Dissertation > Excellent graduate degree dissertation topics show

The Genetic Evolution of H5N1 Subtype Influenza Virus Isolated and Identified from Water of the Tibetan Plateau

Author: WuYanYun
Tutor: HeHongXuan；WangSanHu
School: Henan Agricultural University
Course: Basic Veterinary Science
Keywords: H5N1 subtype of influenza A virus Water samples Adsorption - elution Molecular genetic evolution
CLC: S852.65
Type: Master's thesis
Year: 2008
Downloads: 18
Quote: 0
Read: Download Dissertation

Abstract

May-July 2005, China's Qinghai Lake and the surrounding area for the first time a large number of migratory birds died of the H5N1 strain of highly pathogenic avian influenza. Some migratory birds have the habit of living in the water environment, so that the waters become an important high-risk carriers of the avian influenza virus. In order to understand the occurrence and mode of transmission of avian influenza in the Qinghai-Tibet Plateau, the study established a nitrocellulose membrane filtration method to detect avian influenza viruses in the water environment, the application of this method separation caused by a plant height of water environmental samples from around the Qinghai Lake pathogenic H5N1 subtype of influenza virus and its pathogenicity, biological characteristics, genetic variation has been studied. So as to provide a scientific basis to reveal pathological variation caused by influenza virus and its transmission mechanisms. Nitrocellulose membrane filtration method for avian influenza viruses in water and sewage concentrated, the recoveries were 96.14% and 93.44%, no significant difference between the two. Experimental avian influenza virus in a 10-fold serial dilutions of recycling, recovery, depending on the concentration of the virus is not obvious, the application of the method can effectively play the role of the virus was recovered. In tap water, when the virus Market concentration 96PFU / L, the recoveries were in more than 78.13%. Wastewater, when the Market concentration reaches 96PFU / L, the recovery rate was 47.92%, which decreased recoveries than tap water. This test to compare a glycine buffer, elution of beef extract solution, phosphate buffer eluent most commonly used in the different pH conditions (7,9.5,11) best effect. Experimental results show that, when the highest virus recoveries pH9.5, O.1mol / L glycine buffer as the eluent. The water samples of the Qinghai separation enrichment, the results of a highly pathogenic H5N1 influenza virus isolated. From the the pathogenicity test shows, this isolates of influenza virus infection in ducks only after 24h, a virus is detected in the duck lung, kidney, liver, spleen, brain and breast muscle. 36h after infection timing of virus in the body of toxic highest; 60h when the body's toxic decline, the presence of the virus was not detected in the liver, spleen, kidney, lung, brain, breast muscle virus content remained essentially maintain the peak, the mice were infected with influenza trends and trend after the ducks infected with the virus is almost the same, the only difference is in 60h after infection, influenza virus undetectable in muscle Description the influenza viruses tissue tropism. Proliferation of virus specific pathogen-free (SPF) embryonated eggs, extracting the virus in the allantoic fluid of total RNA, the eight genes primers, the design of the avian influenza virus by reverse transcription - polymerase chain reaction (RT-PCR) technology isolates eight gene fragments were amplified sequence cDNA were cloned in pMD18-T vector identification and sequencing. The results showed that the amplified gene fragment contains the complete open reading frame of the H5N1 influenza virus. DNAStar analysis software molecular genetic evolution of the isolates and 11 avian influenza virus genome eight gene sequence analysis showed that the HA gene of the isolates and the Eurasian separation strains Shandong/2003 of germline homology of 98.6% , and at the same clade; North America the representative strains Ireland/1983 homology of 86%, and in the distant evolutionary branch on the result of this comparison indicate that the isolates originated in the Eurasian germline. Isolates the HA cleavage site of the amino acid sequence as PQRERRRKKR, and more than five consecutive basic amino acid, to be described as a highly pathogenic influenza virus strains. Other seven nucleotide homology and molecular evolution analysis showed that the isolates gene Shangdong/03 strains of the corresponding gene homology of more than 95.7%, indicating that the two closer relationship . Therefore, it can be speculated that this test the isolates Qinghai/2007 (H5N1) is likely to be evolved by the the 2003 Shandong swine flu strain variation.

Related Dissertations

CLC: > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > Animal Medicine ( Veterinary Medicine) > Basic Veterinary Science > Animal Microbiology ( Veterinary Microbiology, ) > Livestock Virology
© 2012 www.DissertationTopic.Net Mobile