It was recently reported that a sixth fatality in the United Kingdom, attributed to MERS CoV, has got World Health Organization officials re-examining the virus. This has resulted in the issuance of a new health bulletin, asking physicians to pay special attention to people presenting with mild “colds” and other respiratory infections. A relative of the latest victim was diagnosed with a mild case of the EMC coronavirus, but has recovered.
Corona viruses were discovered and named in the mid-1960’s. This group of viruses infect the respiratory tracts of both humans and animals, and occasionally infect the digestive system. The coronavirus gets it’s name from the thorn-like projections, almost a halo, around the virus cell.
It has been found that coronaviruses are responsible for about ten to thirty percent of common colds, and are usually seen in the winter and early spring months.
In youngsters and the elderly, the lower respiratory tract is often hit hard, and this group more often than not will get a second coronavirus infection within four months of the first one. This leads researchers to suggest that antibody protection lasts only four months in humans.
The MERS CoV virus
Human coronavirus-EMC (Erasmus Medical Center) MERS CoV first made it’s presence known in June, 2012. The virus was detected in a 60 year old man in Saudi Arabia who presented with a severe respiratory infection and later died. Unable to detect the causative pathogen, physicians sent samples to Erasmus Medical Center in Rotterdam, the Netherlands. Physicians there were able to confirm the infection was caused by a coronavirus. Researchers have now sequenced the virus, and named it Middle East Respiratory Syndrome coronavirus, or MERS CoV.
What is interesting about MERS CoV is that it is similar to the SARS virus. The SARS (Severe Acute Respiratory Syndrome) virus was responsible for an epidemic in 2002-2003. At that time, the virus was believed to be a new type of coronavirus, similar to the virus that infects cats. It spread to 32 countries, affecting 8,459 people and causing over 800 deaths.
Why MERS CoV is considered more infectious than SARS
The SARS coronavirus utilizes a receptor called ACE2 (angiotensin-converting enzyme 2). The ACE2 receptor, found deep in the human respiratory tract, is what limits or restricts the transmission of the SARS virus in humans. The MERS CoV coronavirus has been found to not need or use the ACE2 receptor.
This means that MERS CoV can infect human, bat and pig cells, making it much more infectious and obviously transmittable between humans and animals. It is notable, too, that the human coronavirus cannot, by itself, replicate in bats. This suggests that MERS CoV utilizes an unknown receptor, perhaps found in an animal. The virus now has been found to be passed back and forth between humans and possibly animals.
Symptoms and Treatment for MERS-CoV
With MERS CoV being in the same family as other coronaviruses, symptoms of a respiratory infection will be seen in the affected individual. The difference in this viral infection and the common cold are that the person quickly developes a severe lung infection and renal failure. Onset of the infection is usually two to four days, and the morbidity rate is over 50 percent. This figure is used only because of the small number of proven infections and deaths attributed to MERS CoV to date.
The new virus has been found to possibly be susceptible to interferons. After the SARS outbreak, scientists realized there was no intiviral that would work to stop the virus. They eventually tried recombinant human interferon-beta 1aand had some promising results. Studies are ongoing with interferons being a possible treatment for MERS CoV.