Influenza A(H1N1)pdm09 virus infection in marine mammals in California

Figures & data

Table 1 Antibodies to A(H1N1)pdm09 in seals and sea lions in California, USA, 2009–2012

	% HI positive
	Northern elephant seals	Harbor seals^3	California sea lions^4	Range HI titers
2009^1	5 (2/37)	8 (3/40)	0 (0/80)	<10 to 160
2010^1	30 (11/37)	2 (1/50)	7 (4/55)	<10 to 640
2011^1	48 (29/60)	0 (0/50)	6 (3/48)	<10 to 640
2012
Adult females^2	54 (19/35)	-	-	<10 to 160
Pups 1st sample^2	63 (22/35)	-	-	<10 to 320
Pups 2nd sample^2	75 (15/20)	-	-	<10 to 320

Sera tested by HI at dilutions of 1/10, 1/20, 1/40, 1/80, 1/160, 1/320, 1/640. Titers ≥40 were considered positive.

1 Free-ranging and stranded adults and juveniles in northern and southern California.

2 Free-ranging adults and pups at the Southern California Channel Islands.

3 Seropositive harbor seals were stranded weaned pups from northern and central California with HI titers of 40 to 160.

4 Seropositive California sea lions were stranded and free-ranging subadults and adults from northern and southern California with HI titers of 40 to 80.