SARS-CoV-2 isn’t the only coronavirus that needs attention right now. The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) continues to break out in parts of the world. A new study published in Infectious diseases of poverty detailed a current picture of the spatial diffusion pattern of MERS and the associated socio-ecological factors, supported by an impressive real-time tracking tool of the MERS-CoV evolution and migration history.

The global pandemic of COVID-19 and its enormous social and economic impact have drawn great attention to highly pathogenic human coronaviruses. Coronaviruses can infect mammals and birds, including farm animals and pets. So, in addition to being a public health challenge, they are a concern for the veterinary and economic implications.

Two other coronavirus-related epidemics have emerged in humans in the past 20 years, including Severe Acute Respiratory Syndrome (SARS) and Middle Eastern Respiratory Syndrome (MERS), which were discovered in 2003 and 2012, respectively. Although the previous epidemics have raised awareness of the need for clinically therapeutic or preventive interventions, no effective treatments are currently available.

MERS is a respiratory infectious disease first discovered in the Kingdom of Saudi Arabia (KSA) and caused by the coronavirus (MERS-CoV), the respiratory syndrome in the Middle East, which can be highly pathogenic in humans according to the World Health Organization (WHO). People infected with MERS-CoV may suffer no, mild or severe respiratory diseases or even death. This made it difficult to distinguish this virus from other similar respiratory diseases.

MERS has gradually spread from major epidemic areas in the Middle East to 27 countries on four continents. The vast majority of MERS cases were reported by Saudi Arabia, followed by South Korea. Frequent travelers to and from the Middle East have raised concerns about a global pandemic, given the lack of effective treatment and prevention strategies. In February 2018, the WHO officially included MERS-CoV in the research and development plan to promote research in this area.

No known human SARS cases have been reported since 2005. In contrast, numerous consecutive MERS cases and infection clusters have been reported by the WHO since September 2012. In the midst of the severe acute respiratory syndrome Coronavirus 2 (SARS-CoV- 2) pandemic, it is natural to ask an important question: Can recombination between MERS-CoV and SARS-CoV-2 occur?

In theory, the possibility of recombination between two coronaviruses cannot be completely ruled out when co-infection of the same host occurs because their host species such as humans and bats overlap. A recent study suggested that recombination between two viruses is indeed possible and urged laboratories to develop diagnostic skills to detect recombined coronavirus in patient samples in high-risk areas such as the Middle East. In addition, some evolutionary features of MERS-CoV, such as B. which genes are subject to positive selection can be closely monitored.

A large number of studies are currently focused on SARS-CoV-2. We think it is also important to understand the epidemiological properties and evolutionary history of MERS-CoV at the same time, as the two coronaviruses are genetically related.

Geographical extent of MERS (a) and its relationship to the transport network and land cover (b) in the Middle East. The first invasion time of each spatial unit was defined as the time lag between the first confirmed case for each unit and September 20, 2012, the date on which symptoms began for the first confirmed case in the Middle East region. A large gap between neighboring contours indicates a faster spatial spread of the disease. From Zhang, Shi, Liu et al. (2020)

With the support of my team, we have put a lot of time and effort into collecting comprehensive data of all confirmed MERS cases and related information by June 1, 2020. On this basis, we have compiled three data sets:

  • a list of individual cases in humans worldwide with demographic, exposure and clinical information,
  • ecological-geographical and socio-economic characteristics at the corresponding administrative level in the Middle East and
  • Whole genome sequences from MERS-CoV worldwide.

Based on these datasets, we conducted an in-depth analysis of the epidemiology of MERS and the phylogenetic evolution of MERS-CoV in the most affected regions. This provided a picture of both the population and molecular epidemiology of this pathogen and identified high risk populations and areas that require public health monitoring and action to control the endemic pathogen and prevent a possible pandemic.

We have mapped the distribution of human MERS cases in combination with the type of transmission in the world. We found that zoonotic infections occurred only in the Middle East, although animal contact cases had also been imported into Europe and Southeast Asia. Our analyzes showed that patients ≥ 65 years of age or with underlying diseases had a significantly higher risk of death, and initially determined that the effect of animal contact on the risk of death depends on both age and sex.

MERS’s spatiotemporal maps of geographic expansion showed that the disease has spread faster east (United Arab Emirates and Oman) than other directions since it was first reported in Bisha, central-west Saudi Arabia in September 2012 Accelerate years. Our phylogeographic analysis showed that the spatial-temporal transmission pattern of the main clade was characterized by intense local migration in the Middle East and occasional long-distance exports.

We strongly recommend that viral mutants be closely monitored through active monitoring in both animal and human hosts. While the rapid development of SARS-CoV-2 vaccines is shedding light on how MERS-CoV vaccine candidates can evolve, non-pharmaceutical interventions and animal vaccines should be planned in advance to delay adaptation of MERS-CoV at the source or to block.

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