The Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
MERS-CoV is a new emerging coronavirus that leads to severe acute respiratory infection (SARI), first detected in Saudi Arabia in September 2012. The disease seems to be the outcome of the spread of the virus from camels to humans, causing limited person-to-person spread but not lasting transmission in humans.
The most extensive onset besides the Arabian Peninsula occurred in the Republic of Korea in 2015. It was associated with a traveller coming back from the Arabian Peninsula.
MERS and Wuhan coronavirus are two different types of coronaviruses that are concerned with SARS. They can also lead to severe infections in humans.
MERS-CoV is a kind of coronavirus, analogous to the one that caused SARS (severe acute respiratory syndrome) and the common cold. MERS-CoV has not been formally identified in humans. Like the SARS virus, MERS-CoV is very similar to coronaviruses found in bats. It has been detected in camels, and numerous cases of MERS-CoV in those who handle camels have been stated. Other livestock do not appear to be influenced.
The infection can be transmitted from person to person through respiratory effusions. It may be spread from camels to humans. Those who deal with camels are at greater risk of MERS-CoV infection than people who do not have usual close links with camels.
Infected people experience symptoms of a flu-like illness accompanied by
- atypical pneumonia,
- including dry cough,
- fever, and
- severe breathing difficulty
In some cases, people experience gastrointestinal symptoms as well
Severely infected people experience respiratory failure and may require mechanical ventilation. Older people and those with some illnesses are at considerable risk for severe disease.
In the year 2014, MERS-CoV was detected in two individuals who were not associated with each other in any way. Except that, both were travellers who lived and worked in Saudi Arabia, and both of them were medical professionals. Other countries also detected MERS-CoV positive only who have travelled to/from these areas.
Similar to SARS, there is no medication yet discovered for the treatment of MERS-CoV. The doctors usually give supportive care to relieve the symptoms of the patient.
During the 2003 SARS onset, about 25% of people had severe respiratory failure, and 10% died. On the contrary, mortality in MERS is higher at about 50%.
What is Middle East Respiratory Syndrome Coronavirus (MERS-CoV)?
Let us understand the term first by its literal meaning:
Middle East - The disease was first reported in Saudi Arabia, which is a country in the middle east, in the year 2012.
Respiratory Syndrome - It may cause a range of respiratory diseases
Coronavirus - It is caused by a novel virus called coronavirus
What Is A Coronavirus?
It is a large group of viruses which can cause a wide array of diseases in humans and animals. The disorders can be as simple as a common cold or as severe as SARS or MERS. The viruses are composed of a core of genetic material and a surrounding envelope, which has tiny protein spikes. It gives the appearance of a crown, which in Latin, is termed “corona”.
In December 2019, healthcare professionals recorded the onset of yet another type of coronavirus (the Wuhan virus). It is an RNA virus that is related to both SARS and MERS. It was likely conceived in animals traded in the open-air food market in Wuhan, China. Like MERS, the virus can bring about mild to severe respiratory symptoms in people and appears to be transmitted from person-to-person. Most of the persons infected with this Wuhan coronavirus need immediate hospitalization.
What Are The Symptoms And Complications Of MERS-CoV?
Most people confirmed to have MERS-CoV infection have had a severe respiratory illness with symptoms of:
- Shortness of breath
Some people also experienced nausea/vomiting and diarrhoea, followed by more severe complications such as pneumonia and kidney failure. Nearly 3-4 out of every ten people reported with MERS have died. It was found that most of the people who died have some of the other pre-existing medical conditions that had weakened their immune system, or some medical condition that hadn’t yet been diagnosed. Some chronic illnesses weaken people’s immune system making them more susceptible to fall ill or sick.
Pre-existing conditions among people who got MERS includes:
- Chronic heart disease
- Chronic kidney disease
- Chronic lung disease
Some people with MERS had mild symptoms like that of cold and flu or no symptoms at all. The symptoms start to develop about 5 or 6 days after a person is exposed, but can range from 2-14 days.
MERS-CoV, like other coronaviruses, possibly spreads from an affected person’s respiratory discharges, such as through coughing. However, the precise ways it generally covers is not yet clear.
MERS-CoV has transmitted from affected people to others by maintaining close contact with them. Infected people have spread the disease to others in healthcare settings, such as hospitals. Researchers examining MERS have not seen any ongoing spread of MERS-CoV in the community.
Almost all of the reported cases have been associated with countries in and around the Arabian Peninsula. Most infected people either dwell in the Arabia Peninsula or have recently travelled from the region. The most significant known outbreak of MERS outside the Arabian Peninsula happened in the Republic of Korea in 2015 and was associated with a traveller returning from the Arabian Peninsula.
Public health agencies are continuing to investigate a wide range of cases in several countries to comprehend the mechanism by which MERS-CoV transmits from one person to another.
How Can MERS-CoV Be Prevented?
- Make sure you wash your hands with soap and water frequently, for at least 20 seconds. And if you have a child, assist them in doing the same. If soap and water aren’t available, you can use an alcohol-based sanitizer to fight the germs.
- Avoid touching your eyes, nose, and mouth with unwashed hands.
- Cover your nose and mouth with a tissue when you sneeze or cough, then dispose of the tissue in the trash.
- Clean and disinfect usually touched objects and surfaces, such as doorknobs.
- Avoid personal contact, such as kissing, hugging or sharing cups or eating utensils, with sick people.
- If you are living with or caring for someone who has or is suspected of having MERS-CoV, you need to be extra cautious.
Is There A Vaccine Available For MERS-CoV?
Till date, no vaccine is commercially available that could help prevent the condition.
How Can MERS-CoV Be Treated?
As MERS-CoV is caused by a similar virus which causes SARS, the management of MERS-CoV has been grossed up from experience with the 2002 SARS outbreak and some confined experimental evidence.
Patients with MERS-CoV generally require oxygen supplementation and some severe cases demand mechanical ventilation and intensive-care unit support. No medication is yet discovered that helps cure the condition, and the doctors usually provide supportive care to ease the medical condition of the patient. Many diseases have been tried in the treatment of both SARS as well as MERS-CoV without absolute benefits, and further analysis needs to be done. Management of the individual with MERS is supported by infectious disease, pulmonary, and critical-care professionals.
What Types Of Medical Professionals Treat MERS-CoV Infection?
Most people with MERS would first consult their general practitioner when the illness rapidly progresses. Depending upon the stage of the disease they have, they would be admitted to a hospital due to the reduction in their oxygen levels.
In the hospital, a person infected with MERS would probably be managed by a hospitalist or critical care expert, with deliberations to an infectious-disease doctor and lung doctor (or pulmonologist).
How Is MERS-CoV Diagnosed?
Several laboratory tests are conducted to identify the MERS-CoV infection. Generally, all of such tests fall into the following two categories:
- Molecular analyses, which detects the signs of active infection; and
- Serology tests, which recognize the indications of previous diseases by identifying the antibodies to MERS-CoV. The serology tests are done with an objective of surveillance purposes and not for diagnostic purposes. Let us have a closer look at both the categories of laboratory tests.
Molecular tests are done to diagnose active infection in people who are suspected of having MERS-CoV based on their symptoms and having connections to places where MERS has been reported.
Real-time reverse-transcription polymerase chain reaction (rRT-PCR) trials are the molecular tests that can be used to discern viral RNA in clinical swatches. The laboratory ratification of MERS-CoV infection demands either a positive rRT-PCR result for at least two distinct genomic targets, or a single definite target with the progressivity of a second target.
Many state laboratories in the United States of America are approved to test for MERS-CoV by using rRT-PCR trials curated by CDC. This test is done under the governance of an Emergency Use Authorization because there are no FDA-cleared/approved tests accessible for this purpose in the country.
The accomplishment of rRT-PCR testing depends on numerous factors, including the experience and proficiency of laboratory personnel, laboratory environment (for example, avoidance of contamination), and the type and condition of swatches being analyzed. CDC recommends collecting multiple samples or specimens, including lower (bronchoalveolar lavage, sputum and tracheal aspirates) and upper (e.g., nasopharyngeal and oropharyngeal swabs) respiratory samples, serum, and stool specimens.
CDC estimates a person to be MERS-CoV negative, subsequently one negative rRT-PCR test on the recommended samples. Since a single adverse outcome does not completely eradicate the possibility of MERS-CoV infection, in some cases, further specimens may be analyzed.
CDC estimates a known MERS patient to be harmful for active MERS-CoV infection after two consecutive negative rRT-PCR tests on all samples.
Serology tests are performed to identify any previous infection or antibodies to MERS-CoV in people who may have been subjected to the particular virus. Antibodies are created by the body’s immune system to combat and kill bacteria, virus, and other pathogens during infection. The existence of antibodies to MERS-CoV is a clear indication that the person was formerly indicated with the virus and developed an immune system response.
The evidence so far reveals that there may be a more extensive range of MERS disease than was primarily believed. For instance, public health researchers have recognized the individuals who are PCR-positive but have no symptoms of MERS; we do not know if these groups of people can transmit MERS-CoV. Consequently, public health scientists are working on getting more information on how the virus is transmitted. One approach to do this is through a voluntary examination of blood samples from people who had a close liaison with people known to have MERS.
CDC has a two-stage approach for serological testing - two screening tests and one confirmatory test, to identify antibodies of MERS-CoV.
ELISA (enzyme-linked immunosorbent assay), is a screening test performed to find out the presence and concentration of specific antibodies that link to a viral protein. CDC tests by ELISA for antibodies against two different MERS-CoV proteins, the nucleocapsid (N) and spike (S).
If a clinical sample is measured to be antibody-positive by either ELISA, CDC then utilizes the microneutralization test to substantiate the positive outcome.
The microneutralization assay is a pretty specific confirmatory test that is performed to analyze neutralizing antibodies or antibodies that can counteract virus. This approach is deemed a gold standard for the revelation of distinct antibodies in serum specimens. Although, in contrast with the ELISA, the microneutralization assay is difficult and requires a great deal of time, demanding a minimum of five days before results are accessible.
What Is The Prognosis Of MERS-CoV?
MERS is typically concerned with rapidly developing severe respiratory illnesses, and its mortality rate is very high compared to the SARS CoV outbreak. Since the year 2012, MERS outbreak in Saudi Arabia has gradually continued with a total of 933 persons identified with 401 deaths as of March 2015, for a mortality rate of about 50%. Pneumonia and kidney failure are some of the severe complications of MERS-CoV.
Tags: Wuhan coronavirus, MERS-CoV, Middle East Respiratory Syndrome Coronavirus