Human coronavirus MERS-HCoV (HCoV-EMC before / 2012): A new virus from the Middle East
Version 9.12.13.
The new human Coronavirus MERS-HCoV (formerly HCoV-EMC / 2012), from the Middle East, presents a potential for spread risk, so we consider necessary to report the current situation, and to communicate the diagnostic possibilities we can offer, by molecular genetic tests.
The new human Coronavirus MERS-HCoV (formerly HCoV-EMC / 2012), from the Middle East, presents a potential for spread risk, so we consider necessary to report the current situation, and to communicate the diagnostic possibilities we can offer, by molecular genetic tests.
The Coronavirus (VOCs) infect and cause disease in many species: bats, birds, cats, dogs, pigs, rodents, horses , whales, and people, among others. When infected can cause respiratory disease neurological, enteric, hepatic or variable gravity. HCoV-229E and HCoV-OC43, to cause mild respiratory diseases: in the 60 human Coronavirus two species (HCoVs) were described. Between late 2002 and 2003 SARS-CoV that causes Severe Acute Respiratory Syndrome Severe (Severe Acute Respiratory Syndrome) was described, affecting a few months to 8,422 people in about 30 countries on five continents and causing 916 deaths among them (average lethality of a eleven%). The interest aroused by this virus led to the description of two new species in humans: HCoV-NL63 (2004) and HCoV-HKU1 (2005). Recently, in September 2012, it described a new human Coronavirus (MERS-HCoV: Middle East Respiratory Syndrome-Human Coronavirus) (formerly HCoV-EMC / 2012: Human Coronavirus Erasmus Medical Center, The Netherlands), from a deceased patient in Saudi Arabia, and subsequent instances of the same country, others from Qatar, and retrospectively in an outbreak in Jordan.
Although there have now described a few cases, the damage is severe, with an sintomatológico and epidemiological picture reminiscent of SARS in 2003, and a similar origin (bats) with a possible host different intermediary (probably camels), so we should be prepared for diagnosis.
Coronavirus which affect various species share the same characteristics, differing in several genetic lineages. This has enabled classified into four genera within the Coronaviridae family, subfamily Coronavirinae: AlfaCoronavirus, BetaCoronavirus, GammaCoronavirus and DeltaCoronavirus corresponding to the first three above groups 1, 2 and 3. In the genera AlfaCoronavirus and BetaCoronavirus are species affect people, while gender Gamma- and DeltaCoronavirus only include hitherto described animal virus. The attached table sorting and virus included in these four genera can be observed.
These viruses have a single - stranded RNA genome of positive (+ ssRNA) of 25-32 Kb, and are quite resistant to environmental conditions, remaining infectious after several days in feces of bats. Bats were found as the natural reservoir of SARS-CoV after being implicated civet and racon, which were finally considered intermediate hosts from which human infections occurred. Curiously, this very fact, bats involved in its reservoir, previously it found with other viruses that have produced high human mortality as Nipah virus (bats and pigs), Hendra virus (bats and horses), and Ebola virus (bats) . Coronavirus MERS-HCoV for (formerly HCoV-EMC / 2012), investigates whether camels could be the intermediate host from infected bats, and from that transmission to humans would occur. The human transmission appears possible, to the cases involving members of the same family in Saudi Arabia happen, and in cases involving health workers in Jordan.
initial cases
The first case of infection by human Coronavirus MERS-HCoV (formerly HCoV-EMC / 2012) was described in a 60 year old man who died in (Saudi Arabia) hospital in Jeddah, suffering from an acute respiratory distress syndrome (ARDS: acute Respiratory Distress syndrome) and multiorgan dysfunction syndrome (MODS Multiple Organ dysfunction syndrome) in June 2012. currently, the symptoms presented by patients, this syndrome is called MERS (Middle east Respiratory syndrome). The affected patients, which confirmed the existence of MERS-HCoV infection develop acute and severe respiratory illness with fever, cough, and difficulty breathing, passing away about half of those affected.
After the initial cases, which occurred in four countries of the Arabian Peninsula or close to it, three months later, was found in another patient in London, who had been transferred from Qatar, and survived, like another case of the same country. In Saudi Arabia, he was found in five others, three of which belonged to the same family, and three of them died. Retrospectively, MERS-Coronavirus HCoV (HCoV-EMC before / 2012) has shown that this same virus found in April 2012 affected two toilets in Jordan, who died.
Until March 30, 2013, they had found 17 cases with 11 deaths. The last case of Abu Dhabi a 73 year old male who was transferred to Munich and died on 26 March.
On May 8, 2013, the World Health Organization indicates the existence of 30 laboratory - confirmed cases: two of Jordan, two of Qatar, 23 from Saudi Arabia, two from UK and one of Arab Emirates. Most were male (79.3%), and an age range of 24-94 years (mean 56 years). The first cases are from late March or early April 2012, and the last mato 1 2013 (13 cases between April 14 and May 1, 2013). Most patients with severe acute respiratory illness requiring hospitalization, and sometimes mechanical ventilation. Eighteen of the 30 patients died. Some cases have occurred grouped, and health Jordan April 2012 (2 confirmed and 11 probable cases), or the United Kingdom between members of a family of an infected patient who had recently returned and Saudi Arabia.
Until September 10, 2013, the World Health Organization recognizes the existence of 114 cases, of which 54 have died. These patients DSE distributed as follows:
Countries cases (death)
France 2 (1)
Italy 2 (1)
Jordan 2 (2)
Qatar 5 (2)
Saudi Arabia 90 (44)
Tunisia 3 (1)
United Kingdom (UK) 3 (2)
United Arab Emirates 6 (2)
Total 114 (54)
Characteristics of patients who may be affected (under study)
Suspect patient study:
- Patient with fever> 38 ° C, with pneumonia or ARDS (depending on clinical or radiological characteristics)
and have,
- History of travel to or near the Arabian Peninsula countries (see note 1), within 14 days prior to onset of symptoms.
Or what,
- has had intimate contact (see note 2) with symptomatic traveler, and developing fever and acute respiratory disease (not necessarily pneumonia), inside and 14 days after traveling to countries of the Arabian Peninsula, or close to it.
Or what,
- Be a member of a group of patients with acute respiratory illness (ie fever and pneumonia requiring hospitalization) of unknown etiology which is investigating the presence of MERS-HCoV, in consultation with health institutions.
Confirmed case
Patient with laboratory confirmation of MERS-HCoV (see note 3).
probable case
Probable case is a patient study without laboratory results, or inconclusive results for MERS-HCoV (see note 4) who has had intimate contact (see Note 2) with a laboratory - confirmed case of MERS-HCoV infection.
notes:
1) Countries of the Arabian Peninsula or close to it: Bahrain, Iraq, Iran, Israel, Jordan, Kuwait, Lebanon, Oman, Palestinian Territories, Qatar, Saudi Arabia, Syria, UAE and Yemen.
2) Intimate contact, defined as: a) a person who provides health care to the patient, including medical personnel or family members, or having close contact like; b) anyone who is in the same place (living or visiting) with the patient, when the person is sick.
3) Confirmatory testing laboratory require positive PCR, with at least two specific genomic targets or a single target with sequencing.
4) Examples of laboratory results are inconclusive: positive PCR test with a single molecular target; a positive test with a test that has limited information available; or a negative test with inadequate sample.
Diagnostic methods
The diagnosis of this infection, offers no problems.
Coronavirus MERS-HCoV (before HCoV-EMC / 2012), can be isolated in cell cultures, without any problems, from respiratory samples, as it grows well in cell lines monkey kidney Vero or LLC-MK cells.
Moreover, various protocols have been described genome amplification (RT-PCR) with possibility of using various molecular targets for amplification, and thus avoid possible false positives.
Tests in IVAMI
In IVAMI, from December 2012, we have the procedure amplification by RT-PCR, two amplification molecular targets for if necessary. Genetic testing sequencing of amplicons, allow us to confirm the specificity of the amplifications.
Serology by neutralization, is possible, but required 14 or 21 days to detect seroconversion is not the recommended procedure.
3) Confirmatory testing laboratory require positive PCR, with at least two specific genomic targets or a single target with sequencing.
4) Examples of laboratory results are inconclusive: positive PCR test with a single molecular target; a positive test with a test that has limited information available; or a negative test with inadequate sample.
Diagnostic methods
The diagnosis of this infection, offers no problems.
Coronavirus MERS-HCoV (before HCoV-EMC / 2012), can be isolated in cell cultures, without any problems, from respiratory samples, as it grows well in cell lines monkey kidney Vero or LLC-MK cells.
Moreover, various protocols have been described genome amplification (RT-PCR) with possibility of using various molecular targets for amplification, and thus avoid possible false positives.
Tests in IVAMI
In IVAMI, from December 2012, we have the procedure amplification by RT-PCR, two amplification molecular targets for if necessary. Genetic testing sequencing of amplicons, allow us to confirm the specificity of the amplifications.
Serology by neutralization, is possible, but required 14 or 21 days to detect seroconversion is not the recommended procedure.