Table 4. Detected haemagglutination inhibition antibody titres to low pathogenic avian influenza H5 virus^a and to highly pathogenic avian influenza H5 clade 2.3.4.4 H5N8 virus^b in birds, before, during, and after detection of the highly pathogenic avian influenza H5N8 virus in Europe, the Netherlands, 2007–2015 (n = 1,443 birds).

Strain	Period relative to the outbreakc	Haemagglutination inhibition titre							High background	Total tested	Total positives
		BLD	10–40	40–80	80–160	160–320	320–640	≥ 640
LPAI H5N2a	Before	121	1	0	1	0	0	0	26	149	2
	During	903	16	5	2	1	0	0	18	945	24
	After	324	2	1	0	2	0	0	20	349	5
HPAI H5N8b	Before	123	0	0	0	0	0	0	26	149	0
	During	897	7	20	6	4	5	1	5	945	43
	After	319	4	3	2	1	0	0	20	349	10

BLD: below limit of detection; LPAI: low pathogenic avian influenza; HPAI: highly pathogenic avian influenza.

Lowest serum dilution tested was 10.

^a A/Mallard/Netherlands/3/1999.

^b A/Chicken/Netherlands/EMC-3/2014.

^c The ‘outbreak’ refers to the six months following the detection of the highly pathogenic avian influenza H5N8 virus in Europe and this extends from 14 November 2014 to 13 May 2015. The period before the ‘outbreak’ is from 2007 to 2013, while the period after the ‘outbreak’ is from 1 September to 31 December 2015.