Dataset Information

Intrahost evolutionary dynamics of canine influenza virus in naive and partially immune dogs.

ABSTRACT: The patterns and dynamics of evolution in acutely infecting viruses within individual hosts are largely unknown. To this end, we investigated the intrahost variation of canine influenza virus (CIV) during the course of experimental infections in naïve and partially immune dogs and in naturally infected dogs. Tracing sequence diversity in the gene encoding domain 1 of the hemagglutinin (HA1) protein over the time course of infection provided information on the patterns and processes of intrahost viral evolution and revealed some of the effects of partial host immunity. Viral populations sampled on any given day were generally characterized by mean pairwise genetic diversities between 0.1 and 0.2% and by mutational spectra that changed considerably on different days. Some observed mutations may have affected antigenicity or host range, including reversions of CIV host-associated mutations. Patterns of sequence diversity differed between naïve and vaccinated dogs, with some presumably antigenic mutations transiently reaching high frequency in the latter. CIV populations are therefore characterized by the rapid generation and clearance of genetic diversity. Potentially advantageous mutations arise readily during the course of single infections and may give rise to antigenic escape or host range variants.

SUBMITTER: Hoelzer K

PROVIDER: S-EPMC2863817 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

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Intrahost evolutionary dynamics of canine influenza virus in naive and partially immune dogs.

Hoelzer Karin K Murcia Pablo R PR Baillie Gregory J GJ Wood James L N JL Metzger Stephan M SM Osterrieder Nikolaus N Dubovi Edward J EJ Holmes Edward C EC Parrish Colin R CR

Journal of virology 20100310 10

The patterns and dynamics of evolution in acutely infecting viruses within individual hosts are largely unknown. To this end, we investigated the intrahost variation of canine influenza virus (CIV) during the course of experimental infections in naïve and partially immune dogs and in naturally infected dogs. Tracing sequence diversity in the gene encoding domain 1 of the hemagglutinin (HA1) protein over the time course of infection provided information on the patterns and processes of intrahost ...[more]

PMID: 20219907

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Project description:UnlabelledInfluenza A viruses (IAVs) are maintained mainly in wild birds, and despite frequent spillover infections of avian IAVs into mammals, only a small number of viruses have become established in mammalian hosts. A new H3N2 canine influenza virus (CIV) of avian origin emerged in Asia in the mid-2000s and is now circulating in dog populations of China and South Korea, and possibly in Thailand. The emergence of CIV provides new opportunities for zoonotic infections and interspecies transmission. We examined 14,764 complete IAV genomes together with all CIV genomes publicly available since its first isolation until 2013. We show that CIV may have originated as early as 1999 as a result of segment reassortment among Eurasian and North American avian IAV lineages. We also identified amino acid changes that might have played a role in CIV emergence, some of which have not been previously identified in other cross-species jumps. CIV evolves at a lower rate than H3N2 human influenza viruses do, and viral phylogenies exhibit geographical structure compatible with high levels of local transmission. We detected multiple intrasubtypic and heterosubtypic reassortment events, including the acquisition of the NS segment of an H5N1 avian influenza virus that had previously been overlooked. In sum, our results provide insight into the adaptive changes required by avian viruses to establish themselves in mammals and also highlight the potential role of dogs to act as intermediate hosts in which viruses with zoonotic and/or pandemic potential could originate, particularly with an estimated dog population of ∼ 700 million.ImportanceInfluenza A viruses circulate in humans and animals. This multihost ecology has important implications, as past pandemics were caused by IAVs carrying gene segments of both human and animal origin. Adaptive evolution is central to cross-species jumps, and this is why understanding the evolutionary processes that shape influenza A virus genomes is key to elucidating the mechanisms underpinning viral emergence. An avian-origin canine influenza virus (CIV) has recently emerged in dogs and is spreading in Asia. We reconstructed the evolutionary history of CIV and show that it originated from both Eurasian and North American avian lineages. We also identified the mutations that might have been responsible for the cross-species jump. Finally, we provide evidence of multiple reassortment events between CIV and other influenza viruses (including an H5N1 avian virus). This is a cause for concern, as there is a large global dog population to which humans are highly exposed.

Project description:UnlabelledThe increasing number of zoonotic infections caused by influenza A virus (IAV) subtypes of avian origin (e.g., H5N1 and H7N9) in recent years underscores the need to better understand the factors driving IAV evolution and diversity. To evaluate the current feasibility of global analyses to contribute to this aim, we evaluated information in the public domain to explore IAV evolutionary dynamics, including nucleotide substitution rates and selection pressures, using 14 IAV subtypes in 32 different countries over a 12-year period (2000 to 2011). Using geospatial information from 39,785 IAV strains, we examined associations between subtype diversity and socioeconomic, biodiversity, and agricultural indices. Our analyses showed that nucleotide substitution rates for 11 of the 14 evaluated subtypes tended to be higher in Asian countries, particularly in East Asia, than in Canada and the United States. Similarly, at a regional level, subtypes H5N1, H5N2, and H6N2 exhibited significantly higher substitution rates in East Asia than in North America. In contrast, the selection pressures (measured as ratios of nonsynonymous to synonymous evolutionary changes [dN/dS ratios]) acting on individual subtypes showed little geographic variation. We found that the strongest predictors for the detected subtype diversity at the country level were reporting effort (i.e., total number of strains reported) and health care spending (an indicator of economic development). Our analyses also identified major global gaps in IAV reporting (including a lack of sequences submitted from large portions of Africa and South America and a lack of geolocation information) and in broad subtype testing which, until addressed, will continue to hinder efforts to track the evolution and diversity of IAV around the world.ImportanceIn recent years, an increasing number of influenza A virus (IAV) subtypes, including H5N1, H7N9, and H10N8, have been detected in humans. High fatality rates have led to an increased urgency to better understand where and how novel pathogenic influenza virus strains emerge. Our findings showed that mutational rates of 11 commonly encountered subtypes were higher in East Asian countries than in North America, suggesting that there may be a greater risk for the emergence of novel pathogenic strains in East Asia. In assessing the potential drivers of IAV subtype diversity, our analyses confirmed that reporting effort and health care spending were the best predictors of the observed subtype diversity at the country level. These findings underscore the need to increase sampling and reporting efforts for all subtypes in many undersampled countries throughout the world.

Dataset Information

Intrahost evolutionary dynamics of canine influenza virus in naive and partially immune dogs.

Publications

Intrahost evolutionary dynamics of canine influenza virus in naive and partially immune dogs.

Similar Datasets

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