Saturday, September 29, 2012

Coronavirus `Closely Related’ To HK Bat Strains


Japanese pipistrelles – Credit Wikipedia


# 6595


Bats have been long associated with carrying rabies, but only in recent years have other bat-hosted viruses really gained our attention. Among the first, was the Nipah virus, which was first identified in Malaysia in 1998.


The Nipah virus first jumped from bats to local swine herds, probably via bat droppings into the swine’s environment or food. From there, it jumped to humans, resulting in 265 cases of acute encephalitis and more than 100 deaths (cite).


This first human outbreak was initially thought to be due to Japanese encephalitis, and so precautions around pigs were delayed for nearly two months, allowing the virus to spread.


Over the past decade, Nipah has caused a number of small outbreaks across Southern Asia, although the most intense activity has been centered around Bangladesh. In Australia, Hendra (a close relative to Nipah), is also carried by bats, and has infected horses and humans.


In 2003 and 2004, bats once again became a focal point after viruses similar to the SARS coronavirus were found in horseshoe bats in China (cite).  And in recent years, Fruit bats of the Pteropodidae family have been linked to the Ebola virus (cite).


Since the SARS outbreak, researchers have found a growing number of previously unknown coronaviruses carried by various species of bats.


This from the journal Virology, circa July 2006 (reparagraphed and reformatted for readability).


Molecular diversity of coronaviruses in bats.

Woo PC, Lau SK, Li KS, Poon RW, Wong BH, Tsoi HW, Yip BC, Huang Y, Chan KH, Yuen KY.


Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong.


The existence of coronaviruses in bats is unknown until the recent discovery of bat-SARS-CoV in Chinese horseshoe bats and a novel group 1 coronavirus in other bat species.


Among 309 bats of 13 species captured from 20 different locations in rural areas of Hong Kong over a 16-month period, coronaviruses were amplified from anal swabs of 37 (12%) bats by RT-PCR.


Phylogenetic analysis of RNA-dependent-RNA-polymerase (pol) and helicase genes revealed six novel coronaviruses from six different bat species, in addition to the two previously described coronaviruses.


Among the six novel coronaviruses, four were group 1 coronaviruses (bat-CoV HKU2 from Chinese horseshoe bat, bat-CoV HKU6 from rickett's big-footed bat, bat-CoV HKU7 from greater bent-winged bat and bat-CoV HKU8 from lesser bent-winged bat) and two were group 2 coronaviruses (bat-CoV HKU4 from lesser bamboo bats and bat-CoV HKU5 from Japanese pipistrelles).


An astonishing diversity of coronaviruses was observed in bats.


All of which serves as prelude to a story today out of Hong Kong, where researchers from the University of Hong Kong have compared the gene structure of the newly discovered coronavirus in the Middle East, and find it to be a 90% match to the HKU4 and HKU5 viruses mentioned above.

This story from the South China Morning Post:


Sars-like virus in Middle East 'closely related to Hong Kong bat strains'

Expert says new coronavirus is 90pc similar to two other bugs that were discovered in city


Yuen, an authority in coronaviruses, said the new virus' genetic sequence was 90 per cent similar to the two bat strains found locally, the closest match so far. "We can say the new virus has a common ancestor and come from the same family as the two bat viruses," he said.


No conclusion could be drawn that the Middle Eastern patients had contracted the new virus from bats, he said. It was also genetically distinct from the Sars coronavirus, he added.

(Continue . . . )



While the coronavirus detected in the Middle East is similar to other coronaviruses found in bats, this doesn’t necessarily mean that the two known victims contracted it directly from a bat.  


There may well have been an intermediate host involved (as were the pigs in Malaysia, and possibly civet cats with SARS).


This is another clue, however, in the epidemiological investigation into these two new cases. 


For now – with no sign of additional cases - the World Health Organization (along with many other experts) see the transmission of this virus to humans as being inefficient or `weak’.  


With luck, that status will remain unchanged as we learn more about this emerging virus.


For more on bats, and bat-hosted viruses, you may wish to revisit:


Disease Transmission At The Human-Animal Interface
A New Flu Comes Up To Bat
The Scientific Plausibility of `Contagion’
The Nipah Virus: An Emerging Infectious Threat

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