Volume 19, Number 3—March 2013
Dispatch
Swine Influenza in Sri Lanka
Table 2
Homologous serological reaction profile to subtypes of influenza viruses among pigs, Sri Lanka, 2004–2005 and 2010–2012*
Virus antigen (lineage) | Seroprevalence, no. (%) |
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---|---|---|---|---|---|
Jan 2004–Mar 2005, n = 300 | Feb–Aug 2010, n = 149 | Sep 2010–Mar 2011, n = 284 | Apr–Oct 2011, n = 577 | Nov 2011–May 2012, n = 763 | |
A/swine/Colombo/48/2004 (H3N2) (human-like) | 185 (61.6%) | 06 (4.0%) | 0 | 0 | 0 |
A/swine/HK/2422/98 (H3N2) (swine) (human) | 0 | 0 | 0 | 0 | 0 |
A/Sydney/5/97 (H3N2) (human) | 0 | 0 | 0 | 0 | 0 |
A/swine/HK/1774/99 (H3N2) (European swinelike) | 0 | 0 | 0 | 0 | 0 |
A/HK/44062/2011 (H3N2) (human) | Not tested | Not tested | 0 | 0 | 0 |
A/swine/Colombo/330/2009 (H1N1) (H1N1pdm09) | 0 | 16 (10.7) | 95 (33.5) | 14 (25.1) | 77 (10.1) |
A/swine/HK/29/2009 (H1N1) (Eurasian avian) | 0 | 01 (0.6) | 0 | 0 | 0 |
A/swine/HK/1110/2006 (H1N1) (North American–triple reassortant) | 0 | 01 (0.6) | 0 | 0 | 0 |
A/swine/HK/915/2004 (H1N2) (North American–TR) | 0 | 0 | 0 | 0 | 0 |
A/swine/HK/4167/99 (H1N1) (classical swine) | 0 | 0 | 0 | 0 | 0 |
A/swine/Ghent/G112/2007 (Eurasian avian) | 0 | 0 | 0 | 0 | 0 |
*Hemagglutination inhibition reciprocal antibody titers ≥40 were considered positive. The range of the antibody titers was 40 to ≥1,280. If serum reacted to multiple antigenically related influenza H3 or H1 subtype viruses, we categorized the serum as having a homologous reaction profile to the virus to which titer was ≥4-fold higher than that for other viruses of the same subtype. For example, during 2004–2005, some serum samples were seropositive for influenza A/swine/HK/2422/98 (H3N2) virus; however, because in the same sample, titer to influenza A/swine/Colombo/48/2004 (H3N2) virus was >4-fold higher, reactivity was attributed to the latter.