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Molecular epidemiology of eastern equine encephalitis virus, New York.

Young DS, Kramer LD, Maffei JG, Dusek RJ, Backenson PB, Mores CN, Bernard KA, Ebel GD - Emerging Infect. Dis. (2008)

Bottom Line: To determine whether EEEV overwinters, is periodically reintroduced, or both, we sequenced the E2 and partial NSP3 coding regions of 42 EEEV isolates from New York State and the Eastern Seaboard of the United States.Strong clustering among strains isolated during epizootics in New York from 2003-2005, as well as from 1974-1975, demonstrates that EEEV has overwintered in this focus.This study provides molecular evidence for the introduction of southern EEEV strains to New York, followed by local amplification, perpetuation, and overwintering.

View Article: PubMed Central - PubMed

Affiliation: New York State Department of Health, Albany, New York, USA.

ABSTRACT
Perpetuation, overwintering, and extinction of eastern equine encephalitis virus (EEEV) in northern foci are poorly understood. We therefore sought to describe the molecular epidemiology of EEEV in New York State during current and past epizootics. To determine whether EEEV overwinters, is periodically reintroduced, or both, we sequenced the E2 and partial NSP3 coding regions of 42 EEEV isolates from New York State and the Eastern Seaboard of the United States. Our phylogenetic analyses indicated that derived subclades tended to contain southern strains that had been isolated before genetically similar northern strains, suggesting southern to northern migration of EEEV along the Eastern Seaboard. Strong clustering among strains isolated during epizootics in New York from 2003-2005, as well as from 1974-1975, demonstrates that EEEV has overwintered in this focus. This study provides molecular evidence for the introduction of southern EEEV strains to New York, followed by local amplification, perpetuation, and overwintering.

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Related in: MedlinePlus

Maximum-likelihood phylogenetic tree of eastern equine encephalitis virus strains, based on the complete E2 coding sequence. Numbers at the nodes indicate bootstrap confidence estimated by 1,000 neighbor-joining replicates on the maximum-likelihood tree. The tree was rooted with lineage II (Brazil56), III (Panama86), and IV (Brazil85) strains.
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Figure 2: Maximum-likelihood phylogenetic tree of eastern equine encephalitis virus strains, based on the complete E2 coding sequence. Numbers at the nodes indicate bootstrap confidence estimated by 1,000 neighbor-joining replicates on the maximum-likelihood tree. The tree was rooted with lineage II (Brazil56), III (Panama86), and IV (Brazil85) strains.

Mentions: Phylogenetic analysis of the E2 coding region demonstrated that all isolates sequenced in this study belonged to lineage I (Figure 2), and showed strong spatiotemporal clustering. The 3 strains isolated from Oswego County in 1971 (NY71a, NY71b, and NY71c) clustered together as a result of almost identical E2 coding regions. All 8 strains isolated from Oswego County in 1974 (NY74a–h) and the only strain isolated in 1975 (NY75) grouped together strongly and formed the Oswego74 clade (Figures 2–4). Strong clustering was also evident among strains isolated mainly from Onondaga County during 2003–2005 (the Onondaga03 clade, Figures 2–4). Of the 16 strains in this clade, 13 had identical E2 coding regions (data not shown). Both NY04g and NY04j grouped together and were isolated in close geographic proximity in Sullivan and Ulster Counties, respectively, in the lower Hudson Valley.


Molecular epidemiology of eastern equine encephalitis virus, New York.

Young DS, Kramer LD, Maffei JG, Dusek RJ, Backenson PB, Mores CN, Bernard KA, Ebel GD - Emerging Infect. Dis. (2008)

Maximum-likelihood phylogenetic tree of eastern equine encephalitis virus strains, based on the complete E2 coding sequence. Numbers at the nodes indicate bootstrap confidence estimated by 1,000 neighbor-joining replicates on the maximum-likelihood tree. The tree was rooted with lineage II (Brazil56), III (Panama86), and IV (Brazil85) strains.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2570827&req=5

Figure 2: Maximum-likelihood phylogenetic tree of eastern equine encephalitis virus strains, based on the complete E2 coding sequence. Numbers at the nodes indicate bootstrap confidence estimated by 1,000 neighbor-joining replicates on the maximum-likelihood tree. The tree was rooted with lineage II (Brazil56), III (Panama86), and IV (Brazil85) strains.
Mentions: Phylogenetic analysis of the E2 coding region demonstrated that all isolates sequenced in this study belonged to lineage I (Figure 2), and showed strong spatiotemporal clustering. The 3 strains isolated from Oswego County in 1971 (NY71a, NY71b, and NY71c) clustered together as a result of almost identical E2 coding regions. All 8 strains isolated from Oswego County in 1974 (NY74a–h) and the only strain isolated in 1975 (NY75) grouped together strongly and formed the Oswego74 clade (Figures 2–4). Strong clustering was also evident among strains isolated mainly from Onondaga County during 2003–2005 (the Onondaga03 clade, Figures 2–4). Of the 16 strains in this clade, 13 had identical E2 coding regions (data not shown). Both NY04g and NY04j grouped together and were isolated in close geographic proximity in Sullivan and Ulster Counties, respectively, in the lower Hudson Valley.

Bottom Line: To determine whether EEEV overwinters, is periodically reintroduced, or both, we sequenced the E2 and partial NSP3 coding regions of 42 EEEV isolates from New York State and the Eastern Seaboard of the United States.Strong clustering among strains isolated during epizootics in New York from 2003-2005, as well as from 1974-1975, demonstrates that EEEV has overwintered in this focus.This study provides molecular evidence for the introduction of southern EEEV strains to New York, followed by local amplification, perpetuation, and overwintering.

View Article: PubMed Central - PubMed

Affiliation: New York State Department of Health, Albany, New York, USA.

ABSTRACT
Perpetuation, overwintering, and extinction of eastern equine encephalitis virus (EEEV) in northern foci are poorly understood. We therefore sought to describe the molecular epidemiology of EEEV in New York State during current and past epizootics. To determine whether EEEV overwinters, is periodically reintroduced, or both, we sequenced the E2 and partial NSP3 coding regions of 42 EEEV isolates from New York State and the Eastern Seaboard of the United States. Our phylogenetic analyses indicated that derived subclades tended to contain southern strains that had been isolated before genetically similar northern strains, suggesting southern to northern migration of EEEV along the Eastern Seaboard. Strong clustering among strains isolated during epizootics in New York from 2003-2005, as well as from 1974-1975, demonstrates that EEEV has overwintered in this focus. This study provides molecular evidence for the introduction of southern EEEV strains to New York, followed by local amplification, perpetuation, and overwintering.

Show MeSH
Related in: MedlinePlus