Estimating transfer of bovine virus-diarrhoea virus in Danish cattle by use of register data.

To study how routinely recorded data (also called "register data") might be used in disease monitoring on a regional or national level, a database for bovine virus-diarrhoea virus (BVDV) was made from existing databases, covering the period January 1995-November 1999. This paper includes a general description of the database, including basic statistics for selected variables. Information was largely complete for cattle herds in the milk-recording scheme (MRS), but only partly available for other herds. A methodology was developed to identify when and how a herd initially was infected. For most herds, it was possible to determine when and how BVDV first was introduced. Among the infected herds, most were already infected by the start of the study. BVDV had been present in 40% of the MRS herds and in 9% of the non-MRS herds. In the MRS herds, most new infections were associated with a dam that had been present in the same herd during gestation. Among the non-MRS herds, most new infections were associated with movement of a persistently infected animal. The monthly number of newly infected herds is presented; it is seen that the incidence declined substantially during the study period.

Salmonella dublin in Danish dairy herds: frequency of change to positive serological status in bulk tank milk ELISA in relation to serostatus of neighbouring farms.

Bulk tank milk from 1,429 herds were collected in 3 rounds from 19 different geographic areas. The milk samples were tested by use of indirect LPS-ELISA procedure to detect Salmonella dublin antibodies. From the obtained OD-values herd seroprevalence in the given area was determined and GR-scores calculated for each herd by addition of the number of positive sampling rounds by the 5 geographically closest neighbour herds. In the 19 different areas the calculated prevalence ranged from 0.01 to 0.41. Totally 3,697 GR-scores were given. The mean GR-scores in the areas ranged from 0.0 to 6.5. Higher GR-scores were found in herds changing to seropositive status compared with herds seronegative throughout the study period. The results indicate that the risk for a dairy herd to receive S. dublin infection increases with the disease status among the nearest neighbours and with the prevalence of seropositive herds in the geographic area.

Leisure-time physical activity levels and changes in relation to risk of hip fracture in men and women.

The authors prospectively studied the effect of leisure-time physical activity level on hip fracture risk along with the influence of within-subject changes in activity levels, while taking possible confounding by other health behaviors and poor health into account. Analyses were based on pooled data from three population studies conducted in Copenhagen, Denmark. Among 13,183 women and 17,045 men, 1,121 first hip fractures were identified during follow-up. In comparison with being sedentary, the relative risk (RR) of hip fracture associated with being moderately physically active 2-4 hours per week was 0.72 (95% confidence interval (CI): 0.59, 0.89) in women and 0.75 (95% CI: 0.55, 1.03) in men after adjustment for confounders. Being in the most active leisure activity category did not decrease the risk of hip fracture further. Adjustment for poor health affected the risk estimates only modestly. Subjects who, during follow-up, reduced their physical activity level from the highest or the intermediate activity level to a sedentary level had a higher risk of hip fracture than did those who remained moderately physically active at the intermediate level (multivariate adjusted RR = 2.19, 95% CI: 1.00, 4.84 and RR = 1.89, 95% CI: 1.21, 2.95, for reduction from the highest and intermediate levels, respectively). There was no evidence of a fracture-protective effect from increasing physical activity. In conclusion, moderate levels of physical activity appear to provide protection against later hip fracture. Decline in the physical activity level over time is an important risk factor for hip fracture.

Testing of bulk tank milk for Salmonella Dublin infection in Danish dairy herds.

The usefulness of enzyme-linked immunosorbent assay (ELISA) was investigated as a simple method to screen for Salmonella Dublin infection in dairy herds, examining bulk tank milk samples for lipopolysaccharide (O:1,9,12) antibodies. The cut-off value for the ELISA on bulk tank milk was established based on individual milk samples (n = 2887) and bulk tank milk from 52 herds. Bulk tank milk samples (n = 5108) were collected from 1464 dairy herds located in 19 different areas. About 10% of the dairy herds in Denmark participated in the study. The percentage of herds changing from test-negative to test-positive in each area was correlated with the incidence of S. Dublin outbreaks in the corresponding county (r = 0.48, n = 19; P < 0.025). The mean level of the OD values obtained in the first and third test rounds was not constant (Pr /t/ = 0.0001). The study demonstrated that the probability of being test-negative in the third test round was 0.926 for a herd with 2 previous test-negative results. It was concluded that the investigated ELISA method was in general accordance with the cases of clinical S. Dublin infection recorded, and that the method has a potential for national screening purposes.

Impact of a 10-year nation-wide alcohol campaign on knowledge of sensible drinking limits in Denmark.

In Great Britain and in Denmark, strong efforts have been made to influence knowledge on upper threshold for hazardous drinking. In Denmark, a campaign has been repeated every week 40 from 1990 to 2000 with information on the sensible drinking limits of 21 drinks per week for men and 14 drinks per week for women. The aim of this study was to examine the effect of this ongoing campaign on the level of knowledge of sensible drinking limits for men and women. Random representative samples of 1030 adult Danes were telephone interviewed each year during 1994-1999. Our main finding was that the level of knowledge of sensible drinking limits for own sex increased in all subsets of the population throughout the period. However, at the end of the study period (1999) a total of 80% of highly educated young (18-25 years) men knew sensible drinking limits for own sex, while only 35% of uneducated older (more than 65 years) men had knowledge on sensible drinking limits. The proportions were similar among women. Subjects admitting an intake higher than sensible for own sex, i.e. 21 and 14 drinks per week, respectively, had the highest knowledge of these drinking limits. We conclude that public health campaigns, such as the sensible drinking limit campaign, certainly has an impact on level of awareness in the general population. Furthermore, those drinking more than 21 and 14 drinks per week, respectively, are reached by these campaigns.

A retrospective evaluation of a Bovine Herpesvirus-1 (BHV-1) antibody ELISA on bulk-tank milk samples for classification of the BHV-1 status of Danish dairy herds.

Bulk-tank milk samples analysed in a Bovine Herpesvirus-1 (BHV-1) blocking ELISA are still in use in the Danish BHV-1 programme as a tool to classify dairy herds as BHV-1 infected or BHV-1 free herds. In this retrospective study, we used data from the Danish BHV-1 eradication campaign to evaluate performance characteristics of the BHV-1 blocking ELISA in 1039 BHV-1-seropositive and 502 repeatedly BHV-1-negative dairy herds using the results of blood testing of the individual animals as the true infection status. At a cut-off value of 30% blocking reaction, the herd-level relative sensitivity and relative specificity were 82 and 100%, respectively. The herd-level relative sensitivity depended on the within-herd prevalence of seropositive cows and the cut-off value in the assay, but not on the time interval (up to 90 days) between the collection of the bulk-tank milk sample and the individual serum samples. The BHV-1 blocking ELISA on bulk-tank milk could detect seropositive herds (few), with prevalence proportions as low as one seropositive cow out of 70 cows.