Table 2. Estimated effect of market closure and contaminated environmental sites on AIV and influenza A(H7N9) virus detection in 5 poultry markets under enhanced surveillance, Guangzhou, Guangdong Province, China, 2014*.

Variable	Retail LPMs, aOR (95% CI)†				Wholesale LPM, aOR (95% CI)				DPM, aOR (95% CI)
	rRT-PCR		H7N9 culture		rRT-PCR		H7N9 culture		rRT-PCR
	AIV	H7N9			AIV	H7N9			AIV	H7N9
Period
Before market closure	Ref	Ref	Ref		Ref	–‡	–‡		Ref	Ref
During market closure	0.25 (0.16–0.39)	0.21 (0.12–0.36)	0.08 (0.02–0.42)		1.60 (0.52–4.90)	0.22 (0.10–0.50)	0.11 (0.01–0.89)		0.30 (0.09–0.98)	0.68 (0.12–3.89)
After market closure	1.78 (1.20–2.63)	0.58 (0.35–0.95)	0.73 (0.27–1.98)		10.3 (3.52–30.3)	Ref	Ref		5.27 (1.97–14.1)	3.32 (0.68–16.1)
Environmental samples tested
Poultry cage	Ref	Ref	Ref		Ref	Ref	§		–	–
Defeathering machine	1.15 (0.61–2.14)	1.66 (0.74–3.70)	1.25 (0.20–7.87)		2.49 (1.09–5.68)	1.21 (0.40–3.65)	§		–	–
Chopping board	2.64 (1.60–4.37)	2.12 (1.06–4.26)	3.52 (0.88–14.0)		–	–	–		0.56 (0.22–1.41)	3.18 (0.98–10.3)
Processing table	1.16 (0.73–1.85)	1.15 (0.59–2.25)	1.09 (0.26–4.67)		–	–	–		Ref	Ref
Bucket holding poultry meat	–	–	–		0.97 (0.38–2.44)	0.17 (0.02–1.40)	§		–	–
Wastewater	1.60 (0.95–2.67)	1.23 (0.58–2.62)	1.41 (0.28–7.14)		1.38 (0.70–2.73)	0.91 (0.37–2.22)	§		1.15 (0.44–3.06)	1.16 (0.31–4.36)
Drinking water	–	–	–		2.02 (0.44–9.38)	2.32 (0.40–13.4)	§		–	–

*AIV, avian influenza virus; aOR, adjusted odds ratio; DPM, dressed poultry market; LPM, live poultry market; ref, reference; rRT-PCR, real-time reverse transcription PCR; –, no samples tested.
†Also adjusted for potential market differences for the 3 retail markets.
‡No influenza A(H7N9) virus was detected before market closure in wholesale markets, and data from this period were excluded from the regression model.
§There were too few H7N9 virus–positive samples by culture in contaminated environmental sites in wholesale markets and DPM overall for us to estimate the effects. A simplified model was used for wholesale markets.