What is MERS ?

What is MERS? What you need to know

June 23, 2015

MERS

Middle East respiratory syndrome coronavirus (MERS-CoV), previously known as novel coronavirus (nCoV), is a viral respiratory illness, which was first reported in Saudi Arabia, in 2012. The source of MERS is currently unknown, though it is likely to have originated from an animal.

The MERS virus is currently spreading in South Korea. This, in combination with the fact that coronaviruses can often mutate, is leading to increased fears it could become a pandemic.

MERS-CoV is dissimilar to other coronaviruses; there is currently no vaccine.

Most confirmed cases of MERS-CoV have displayed symptoms of severe acute respiratory illness. Approximately 36% of reported patients with MERS have died.


Fast facts on MERS

Here are some key points about MERS-CoV. More detail and supporting information is in the main article.

  • MERS-CoV was first reported in Saudi Arabia in 2012.
  • MERS-CoV belongs to the coronavirus family.
  • All cases have been linked to countries in and neighboring the Arabian Peninsula.
  • Cases of MERS-CoV reported in other countries were travel-related and first developed in the Middle East.
  • It is thought mammals play a role in the transmission of the virus - bats and camels remaining a high contender.
  • In addition to humans, strains of MERS-CoV have been identified in camels in Qatar, Egypt and Saudi Arabia, and in a bat in Saudi Arabia.
  • Doctors describe MERS-CoV as a flu-like illness with signs and symptoms of pneumonia
  • Sufferers of MERS-CoV will generally develop severe acute respiratory illness. Some people have reported mild respiratory illness with others showing no symptoms.
  • There are no specific treatments for patients who become ill with MERS-CoV infection.
  • Out of the confirmed cases of MERS-CoV, 36% have been fatal.

MERS Outbreak updates

June 5, 2015
In light of the recent outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV), WHO and the Republic of Korea's Ministry of Health and Welfare will conduct a joint mission in the Republic of Korea. This joint mission is to gain information and review the situation in the Republic of Korea including the epidemiological pattern, the characteristic of the virus and clinical features. Based on current data and WHO's risk assessment, there is no evidence to suggest sustained human-to-human transmission in communities and no evidence of airborne transmission.

June 2, 2015
The outbreak of MERS-CoV in the Republic of Korea continues to evolve. The Republic of Korea's first, or "index", case was confirmed on May 20, 2015. To date, contact tracing has identified a total of 25 laboratory-confirmed cases, including the index case and among health care workers caring for him, patients who were being cared for at the same clinics or hospitals, and family members and visitors. Two of these confirmed cases have been fatal.

June 2, 2015
A total of 1,179 laboratory-confirmed cases of human infection with MERS-CoV have been reported to WHO since 2012, including at least 442 deaths.

What is MERS-CoV?

MERS-CoV belongs to the coronavirus family. Human coronaviruses were first classified in the mid 1960s. The coronavirus subgroups are referred to as alpha, beta, gamma and delta. There are currently six coronaviruses that can affect humans including:

Alpha coronaviruses

  • Human coronavirus 229E
  • Human coronavirus NL63 (HCoV-NL63, New Haven coronavirus).

Beta coronaviruses

  • Human coronavirus OC43
  • Human coronavirus HKU1
  • SARS-CoV
  • Middle East respiratory syndrome coronavirus (MERS-CoV).

Coronaviruses typically infect one species type or those that are closely related. However, SARS-CoV infects both humans and animals including monkeys, Himalayan palm civets, raccoon dogs, cats, dogs, and rodents. The common cold is a virally related syndrome. It is connected to over 100 separate viruses, including human coronavirus. MERS-CoV is a species in lineage C of the genus beta coronavirus, which presently includes tylonycteris bat coronavirus HKU4 and pipistrellus bat coronavirus HKU5. Although it features in the same subgroup, MERS-CoV is different from the coronavirus that caused severe acute respiratory virus (SARS) in 2003. One parallel between MERS-CoV and SARS is that they both are similar to coronaviruses found in bats. MERS-CoV appears most closely to resemble the not-yet-classified viruses from insectivorous European and African bats in the Vespertilionidae and Nycteridae families.

All cases have been linked to countries in and neighboring the Arabian Peninsula including:

  • Bahrain
  • Iraq
  • Iran
  • Israel
  • Jordan
  • Kuwait
  • Lebanon
  • Oman
  • Palestine
  • Qatar
  • Saudi Arabia
  • Syria
  • United Arab Emirates (UAE)
  • The West Bank
  • Yemen.

Cases of MERS-CoV reported in other countries were travel-related and first developed in the Middle East. Countries that have declared cases are:

Middle East

  • Egypt
  • Iran
  • Jordan
  • Kuwait
  • Lebanon
  • Oman
  • Qatar
  • Saudi Arabia (KSA)
  • United Arab Emirates (UAE)
  • Yemen.

Europe

  • Austria
  • France
  • Germany
  • Greece
  • Italy
  • Netherlands
  • Turkey
  • United Kingdom.

Africa

  • Algeria
  • Tunisia.

Asia

  • China
  • Republic of Korea
  • Malaysia
  • Philippines.

Americas

  • US.

Video: MERS Virus Outbreak: Everything You Need to Know

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What causes MERS-CoV?

The cause of MERS-CoV is not yet fully understood. Although not confirmed, the infection could be primarily zoonotic in nature, with limited human-to-human transmission. It is thought mammals play a role in the transmission of the virus - bats and camels remaining a high contender.

In addition to humans, strains of MERS-CoV have been identified in:

  • Camels in Qatar, Egypt and Saudi Arabia
  • A bat in Saudi Arabia.

MERS-CoV antibodies were found in camels across Africa and the Middle East, indicating that they had previously been infected with MERS-CoV or a closely related virus. Researchers from three centers in the United States and two in Saudi Arabia conducted complete genetic sequences for MERS-CoV isolates generated from five camels, the results verified them identical to published sequences of human isolates. Goats, cows, sheep, water buffalo, swine and wild birds have been tested for antibodies to MERS-CoV; none have yet been detected. The findings above support the hypothesis that camels are a probable source of infection transfer to humans, while bats may be the ultimate reservoir of the virus. The high infectious dose would require very close contact between an infected camel and humans for instigation of human MERS-CoV infection by camels. It has been suggested the virus could infect humans by air, via camel milk or meat.

Experts have commented that although the respiratory route of transmission is the most likely, the paper has exhibited that MERS-CoV can survive in raw camel milk marginally longer than milk of other species, proposing the foodborne path of transmission should be investigated further.

Signs and symptoms of MERS

The most common signs and symptoms of MERS-CoV are:

  • Fever 37,7 C or higher
  • Cough
  • Breathing difficulties
  • Chills
  • Chest pain
  • Body aches
  • Sore throat
  • Malaise - a general feeling of being unwell
  • Headache
  • Diarrhea
  • Nausea/Vomiting
  • Runny nose
  • Renal (kidney) failure
  • Pneumonia.

Doctors describe it as flu-like illness with signs and symptoms of pneumonia. Early reports described symptoms as similar to those found in SARS-CoV (severe acute respiratory syndrome) cases. However, SARS infections did not cause renal failure, unlike MERS-CoV. Sufferers of MERS-CoV will generally develop severe acute respiratory illness. Some people have reported mild respiratory illness with others showing no symptoms.

Who is most at risk?

The following groups of people are more susceptible to MERS-CoV infections and complications:

  • Patients with chronic diseases, such as diabetes, chronic lung disease and heart conditions
  • The elderly
  • Organ transplant recipients who are on immunosuppressive medications
  • Other patients whose immune systems are weak, such as cancer patients undergoing treatment.

Out of the confirmed cases of MERS-CoV, 36% have been fatal.

Tests and diagnosis

The polymerase chain reaction (PCR) test is used to detect and diagnose infectious disease and can confirm positive cases of MERS-CoV by means of a sample from the patient's respiratory tract. A blood test can determine if an individual has previously been infected, by testing for MERS-CoV antibodies.

Treatment and prevention

According to the US Centers for Disease Control and Prevention (CDC) and WHO (World Health Organization), there are no specific treatments for patients who become ill with MERS-CoV infection.

All doctors can currently do is provide supportive medical care to help relieve the symptoms. Supportive care means providing treatment to prevent, control or relieve complications and side effects, as well as attempting to improve the patient's comfort and quality of life. Supportive care (supportive therapy) does not include treating or improving the illness/condition.
Travel advice has been provided to reduce the risk of MERS-CoV infection amongst travelers, which includes information such as:

  • There is an increased chance of illness for those travelers with pre-existing chronic conditions
  • There is an increased chance of illness for travelers suffering from flu and traveller's diarrhea
  • Frequent hand-washing is advised with soap and water
  • Avoid undercooked meat or food prepared under unhygienic conditions
  • Ensure fruit and vegetables are properly washed before consumption
  • If a traveller develops acute respiratory illness with fever, they should minimize close contact with others, wear a medical mask, sneeze into a sleeve, flexed elbow or tissue (making sure it is disposed of properly after use)
  • If during 14 days after returning from travel acute respiratory illness with fever develops; medical attention should be sought immediately
  • All cases should be reported to the local health authorities; they monitor for MERS-CoV.

While MERS-CoV is contagious, the virus does not appear to pass between humans without close contact, for example, caring for a patient without protective precaution. Therefore, guidance should be pursued from a health care professional if symptoms materialize.

With so little still known about the virus strain, any advice or recommendation should be considered temporary and subject to change.

Confirmed cases and deaths

The following figures are the total number of MERS-CoV cases and deaths as of June 9, 2015 as reported by WHO.

Total cases confirmed by the World Health Organization (WHO):

No. of cases No. of deaths Fatality %
1,236 445 36%

Written by Hannah Nichols

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