Table 3

Classification of evidence used, sources of data, and the effects of assumptions made and bias on final estimates

									Potential effects of bias on final estimates
Evidence	Incidence/AR Class^Sources	Indigenous (%) Class^Sources	Foodborne (%) Class^Sources	Presenting to GPs (%) Class^Sources	Hospital admissions (%) Class^Sources	Hospital bed days (mean) Class^Sources	Deaths (%) Class^Sources	Principal assumption	Cases	Total burden
Total burden includes cases, healthcare usage, and deaths.
Data sources are from box 1 (see text).
*VTEC O157 data.
†Shigella spp data.
‡Cryptosporidium parvum data.
§All known pathogens.
n/c, not calculated; nia, not indigenous acquired; nft, no foodborne transmission. AR, ascertainment ratio—ratio of the estimated number of cases of illness in the population due to specific pathogens to the number of laboratory reports in the national database for laboratory confirmed infections;
NLV, Norwalk-like viruses; SLV, Sappora-like viruses; VTEC, verocytotoxin producing Escherichia coli.
Bacteria
Aeromonas spp	Measured^A,F	Measured^A	Inferred^K	n/c-nft	n/c-nft	n/c-nft	n/c-nft	Foodborne %	Moderate	Negligible
Bacillus spp	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Minor	Negligible
Campylobacter spp	Measured^A,F	Measured^G	Measured^B	Measured^F	Measured^G	Measured^G	Inferred^K	Deaths %	Major	Major
Clostridium perfringens	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Moderate	Moderate
Cl difficile cytotoxin	Measured^A,F	Measured^A	Measured^B	n/c-nft	n/c-nft	n/c-nft	n/c-nft	—	Negligible	Negligible
VTEC O157	Extrapolated^A	Measured^I	Measured^B	Extrapolated^A	Measured^I,J	Measured^D	Measured^I,J	Incidence	Negligible	Moderate
Non O157 VTEC	Inferred*^J	Inferred*	Inferred*	Inferred*	Inferred*	Inferred*	Inferred*	Incidence	Negligible	Negligible
Other Escherichia coli	Measured^A,F	Inferred†	Inferred†	Measured^F	Measured^D	Measured^D	Measured^D	Pathogenicity	Major	Moderate
Listeria monocytogenes	Extrapolated^H	Measured^H	Inferred^K	Extrapolated^H	Measured^H	Measured^D	Measured^H	Incidence	Negligible	Moderate
Salmonellas non-typhoidal	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Moderate	Major
S paratyphi	Extrapolated^A	Measured^A	Inferred^K	Extrapolated^A	Measured^D	Measured^D	Inferred^K	Incidence	Negligible	Negligible
S enterica typhi	Extrapolated^A	Measured^A	Inferred^K	Extrapolated^A	Measured^D	Measured^D	Inferred^K	Incidence	Negligible	Negligible
Shigella spp	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Minor	Negligible
Staphylococcus aureus	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Minor	Negligible
Vibrio cholerae O1/O139	Extrapolated^A	Measured^A	n/c-nia	n/c-nia	n/c-nia	n/c-nia	n/c-nia	—	None	None
V cholerae non O1/O139	Measured^A,F	Measured^A	Inferred^K	Measured^F	Inferred^K	Measured^D	Inferred^K	Foodborne %	Negligible	Negligible
Other vibrio species	Measured^A,F	Measured^A	Inferred^K	Measured^F	Inferred^K	Measured^D	Inferred^K	Foodborne %	Negligible	Negligible
Yersinia spp	Measured^A,F	Measured^A	Inferred^K	Measured^F	Inferred^K	Measured^D	Inferred^K	Pathogenicity	Major	Moderate

Parasites
Cryptosporidium parvum	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Minor	Minor
Cyclospora cayatenensis	Inferred^K	Measured^A	Inferred^K	Inferred‡	Inferred^K	Inferred‡	Inferred^K	Incidence	Negligible	Negligible
Giardia duodenalis	Measured^A,F	Measured^A	Inferred^K	Measured^F	Measured^D	Measured^D	Measured^B	Foodborne %	Negligible	Negligible

Viruses
Adenovirus 40/41	Measured^A,F	Measured^A	Measured^B	n/c-nft	n/c-nft	n/c-nft	n/c-nft	—	Negligible	Negligible
Astrovirus	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Negligible	Negligible
NLV	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Major	Moderate
Rotavirus	Measured^A,F	Measured^A	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	—	Moderate	Moderate
SLV	Measured^A,F	Measured^A	Measured^B	n/c-nft	n/c-nft	n/c-nft	n/c-nft	—	Moderate	Moderate

Unknown agents	Measured^A,C,F	Inferred§	Measured^B	Measured^F	Measured^B	Measured^D	Measured^B	Indigenous %	Major	Major