Comparison of Alternative Meat Inspection Regimes for Pigs From Non-Controlled Housing – Considering the Cost of Error

Denmark has not had cases of bovine tuberculosis (bovTB) for more than 30 years but is obliged by trade agreements to undertake traditional meat inspection (TMI) of finisher pigs from non-controlled housing to detect bovTB. TMI is associated with higher probability of detecting bovTB but is also more costly than visual-only inspection (VOI). To identify whether VOI should replace TMI of finisher pigs from non-controlled housing, the cost of error – defined here as probability of overlooking infection and associated economic costs - should be assessed and compared with surveillance costs. First, a scenario tree model was set up to assess the ability of detecting bovTB in an infected herd (HSe) calculated for three within-herd prevalences, WHP (1, 5 and 10%), for four different surveillance scenarios (TMI and VOI with or without serological test, respectively). HSe was calculated for six consecutive 4-week surveillance periods until predicted bovTB detection (considered high-risk periods HRP). 1-HSe was probability of missing all positives by each HRP. Next, probability of spread of infection, Pspread, and number of infected animals moved were calculated for each HRP. Costs caused by overlooking bovTB were calculated taking into account Pspread, 1-HSe, eradication costs, and trade impact. Finally, the average annual costs were calculated by adding surveillance costs and assuming one incursion of bovTB in either 1, 10 or 30 years. Input parameters were based on slaughterhouse statistics, literature and expert opinion. Herd sensitivity increased by high-risk period and within-herd prevalence. Assuming WHP=5%, HSe reached median 90% by 2nd HRP for TMI, whereas for VOI this would happen after 6th HRP. Serology had limited impact on HSe. The higher the probability of infection, the higher the probability of detection and spread. TMI resulted in lowest average annual costs, if one incursion of bovTB was expected every year. However, when assuming one introduction in 10 or 30 years, VOI resulted in lowest average costs. It may be more cost-effective to focus on imported high-risk animals coming into contact with Danish livestock, instead of using TMI as surveillance on all pigs from non-controlled housing

Sundhed og velfærd hos kalve og opdræt

I interviewene blev kalvene fremhævet som et både problematisk og kritisk område i den økologiske besætning (kapitel 2 & 3). Fodring, paratuberkulose (især i forbindelse med kalvens første døgn hos moderen), opstaldning, udeophold og medicinering blev nævnt som mulige årsager til problemer. Det blev desuden nævnt, at der kunne være problemer med at sammensætte en god foderration. Vedrørende opstaldning af kalvene blev kalvenes patning på hinanden nævnt som et problem. Enkelte konsulenter nævnte manglende hygiejne og generelle problemer med opstaldningen. Sygdomsproblemer som følge af coccidiose ved kalvenes tidlige udeophold blev af de fleste nævnt som et stort problem. Flere dyrlæger nævnte, at eftersom reglerne vedrørende medicinhåndtering i økologiske besætninger er stramme, ville dette kunne resultere i, at kalvene ikke ville blive behandlet i det omfang, der var behov for. En diskussion af kalvenes rolle i besætningen – blandt andet hvorvidt de er lavt prioriterede – er uundgåelig i denne sammenhæng, og mange af de interviewede kom da også ind på denne overordnede problemstilling: Kalvene er en gruppe dyr, der helst skal have de lavest mulige omkostninger. Det blev anført, at kalvene er besætningens fremtid, og at deres rolle skal være mere i fokus. Ved omlægning til økologisk drift forventer landmanden umiddelbart, at dyrenes sundhedstilstand fastholdes eller forbedres. Som det fremgik af kapitel 2, var der især blandt dyrlæger og konsulenter bekymring for kalvenes trivsel i den økologiske besætning. De fleste interviewede dyrlæger og konsulenter forventede på det nærmeste en dramatisk overgang til "det værre" for kalvenes vedkommende. På længere sigt – i den stabile økologiske besætning – forventedes kalvene fortsat at være en udsat gruppe. En sådan forventning må siges at være i modstrid med den økologiske grundidé og de forventninger, der indirekte udtrykkes i gældende regler vedrørende kalve. Dyrlæger og konsulenter betragter ofte kalvene som en kvægbesætnings mest udsatte dyregruppe ("tabergruppen"), som ikke prioriteres højt med hensyn til tildeling af arbejdstid og staldfaciliteter

Surveillance for Salmonella over the years - the Danish perspective

This paper describes some of the initiatives that have been implemented by the Danish swine industry with the aim to reduce the prevalence of Salmonella. Initially, main focus was on pre-harvest initiatives and correct identification of herds with high levels of Salmonella. Then, focus has changed to post-harvest initiatives, such as improved slaughter hygiene. Recently, decontamination applied after slaughter and cost-effectiveness in surveillance have received increasing attention

Assessment of the Risk to Public Health due to Use of Antimicrobials in Pigs—An Example of Pleuromutilins in Denmark

Antibiotic consumption in pigs can be optimized by developing treatment guidelines, which encourage veterinarians to use effective drugs with low probability of developing resistance of importance for human health. In Denmark, treatment guidelines for use in swine production are currently under review at the Danish Veterinary and Food Administration. Use of pleuromutilins in swine has previously been associated with a very low risk for human health. However, recent international data and sporadic findings of novel resistance genes suggest a change of risk. Consequently, a reassessment was undertaken inspired by a risk assessment framework developed by the European Medicines Agency. Livestock-associated methicillin-resistant Staphylococcus aureus of clonal complex 398 (MRSA CC398) and enterococci were identified as relevant hazards. The release assessment showed that the probability of development of pleuromutilin resistance was high in MRSA CC398 (medium uncertainty) and low in enterococci (high uncertainty). A relatively small proportion of Danes has an occupational exposure to pigs, and foodborne transmission was only considered of relevance for enterococci, resulting in an altogether low exposure risk. The human consequences of infection with pleuromutilin-resistant MRSA CC398 or enterococci were assessed as low for the public in general but high for vulnerable groups such as hospitalized and immunocompromised persons. For MRSA CC398, the total risk was estimated as low (low uncertainty), among other due to the current guidelines on prevention of MRSA in place at Danish hospitals, which include screening of patients with daily contact to pigs on admittance. Moreover, MRSA CC398 has a medium human–human transmission potential. For enterococci, the total risk was estimated as low due to low prevalence of resistance, low probability of spread to humans, low virulence, but no screening of hospitalized patients, high ability of acquiring resistance genes, and a limited number of alternative antimicrobials (high uncertainty). This assessment reflects the current situation and should be repeated if pleuromutilin consumption increases substantially, resulting in increased prevalence of mobile, easily transmissible resistance mechanisms. Continuous monitoring of pleuromutilin resistance in selected human pathogens should therefore be considered. This also includes monitoring of linezolid resistance, since resistance mechanisms for pleuromutilins and oxazolidones are often coupled

Pork and the number of human multi-resistant Salmonella Typhimurium DT104 cases

As part of a revision of the Danish Salmonella policy, we estimated the impact of nationally produced pork compared to imported pork on the number of human sporadic domestic cases of multi-resistant Salmonella Typhimurium DT104 (MRDT104) in Denmark. We also estimated the number of deaths related to the presumed excess mortality associated with MRDT104. Data on exposure from domestic and imported pork were built into a simple simulation model in @Risk, and Monte Carlo simulations were used. Our results showed that imported pork resulted in 20 times as many human cases as domestic (2 human cases per year), and 1 extra death in 50 years. If the prevalence of MRDT104 in domestic pork increased 5 times, the absolute number of human cases (related to Danish pork) would be 8-11. The excess mortality due to this rise in human cases will be negligible compared to the mortality caused by other Salmonellae

Survival of Salmonella and Escherichia coli in pig slurry: simulation of decay

Spreading of slurry infected with multi-resistant Salmonella Typhimurium DT104 (MRDT104) on arable land might constitute a risk of transmission to wildlife. To estimate survival time on farmland, we modeled the bacterial decay based on Escherichia coli data from a plot study carried out in spring 2002 in Denmark. Time until undetectable levels were modeled under different scenarios: 1) E. coli in swine slurry, 2) Salmonella in slurry from clinically infected swineherds, and 3) MRDT104 in slurry from sub-clinically infected swineherds. A log-linear model extended with time2 and time3 was used to describe bacterial decay. For scenarios 2 and 3, we assumed that the level of bacteria in the slurry would be log 4.0 cfu/g and log 3.4 cfu/g, respectively, and a similar effect of spreading and decimation to that of E. coli. Hereby, it was estimated that Salmonella counts fell below detectable levels after 10 and 5 days, respectively

Cost-benefit analysis of measures to reduce Salmonella in Danish pork

The Danish control program for Salmonella in pork was initiated in 1995, and since then the number of human cases of salmonellosis in Denmark has dropped significantly. The question is, how further reductions can be attained in a cost-effective way

Comparison of Antimicrobial Consumption Patterns in the Swiss and Danish Cattle and Swine Production (2007–2013)

Veterinary antimicrobial consumption patterns vary considerably across Europe. These differences are not only limited to the total amount consumed but are also observed with regards to the relative proportion of the various antimicrobial classes used. Currently, most of the data on veterinary antimicrobials are reported at sales level without any information on the consumption by different animal species. This hinders a proper comparison of antimicrobial consumption at the species level between countries. However, it is imperative to improve our understanding on antimicrobial usage patterns at the species level, as well as on the drivers contributing to those differences. This will allow for development of tailored interventions with the lowest possible risk for human health, while ensuring effective treatment of diseased livestock. An important step to attain such an objective is to perform detailed comparisons of the antimicrobial consumption in each species between countries. We compared antimicrobial consumption estimates for cattle and pigs in Switzerland and Denmark, in order to distinguish species-specific patterns and trends in consumption from 2007 to 2013. Swiss data were obtained from a previous study that assessed methodologies to stratify antimicrobial sales per species; Danish antimicrobial consumption estimates were assembled from Danish Integrated Antimicrobial Resistance Monitoring and Research Programme reports. A decrease in antimicrobial consumption in milligrams per kilogram of biomass was observed for both countries (4.5% in Denmark and 34.7% in Switzerland) when comparing 2013 to 2007. For pigs and cattle, the overall consumption per kilogram of biomass of most antimicrobial classes was higher in Switzerland than in Denmark. Large variations in the relative consumption of different antimicrobial classes were also evident. Sulfonamides/trimethoprim and tetracyclines were consumed in a higher proportion in Switzerland than in Denmark, whereas the relative consumption of penicillins was higher in Denmark. The differences observed in veterinary antimicrobial consumption are not solely related to animal demographic characteristics in these two countries. Other factors, such as the level of biosecurity and farming practices, veterinarians and farmers' education, or governmental/industry programs put in place might also partly explain these variations. These differences should be taken into account when aiming to implement targeted interventions to reduce antimicrobial consumption

Longitudinal study of Salmonella enterica serovar Typhimurium infection in three Danish farrow-to-finish swineherds

A longitudinal study on Salmonella enterica was carried out in 3 Danish farrow-to-finish swineherds in 2001. Litters from each herd were divided into 2 cohorts of 30 pigs each (180 pigs in total). Individual pigs were examined for bacteriology and serology monthly from weaning to slaughter. At weaning, individual sows were also examined for bacteriology and serology. In total, 88 pigs were found to be shedding on ≥1 occasion. Only Salmonella enterica serovar Typhimurium was detected. The culture-prevalence peaked in the nursery, and subsequently declined to undetectable levels before slaughter. The sero-prevalence peaked approximately 60 days after peak culture-prevalence. Salmonella was detected in individual fecal samples at least once in 53% of the pigs, while 62% were sero-positive more than once. Only 3.7% of all pigs were found to be culture-positive on ≥1 occasion. The average shedding time was estimated to have been 18 days