Middle East respiratory syndrome coronavirus (MERS-CoV) neutralising antibodies in a high-risk human population, Morocco, November 2017 to January 2018

Low-Level Zoonotic Transmission of Clade C MERS-CoV in Africa: Insights from Scoping Review and Cohort Studies in Hospital and Community Settings

Human outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) are more common in Middle Eastern and Asian human populations, associated with clades A and B. In Africa, where clade C is dominant in camels, human cases are minimal. We reviewed 16 studies (n = 6198) published across seven African countries between 2012 and 2024 to assess human MERS-CoV cases. We also analyzed data from four cohort studies conducted in camel-keeping communities between 2018 and 2024 involving camel keepers, camel slaughterhouse workers, and hospital patients with acute respiratory illness (ARI). The analysis showed a pooled MERS-CoV prevalence of 2.4% (IQR: 0.6, 11.4) from 16 publications and 1.14% from 4 cohort studies (n = 2353). Symptomatic cases were rarely reported, with most individuals reporting camel contact, and only 12% had travel history to the Middle East. There was one travel-associated reported death, resulting in a mortality rate of 0.013%. The findings suggest a low camel-to-human transmission of clade C MERS-CoV in Africa. Ongoing research focuses on genomic comparisons between clade C and the more virulent clades A and B, alongside the surveillance of viral evolution. This study highlights the need for continuous monitoring but indicates that MERS-CoV clade C currently poses a minimal public health threat in Africa.

MERS-CoV seroconversion amongst Malaysian Hajj pilgrims returning from the Middle East, 2016-2018: results from the MERCURIAL multiyear prospective cohort study

Prospective cohort study to investigate the potential exposure to the Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) following Hajj pilgrims is still very limited. Here, we report the antibody seroconversion study results obtained from successive three years cohort studies (2016-2018) involving the Malaysian Hajj pilgrims returning from the Middle East. A cohort study of Hajj pilgrims from Malaysia enrolled 2,863 participants from 2016-2018, all of whom consented to provide paired blood samples for both pre- and post-Hajj travel to the Middle East. ELISAs and micro-neutralization assays were performed to detect the presence of MERS-CoV IgG antibodies. Sociodemographic data, symptoms experienced during Hajj, and history of exposure to camels or camel products were recorded using structured pre- and post-Hajj questionnaires. A 4-fold increase in anti-MERS-CoV IgG between paired pre-Hajj and post-Hajj serum samples in twelve participants was observed. None of the twelve ELISA-positive sera had detectable levels of virus-neutralizing antibodies. All reportedly had mild symptoms of respiratory symptoms at a certain point during the pilgrimage, implying mild or asymptomatic infections. No association between post-Hajj serum positivity and a history of exposure to camels or camel products was obtained. Findings from the study suggest that serologic conversion to MERS-CoV occurred in at least 0.6% of the Hajj pilgrims returning from the Middle East. Since all the seroconvertants had mild to no symptoms during the sampling period, it highlights the likelihood of occurrence of only low infectivity spillover infections among the Hajj pilgrims.

Serosurvey for Middle East respiratory syndrome coronavirus antibody in dromedary camels and human patients at a secondary care hospital, Illela, Northwest Nigeria

Middle East respiratory syndrome (MERS) is a serious emerging zoonosis. It is characterized by severe infection of the respiratory tract in humans. Dromedary camels are considered to be the most probable origin of the pathogenic Middle East respiratory syndrome coronavirus (MERS-CoV). This cross-sectional survey was carried out to ascertain the seroprevalence of MERS-CoV in dromedary camels at Illela border and human patients in a secondary care hospital in Illela, Sokoto State, Nigeria from November 2016 to January 2017. Serum samples from 74 camels and 39 human patients were collected while a data form was administered to the camel handlers (40) and human patients to obtain information on zoographic characteristics of dromedary camels, demographic characteristics of camel handlers and human patients and some practices of both groups which are likely to predispose to MERS-CoV infection. The serum samples were analyzed for antibodies against MERS-CoV using the indirect Enzyme-Linked Immuno-Sorbent Assay (ELISA). All the camels sampled were seropositive against MERS-CoV and 74% of the human patients had antibodies against MERS. All handlers treated their camels without consulting veterinarians and there was little or no biosecurity measures undertaken. Age, sex, and occupation were not significant determinants for the presence of MERS-CoV antibody in human patients sampled. This study serves as a baseline for similar researches and due to the high seroprevalence obtained in this study for both camels and humans, there is need for trained personnel, surveillance and diagnostic tools at our border posts and animal markets.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00580-022-03351-3.

Unresolved questions in the zoonotic transmission of MERS

The Middle East Respiratory Syndrome-coronavirus (MERS-CoV) is the second of three zoonotic coronaviruses to infect humans since 2002, causing severe pneumonia. Unlike SARS-CoV-1 and SARS-CoV-2, the causes of the severe acute respiratory syndrome and Covid-19, respectively, MERS-CoV is enzootic in dromedary camels, a domestic/companion animal present across Africa, the Middle East and Central or South Asia and is sporadically transmitted to humans. However, it does not transmit readily from human to human except in hospital and household settings. Human MERS disease is reported only from the Arabian Peninsula (and only since 2012 even though the virus was detected in camels from at least the early 1990's) and in travelers from this region. Remarkably, no zoonotic MERS disease has been detected in Africa or Asia, even in areas of high density of MERS-CoV infected dromedaries. Here, we review aspects of MERS biology and epidemiology that might contribute to this lack of correlation between sites of camel infection and human zoonotic disease. Since MERS-CoV or MERS-like CoV have pandemic potential, further investigations into this disparity is critical, to forestall pandemics caused by this virus.

Effect of identified non-synonymous mutations in DPP4 receptor binding residues among highly exposed human population in Morocco to MERS-CoV through computational approach

Dipeptidyl peptidase 4 (DPP4) has been identified as the main receptor of MERS-CoV facilitating its cellular entry and enhancing its viral replication upon the emergence of this novel coronavirus. DPP4 receptor is highly conserved among many species, but the genetic variability among direct binding residues to MERS-CoV restrained its cellular tropism to humans, camels and bats. The occurrence of natural polymorphisms in human DPP4 binding residues is not well characterized. Therefore, we aimed to assess the presence of potential mutations in DPP4 receptor binding domain (RBD) among a population highly exposed to MERS-CoV in Morocco and predict their effect on DPP4 –MERS-CoV binding affinity through a computational approach. DPP4 synonymous and non-synonymous mutations were identified by sanger sequencing, and their effect were modelled by mutation prediction tools, docking and molecular dynamics (MD) simulation to evaluate structural changes in human DPP4 protein bound to MERS-CoV S1 RBD protein. We identified eight mutations, two synonymous mutations (A291 =, R317 =) and six non-synonymous mutations (N229I, K267E, K267N, T288P, L294V, I295L). Through docking and MD simulation techniques, the chimeric DPP4 –MERS-CoV S1 RBD protein complex models carrying one of the identified non-synonymous mutations sustained a stable binding affinity for the complex that might lead to a robust cellular attachment of MERS-CoV except for the DPP4 N229I mutation. The latter is notable for a loss of binding affinity of DPP4 with MERS-CoV S1 RBD that might affect negatively on cellular entry of the virus. It is important to confirm our molecular modelling prediction with in-vitro studies to acquire a broader overview of the effect of these identified mutations.

Molecular modelling on SARS-CoV-2 papain-like protease: an integrated study with homology modelling, molecular docking, and molecular dynamics simulations

SARS-CoV-2 PLpro was investigated as a therapeutic target for potent antiviral drugs due to its essential role in not only viral replication but also in regulating the inborn immune response. Several computational approaches, including homology modelling, molecular docking, and molecular dynamics (MD) studies, were employed to search for promising drugs in treating SARS-CoV-2. Eighty-one compounds, sub-structurally similar to the antiviral drug, were used as potential inhibitors of PLpro. From our results, three complexes containing the ligands with Pubchem IDs: 153012995, 12149203, and 123608715 showed lower binding energies than the control (Ritonavir), indicating that they may become promising inhibitors for PLpro. MD was performed in a water solvent to validate the stability of the three complexes. All complexes achieved stable structure during the simulation as no significant fluctuations were observed in the validation parameters. Moreover, the binding energy for each complex was estimated using the MM-GBSA method. Complex 1 was the most stable structure based on the lowest binding energy score and its structure remained in a similar cavity with the docket snapshot. Based on our studies, three ligands were assumed to be potential inhibitors. The ligand of complex 1 may become the most promising antiviral drug against SARS-CoV-2 targeting PLpro.

Phenotypic and genetic characterization of MERS coronaviruses from Africa to understand their zoonotic potential

The absence of zoonotic MERS-CoV in Africa in spite of an abundance of MERS-CoV–infected dromedaries has remained an enigma. We demonstrate that geographically and genetically distinct viruses from Africa have low replication competence in the human lung, providing a possible explanation for the absence of severe MERS disease in Africa. The findings suggest that MERS-CoV now entrenched in the Arabian Peninsula has acquired increased pathogenic potential for humans. We demonstrate that the spike protein contributes to this phenotypic difference. If pathogenic clade B viruses from the Arabian Peninsula are introduced into Africa, they are likely to become dominant, as they have in the Arabian Peninsula, and to be associated with adverse health impacts in Africa and increased pandemic threat.

Coronaviruses are pathogens of pandemic potential. Middle East respiratory syndrome coronavirus (MERS-CoV) causes a zoonotic respiratory disease of global public health concern, and dromedary camels are the only proven source of zoonotic infection. More than 70% of MERS-CoV–infected dromedaries are found in East, North, and West Africa, but zoonotic MERS disease is only reported from the Arabian Peninsula. We compared viral replication competence of clade A and B viruses from the Arabian Peninsula with genetically diverse clade C viruses found in East (Egypt, Kenya, and Ethiopia), North (Morocco), and West (Nigeria and Burkina Faso) Africa. Viruses from Africa had lower replication competence in ex vivo cultures of the human lung and in lungs of experimentally infected human-DPP4 (hDPP4) knockin mice. We used lentivirus pseudotypes expressing MERS-CoV spike from Saudi Arabian clade A prototype strain (EMC) or African clade C1.1 viruses and demonstrated that clade C1.1 spike was associated with reduced virus entry into the respiratory epithelial cell line Calu-3. Isogenic EMC viruses with spike protein from EMC or clade C1.1 generated by reverse genetics showed that the clade C1.1 spike was associated with reduced virus replication competence in Calu-3 cells in vitro, in ex vivo human bronchus, and in lungs of hDPP4 knockin mice in vivo. These findings may explain why zoonotic MERS disease has not been reported from Africa so far, despite exposure to and infection with MERS-CoV.

Evolution, Ecology, and Zoonotic Transmission of Betacoronaviruses: A Review

Coronavirus infections have been a part of the animal kingdom for millennia. The difference emerging in the twenty-first century is that a greater number of novel coronaviruses are being discovered primarily due to more advanced technology and that a greater number can be transmitted to humans, either directly or via an intermediate host. This has a range of effects from annual infections that are mild to full-blown pandemics. This review compares the zoonotic potential and relationship between MERS, SARS-CoV, and SARS-CoV-2. The role of bats as possible host species and possible intermediate hosts including pangolins, civets, mink, birds, and other mammals are discussed with reference to mutations of the viral genome affecting zoonosis. Ecological, social, cultural, and environmental factors that may play a role in zoonotic transmission are considered with reference to SARS-CoV, MERS, and SARS-CoV-2 and possible future zoonotic events.

A review targeting the infection by CHIKV using computational and experimental approaches

The rise of normal body temperature of 98.6 °F beyond 100.4 °F in humans indicates fever due to some illness or infection. Viral infections caused by different viruses are one of the major causes of fever. One of such viruses is, Chikungunya virus (CHIKV) is known to cause Chikungunya fever (CHIKF) which is transmitted to humans through the mosquitoes, which actually become the primary source of transmission of the virus. The genomic structure of the CHIKV consists of the two open reading frames (ORFs). The first one is a 5' end ORF and it encodes the nonstructural protein (nsP1-nsP4). The second is a 3' end ORF and it encodes the structural proteins, which is consisted of capsid, envelope (E), accessory peptides, E3 and 6 K. Till date, there is no effective vaccine or medicine available for early detection of the CHIKV infection and appropriate diagnosis to cure the patients from the infection. NSP3 of CHIKV is the prime target of the researchers as it is responsible for the catalytic activity. This review has updates of literature on CHIKV; pathogenesis of CHIKV; inhibition of CHIKV using theoretical and experimental approaches.Communicated by Ramaswamy H. Sarma.

T-cell responses to MERS coronavirus infection in people with occupational exposure to dromedary camels in Nigeria: an observational cohort study

BACKGROUND

Middle East respiratory syndrome (MERS) remains of global public health concern. Dromedary camels are the source of zoonotic infection. Over 70% of MERS coronavirus (MERS-CoV)-infected dromedaries are found in Africa but no zoonotic disease has been reported in Africa. We aimed to understand whether individuals with exposure to dromedaries in Africa had been infected by MERS-CoV.

METHODS

Workers slaughtering dromedaries in an abattoir in Kano, Nigeria, were compared with abattoir workers without direct dromedary contact, non-abattoir workers from Kano, and controls from Guangzhou, China. Exposure to dromedaries was ascertained using a questionnaire. Serum and peripheral blood mononuclear cells (PBMCs) were tested for MERS-CoV specific neutralising antibody and T-cell responses.

FINDINGS

None of the participants from Nigeria or Guangdong were MERS-CoV seropositive. 18 (30%) of 61 abattoir workers with exposure to dromedaries, but none of 20 abattoir workers without exposure (p=0·0042), ten non-abattoir workers or 24 controls from Guangzhou (p=0·0002) had evidence of MERS-CoV-specific CD4+ or CD8+ T cells in PBMC. T-cell responses to other endemic human coronaviruses (229E, OC43, HKU-1, and NL-63) were observed in all groups with no association with dromedary exposure. Drinking both unpasteurised camel milk and camel urine was significantly and negatively associated with T-cell positivity (odds ratio 0·07, 95% CI 0·01-0·54).

INTERPRETATION

Zoonotic infection of dromedary-exposed individuals is taking place in Nigeria and suggests that the extent of MERS-CoV infections in Africa is underestimated. MERS-CoV could therefore adapt to human transmission in Africa rather than the Arabian Peninsula, where attention is currently focused.

FUNDING

The National Science and Technology Major Project, National Institutes of Health.

The Middle East respiratory syndrome coronavirus in the breath of some infected dromedary camels (Camelus dromedarius)

Dromedary camels remain the currently identified reservoir for the Middle East respiratory syndrome coronavirus (MERS-CoV). The virus is released in the secretions of the infected camels, especially the nasal tract. The virus shedding curve through the nasal secretions was studied. Although human transmission of the virus through the respiratory tract of close contact people with dromedary reported previously, the exact mechanism of transmission is still largely unknown. The main goal of this study was to check the possibility of MERS-CoV shedding in the exhaled air of the infected camels. To achieve this goal, we conducted a follow-up study in one of the dromedary camel herds, December 2018–April 2019. We tested nasal swabs, breath samples from animals within this herd by the real-time PCR. Our results showed that some of the tested nasal swabs and breath were positive from 24 March 2019 until 7 April 2019. The phylogenetic analysis of the obtained S and N gene sequences revealed the detected viruses are clustering together with some human and camel samples from the eastern region, especially from Al-Hufuf city, as well as some samples from Qatar and Jordon. These results are clearly showing the possibility of shedding of the virus in the breath of the infected camels. This could explain, at least in part, the mechanism of transmission of MERS-CoV from animals to humans. This study is confirming the shedding of MERS-CoV in the exhaled air of the infected camels. Further studies are needed for a better understanding of the MERS-CoV.

Understanding the binding affinity of noscapines with protease of SARS-CoV-2 for COVID-19 using MD simulations at different temperatures

The current outbreak of a novel coronavirus, named as SARS-CoV-2 causing COVID-19 occurred in 2019, is in dire need of finding potential therapeutic agents. Recently, ongoing viral epidemic due to coronavirus (SARS-CoV-2) primarily affected mainland China that now threatened to spread to populations in most countries of the world. In spite of this, there is currently no antiviral drug/ vaccine available against coronavirus infection, COVID-19. In the present study, computer-aided drug design-based screening to find out promising inhibitors against the coronavirus (SARS-CoV-2) leads to infection, COVID-19. The lead therapeutic molecule was investigated through docking and molecular dynamics simulations. In this, binding affinity of noscapines(23B)-protease of SARS-CoV-2 complex was evaluated through MD simulations at different temperatures. Our research group has established that noscapine is a chemotherapeutic agent for the treatment of drug resistant cancers; however, noscapine was also being used as anti-malarial, anti-stroke and cough-suppressant. This study suggests for the first time that noscapine exerts its antiviral effects by inhibiting viral protein synthesis.

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

The COVID-19 pandemic: implications for the cytology laboratory

The coronavirus disease 2019 (COVID-19) is a pandemic caused by the SARS-CoV-2 virus. The infection has predominantly respiratory transmission and is transmitted through large droplets or aerosols, and less commonly by contact with infected surfaces or fomites. The alarming spread of the infection and the severe clinical disease that it may cause have led to the widespread institution of social distancing measures. Because of repeated exposure to potentially infectious patients and specimens, health care and laboratory personnel are particularly susceptible to contract COVID-19. This review paper provides an assessment of the current state of knowledge about the disease and its pathology, and the potential presence of the virus in cytology specimens. It also discusses the measures that cytology laboratories can take to function during the pandemic, and minimize the risk to their personnel, trainees, and pathologists. In addition, it explores potential means to continue to educate trainees during the COVID-19 pandemic.

Estimating clinical severity of COVID-19 from the transmission dynamics in Wuhan, China

As of 29 February 2020 there were 79,394 confirmed cases and 2,838 deaths from COVID-19 in mainland China. Of these, 48,557 cases and 2,169 deaths occurred in the epicenter, Wuhan. A key public health priority during the emergence of a novel pathogen is estimating clinical severity, which requires properly adjusting for the case ascertainment rate and the delay between symptoms onset and death. Using public and published information, we estimate that the overall symptomatic case fatality risk (the probability of dying after developing symptoms) of COVID-19 in Wuhan was 1.4% (0.9-2.1%), which is substantially lower than both the corresponding crude or naïve confirmed case fatality risk (2,169/48,557 = 4.5%) and the approximator1 of deaths/deaths + recoveries (2,169/2,169 + 17,572 = 11%) as of 29 February 2020. Compared to those aged 30-59 years, those aged below 30 and above 59 years were 0.6 (0.3-1.1) and 5.1 (4.2-6.1) times more likely to die after developing symptoms. The risk of symptomatic infection increased with age (for example, at ~4% per year among adults aged 30-60 years).

Nowcasting and forecasting the potential domestic and international spread of the 2019-nCoV outbreak originating in Wuhan, China: a modelling study

BACKGROUND

Since Dec 31, 2019, the Chinese city of Wuhan has reported an outbreak of atypical pneumonia caused by the 2019 novel coronavirus (2019-nCoV). Cases have been exported to other Chinese cities, as well as internationally, threatening to trigger a global outbreak. Here, we provide an estimate of the size of the epidemic in Wuhan on the basis of the number of cases exported from Wuhan to cities outside mainland China and forecast the extent of the domestic and global public health risks of epidemics, accounting for social and non-pharmaceutical prevention interventions.

METHODS

We used data from Dec 31, 2019, to Jan 28, 2020, on the number of cases exported from Wuhan internationally (known days of symptom onset from Dec 25, 2019, to Jan 19, 2020) to infer the number of infections in Wuhan from Dec 1, 2019, to Jan 25, 2020. Cases exported domestically were then estimated. We forecasted the national and global spread of 2019-nCoV, accounting for the effect of the metropolitan-wide quarantine of Wuhan and surrounding cities, which began Jan 23-24, 2020. We used data on monthly flight bookings from the Official Aviation Guide and data on human mobility across more than 300 prefecture-level cities in mainland China from the Tencent database. Data on confirmed cases were obtained from the reports published by the Chinese Center for Disease Control and Prevention. Serial interval estimates were based on previous studies of severe acute respiratory syndrome coronavirus (SARS-CoV). A susceptible-exposed-infectious-recovered metapopulation model was used to simulate the epidemics across all major cities in China. The basic reproductive number was estimated using Markov Chain Monte Carlo methods and presented using the resulting posterior mean and 95% credibile interval (CrI).

FINDINGS

In our baseline scenario, we estimated that the basic reproductive number for 2019-nCoV was 2·68 (95% CrI 2·47-2·86) and that 75 815 individuals (95% CrI 37 304-130 330) have been infected in Wuhan as of Jan 25, 2020. The epidemic doubling time was 6·4 days (95% CrI 5·8-7·1). We estimated that in the baseline scenario, Chongqing, Beijing, Shanghai, Guangzhou, and Shenzhen had imported 461 (95% CrI 227-805), 113 (57-193), 98 (49-168), 111 (56-191), and 80 (40-139) infections from Wuhan, respectively. If the transmissibility of 2019-nCoV were similar everywhere domestically and over time, we inferred that epidemics are already growing exponentially in multiple major cities of China with a lag time behind the Wuhan outbreak of about 1-2 weeks.

INTERPRETATION

Given that 2019-nCoV is no longer contained within Wuhan, other major Chinese cities are probably sustaining localised outbreaks. Large cities overseas with close transport links to China could also become outbreak epicentres, unless substantial public health interventions at both the population and personal levels are implemented immediately. Independent self-sustaining outbreaks in major cities globally could become inevitable because of substantial exportation of presymptomatic cases and in the absence of large-scale public health interventions. Preparedness plans and mitigation interventions should be readied for quick deployment globally.

FUNDING

Health and Medical Research Fund (Hong Kong, China).