Biomedical subjects

Tine Hald

Publications and source records attributed to Tine Hald.

5 recordsLinked to original sources

PubMed2006

Human health impact of Salmonella contamination in imported soybean products: a semiquantitative risk assessment.

The objectives of our study were to estimate the number of reported cases of human salmonellosis in Denmark that can be attributed to the occurrence of Salmonella in soy-based animal feed and to assess whether certain serotypes can be considered of less importance to human health. The assessment was based on a comparison of Salmonella serotypes isolated from feedstuffs, swine, cattle, and humans, primarily collected through the Danish Salmonella surveillance programs, supplemented with international data sources. The results are presented in three different forms: a qualitative assessment of all serotypes isolated from animal feed and/or food-producing animals based on their detection in humans; a semiquantitative ranking of serotypes by the apparent differences in their public health impact; and an estimate of the number of reported cases of human salmonellosis that can be attributed to the occurrence of Salmonella in soy-based animal feed. Salmonella isolates included in this study belonged to 91 distinct serotypes. Of the 82 serotypes found in both production animals and humans, 45 were also found in feed. In the period from 1999 to 2003, 14.4% of reported human infections were caused by serotypes also isolated from animal feed. Based on a modified version of a previously published risk model, we estimated that up to 1.7% of the total number of reported human cases and 2.1% of domestically acquired infections in the period 1999-2003 could be attributed to feedborne serotypes acquired through the consumption of Danish pork and beef. We concluded that more than 90% of serotypes have the potential, if they occur in feedstuffs, for infecting humans via production animals or foods of animal origin.

Animal Feed↗

PubMed2004

Estimating the number of undetected multi-resistant Salmonella Typhimurium DT104 infected pig herds in Denmark.

In Denmark, the detection of multi-resistant Salmonella Typhimurium DT104 (MRDT104)-infected pig herds relies on the national Salmonella surveillance programme at the farm and slaughterhouse levels of production. With the surveillance sampling protocol and the diagnostic methods currently used, some herds might remain undetected. The number of undetected Danish pig herds infected with MRDT104 in the period 1 August 2001-31 July 2002 was estimated and compared with the number of culture-confirmed detected herds. A flow chart was constructed to illustrate where infected herds will go undetected in the surveillance system and Monte Carlo simulation was used to model the actual number of pig herds infected with MRDT1104. We estimated that 52 (90% CI [28, 178]) finisher herds were infected with MRDT104 compared to 23 (44%) detected. Among sow herds with production of weaners or growers, we estimated that 38 (90% CI [23, 74]) were infected with MRDT104 compared to 7 (18%) actually detected. Among breeder and multiplier herds, we estimated that five (90% CI [3, 8]) herds were infected with MRDT104 compared to three (60%) detected. In total, we estimated that 102 pig herds were infected with MRDT104 from 1 August 2001 till 31 July 2002 (90% CI [63, 228]). In comparison, 33 (32%) infected herds were detected in this period. The predicted proportion of undetected herds varied considerably with herd type. We infer that the proportion of detected MRDT104 infected herds depended on the intensity of the combined serological and bacteriological testing.

Animals↗

PubMed2004

A Bayesian approach to quantify the contribution of animal-food sources to human salmonellosis.

Based on the data from the integrated Danish Salmonella surveillance in 1999, we developed a mathematical model for quantifying the contribution of each of the major animal-food sources to human salmonellosis. The model was set up to calculate the number of domestic and sporadic cases caused by different Salmonella sero and phage types as a function of the prevalence of these Salmonella types in the animal-food sources and the amount of food source consumed. A multiparameter prior accounting for the presumed but unknown differences between serotypes and food sources with respect to causing human salmonellosis was also included. The joint posterior distribution was estimated by fitting the model to the reported number of domestic and sporadic cases per Salmonella type in a Bayesian framework using Markov Chain Monte Carlo simulation. The number of domestic and sporadic cases was obtained by subtracting the estimated number of travel- and outbreak-associated cases from the total number of reported cases, i.e., the observed data. The most important food sources were found to be table eggs and domestically produced pork comprising 47.1% (95% credibility interval, CI: 43.3-50.8%) and 9% (95% CI: 7.8-10.4%) of the cases, respectively. Taken together, imported foods were estimated to account for 11.8% (95% CI: 5.0-19.0%) of the cases. Other food sources considered had only a minor impact, whereas 25% of the cases could not be associated with any source. This approach of quantifying the contribution of the various sources to human salmonellosis has proved to be a valuable tool in risk management in Denmark and provides an example of how to integrate quantitative risk assessment and zoonotic disease surveillance.

Animals↗

PubMed2003

Salmonella control programs in Denmark.

We describe Salmonella control programs of broiler chickens, layer hens, and pigs in Denmark. Major reductions in the incidence of foodborne human salmonellosis have occurred by integrated control of farms and food processing plants. Disease control has been achieved by monitoring the herds and flocks, eliminating infected animals, and diversifying animals (animals and products are processed differently depending on Salmonella status) and animal food products according to the determined risk. In 2001, the Danish society saved U.S.$25.5 million by controlling Salmonella. The total annual Salmonella control costs in year 2001 were U.S.$14.1 million (U.S.$0.075/kg of pork and U.S.$0.02/kg of broiler or egg). These costs are paid almost exclusively by the industry. The control principles described are applicable to most industrialized countries with modern intensive farming systems.

Animals↗

PubMedDate not supplied

Principles, application areas and an example of risk assessment conducted at the Danish Institute for Food and Veterinary Research.

The Department for Epidemiology and Risk Analysis at the Danish Institute for Food and Veterinary Research (DFVF) is concerned with risk analyses in the areas of food safety, zoonoses, antimicrobial resistance and OIE (World Organisation for Animal Health) list A and B diseases. The DFVF is responsible for the risk assessment component of the risk analysis process and provides advice and support for the risk management and risk communication component, which is generally under the auspices of the Danish Veterinary and Food Administration (DVFA). The paper presents guidelines for the conduct of risk assessments at the DFVF. Important elements of these guidelines are the independence between risk assessment and risk management, the commitment to science-based, transparent and fully documented procedures and adherence to a protocol that regulates the cooperation between DFVF and DVFA. Typical steps of a quantitative risk assessment are the description of the risk scenario, information retrieval, mathematical modelling with stochastic simulation, final risk estimation with a sensitivity analysis and reporting. The procedure is exemplified using a Monte Carlo simulation model for the assessment of the risk of BSE transmission to calves by tallow-based calf milk replacer.

Animal Welfare↗