Origin
• MERS-CoV discovered in 2012 is responsible for causing Acute Respiratory Syndrome in humans.
• Zoonotic disease
• Many phylogenetic studies suggest a bat origin
• First case of MERS was reported in Saudi Arabia.
• Dr.Zaki ,an Egyptian Virologist identified the new virus after working on a 60 year old Saudi patient who died from an acute respiratory condition.
MERS-CoV (HCoV-EMC/2012)
About MERS-COV
MERS-CoV is a ssRNA virus . Three MERS-COV proteins are expressed on the envelope of virus the Surface spike protein(S protein), Membrane ( M protein) and Envelope (E protein). S protein helps in attachment to the host cell membrane.
MERS-CoV belongs to C-lineage of Beta Coronavirus.Unlike the SARS virus which acts through ACE-2 receptors the MERS-COV acts through the DPP-4/CD 26 (Dipeptidyl peptidase -4) receptors .
MERS-COV attacks the Non ciliated bronchial epithelial cells and Type 2 pneumocytes unlike the SARS virus which attacks the Ciliated Bronchial epithelial cells.
Relation to Dromedary(Arabian) Camels
Studies proved that the virus isolated from humans is similar to that isolated from the Dromedary Camels .
Dromedary camels are the main reservoir host of MERS-COV. Antibodies to MERS-COV have been detected in infected camels.
It is uncertain how bats have spread the virus to dromedaries.
Transmission
Human to human transmission is less likely to occur but has been reported among the health care workers.
People who were in proximity to the dromedaries were the most affected.
Clinical Presentations
Severity of cases ranged from mild cough and fever to severe symptoms like pneumonia and acute respiratory syndrome.
Immunocompromised patients and organ dysfunction patients were the most affected .
Some cases presented with atypical symptoms like diarrhea.
WHO REPORT
According to WHO ( as per November 2019) a total of 2494 patients from 27 countries have been infected from across the globe.
Approximately 858 patients have died (34.4% fatality rate). Most of the patients who died suffered from comorbidities.
Of those infected,2102 patients reported from Saudi Arabia with 780 deaths (37.1%fatality rate).
(Antibodies to MERS-COV)
Treatment strategies
There are no licensed therapies of proven efficacy for MERS-COV or any other Corona virus infection.
Symptomatic treatment like respiratory and cardiac support is provided to patients.
Combination treatment with Ribavarin and Interferon alpha 2b improved clinical outcomes in infected Nonhuman primates.
WHY MORTALITY RATE IS HIGH??(A huge 34.4%)
MERS-COV causes an Innate immunity deficiency state that results secondary to inhibition of a first viral responder to viral Infection Interferon(IFN).
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