Thursday, January 17, 2013

EID Journal: EMC/2012–related Coronaviruses in Bats

 

Coronavirus

Photo Credit NIAID

 

# 6864

 

Yesterday, in EID Journal: Ebola Virus Antibodies From Bats In Bangladesh, we looked at the possible carriage of the Ebola virus in Asian bats, and reviewed some of the history of emerging zoonotic diseases that can be carried by these winged mammals.

 

Today,we have another Chiropterist’s delight, an EID Journal dispatch that reports on the presence of betacoronaviruses – similar to the ones that infected a small number of people in the Middle East last year – among bats sampled in Ghana, and across four European nations.

 

First, a brief review of the outbreak of this novel coronavirus, which began in April of 2012.  This from the World Health Organization.

 

Background and summary of novel coronavirus infection – as of 21 December 2012

Over the past three months, WHO has received reports of nine cases of human infection with a novel coronavirus. Coronaviruses are a large family of viruses; different members of this family cause illness in humans and animals. In humans, these illnesses range from the common cold to infection with Severe Acute Respiratory Syndrome (SARS) coronavirus (SARS CoV).

 

This summary provides the latest information on all reported cases and provides details of a WHO mission to Jordan, which has concluded since the last web update.

 

Thus far, the laboratory confirmed cases have been reported by Qatar (two cases), Saudi Arabia (five cases) and Jordan (two cases). All patients were severely ill, and five have died.

 

<SNIP>

 

WHO recognizes that the emergence of a new coronavirus capable of causing severe disease raises concerns because of experience with SARS. Although this novel coronavirus is distantly related to the SARS CoV, they are different. Based on current information, it does not appear to transmit easily or sustainably between people, unlike the SARS virus.

(Continue . . . )

 

 

While we’ve not seen any new reports of illness from this virus in several months, the memories of the SARS outbreak in 2002-2003 remain fresh. Although this new Coronavirus (dubbed Human Betacoronavirus EMC/2012) isn’t SARS, it does come from the same family.

 

Last September, in Coronavirus `Closely Related’ To HK Bat Strains, we looked at research from the University of Hong Kong that compared the genetic structure of this newly discovered coronavirus with other coronaviruses, and found it to be a 90% match to the HKU4 and HKU5 strains collected in the middle of the last decade in Hong Kong.


Since then we’ve seen additional evidence suggesting that bats are likely this virus’s natural reservoir in mBio: New Coronavirus Linked To Bats and mBio: Coronavirus Has An Affinity For Multiple Hosts.

 

But so far, the viruses found in bats have been similar, but not a really close match to the HCOV EMC/2012 virus.

 

In an EID Journal dispatch published today, we get word of the closest match to date between this mystery-shrouded emerging coronavirus, and viruses identified in bats.

 

First the link and abstract (or follow the link to read it in its entirety), then I’ll return with a summation.

 

Human Betacoronavirus 2c EMC/2012–related Viruses in Bats, Ghana and Europe

Augustina Annan, Heather J. Baldwin, Victor Max Corman, Stefan M. Klose, Michael Owusu, Evans Ewald Nkrumah, Ebenezer Kofi Badu, Priscilla Anti, Olivia Agbenyega, Benjamin Meyer, Samuel Oppong, Yaw Adu Sarkodie, Elisabeth K.V. Kalko, Peter H.C. Lina, Elena V. Godlevska, Chantal Reusken, Antje Seebens, Florian Gloza-Rausch, Peter Vallo, Marco Tschapka, Christian Drosten, and Jan Felix Drexler

Abstract

We screened fecal specimens of 4,758 bats from Ghana and 272 bats from 4 European countries for betacoronaviruses. Viruses related to the novel human betacoronavirus EMC/2012 were detected in 46 (24.9%) of 185 Nycteris bats and 40 (14.7%) of 272 Pipistrellus bats. Their genetic relatedness indicated EMC/2012 originated from bats.

 

The entire report is much longer, and quite detailed, but briefly:

 

Fecal specimens were collected from 14 bat species from 7 locations across Ghana and 5 areas in Germany, the Netherlands, Romania, and Ukraine, and analyzed for the presence of HCOV EMC/2012-like viruses using nested reverse transcription PCR (RT-PCR). 

 

Previously, 2c bat CoVs have only been detected in vespertilionid bats, but in Ghana they detected related viruses in Nycteris bats as well. While similar to the HCOV EMC/2012 virus, they were from a genetically distinct group. 

 

The authors write:

 

This novel Nycteris bat CoV differed from the 2c-prototype viruses HKU4 and HKU5 by 8.8%–9.6% and from EMC/2012 by 7.5% and thus constituted a novel RGU.

 

In 2008 a bat coronavirus was identified in the Netherlands called VM314 that partial sequencing has shown to be fairly closely related to HCOV EMC/2012.

 

In examining 272 P. pipistrellus, P. nathusii, and P. pygmaeus bats from the Netherlands, Romania, and Ukraine they found 14% carried coronaviruses that were closely related to VM314.


The authors write:

 

The VM314-associated Pipistrellus bat betacoronaviruses differed from EMC/2012 by 1.8%. The difference between EMC/2012 and HKU5 was 5.5%–5.9%.

 

In summary, HKU5, EMC/2012, and the VM314-associated clade form 1 RGU according to our classification system, and the VM314-Pipistrellus bat clade contains the closest relatives of EMC/2012.

 

HKU4 and the Nycteris CoV define 2 separate tentative species in close equidistant relationship.

 

After calling for surveillance and screening of bats in the Middle East where these scattered human infections have been documented, the authors conclude:

The genomic data suggest that EMC/2012, like hCoV-229E and SARS-CoV, might be another human CoV for which an animal reservoir of closely related viruses could exist in Old World insectivorous bats(4,9).

 

Whether cross-order (e.g., chiropteran, carnivore, primate) host switches, such as suspected for SARS-CoV, have occurred for 2c clade bat CoVs remains unknown.

 

However, we showed previously that CoVs are massively amplified in bat maternity colonies in temperate climates (13). This amplification also might apply to the Nycteris bat CoV because, as shown previously for vespertilionid bats from temperate climates (14), detection rates of CoV are significantly higher among juvenile and lactating Nycteris bats.

 

In light of the observed high virus concentrations, the use of water from bat caves and bat guano as fertilizer for farming and the hunting of bats as wild game throughout Africa (15) may facilitate host switching events.

 

To our knowledge, no CoV has been isolated directly from bats. Further studies should still include attempts to isolate full virus genomes and to identify virulence factors that might contribute to the high pathogenicity of EMC/2012 (7).

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