Influenza-A Viruses in Ducks in Northwestern Minnesota: Fine Scale Spatial and Temporal Variation in Prevalence and Subtype Diversity

Waterfowl from northwestern Minnesota were sampled by cloacal swabbing for Avian Influenza Virus (AIV) from July – October in 2007 and 2008. AIV was detected in 222 (9.1%) of 2,441 ducks in 2007 and in 438 (17.9%) of 2,452 ducks in 2008. Prevalence of AIV peaked in late summer. We detected 27 AIV subtypes during 2007 and 31 during 2008. Ten hemagglutinin (HA) subtypes were detected each year (i.e., H1, 3–8, and 10–12 during 2007; H1-8, 10 and 11 during 2008). All neuraminidase (NA) subtypes were detected during each year of the study. Subtype diversity varied between years and increased with prevalence into September. Predominant subtypes during 2007 (comprising ≥5% of subtype diversity) included H1N1, H3N6, H3N8, H4N6, H7N3, H10N7, and H11N9. Predominant subtypes during 2008 included H3N6, H3N8, H4N6, H4N8, H6N1, and H10N7. Additionally, within each HA subtype, the same predominant HA/NA subtype combinations were detected each year and included H1N1, H3N8, H4N6, H5N2, H6N1, H7N3, H8N4, H10N7, and H11N9. The H2N3 and H12N5 viruses also predominated within the H2 and H12 subtypes, respectively, but only were detected during a single year (H2 and H12 viruses were not detected during 2007 and 2008, respectively). Mallards were the predominant species sampled (63.7% of the total), and 531 AIV were isolated from this species (80.5% of the total isolates). Mallard data collected during both years adequately described the observed temporal and spatial prevalence from the total sample and also adequately represented subtype diversity. Juvenile mallards also were adequate in describing the temporal and spatial prevalence of AIV as well as subtype diversity

Epidemiology of a phocine distemper virus outbreak along the North Atlantic coast of the United States

Due to an increase in pinniped strandings with consistent pathological findings throughout the North Atlantic coast of the United States during the summer and fall of 2006, an unusual mortal- ity event (UME) was declared by the National Oceanic and Atmospheric Administration's (NOAA) National Marine Fisheries Service (NMFS) on 20 October 2006. The goals of this investigation were to describe the magnitude and duration of the peak in mortalities involved in the UME and to evaluate associations with potential causative agents. Seal strandings during the UME were compared to historical strandings in the area to characterize the epidemiologic pat- terns of the UME. Temporal increases in phocine distemper virus (PDV) prevalence as detected by serology and polymerase chain reaction (PCR) were significantly correlated with increased seal stranding frequency. During July to October 2006, there was a significant spatial and tempo- ral cluster of PDV positive seals centered near Cape Ann, Massachusetts. Our findings provide evidence that PDV infections increased in harbor seals along the North Atlantic coast of the U.S. in 2006, and PDV likely played a role in a UME that involved harbor seals (Phoca vitulina), harp seals Phoca groenlandica), hooded seals (Cystophora cristata), and gray seals (Halichoerus grypus)

Epidemiology of a phocine distemper virus outbreak along the North Atlantic coast of the United States

Due to an increase in pinniped strandings with consistent pathological findings throughout the North Atlantic coast of the United States during the summer and fall of 2006, an unusual mortal- ity event (UME) was declared by the National Oceanic and Atmospheric Administration's (NOAA) National Marine Fisheries Service (NMFS) on 20 October 2006. The goals of this investigation were to describe the magnitude and duration of the peak in mortalities involved in the UME and to evaluate associations with potential causative agents. Seal strandings during the UME were compared to historical strandings in the area to characterize the epidemiologic pat- terns of the UME. Temporal increases in phocine distemper virus (PDV) prevalence as detected by serology and polymerase chain reaction (PCR) were significantly correlated with increased seal stranding frequency. During July to October 2006, there was a significant spatial and tempo- ral cluster of PDV positive seals centered near Cape Ann, Massachusetts. Our findings provide evidence that PDV infections increased in harbor seals along the North Atlantic coast of the U.S. in 2006, and PDV likely played a role in a UME that involved harbor seals (Phoca vitulina), harp seals Phoca groenlandica), hooded seals (Cystophora cristata), and gray seals (Halichoerus grypus)