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We hope that our project can | We hope that our project can | ||
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− | <li> | + | <li>Provide rapid detection method with higher accuracy at a lower production cost;</li> |
− | <li> | + | <li>Stop Influenza A pandemic by early on-site detection; and </li> |
− | <li> | + | <li>Ease the stress on public health service when disease attacks, especially in less developed countries. </li></ol> </p> |
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− | < | + | <p style="font-family: quicksand;font-size:150%;">Influenza Type A </p> |
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<center><img src="https://static.igem.org/mediawiki/2017/f/f6/Cuhk17_influenzaA2.png" width="40%" height="auto;"></center> | <center><img src="https://static.igem.org/mediawiki/2017/f/f6/Cuhk17_influenzaA2.png" width="40%" height="auto;"></center> | ||
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− | + | <p style="font-family: roboto;font-size:115%;"> | |
Influenza is a prevalent acute respiratory disease circulating among human and other animals (1). Influenza A can be spread rapidly throughout poultry flocks and cause severe illness, or even death in human. The most notorious pandemic was the “Spanish Flu” in 1918, which killed 50 million people worldwide (1). Influenza A virus poses large social and economic burden. Each year in the United States, it is estimated that around 600,000 lives and $90 billion US dollars are lost due to influenza A virus (2). The existing form of influenza virus genome is segmented antisense RNA. Influenza A can be subtyped according to the types of hemagglutinin (HA) and neuraminidase (NA) glycoprotein on the virus surface (above figure). NA protein can cleave terminal sialic acid residue and promote virion release (3). Since there are 18 types of HA and 11 types of NA, there are 198 possible subtypes. Different influenza A subtypes possess different properties. For example, the mortality rate of infection by the subtypes H5N1 and H7N9 is much higher than that of H1N1. | Influenza is a prevalent acute respiratory disease circulating among human and other animals (1). Influenza A can be spread rapidly throughout poultry flocks and cause severe illness, or even death in human. The most notorious pandemic was the “Spanish Flu” in 1918, which killed 50 million people worldwide (1). Influenza A virus poses large social and economic burden. Each year in the United States, it is estimated that around 600,000 lives and $90 billion US dollars are lost due to influenza A virus (2). The existing form of influenza virus genome is segmented antisense RNA. Influenza A can be subtyped according to the types of hemagglutinin (HA) and neuraminidase (NA) glycoprotein on the virus surface (above figure). NA protein can cleave terminal sialic acid residue and promote virion release (3). Since there are 18 types of HA and 11 types of NA, there are 198 possible subtypes. Different influenza A subtypes possess different properties. For example, the mortality rate of infection by the subtypes H5N1 and H7N9 is much higher than that of H1N1. | ||
+ | </p> | ||
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− | < | + | <p style="font-family: quicksand;font-size:150%;">Avian influenza </p> |
− | + | <p style="font-family: roboto;font-size:115%;"> | |
In this project, we aim to construct a set of artificial RNA biosensors to detect different influenza A viral genes, including the hemagglutinin and neuraminidase genes. We consulted local medical expert (link) and found that there is an urgent need for fast and on-site subtyping method for Avian influenza compared with other subtypes in Hong Kong. | In this project, we aim to construct a set of artificial RNA biosensors to detect different influenza A viral genes, including the hemagglutinin and neuraminidase genes. We consulted local medical expert (link) and found that there is an urgent need for fast and on-site subtyping method for Avian influenza compared with other subtypes in Hong Kong. | ||
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− | Therefore, we focused on constructing biosensors for subtyping the notorious Avian influenza. Among the subtypes, subtypes H5N1 and H7N9 are the most urgent subtypes that require need method to diagnose. | + | Therefore, we focused on constructing biosensors for subtyping the notorious Avian influenza. Among the subtypes, subtypes H5N1 and H7N9 are the most urgent subtypes that require need method to diagnose. </p> |
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+ | <p style="font-family: quicksand;font-size:150%;">H5N1: The notorious flu </p> | ||
+ | <p style="font-family: roboto;font-size:115%;"> | ||
+ | H5N1 is the most notorious highly pathogenic avian influenza. The first epidemic outbreak of H5N1 in human happened in Hong Kong in 1997. The flu was then spread to the entire Asia. According to the World Health Organization, there was 859 confirmed human cases since 2003 which killed 453 people with a mortality rate of 52% (5). The disease not only create tremendous economic burden to the health care system, it also greatly impact the poultry industry. During the outbreak of H5N1 in Hong Kong, 3.5 million chicken was slaughtered. About $10 billion US dollars had lost due to H5N1 outbreak (6). Although the risk of H5N1 pandemic outbreak in human population is considered to be low recently, it is considered as endemic in poultry in six countries (Bangladesh, China, Egypt, India, Indonesia, and Vietnam) (7). </p> | ||
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− | < | + | <p style="font-family: quicksand;font-size:150%;">H7N9: The next H5N1? </p> |
− | + | <p style="font-family: roboto;font-size:115%;"> | |
− | + | H7 virus was thought to be only circulated among avian hosts but human infection is recently reported. The first case of human infection was recorded in China in 2013 (8). According to the World Health Organization (WHO), 1533 human infection cases were reported, with a mortality rate of 39% (9). In Hong Kong, 4 confirmed human cases were reported so far. H7N9 cased economic loss of about $6.5 billion in China (10). Among all the avian influenza virus, H7N9 virus was found to have the highest ability to infect humans and circulate in birds (11). WHO warned that the human infections are unusual and need to be carefully monitored. According to the Centers for Disease Control and Prevention (CDC) of the United States (12), H7N9 is the subtype that has the greatest potential to cause a pandemic in recent year compared with other subtypes. It is worried that H7N9 may cause next pandemic since the virus is evolving mechanism for human- to- human transmission (13). </p> | |
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− | + | <p><h3>The need for new subtyping method </h3></p> | |
− | + | <p style="font-family: roboto;font-size:115%;"> | |
− | < | + | |
− | < | + | |
− | <h3>The need for new subtyping method </h3> | + | |
To avoid possible epidemic and pandemic outbreak, World Health Organization (WHO) has a well-established Global Influenza Surveillance and Response System (GISRS) (3). With combined effort of more than 120 national laboratories, the potential epidemic strain of influenza A virus will be selected to make vaccine to prevent possible outbreak (3). To effectively monitor the spread of avian influenza, a simple and rapid on- site method is needed for detecting the virus in both human and poultry. However, nowadays on-site diagnostic method, such as Rapid Influenza Diagnostic Tests (RIDTs), can only identify the influenza A virus but cannot subtype it (14). Traditional influenza A subtyping method rely on qRT-PCR (15). Although the technique is highly sensitive and specific (16) , it is not suitable to be relied on during the spread of disease, since it requires long time, and cannot perform in poor condition where expensive equipment and technical expertise are not available. Failure of immediate respond to the spread of disease may result in pandemic (17). Meanwhile, a novel type of riboswitch, namely toehold switch, shows its potential in detecting viral RNA on- site with short detection time and low production cost. | To avoid possible epidemic and pandemic outbreak, World Health Organization (WHO) has a well-established Global Influenza Surveillance and Response System (GISRS) (3). With combined effort of more than 120 national laboratories, the potential epidemic strain of influenza A virus will be selected to make vaccine to prevent possible outbreak (3). To effectively monitor the spread of avian influenza, a simple and rapid on- site method is needed for detecting the virus in both human and poultry. However, nowadays on-site diagnostic method, such as Rapid Influenza Diagnostic Tests (RIDTs), can only identify the influenza A virus but cannot subtype it (14). Traditional influenza A subtyping method rely on qRT-PCR (15). Although the technique is highly sensitive and specific (16) , it is not suitable to be relied on during the spread of disease, since it requires long time, and cannot perform in poor condition where expensive equipment and technical expertise are not available. Failure of immediate respond to the spread of disease may result in pandemic (17). Meanwhile, a novel type of riboswitch, namely toehold switch, shows its potential in detecting viral RNA on- site with short detection time and low production cost. | ||
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− | < | + | <p><h3>RNA toehold switches </h3></p> |
− | <h3>RNA toehold switches </h3> | + | |
<center><img src="https://static.igem.org/mediawiki/2017/3/35/Toehold.jpg" width="50%" height="auto;"></center> | <center><img src="https://static.igem.org/mediawiki/2017/3/35/Toehold.jpg" width="50%" height="auto;"></center> | ||
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− | < | + | <p><h3>Cell free system </h3></p> |
− | <h3>Cell free system </h3> | + | |
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<center><img src="https://static.igem.org/mediawiki/2017/9/9c/Cellfreesystem2.png" width="50%" height="auto" ;"></center> | <center><img src="https://static.igem.org/mediawiki/2017/9/9c/Cellfreesystem2.png" width="50%" height="auto" ;"></center> | ||
Cell free system is a mixture of cytoplasmic and nuclear components from E. coli for in vitro transcription and translation (Sitaraman, 2004). Recent studies revealed that cell free system can be stored in room temperature after freeze drying (Pardee et al., | Cell free system is a mixture of cytoplasmic and nuclear components from E. coli for in vitro transcription and translation (Sitaraman, 2004). Recent studies revealed that cell free system can be stored in room temperature after freeze drying (Pardee et al., | ||
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− | Altogether, the project aims to apply toehold switch technology in influenza A subtyping and offer convenient tool to facilitate the design of toehold switch. It is hoped that our method could suppress the spread of pathogenic Influenza in a timely manner. </ | + | Altogether, the project aims to apply toehold switch technology in influenza A subtyping and offer convenient tool to facilitate the design of toehold switch. It is hoped that our method could suppress the spread of pathogenic Influenza in a timely manner. </p> |
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− | <h3>Reference: </h3> | + | <p><h3>Reference: </h3></p> |
1. Global Influenza Programme [Internet]. World Health Organization. 2017 [cited 31 May 2017]. Available from: http://www.who.int/influenza/en/ | 1. Global Influenza Programme [Internet]. World Health Organization. 2017 [cited 31 May 2017]. Available from: http://www.who.int/influenza/en/ | ||
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Revision as of 14:58, 24 October 2017