antigen on FFPE tissue, even though they belong, at least in part, to the same epitope group. In summary, three tested human mAbs demonstrated capacity for detection of MERS-CoV antigen on FFPE samples and may be implemented in double or triple immunohistochemical methods.

Molecular Study and Phylogenetic Analysis of Middle East Respiratory Syndrome Corona Virus (MERSCoV) in Camel and Human

Middle East Respiratory Syndrome Corona Virus (MERSCoV) have been reported in Arabian peninsula and sporadic cases in Europe and Asia. This study was conducted to evaluate the genetic analysis of this virus in human and camel at the first time in Iraq. Two hundred samples were collected from camels and human who suffering from respiratory symptoms, these samples treated with RNA extraction kit then amplification the genetic material by PCR which give 5% positive results. The amplicon then sequenced, registration in gene bank of NCBI for getting accession numbers. The local strains give close relationship with neighbor countries as Saudi Arabia and Jordan strains when using MEGA analysis software.

Selection and Characterization of Monoclonal Antibodies Targeting Middle East Respiratory Syndrome Coronavirus through a Human Synthetic Fab Phage Display Library Panning

Since its first report in the Middle East in 2012, the Middle East respiratory syndrome-coronavirus (MERS-CoV) has become a global concern due to the high morbidity and mortality of individuals infected with the virus. Although the majority of MERS-CoV cases have been reported in Saudi Arabia, the overall risk in areas outside the Middle East remains significant as inside Saudi Arabia. Additional pandemics of MERS-CoV are expected, and thus novel tools and reagents for therapy and diagnosis are urgently needed. Here, we used phage display to develop novel monoclonal antibodies (mAbs) that target MERS-CoV. A human Fab phage display library was panned against the S2 subunit of the MERS-CoV spike protein (MERS-S2P), yielding three unique Fabs (S2A3, S2A6, and S2D5). The Fabs had moderate apparent affinities (Half maximal effective concentration (EC50 = 123-421 nM) for MERS-S2P, showed no cross-reactivity to spike proteins from other CoVs, and were non-aggregating and thermostable (Tm = 61.5-80.4 °C). Reformatting the Fabs into IgGs (Immunoglobulin Gs) greatly increased their apparent affinities (KD = 0.17-1.2 nM), presumably due to the effects of avidity. These apparent affinities were notably higher than that of a previously reported anti-MERS-CoV S2 reference mAb (KD = 8.7 nM). Furthermore, two of the three mAbs (S2A3 and S2D5) bound only MERS-CoV (Erasmus Medical Center (EMC)) and not other CoVs, reflecting their high binding specificity. However, the mAbs lacked MERS-CoV neutralizing activity. Given their high affinity, specificity, and desirable stabilities, we anticipate that these anti-MERS-CoV mAbs would be suitable reagents for developing antibody-based diagnostics in laboratory or hospital settings for point-of-care testing.

Species-Specific Colocalization of Middle East Respiratory Syndrome Coronavirus Attachment and Entry Receptors

MERS-CoV uses the S1^B domain of its spike protein to attach to its host receptor, dipeptidyl peptidase 4 (DPP4). The tissue localization of DPP4 has been mapped in different susceptible species. On the other hand, the S1^A domain, the N-terminal domain of this spike protein, preferentially binds to several glycotopes of α2,3-sialic acids, the attachment factor of MERS-CoV. Here we show, using a novel method, that the S1^A domain specifically binds to the nasal epithelium of dromedary camels, alveolar epithelium of humans, and intestinal epithelium of common pipistrelle bats. In contrast, it does not bind to the nasal epithelium of pigs or rabbits, nor does it bind to the intestinal epithelium of serotine bats and frugivorous bat species. This finding supports the importance of the S1^A domain in MERS-CoV infection and tropism, suggests its role in transmission, and highlights its potential use as a component of novel vaccine candidates.

Middle East respiratory syndrome coronavirus (MERS-CoV) uses the S1^B domain of its spike protein to bind to dipeptidyl peptidase 4 (DPP4), its functional receptor, and its S1^A domain to bind to sialic acids. The tissue localization of DPP4 in humans, bats, camelids, pigs, and rabbits generally correlates with MERS-CoV tropism, highlighting the role of DPP4 in virus pathogenesis and transmission. However, MERS-CoV S1^A does not indiscriminately bind to all α2,3-sialic acids, and the species-specific binding and tissue distribution of these sialic acids in different MERS-CoV-susceptible species have not been investigated. We established a novel method to detect these sialic acids on tissue sections of various organs of different susceptible species by using nanoparticles displaying multivalent MERS-CoV S1^A. We found that the nanoparticles specifically bound to the nasal epithelial cells of dromedary camels, type II pneumocytes in human lungs, and the intestinal epithelial cells of common pipistrelle bats. Desialylation by neuraminidase abolished nanoparticle binding and significantly reduced MERS-CoV infection in primary susceptible cells. In contrast, S1^A nanoparticles did not bind to the intestinal epithelium of serotine bats and frugivorous bat species, nor did they bind to the nasal epithelium of pigs and rabbits. Both pigs and rabbits have been shown to shed less infectious virus than dromedary camels and do not transmit the virus via either contact or airborne routes. Our results depict species-specific colocalization of MERS-CoV entry and attachment receptors, which may be relevant in the transmission and pathogenesis of MERS-CoV.

IMPORTANCE MERS-CoV uses the S1^B domain of its spike protein to attach to its host receptor, dipeptidyl peptidase 4 (DPP4). The tissue localization of DPP4 has been mapped in different susceptible species. On the other hand, the S1^A domain, the N-terminal domain of this spike protein, preferentially binds to several glycotopes of α2,3-sialic acids, the attachment factor of MERS-CoV. Here we show, using a novel method, that the S1^A domain specifically binds to the nasal epithelium of dromedary camels, alveolar epithelium of humans, and intestinal epithelium of common pipistrelle bats. In contrast, it does not bind to the nasal epithelium of pigs or rabbits, nor does it bind to the intestinal epithelium of serotine bats and frugivorous bat species. This finding supports the importance of the S1^A domain in MERS-CoV infection and tropism, suggests its role in transmission, and highlights its potential use as a component of novel vaccine candidates.

Middle East respiratory syndrome coronavirus infection in non-camelid domestic mammals

Dromedary camels are natural host of the Middle East respiratory syndrome coronavirus (MERS-CoV). However, there are limited studies of MERS-CoV infection of other domestic mammals exposed to infected dromedaries. We expanded our surveillance among camels in Egypt, Tunisia, and Senegal to include other domestic mammalian species in contact with infected camels. A total of 820 sera and 823 nasal swabs from cattle, sheep, goats, donkeys, buffaloes, mules, and horses were collected. Swabs were tested using RT-PCR and virus RNA-positive samples were genetically sequenced and phylogenetically analysed. Sera were screened using virus microneutralization tests and positive sera (where available) were confirmed using plaque reduction neutralization tests (PRNT). We detected 90% PRNT confirmed MERS-CoV antibody in 35 (55.6%) of 63 sera from sheep collected from Senegal, two sheep (1.8%) of 114 in Tunisia and a goat (0.9%) of 107 in Egypt, with titres ranging from 1:80 to ≥1:320. We detected MERS-CoV RNA in swabs from three sheep (1.2%) of 254 and five goats (4.1%) of 121 from Egypt and Senegal, as well as one cow (1.9%) of 53 and three donkeys (7.1%) of 42 from Egypt. Partial sequences of the RT-PCR amplicons confirmed specificity of the results. This study showed that domestic livestock in contact with MERS-CoV infected camels may be at risk of infection. We recommend expanding current MERS-CoV surveillance in animals to include other livestock in close contact with dromedary camels. The segregation of camels from other livestock in farms and live animal markets may need to be considered.