Influenza A Viruses and Antibody Response in High-Latitude Urban Wintering Mallards (Anas platyrhynchos), Alaska, 2012-2015

USGS band number on metal tarsus (leg) band. Each band has a unique number assigned by the Bird Banding Lab, Patuxent Wildlife Research Center, Patuxent, Maryland. Bands generally begin with a 3-4 digit prefix followed by a 5 digit suffix, e.g., 1347.59381. The initial capture and banding event and associated band number are reported to the USGS Bird Banding Laboratory in the year of banding and all banding data can be access through the Bird Banding Laboratory.

"Year" a sample was collected. This collection year spans two calendar years starting from August of the first year to April of the following year. Thus, values entered here represent a range (e.g. 2012/2013).

Definition: Age (year Class) Codes specified by the USGS, Bird Banding Laboratory, Patuxent Wildlife Research Center. Age codes and definitions: UNK – Unknown age AHY – After hatching year. A bird known to have hatched before the calendar year of banding; year of hatch otherwise unknown. HY – Hatching year. A bird capable of sustained flight and known to have hatched during the calendar year in which it was banded. L – Local. A young bird incapable of sustained flight. After a young bird achieves sustained flight it becomes an "HY" until December 31. SY – Second year. A bird known to have hatched in the calendar year preceding the year of banding and in its second calendar year of life. Example: Banded 1997 - Hatched 1996. ASY – After second year. A bird known to have hatched earlier than the calendar year preceding the year of banding; year of hatch otherwise unknown. Example: Banded 1997 - Hatched 1995 or earlier. TY – Third year. A bird known to have hatched in the calendar year two years prior to the year of banding, now in its third calendar year of life. Example: Banded 1997 - Hatched 1995. ATY – After third year. A bird known to have hatched prior to two years prior to the year of banding, now in at least its fourth calendar year of life. Example: Banded 1997 - Hatched 1994 or earlier.

Test result for Influenza A Virus from swab samples. A duck was considered positive for IAV RNA if Ct values for the cloacal swab and/or the oropharyngeal swab was ≤ 45.0. The number of cycles required for the fluorescent signal of a molecular probe for the influenza A matrix gene target to exceed background levels in a real-time reverse transcriptase polymerase chain reaction (rRT-PCR) applied to swab samples stored in viral transport media as described by Spackman et al. (2002). The RT-PCR is run for up to 45 cycles using reaction conditions described in the previous reference. Negative samples, defined by "0," had no value exceeding background levels.

USGS band number on metal tarsus (leg) band. Each band has a unique number assigned by the Bird Banding Lab, Patuxent Wildlife Research Center, Patuxent, Maryland. Bands generally begin with a 3-4 digit prefix followed by a 5 digit suffix, e.g., 1347.59381. The initial capture and banding event and associated band number are reported to the USGS Bird Banding Laboratory in the year of banding and all banding data can be access through the Bird Banding Laboratory.

"Year" a sample was collected. This collection year spans two calendar years starting from August of the first year to April of the following year. Thus, values entered here represent a range (e.g. 2012/2013).

Definition: Age (year Class) Codes specified by the USGS, Bird Banding Laboratory, Patuxent Wildlife Research Center. Age codes and definitions: UNK – Unknown age AHY – After hatching year. A bird known to have hatched before the calendar year of banding; year of hatch otherwise unknown. HY – Hatching year. A bird capable of sustained flight and known to have hatched during the calendar year in which it was banded. L – Local. A young bird incapable of sustained flight. After a young bird achieves sustained flight it becomes an "HY" until December 31. SY – Second year. A bird known to have hatched in the calendar year preceding the year of banding and in its second calendar year of life. Example: Banded 1997 - Hatched 1996. ASY – After second year. A bird known to have hatched earlier than the calendar year preceding the year of banding; year of hatch otherwise unknown. Example: Banded 1997 - Hatched 1995 or earlier. TY – Third year. A bird known to have hatched in the calendar year two years prior to the year of banding, now in its third calendar year of life. Example: Banded 1997 - Hatched 1995. ATY – After third year. A bird known to have hatched prior to two years prior to the year of banding, now in at least its fourth calendar year of life. Example: Banded 1997 - Hatched 1994 or earlier.

Test result for antibodies to Influenza A Virus (IAV) in serum samples. A duck was considered positive for antibodies to IAV if the Signal to Noise ratio was ≤ 50.0.

USGS band number on metal tarsus (leg) band. Each band has a unique number assigned by the Bird Banding Lab, Patuxent Wildlife Research Center, Patuxent, Maryland. Bands generally begin with a 3-4 digit prefix followed by a 5 digit suffix, e.g., 1347.59381. The initial capture and banding event and associated band number are reported to the USGS Bird Banding Laboratory in the year of banding and all banding data can be access through the Bird Banding Laboratory.

Definition: Age (year Class) Codes specified by the USGS, Bird Banding Laboratory, Patuxent Wildlife Research Center. Age codes and definitions: UNK – Unknown age AHY – After hatching year. A bird known to have hatched before the calendar year of banding; year of hatch otherwise unknown. HY – Hatching year. A bird capable of sustained flight and known to have hatched during the calendar year in which it was banded. L – Local. A young bird incapable of sustained flight. After a young bird achieves sustained flight it becomes an "HY" until December 31. SY – Second year. A bird known to have hatched in the calendar year preceding the year of banding and in its second calendar year of life. Example: Banded 1997 - Hatched 1996. ASY – After second year. A bird known to have hatched earlier than the calendar year preceding the year of banding; year of hatch otherwise unknown. Example: Banded 1997 - Hatched 1995 or earlier. TY – Third year. A bird known to have hatched in the calendar year two years prior to the year of banding, now in its third calendar year of life. Example: Banded 1997 - Hatched 1995. ATY – After third year. A bird known to have hatched prior to two years prior to the year of banding, now in at least its fourth calendar year of life. Example: Banded 1997 - Hatched 1994 or earlier.

Influenza A virus (IAV) seroprevalence histories of Mallards Captured/Recaptured in Anchorage, AK From September-April (2014-2015). Each character in the domain value corresponds chronologically to the capture event (month&year) as follows: character position 1 = September, 2014; character position 2 = October, 2014; character position 3 = November, 2014; character position 4 = December, 2014; character position 5 = January, 2015; character position 6 = February, 2015; character position position 7 = March, 2015; character position 8 = April, 2015. There are 2 potential immune states: "A" Seropositive & "B" Seronegative. A "0" indicates the bird was not captured/tested during that capture event. As an examples, the seroprevalence history for band #2047-55089 is "00AA00A0," indicating the duck was not sampled in September and October of 2014, nor in January, February and April of 2015. This same duck was identified as seropositive to IAV in November and December of 2014 as well as March of 2015.

USGS band number on metal tarsus (leg) band. Each band has a unique number assigned by the Bird Banding Lab, Patuxent Wildlife Research Center, Patuxent, Maryland. Bands generally begin with a 3-4 digit prefix followed by a 5 digit suffix, e.g., 1347.59381. The initial capture and banding event and associated band number are reported to the USGS Bird Banding Laboratory in the year of banding and all banding data can be access through the Bird Banding Laboratory.

Location of wild bird sampling defined as either Fairbanks, Alaska or Anchorage, Alaska.

"Year" a sample was collected. This collection year spans two calendar years starting from August of the first year to April of the following year. Thus, values entered here represent a range (e.g. 2012/2013).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).

Virus microneutralization (MN) assay results reported as influenza A virus (IAV) titer value for mallards captured in Fairbanks during 2012/2013 or Anchorage during 2014/2015. Each positive serum sample was diluted two-fold in MEM on a 96 well v-bottom plate (final volume of 25 µl. well at dilutions 1:20 to 1:640). If cytopathic effect (CPE) was observed at the minimum 1:20 dilution, the sample was classified as negative. If no CPE was observed at the minimum 1:20 dilution, the positive titer was recorded as the highest dilution at which no CPE was observed. Values "<20" represent a negative result. Values greater than or equal to 20 represent a positive result. Alternatively stated a value of 20 or greater indicates that the duck had a positive titer of antibodies to the corresponding IAV subtype defined in the Attribute label (e.g. H1N1).