Middle East Respiratory Syndrome (MERS) a Threat to Asian Countries

 

Mr. Hariprasath Pandurangan

Lecturer, Mettu University

 

ABSTRACT:

Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (MERS‐CoV) that was first identified in Saudi Arabia in 2012. Coronaviruses are a large family of viruses that can cause diseases ranging from the common cold to Severe Acute Respiratory Syndrome (SARS). Typical MERS symptoms include fever, cough and shortness of breath. Approximately 36% of reported patients with MERS have died. Although the majority of human cases of MERS have been attributed to human-to-human infections, camels are likely to be a major reservoir host for MERS-CoV and an animal source of MERS infection in humans. However, the exact role of camels in transmission of the virus and the exact route(s) of transmission are unknown. The virus does not seem to pass easily from person to person unless there is close contact, such as occurs when providing unprotected care to a patient. Currently there is no specific treatment is available and so treatment is supportive and based on the patient’s clinical condition.

 

 

 

INTRODUCTION:

After swine flu and Ebola, the Middle East Respiratory Syndrome Corona Virus (MERS-CoV) is the new global threat that has put many Asian countries, including India, on high alert. This was first identified in Saudi Arabia in 2012 and currently it affecting 26 countries and 5 continents. The transmission of the virus has occurred in hospitals, including from patients to doctors and between patients, even before MERS-CoV was diagnosed. It is not always possible to identify patients with MERS-CoV at an early stage so to assess the transmission of disease supplemental surveillance strategies are urgently needed beyond the currently recommended measures. According to the WHO, 1,244 MERS cases have been reported globally to date, with at least 446 deaths. [1]

 

Definition:

Middle East Respiratory Syndrome (MERS) is an illness caused by a virus (more specifically, a coronavirus) called Middle East Respiratory Syndrome Coronavirus (MERS-CoV), it mainly affects the respiratory system. Most MERS patients developed severe acute respiratory illness with symptoms of fever, cough and shortness of breath. About 3-4 out of every 10 patients reported with MERS have died. [2]

 

Source of the virus:

MERS-CoV is a zoonotic virus that is transmitted from animals to humans. The origins of the virus are not fully understood but, according to the analysis of different virus genomes, it is believed that it originated in bats and was transmitted to camels sometime in the distant past. [2]

 

 

 

Mode of transmission:

Animals to human transmission:

The route of transmission from animals to humans is not fully understood, but camels are likely to be a major reservoir host for MERS-CoV and an animal source of infection in humans. Strains of MERS-CoV that are identical to human strains have been isolated from camels in several countries, including Egypt, Oman, Qatar, and Saudi Arabia. [2-3]

 

Human to human transmission:

MERS-CoV, like other coronaviruses, is thought to spread from an infected person’s respiratory secretions, such as through coughing. However, the precise ways the virus spreads are not currently well understood.

 

MERS-CoV has spread from ill people to others through close contact, such as caring for or living with an infected person. Infected people have spread MERS-CoV to others in healthcare settings, such as hospitals. Researchers studying MERS have not seen any ongoing spreading of MERS-CoV in the community. [2-3]

 

Risk factors:

·        Recent Travelers from the Arabian Peninsula

·        Close Contacts of a Confirmed Case of MERS

·        Healthcare Personnel Not Using Recommended Infection-Control Precautions

·        People with Exposure to Camels

 

Clinical Presentation:

Most people confirmed to have MERS-CoV infection have had severe acute respiratory illness with symptoms of:

·        Fever

·        Cough

·        Shortness of breath

 

Some people also had gastrointestinal symptoms including diarrhea and nausea/vomiting. For many people with MERS, more severe complications followed, such as pneumonia and kidney failure. About 3-4 out of every 10 people reported with MERS have died. Most of the people who died had an underlying medical condition. Some infected people had mild symptoms (such as cold-like symptoms) or no symptoms at all; they recovered.

 

Based on what researchers know so far, people with pre-existing medical conditions (also called comorbidities) may be more likely to become infected with MERS-CoV, or have a severe case. Pre-existing conditions from reported cases for which we have information have included diabetes; cancer; and chronic lung, heart, and kidney disease. Individuals with weakened immune systems are also at higher risk for getting MERS or having a severe case. [4-5]

Clinical Course:

The median incubation period for secondary cases associated with limited human-to-human transmission is approximately 5 days (range 2-14 days). In MERS-CoV patients, the median time from illness onset to hospitalization is approximately 4 days. In critically ill patients, the median time from onset to intensive care unit (ICU) admission is approximately 5 days, and median time from onset to death is approximately 12 days. In one series of 12 ICU patients, the median duration of mechanical ventilation was 16 days, and median ICU length of stay was 30 days, with 58% mortality at 90 days. Radiographic findings may include unilateral or bilateral patchy densities or opacities, interstitial infiltrates, consolidation, and pleural effusions. Rapid progression to acute respiratory failure, acute respiratory distress syndrome (ARDS), refractory hypoxemia, and extrapulmonary complications (acute kidney injury requiring renal replacement therapy, hypotension requiring vasopressors, hepatic inflammation, septic shock) has been reported. [6-8]

 

Laboratory Findings:

Laboratory findings at admission may include leukopenia, lymphopenia, thrombocytopenia, and elevated lactate dehydrogenase levels. Co-infection with other respiratory viruses and a few cases of co-infection with community-acquired bacteria at admission has been reported; nosocomial bacterial and fungal infections have been reported in mechanically-ventilated patients. MERS-CoV virus can be detected with higher viral load and longer duration in the lower respiratory tract compared to the upper respiratory tract, and has been detected in feces, serum, and urine. However, very limited data are available on the duration of respiratory and extrapulmonary MERS-CoV shedding.[9]

 

Prevention:

Animal to Human Transmission:

1.      Practicing of  general hygiene measures, including regular hand washing before and after touching animals, and should avoid contact with sick animals.

2.      Avoiding consumption of raw or undercooked animal products, including milk and meat, carries a high risk of infection from a variety of organisms that might cause disease in humans.

3.      Camel meat and camel milk are nutritious products that can continue to be consumed after pasteurization, cooking, or other heat treatments.

4.      The patients with diabetes, renal failure, chronic lung disease, and immunocompromised persons are considered to be at high risk of severe disease from MERS-CoV infection. So they should avoid contact with camels, drinking raw camel milk or camel urine, or eating meat that has not been properly cooked. [2]

 

Human to Human Transmission:

CDC routinely advises that people help protect themselves from respiratory illnesses by taking everyday preventive actions:

·        Wash your hands often with soap and water for 20 seconds, and help young children do the same. If soap and water are not available, use an alcohol-based hand sanitizer.

·        Cover your nose and mouth with a tissue when you cough or sneeze, then throw the tissue in the trash.

·        Avoid touching your eyes, nose and mouth with unwashed hands.

·        Avoid personal contact, such as kissing, or sharing cups or eating utensils, with sick people.

·        Clean and disinfect frequently touched surfaces and objects, such as doorknobs.[2]

 

Clinical Management and Treatment:

No specific treatment for MERS-CoV infection is currently available. Clinical management includes supportive management of complications and implementation of recommended infection prevention and control measures

 

Interim Infection Prevention and Control Recommendations for Hospitalized Patients with Middle East Respiratory Syndrome Coronavirus:

 

1. Minimize Chance for Exposures:

Ensure facility policies and practices are in place to minimize exposures to respiratory pathogens including MERS-CoV. Measures should be implemented before patient arrival, upon arrival, and throughout the duration of the affected patient’s presence in the healthcare setting.

 

2. Ensure Adherence to Standard, Contact and Airborne Precautions:

Standard precautions assume that every person is potentially infected or colonized with a pathogen that could be transmitted in the healthcare setting. Elements of standard precautions that apply to patients with respiratory infections should be followed. Attention should be paid to training and proper donning, doffing and disposal of any personal protective equipment.

 

3. Manage Visitor Access:

·        Establish procedures for monitoring, managing and training visitors.

·        All visitors should follow respiratory hygiene and cough etiquette precautions while in the common areas of the facility.

·        Restrict visitors from entering the MERS-CoV patient’s room. Facilities can consider exceptions based on end-of-life situations or when a visitor is essential for the patient’s emotional well-being and care.

·        Visitors who have been in contact with the patient before and during hospitalization are a possible source of MERS-CoV for other patients, visitors, and staff.

 

4. Implement Engineering Controls:

Consider designing and installing engineering controls to reduce or eliminate exposures by shielding HCP and other patients from infected individuals. Examples of engineering controls include physical barriers or partitions to guide patients through triage areas, curtains between patients in shared areas,  closed suctioning systems for airway suctioning for intubated patients, as well as appropriate air-handling systems (with appropriate directionality, filtration, exchange rate, etc.) that are installed and properly maintained.

 

5. Train and Educate Healthcare Personnel (HCP):

·        Provide all HCP with job- or task-specific education and training on preventing transmission of infectious agents, including refresher training.

·        HCP must be medically cleared, trained, and fit tested for respiratory protection device use (e.g., N95 filtering facepiece respirators), or medically cleared and trained in the use of an alternative respiratory protection device (e.g., Powered Air-Purifying Respirator, PAPR) whenever respirators are required.

·        Ensure that HCP are educated, trained, and have practiced the appropriate use of PPE prior to caring for a patient, including attention to correct use of PPE and prevention of contamination of clothing, skin, and environment during the process of removing such equipment.

 

6. Implement Environmental Infection Control

·        Ensure that cleaning and disinfection procedures are followed consistently and correctly.

·        Standard cleaning and disinfection procedures are appropriate for MERS-CoV in healthcare settings, including those patient-care areas in which aerosol-generating procedures are performed.

 

7. Establish Reporting within Hospitals and to Public Health Authorities

·        Implement mechanisms and policies that promptly alert key facility staff including infection control, healthcare epidemiology, hospital leadership, occupational health, clinical laboratory, and frontline staff about suspected or known MERS-CoV patients.

·        Communicate and collaborate with public health authorities.

Ÿ  Promptly notify public health authorities of suspected or known patients with MERS-CoV.

Ÿ  Facilities should designate specific persons within the healthcare facility who are responsible for communication with public health officials and dissemination of information to HCP. [10-11]

 

REFERENCES:

1.       World Health Organisation. Key facts of Middle East respiratory syndrome coronavirus infection. 2015. Retrieved from http://www.who.int/mediacentre/factsheets/mers-cov/en/

2.       Centre for Disease Control and Prevention. Middle East respiratory syndrome coronavirus. 2015. Retrieved from http://www.cdc.gov/coronavirus/mers/about/index.html

3.       Assiri A, Al-Tawfiq JA, Al-Rabeeah AA, Al-Rabiah FA, Al-Hajjar S, Al-Barrak A, et al. Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. Lancet Infect Dis. 2013 Sep; 13(9):752-61.

4.       Drosten C, Seilmaier M, Corman VM, Hartmann W, Scheible G, Sack S, et al. Clinical features and virological analysis of a case of Middle East respiratory syndrome coronavirus infection. Lancet Infect Dis. 2013 Sep; 13(9):745-51.

5.       Guery B, Poissy J, el Mansouf L, Séjourné C, Ettahar N, Lemaire X, et al. Clinical features and viral diagnosis of two cases of infection with Middle East respiratory syndrome coronavirus: a report of nosocomial transmission. Lancet. 2013 Jun 29; 381(9885):2265-72. doi: 10.1016/S0140-6736(13)60982-4. Erratum in: Lancet. 2013 Jun 29; 381(9885):2254.

6.       Arabi YM, Arifi AA, Balkhy HH, Najm H, Aldawood AS, Ghabashi A, et al. Clinical course and outcomes of critically ill patients with Middle East respiratory syndrome coronavirus infection. Ann Intern Med. 2014 Mar 18; 160(6):389-97.

7.       Assiri A, McGeer A, Perl TM, Price CS, Al Rabeeah AA, Cummings DA, et al. Hospital outbreak of Middle East respiratory syndrome coronavirus. N Engl J Med. 2013 Aug 1; 369(5):407-16.

8.       Bermingham A, Chand MA, Brown CS, Aarons E, Tong C, Langrish C, et al. Severe respiratory illness caused by a novel coronavirus, in a patient transferred to the United Kingdom from the Middle East, September 2012. Euro Surveill. 2012 Oct 4; 17(40):20290.

9.       Memish ZA, Al-Tawfiq JA, Makhdoom HQ, Assiri A, Alhakeem RF, Albarrak A, et al. Respiratory Tract Samples, Viral Load and Genome Fraction Yield in patients with Middle East Respiratory Syndrome. J Infect Dis. 2014 May 15. Page 292.

10.     National Center for Immunization and Respiratory Diseases (NCIRD). Preventing MERS-CoV from Spreading to Others in Homes and Communities. 2015. Retrieved from http://www.cdc.gov/coronavirus/mers/hcp/home-care-patient.html

11.     National Center for Immunization and Respiratory Diseases (NCIRD). Interim guidelines for health care professionals. 2015. Retrieved from http://www.cdc.gov/coronavirus/mers/hcp/home-care-patient.html

 

 

 

 

Received on 19.10.2017       Modified on 30.10.2017

Accepted on 15.11.2017      ©A&V Publications All right reserved