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Middle East respiratory syndrome - coronavirus Dr.T.V.Rao MD
What is Middle East Respiratory Syndrome (MERS) Middle East Respiratory Syndrome (MERS) is viral respiratory illness first reported in Saudi Arabia in 2012. It is caused by a coronavirus called MERS-CoV. Most people who have been confirmed to have MERS-CoV infection developed severe acute respiratory illness. They had fever, cough, and shortness of breath. About 30% of people confirmed to have MERS-CoV infection have died.
Middle East Respiratory Syndrome (MERS) belongs to Coronavirus infections Coronaviruses are a large family of viruses that cause a range of illnesses in humans, from the common cold to the Severe Acute Respiratory Syndrome (SARS). Viruses in this family also cause a number of animal diseases
Middle East respiratory syndrome coronavirus (MERS-CoV) This strain of coronavirus that causes MERS was first identified in 2012 in Saudi Arabia. Our understanding of the virus and the disease it causes is continuing to evolve.
Structure of mers virus
The infection is linked to all the cases have been linked to countries in the Arabian Peninsula. This virus has spread from ill people to others through close contact, such as caring for or living with an infected person. However, there is no evidence of sustained spreading in community settings.
Why palm tress in the MERS-CoV acquisition model...? A hypothesis?
The Middle East respiratory syndrome coronavirus The Middle East respiratory syndrome coronavirus (MERS-CoV), also termed EMC/2012 (HCoV-EMC/2012), is positive-sense, single-stranded RNA novel species of the genus Beta coronavirus.
MERS-CoV Reported at Several places As of 14 May 2014, MERS-CoV cases have been reported in several countries, including Saudi Arabia, Malaysia, Jordan, Qatar, Egypt, the United Arab Emirates, Tunisia, Kuwait, Oman, the Philippines, Indonesia (none was confirmed), the United Kingdom, and the United States.
Virus and clades The virus MERS-CoV is a new member of the beta group of coronavirus, Beta coronavirus, lineage C. MERS-CoV genomes are phylogenetic ally classified into two clades, clade A and B. The earliest cases of MERS were of clade A clusters (EMC/2012 and Jordan-N3/2012), and new cases are genetically distinct (clade B).
First case of MERS-CoV The first confirmed case was reported in Saudi Arabia 2012. Egyptian virologist Dr. Ali Mohamed Zaki isolated and identified a previously unknown coronavirus from the man's lungs. Dr. Zaki then posted his findings on 24 September 2012 on ProMED-mail. The isolated cells showed cytopathic effects (CPE), in the form of rounding and syncytia formation.
Second case of MERS-CoV A second case was found in September 2012. A 49-year-old male living in Qatar presented similar flu symptoms, and a sequence of the virus was nearly identical to that of the first case. In November 2012, similar cases appeared in Qatar and Saudi Arabia. Additional cases were noted, with deaths associated, and rapid research and monitoring of this novel coronavirus began.
Tropism in mers in humans, the virus has a strong tropism for nonciliated bronchial epithelial cells, and it has been shown to effectively evade the innate immune responses and antagonize interferon (IFN) production in these cells. This tropism is unique in that most respiratory viruses target ciliated cells Due to the clinical similarity between MERS-CoV and SARS-CoV, it was proposed that they may use the same cellular receptor; the exopeptidase, angiotensin converting enzyme 2 (ACE2). However, it was later discovered that neutralization of ACE2 by recombinant antibodies does not prevent MERS-CoV infection.
Incubation period The median incubation period for secondary cases associated with limited human-to-human transmission is approximately 5 days (range 2-13 days). In MERS-CoV patients, the median time from illness onset to hospitalization is approximately 4 days.
Common clinical presentations common signs and symptoms include fever, chills/rigors, headache, non-productive cough, dyspnea, and myalgia. Other symptoms can include sore throat, coryza, nausea and vomiting, dizziness, sputum production, diarrhea, vomiting, and abdominal pain. Atypical presentations including mild respiratory illness without fever and diarrheal illness preceding development of pneumonia have been reported. Patients who progress to requiring admission to an intensive care unit (ICU) often have a history of a febrile upper respiratory tract illness with rapid progression to pneumonia within a week of illness onset.
Patients present with Watch for these symptoms: Fever (100° Fahrenheit or higher). Take your temperature twice a day. Coughing Shortness of breath Other early symptoms to watch for are chills, body aches, sore throat, headache, diarrhoea, nausea/vomiting, and runny nose.
Probable Case A probable case is a PUI with absent or inconclusive4 laboratory results for MERS-CoV infection who is a close contact2 of a laboratory-confirmed MERS-CoV case.
Patient Under Investigation (PUI) A patient under investigation (PUI) is a person with the following characteristics: Fever (?38°C, 100.4°F) and pneumonia or acute respiratory distress syndrome (based on clinical or radiological evidence)
Patient Under Investigation (PUI) a history of travel from countries in or near the Arabian Peninsula1 within 14 days before symptom onset, OR close contact2 with a symptomatic traveller who developed fever and acute respiratory illness (not necessarily pneumonia) within 14 days after traveling from countries in or near the Arabian Peninsula
Patient Under Investigation (PUI) a member of a cluster of patients with severe acute respiratory illness (e.g. fever and pneumonia requiring hospitalization) of unknown aetiology in which MERS-CoV is being evaluated, in consultation with state and local health departments.
Radiological findings 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),
Co-infections in MERS 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 and Pregnancy There have been less of a handful cases of confirmed MERS-CoV in pregnancy. So it is very difficult to draw conclusions on the effect of MERS to pregnancy. However traditionally pregnant mother are considered to be in the high risk group for MERS complications due to the changes in their immune response and the fetal effects of a severe respiratory syndrome.
Role of laboratories Most state laboratories are approved to test for Middle East Respiratory Syndrome Coronavirus (MERS-CoV) using CDC's rRT-PCR assay. However, they should coordinate with CDC for specimen testing since widely available diagnostic tests are not suitable.
What specimen to collect as Broncho alveolar lavage sputum and tracheal aspirates contain the highest viral loads and these should be collected when possible
Rt-pcr the gold standard use of CDC's 2012 real-time reverse transcription–PCR assay to test for MERS-CoV in clinical respiratory, blood, and stool specimens.
When to consider as MERS-CoV Infection Clusters4 of patients with severe acute respiratory illness (e.g., fever and pneumonia requiring hospitalization) without recognized links to a case of MERS-CoV infection or to travellers from countries in or near the Arabian Peninsula should be evaluated for common respiratory pathogens.3 If the illnesses remain unexplained, providers should consider testing for MERS-CoV, in consultation with state and local health departments.
infection control measures Healthcare personnel should adhere to recommended infection control measures, including standard, contact, and airborne precautions, while managing symptomatic close contacts, patients under investigation, and patients who have probable or confirmed MERS-CoV infections. Recommended infection control precautions should also be utilized when collecting specimens.
Preventive measures in the hospital focus on the hospital setting, the recommendations for personal protective equipment (PPE), source control (i.e., placing a facemask on potentially infected patients when outside of an airborne infection isolation room), and environmental infection control measures are applicable to any healthcare setting.
Updated recommendation suspected high rate of morbidity and mortality among infected patients Evidence of limited human-to-human transmission Poorly characterized clinical signs and symptoms Unknown modes of transmission of MERS-CoV Lack of a vaccine and chemoprophylaxis
Interim Laboratory Biosafety Guidelines Timely communication between clinical and laboratory staff is essential to minimize the risk incurred in handling specimens from patients with possible MERS-CoV infection. Such specimens should be labeled accordingly, and the laboratory should be alerted to ensure proper specimen handling.
Standard precautions Apply routinely in all health-care settings for all patients. Standard precautions include: hand hygiene and use of personal protective equipment (PPE) to avoid direct contact with patients’ blood, body fluids, secretions (including respiratory secretions) and non-intact skin. When providing care in close contact with a patient with respiratory symptoms (e.g.-coughing or sneezing), use eye protection, because sprays of secretions may occur. Standard precautions include: prevention of needle-stick or sharps injury; safe waste management;cleaning and disinfection of equipment; and cleaning of the environment
Droplet precautions Use a medical mask if working within 1 meter of the patient. Place patients in single rooms, or group together those with the same etiological diagnosis. If an etiological diagnosis is not possible, group patients with similar clinical diagnosis and based on epidemiological risk factors, with a spatial separation of at least 1 meter. Limit patient movement and ensure that patients wear medical masks when outside their rooms
Airborne precautions Ensure that healthcare workers performing aerosol-generating procedures use PPE, including gloves, long-sleeved gowns, eye protection and particulate respirators (N95 or equivalent). Whenever possible, use adequately ventilated single rooms when performing aerosol-generating procedures
working with potentially infectious materials Laboratory workers should wear personal protective equipment (PPE) which includes disposable gloves, laboratory coat/gown, mask, and eye protection when handling potentially infectious specimens.
MERS and Travel CDC does not recommend that anyone change their travel plans because of MERS. The current CDC travel notice is an Alert (Level 2), which provides special precautions for travelers. Because spread of MERS has occurred in healthcare settings, the alert advises travelers going to countries in or near the Arabian Peninsula to provide healthcare services to practice CDC’s recommendations for infection control of confirmed or suspected cases and to monitor their health closely. Travellers who are going to the area for other reasons are advised to follow standard precautions, such as hand washing and avoiding contact with people who are ill.
Many countries tracking mers infection spread
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