Serologic Detection of Middle East Respiratory Syndrome Coronavirus Functional Antibodies.

We developed and validated 2 species-independent protein-based assays to detect Middle East respiratory syndrome coronavirus functional antibodies that can block virus receptor-binding or sialic acid-attachment. Antibody levels measured in both assays correlated strongly with virus-neutralizing antibody titers, proving their use for serologic confirmatory diagnosis of Middle East respiratory syndrome.

Sensitive and Specific Detection of Low-Level Antibody Responses in Mild Middle East Respiratory Syndrome Coronavirus Infections.

Middle East respiratory syndrome coronavirus (MERS-CoV) infections in humans can cause asymptomatic to fatal lower respiratory lung disease. Despite posing a probable risk for virus transmission, asymptomatic to mild infections can go unnoticed; a lack of seroconversion among some PCR-confirmed cases has been reported. We found that a MERS-CoV spike S1 protein-based ELISA, routinely used in surveillance studies, showed low sensitivity in detecting infections among PCR-confirmed patients with mild clinical symptoms and cross-reactivity of human coronavirus OC43-positive serum samples. Using in-house S1 ELISA and protein microarray, we demonstrate that most PCR-confirmed MERS-CoV case-patients with mild infections seroconverted; nonetheless, some of these samples did not have detectable levels of virus-neutralizing antibodies. The use of a sensitive and specific serologic S1-based assay can be instrumental in the accurate estimation of MERS-CoV prevalence.

Lack of Middle East Respiratory Syndrome Coronavirus Transmission in Rabbits.

Middle East respiratory syndrome coronavirus (MERS-CoV) transmission from dromedaries to humans has resulted in major outbreaks in the Middle East. Although some other livestock animal species have been shown to be susceptible to MERS-CoV, it is not fully understood why the spread of the virus in these animal species has not been observed in the field. In this study, we used rabbits to further characterize the transmission potential of MERS-CoV. In line with the presence of MERS-CoV receptor in the rabbit nasal epithelium, high levels of viral RNA were shed from the nose following virus inoculation. However, unlike MERS-CoV-infected dromedaries, these rabbits did not develop clinical manifestations including nasal discharge and did shed only limited amounts of infectious virus from the nose. Consistently, no transmission by contact or airborne routes was observed in rabbits. Our data indicate that despite relatively high viral RNA levels produced, low levels of infectious virus are excreted in the upper respiratory tract of rabbits as compared to dromedary camels, thus resulting in a lack of viral transmission.

How Do the First Days Count? A Case Study of Qatar Experience in Emergency Risk Communication during the MERS-CoV Outbreak.

This case study is the first to be developed in the Middle East region to document what happened during the response to the 2013 MERS outbreak in Qatar. It provides a description of key epidemiologic events and news released from a prime daily newspaper and main Emergency Risk Communication (ERC) actions that were undertaken by public health authorities. Using the Crisis and Emergency Risk Communication (CERC) theoretical framework, the study analyzes how the performed ERC strategies during the first days of the outbreak might have contributed to the outbreak management. METHODS: MERS-CoV related events were chronologically tracked, together with the relevant stories that were published in a major newspaper over the course of three distinct phases of the epidemic. The collected media stories were then assessed against the practiced emergency risk communication (ERC) activities during the same time frame. RESULTS: The Crisis & Emergency Risk Communication (CERC) framework was partially followed during the early days of the MERS-CoV epidemic, which were characterized by overwhelming uncertainty. The SCH's commitment to a proactive and open risk communication strategy since day one, contributed to creating the SCH's image as a credible source of information and allowed for the quick initiation of the overall response efforts. Yet, conflicting messages and over reassurance were among the observed pitfalls of the implemented ERC strategy. CONCLUSION: The adoption of CERC principles can help restore and maintain the credibility of responding agencies. Further work is needed to develop more rigorous and comprehensive research strategies that address sharing of information by mainstream as well as social media for a more accurate assessment of the impact of the ERC strategy.

Risk Factors for Primary Middle East Respiratory Syndrome Coronavirus Infection in Camel Workers in Qatar During 2013-2014: A Case-Control Study.

The transmission routes and risk factors for zoonotic Middle East respiratory syndrome coronavirus (MERS-CoV) infections are still unknown. We used the World Health Organization questionnaire for MERS-CoV case-control studies to assess risk factors for human MERS-CoV seropositivity at a farm complex in Qatar. Nine camel workers with MERS-CoV antibodies and 43 workers without antibodies were included. Some camel-related activities may pose a higher risk of MERS-CoV infection, as may cross-border movements of camels, poor hand hygiene, and overnight hospital stays with respiratory complaints. The risk factors identified in this study can be used to develop infection prevention and control measures for human MERS-CoV infections.

High proportion of MERS-CoV shedding dromedaries at slaughterhouse with a potential epidemiological link to human cases, Qatar 2014.

Two of the earliest Middle East respiratory syndrome (MERS) cases were men who had visited the Doha central animal market and adjoining slaughterhouse in Qatar. We show that a high proportion of camels presenting for slaughter in Qatar show evidence for nasal MERS-CoV shedding (62/105). Sequence analysis showed the circulation of at least five different virus strains at these premises, suggesting that this location is a driver of MERS-CoV circulation and a high-risk area for human exposure. No correlation between RNA loads and levels of neutralizing antibodies was observed, suggesting limited immune protection and potential for reinfection despite previous exposure.

Occupational Exposure to Dromedaries and Risk for MERS-CoV Infection, Qatar, 2013-2014.

We determined the presence of neutralizing antibodies to Middle East respiratory syndrome coronavirus in persons in Qatar with and without dromedary contact. Antibodies were only detected in those with contact, suggesting dromedary exposure as a risk factor for infection. Findings also showed evidence for substantial underestimation of the infection in populations at risk in Qatar.

Reliable typing of MERS-CoV variants with a small genome fragment.

BACKGROUND: Middle East Respiratory Syndrome coronavirus (MERS-CoV) is an emerging pathogen that causes lower respiratory tract infection in humans. Camels are the likely animal source for zoonotic infection, although exact transmission modes remain to be determined. Human-to-human transmission occurs sporadically. The wide geographic distribution of MERS-CoV among dromedary camels and ongoing transmissions to humans provides concern for the evolution of a MERS-CoV variant with efficient human-to-human transmission capabilities. Phylogenetic analysis of MERS-CoV has occurred by analysis of full-length genomes or multiple concatenated genome fragments, which is time-consuming, costly and limited to high viral load samples. OBJECTIVE: To develop a simple, reliable MERS-CoV variant typing assay to facilitate monitoring of MERS-CoV diversity in animals and humans. STUDY DESIGN: Phylogenetic analysis of presently known full-length MERS-CoV genomes was performed to identify genomic regions with sufficient phylogenetic content to allow reliable MERS-CoV variant typing. RT-PCR assays targeting these regions were designed and optimized. RESULTS: A reverse-transcription PCR assay for MERS-CoV targeting a 615 bp spike fragment provides a phylogenetic clustering of MERS-CoV variants comparable to that of full-length genomes. The detection limit corresponds to a cycle treshold value of ∼ 35 with standard upE real time PCR assays on RNA isolated from MERS-CoV EMC. Nasal swabs from RT-PCR positive camels (Ct values 12.9-32.2) yielded reliable sequence information in 14 samples. CONCLUSIONS: We developed a simple, reliable MERS-CoV variant typing assay which is crucial in monitoring MERS-CoV circulation in real time with relatively little investment on location.

Immunogenicity of an adenoviral-based Middle East Respiratory Syndrome coronavirus vaccine in BALB/c mice.

A new type of coronavirus has been identified as the causative agent underlying Middle East Respiratory Syndrome (MERS). The MERS coronavirus (MERS-CoV) has spread in the Middle East, but cases originating in the Middle East have also occurred in the European Union and the USA. Eight hundred and thirty-seven cases of MERS-CoV infection have been confirmed to date, including 291 deaths. MERS-CoV has infected dromedary camel populations in the Middle East at high rates, representing an immediate source of human infection. The MERS-CoV spike (S) protein, a characteristic structural component of the viral envelope, is considered as a key target of vaccines against coronavirus infection. In an initial attempt to develop a MERS-CoV vaccine to ultimately target dromedary camels, we constructed two recombinant adenoviral vectors encoding the full-length MERS-CoV S protein (Ad5.MERS-S) and the S1 extracellular domain of S protein (Ad5.MERS-S1). BALB/c mice were immunized with both candidate vaccines intramuscularly and boosted three weeks later intranasally. All the vaccinated animals had antibody responses against spike protein, which neutralized MERS-CoV in vitro. These results show that an adenoviral-based vaccine can induce MERS-CoV-specific immune responses in mice and hold promise for the development of a preventive vaccine that targets the animal reservoir, which might be an effective measure to eliminate transmission of MERS-CoV to humans.

Isolation of MERS coronavirus from a dromedary camel, Qatar, 2014.

We obtained the full genome of Middle East respiratory syndrome coronavirus (MERS-CoV) from a camel in Qatar. This virus is highly similar to the human England/Qatar 1 virus isolated in 2012. The MERS-CoV from the camel efficiently replicated in human cells, providing further evidence for the zoonotic potential of MERS-CoV from camels.