Financial evaluation of vaccination and testing alternatives for control of parvovirus-induced reproductive failure in swine.

OBJECTIVE

To identify the preferable testing and vaccination strategy for control of porcine parvovirus (PPV) during a 6-month period.

DESIGN

Decision-tree analysis and computer simulations.

SAMPLE POPULATION

Computer modeling of 300-sow farrow-to-finish herd.

PROCEDURE

Serologic testing of 30 females to estimate herd PPV prevalence versus not testing any females was the initial decision alternative. On the basis of serologic test results, herds were classified into 1 of 3 PPV-risk categories: low (> or = 80% seropositive females), moderate (40 to < 80% seropositive females), or high (< 40% seropositive females). Vaccinating all females, only gilts, or not vaccinating was the second decision alternative.

RESULTS

For initial model assumptions (test sensitivity and specificity = 0.95; test cost = $5/female; vaccination cost = $0.30/dose; vaccination efficacy = 0.95; and foregone gross margin = $10.85/pig), vaccination of all females (with or without serologic testing) was preferable, but the financially preferable option was to omit serologic testing. Most profitable vaccination option varied with foregone gross margin, vaccination cost, and efficacy. For herds in which all sows were known to be immune, vaccinating only gilts was financially preferable, and serologic testing was not warranted. Variation is expected monetary losses was less in vaccination options than with nonvaccination.

CLINICAL IMPLICATIONS

For most herds in the United States, serologic screening for PPV prior to selection of a vaccination program is unlikely to be cost-effective, because vaccination is inexpensive ($0.30/dose) and effective (95%). At current profit margins ($10.85/pig), vaccination of all females has the least-risk and is the preferred option.