The recurring nature of influenza epidemics and pandemics is a consequence of the genetic and antigenic variability of the virus. This changeability in turn arises from mutations introduced by the error prone polymerase and the shuffling of viral gene segments among strains in the process of reassortment. The importance of reassortment among human and animal influenza viruses to the genesis of pandemic strains has been appreciated for many years. More recent phylogenic and epidemiological studies have furthermore established a significant role for reassortment between seasonal influenza viruses in the generation of novel epidemic strains. Nevertheless, little is known about how efficiently and under what circumstances reassortment occurs in a host co-infected with two influenza viruses. Through the proposed research we plan to address this gap in knowledge. Using both cell culture and guinea pig models, we will first determine the frequency with which reassortment occurs in the absence of selective pressures. We will then introduce systematically a number of variables, such as pre-existing immunity or a time interval between infections, and determine whether each increases or decreases the number of reassortant progeny arising from the co-infection. In this way, we will establish the parameters that govern the process of influenza virus reassortment. Since reassortant strains will be epidemiologically significant only if they are transmitted to additional hosts, we will also evaluate the size of the bottleneck created by influenza virus transmission. Thus, through carefully controlled experimental studies, we propose to reveal novel insights in the mechanisms governing influenza virus evolution and the emergence of epidemic and pandemic strains.

Public Health Relevance

Through regular epidemics and infrequent pandemics, influenza affects a significant proportion of the population every year. Reassortment, the process by which two differing influenza viruses exchange genes, is one mechanism by which antigenically novel strains capable of causing these outbreaks arise. By defining the circumstances under which reassortment can proceed, our proposed research will enable public health efforts aimed at predicting and limiting the emergence of new influenza virus strains. !!

Agency
National Institute of Health (NIH)
Type
Research Project (R01)
Project #
5R01AI099000-03
Application #
8711262
Study Section
Virology - B Study Section (VIRB)
Program Officer
Hauguel, Teresa M
Project Start
Project End
Budget Start
Budget End
Support Year
3
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Emory University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
City
Atlanta
State
GA
Country
United States
Zip Code
30322
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Lowen, Anice C; Steel, John (2014) Roles of humidity and temperature in shaping influenza seasonality. J Virol 88:7692-5
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