TABLE 4.

Genome copy numbers of HAV present in different clam batches linked to the 2008 outbreak and estimated risk of illness

Harvesting date	Genome copies/g shellfish	Estimated attack ratea
		Uncooked	Lightly cooked	Well cooked
March 2007	1.5 × 104	0.81	0.13	0.04
September 2007	5.1 × 103	0.71	0.05	0.01
December 2007	8.8 × 104	0.90	0.38	0.17
	5.6 × 103	0.72	0.05	0.02
May 2008	1.3 × 104	0.80	0.11	0.03
	3.2 × 103	0.66	0.03	0.01
	1.2 × 105	0.91	0.43	0.21

^aEstimation based on the echovirus 12 reported dose-response model (34, 36). Exposure dose was figured by applying the formula and parameters described in Table 1. Data were figured by applying corrective factors derived by extraction and enzyme efficiencies. The final concentration of infectious virus after cooking was estimated by applying a reduction of the initial infectious virus in cooked shellfish as specified in Table 1 (1, 8).