Table 3.

Number of carriers of MRSA CC398 in Denmark based on information from National statistics, relevant literature and expert opinion.

Group	No. of persons	Carrier proportion (%)	No. of carriers assuming all herds positive	No. of carriers assuming 69% positive herdsa
Swine farmer/employee, full time	8,000b	74c	5,920	4,085
Farm employee, weekly work with swine	1,000d	74e	740	511
Swine veterinarians and advisors with daily contact to swine	200	74e	148	148
Craftsmen with weekly contact or less to swine	7,564d	11f	821	566
Swine transport workers	453d	22g	100	100
Abattoir workers	6,600d	4h	264	264
Household members to all persons listed above	26,199b	6i	1,511	1,073
Remaining society	5,600,000	0.10j	5,607	3,980
Sum of carriers		0.27	15,111	10,615

^aResult of a screening in 2014.

^bData from Danish Statistics, combined with best guesses among the authors validated through contact to experts.

^cUnpublished data from ongoing Danish study into 10 swine herds infected with MRSA CC398. Here, 74% of the employees were positive and 10% of the household members.

^dEstimates from the Danish swine industry.

^eAs a worst case assumption, it was assumed that weekly work with swine would result in the same carrier rate as daily work with swine, and that swine vets would have the same carrier rate as persons with daily contact to swine.

^fFor craftsmen with weekly contact or less, it was assumed that 74% would be positive when they leave the farm, but that they will be negative the day after—hence 74%/7 = 11%.

^gBased on Van Cleef et al. (62).

^hBased on a weighted average of the prevalence observed in abattoir employees presented in Ref. (59, 62, 63).

ⁱAuthors’ best guess based among others on unpublished data described in b. An average household has 2.1 members according to data from Danish Statistics—in the present case 1.1 persons apart from the person with contact to swine.

^jAuthors’ best guess.

MRSA, methicillin-resistant S. aureus.