Difference between revisions of "Bat Influenza A"

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[[Image:Yellow shouldered bat.jpeg|thumb|400px|right|''Little yellow-shouldered bat <i>"Sturnira lilium"</i>[http://es.wikipedia.org/wiki/Sturnira_lilium]]]
 
[[Image:Yellow shouldered bat.jpeg|thumb|400px|right|''Little yellow-shouldered bat <i>"Sturnira lilium"</i>[http://es.wikipedia.org/wiki/Sturnira_lilium]]]
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==Introduction==
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a. Bat ecology and virology
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b. Influenza A virology
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==Detection of novel Influenza A virus in bats==
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==a. Guatemala==
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A study done by Tong et al. in 2009-2010 revealed that bats could be a potential reservoir host for influenza A virus. They collected a total of 316 bats from 21 different species across 8 locations in southern Guatemala. They took oral and rectal swab samples from each bat. To test their hypothesis that these bats might harbor influenza viruses, Tong et al. developed a pan-influenza virus RT-PCR that detects the catalytic subunit of RNA polymerase, the polymerase basic protein (PB1). PB1 is one of the most conserved proteins within RNA viruses. By running a PCR reaction with this PB1 RT-PCR primer, they could search for novel influenza viruses within the bat’s genomes. Tong et al. found that three of the 316 bat rectal swab samples, all from the “little-yellow shouldered bat” (Sturnia lilium), were positive for influenza virus. The three samples contained 105-106 viral genome copies per 100 μL of rectal swab suspension, indicating a positive result. Two of the positive samples were captured in 2009 in El Jobo, Guatemala, and the third was captured in 2010 from Agüero, Guatemala (about 50 km away) (Tong et al., 2012)
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Interestingly, tissue samples (liver, intestine, and kidney) taken from these bats all tested positive for viral material, but the oral swab samples tested negative. Tang et al. hypothesizes that this difference in viral material location means that the influenza virus spreads through the bat in an infectious process, compared to orally ingesting infected material. Since the viral material was found within the rectum of the bats, it is most likely that the virus can be contracted through contact with infected bat feces (Tong et al., 2012).
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==b. Peru==
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Another study done by Tong et al. in 2010 identified another novel influenza A virus, named H18N11, from a flat-faced fruit bat (Artibeus planirostris) in Truenococha, Peru. The intestine tissue from this bat specimen tested strongly positive for influenza virus, while the other tissues tested negative.
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A phylogenetic analysis comparing the influenza A genome between the Guatemala and Peru bats showed that the viruses were closely related, but there is a distinct lineage between them. Surprisingly, the four viral RNA polymerase gene segments, PB1, PB2, PA, and NA, have more genetic diversity than all of the genetic diversity present in these genes in all non-bat groups (avian, mammalian, etc.) combined. This large diversity in viral genome shows that New World bat species are possibly the hosts to a large, diverse set of influenza viruses. 
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==Potential for human infection==
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==a. Viral genetic reassortment==
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For both H17 and H18 influenza
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==b. Structural differences between bat and human influenza A==
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By investigating the crucial structural components of influenza A and comparing their genes to the bat influenza virus, it was concluded by Tang et al. (2012) that the bat virus
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i. HA proteins
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ii. Sialic acid receptor binding

Revision as of 20:50, 14 March 2014

Little yellow-shouldered bat "Sturnira lilium"[1]

Introduction

a. Bat ecology and virology b. Influenza A virology

Detection of novel Influenza A virus in bats

a. Guatemala

A study done by Tong et al. in 2009-2010 revealed that bats could be a potential reservoir host for influenza A virus. They collected a total of 316 bats from 21 different species across 8 locations in southern Guatemala. They took oral and rectal swab samples from each bat. To test their hypothesis that these bats might harbor influenza viruses, Tong et al. developed a pan-influenza virus RT-PCR that detects the catalytic subunit of RNA polymerase, the polymerase basic protein (PB1). PB1 is one of the most conserved proteins within RNA viruses. By running a PCR reaction with this PB1 RT-PCR primer, they could search for novel influenza viruses within the bat’s genomes. Tong et al. found that three of the 316 bat rectal swab samples, all from the “little-yellow shouldered bat” (Sturnia lilium), were positive for influenza virus. The three samples contained 105-106 viral genome copies per 100 μL of rectal swab suspension, indicating a positive result. Two of the positive samples were captured in 2009 in El Jobo, Guatemala, and the third was captured in 2010 from Agüero, Guatemala (about 50 km away) (Tong et al., 2012) Interestingly, tissue samples (liver, intestine, and kidney) taken from these bats all tested positive for viral material, but the oral swab samples tested negative. Tang et al. hypothesizes that this difference in viral material location means that the influenza virus spreads through the bat in an infectious process, compared to orally ingesting infected material. Since the viral material was found within the rectum of the bats, it is most likely that the virus can be contracted through contact with infected bat feces (Tong et al., 2012).

b. Peru

Another study done by Tong et al. in 2010 identified another novel influenza A virus, named H18N11, from a flat-faced fruit bat (Artibeus planirostris) in Truenococha, Peru. The intestine tissue from this bat specimen tested strongly positive for influenza virus, while the other tissues tested negative. A phylogenetic analysis comparing the influenza A genome between the Guatemala and Peru bats showed that the viruses were closely related, but there is a distinct lineage between them. Surprisingly, the four viral RNA polymerase gene segments, PB1, PB2, PA, and NA, have more genetic diversity than all of the genetic diversity present in these genes in all non-bat groups (avian, mammalian, etc.) combined. This large diversity in viral genome shows that New World bat species are possibly the hosts to a large, diverse set of influenza viruses.

Potential for human infection

a. Viral genetic reassortment

For both H17 and H18 influenza

b. Structural differences between bat and human influenza A

By investigating the crucial structural components of influenza A and comparing their genes to the bat influenza virus, it was concluded by Tang et al. (2012) that the bat virus

i. HA proteins ii. Sialic acid receptor binding