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Preliminary Overview of 27 NCoV Cases, May 3, 2013

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  • Preliminary Overview of 27 NCoV Cases, May 3, 2013

    Preliminary Overview of 27 NCoV Cases, May 3, 2013
    Laidback Al, Senior Moderator, www.FluTrackers.com
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    A novel betacoronavirus (NCoV) infecting humans was first identified in late of 2012. Through April 15, 2013, a total of 17 cases have been reported from various countries. Incomplete case patient data on the first 17 NCoV cases can be found at this ECDC link.

    In the past three days, another 10 cases have been reported, all from Saudi Arabia (FT Link). This discussion presents an over view of the first 27 cases of NCoV. The publicly available information on these cases is limited and sometimes official sources provide conflicting data. The data and discussions presented here are based on the information available as of May 3, 2013.



    Coronaviruses and NCoV terminology

    Coronaviruses are a large, diverse group of viruses that affect many animal species. A few of these viruses cause a wide range of respiratory illness in humans, typically with "common cold" symptoms. Genetic sequence data indicate that this new virus is a beta-coronavirus similar to bat coronaviruses, but not similar to any other coronavirus previously described in humans, including the coronavirus that caused severe acute respiratory syndrome (SARS) . . . (link)
    This coronavirus is referred to as betacoronavirus 2c EMC2012, but it is also cited in the research literature as HCoV-EMC/2012, NCoV, HCoV, and HCoV-EMC. “HCoV-EMC/2012 is the sixth coronavirus known to infect humans and the first human virus within betacoronavirus lineage C” (link). As noted by the CDC article this coronavirus shares similarities with bat coronavirus (link). Sequence analysis of fecal specimens of bats in Ghana and Europe led researchers to conclude that EMC/2012 originated from bats (link).

    Case Numbering Conventions

    Unfortunately there is no official international case numbering convention for confirmed cases of NCoV or, for that matter, case patients of other novel infectious diseases such as A(H7N9) or A(H5N1). Various organizations used different numbers to identify cases, some are ordered by onset date, others by date reported. Perhaps in order to preserve case anonymity, sometimes family relationships are not even reported among a cluster of family members. The lack of a consistent numbering convention complicates issues in tracking epidemiological information about NCoV cases and can lead to confusion among public health agencies.

    Background

    The first case confirmed with this NCoV was reported in a 60 year old male who lived in Saudi Arabia. He died from severe pneumonia complicated by renal failure in Jeddah on 24 June 2012. The genome of the new coronavirus was isolated from this case, sequenced and the genetic code put in the public domain. In September 2012, a second case, a 49 year old male living in Qatar, presented with symptoms similar to the first case. He was transferred for care in Europe [5]. A virus was isolated from this case, sequenced and the genetic code put in the public domain. It was almost identical to the virus from the case in Saudi Arabia. In November 2012, additional cases with similar symptomatology were diagnosed in Qatar and Saudi Arabia (Table 1), including a family cluster of three confirmed cases and one probable case.

    Subsequently, two fatal cases were confirmed retrospectively in Jordan from within a cluster of 11 people with severe lower respiratory infections that were associated with a hospital in April 2012. Although the nine other cases fit the WHO definition for probable novel coronavirus infections they were less severe than the confirmed cases. It has not yet been possible to undertake confirmatory virological or serological testing.

    The retrospective finding of two cases in Jordan raises the issue of whether this is a new infection in humans or one that has been occurring for some time. Equally, although the first cases were all connected with the Middle-East, it is noticeable that they came from widely separated places. Since similar animal coronaviruses can be found in bats in all regions of the world, it is possible that these infections are to be found sporadically in many countries. This makes a strong case for further studies of animal coronaviruses and prospective and retrospective searches for cases in other regions. The testing of people with respiratory tract infections among those coming to Europe between September and November 2012 did not reveal any additional infections to the three already mentioned (Cases 4, 6 & 10).

    Only the most recent case (Case 12) has shown mild influenza-like symptoms. All other confirmed patients have presented with severe lower respiratory tract infection such as pneumonia. A number of cases have also developed renal failure during the course of illness. The proportion of deaths is high; six out of twelve with two others still receiving high level care. The age range is from 25 to 60 years and a noticeable feature is that only two cases are female. ( link)
    Incubation Period

    Severe acute respiratory syndrome (SARS), a coronavirus similar to NCoV, is reported to have an median incubation period of 4 days (link). Several researcher have proposed that an incubation period of 3 to 5 days may be indicative of an NCoV infection while an incubation period of 2 days or less is suggestive of influenza infections (link).

    Gender, Age, and Mortality

    Of the 27 reported cases of NCoV, males outnumber females about 5:1, 22 cases are male and 4 are female, and one has gender unreported. Age is reported for 26 of the 27 cases, Reported ages range 24 to 94 years old. Average age and median age are the same, 51 years. Of the 27 cases, 16 have died, approximately 59%. Because so few females have been infected, it is not appropriate to compare mortality rates by gender.

    Geographic Distribution

    Residents of five countries have been infected by NCoV, Jordan, Kingdom of Saudi Arabia, Qatar, United Arab Emirates, and the United Kingdom. Initial animal-human transmission seems to be occurring on the Arabian Peninsula.

    Clusters


    Although only 27 cases of NCoV have been reported. Five separate clusters have already been identified. Of these, two clusters represents human-to-human transmission.

    Cluster 1 Jordan Cluster April 2012


    Two fatal cases, a 45 year-old woman and a 25 year-old man, from Jordan in April 2012. The 2 cases were discovered through testing of samples from a cluster of 11 pneumonia cases in health care workers that occurred at that time. These two individuals were health care workers and most likely contracted the infection from a treated patient or coworker.

    Cluster 2 Saudi Arabia Cluster November 2012

    In late October and early November, 2013, three male family members were confirmed with NCoV in Riyadh, Saudi Arabia. Two males were in their 30s and third was 70 years old. The 70-year old male and a 39 year old male died. The third male, a 31-years old, apparently recovered. It is presumed the 70 year old male was the father of one or both of the younger men.

    Cluster 3, United Kingdom Cluster January 2013


    A father and his son and female relative in the United Kingdom represent the third cluster of cases. The son and female relative contracted the infection from the father after he returned to the United Kingdom from Saudi Arabia. This cluster also presents clear evidence of H2H transmission.
    The index cases of this cluster is a 60-year-old male who resided in Birmingham England. He had a 39-year-old son who was suffering from brain cancer and was diagnosed with a low chance of survival in November 2012. The son moved to Birmingham near his father to receive chemotherapy treatment in January 2013.

    Between December 16 and January 20<sup>th</sup>, the index case traveled to Pakistan to inform relatives about his son’s cancer. On his return to his home to Birmingham, he stopped in Mecca, Saudi Arabia beginning on January 20 to pray for the recovery of his son. He experienced symptom onset on January 24, 2013 while still in Saudi Arabia and returned to the United Kingdom on January 28, 2013. He was hospitalized on January 31, 2013.

    Following his return from Saudi Arabia on January 31, 2013, The index case had contact with both his son and female relative when he returned home. The female relative began experiencing symptoms on February 5. The son began experiencing symptoms on February 7<sup>th</sup>, presumably while being treated with chemotherapy. On February 17<sup>th</sup>, 10 days later, the son died from the infection. Neither he nor the female relative had traveled outside the United Kingdom. The father died on March 19, 2013 (link).

    While official reports only note the third cases in this cluster as a female relative, a media report indicates that this female relative was the sister of the index case. From the link above:

    Doctors believe Abid transmitted the disease to his son in the first few days after arriving back from Mecca. Abid's sister Zaida was also confirmed to have the virus, but because she had a healthy immune system, she quickly recovered.


    Cluster 4, Saudi Arabia Cluster March 2013


    Little information is available about this cluster. One of the contacts of a 39 year old male who died on March 3, 2013 tested positive for NCoV. This individual recovered and no further information is currently available.

    Cluster 5, Saudi Arabia Cluster April 2013

    Two of the three cases reported from Saudi Arabia on May 3, 2013 are reported to be family members. No further information is available.

    Discussion

    NCoV is a deadly virus, it has killed 16 of 27 infected people. Of the nine cases between 59 and 94, all have died. The case data indicated that this coronavirus has the capability of spreading human to human. The cluster data suggests that close personal contact is necessary for human-to-human transmission. Further research is necessary to assess aerosolized transmission, however fomite transmission might be limited. In an article entitled Human coronaviruses: Clinical features and phylogenetic analysis, the authors indicate that 2c EMC2012 is a very fragile virus, with a survival time not exceeding 24 hours outside the human body.<object style="position:absolute;z-index:1000" type="application/x-dgnria" id="plugin0" height="0" width="0">

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    Last edited by Laidback Al; May 4th, 2013, 08:24 PM. Reason: Updated map and added note about the United Kingdom cluster amd adjusted gender count
    http://novel-infectious-diseases.blogspot.com/
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