Marina Pieters

Bio: Marina Pieters is an academic researcher from University of Minnesota. The author has contributed to research in topics: Herd immunity & Vaccination. The author has an hindex of 1, co-authored 1 publications receiving 337 citations.

The Impact of Fusarium Mycotoxins on Human and Animal Host Susceptibility to Infectious Diseases

Abstract: Contamination of food and feed with mycotoxins is a worldwide problem. At present, acute mycotoxicosis caused by high doses is rare in humans and animals. Ingestion of low to moderate amounts of Fusarium mycotoxins is common and generally does not result in obvious intoxication. However, these low amounts may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host pathogen interactions and thus a different outcome of infection. This review summarizes the current state of knowledge about the impact of Fusarium mycotoxin exposure on human and animal host susceptibility to infectious diseases. On the one hand, exposure to deoxynivalenol and other Fusarium mycotoxins generally exacerbates infections with parasites, bacteria and viruses across a wide range of animal host species. Well-known examples include coccidiosis in poultry, salmonellosis in pigs and mice, colibacillosis in pigs, necrotic enteritis in poultry, enteric septicemia of catfish, swine respiratory disease, aspergillosis in poultry and rabbits, reovirus infection in mice and Porcine Reproductive and Respiratory Syndrome Virus infection in pigs. However, on the other hand, T-2 toxin has been shown to markedly decrease the colonization capacity of Salmonella in the pig intestine. Although the impact of the exposure of humans to Fusarium toxins on infectious diseases is less well known, extrapolation from animal models suggests possible exacerbation of, for instance, colibacillosis and salmonellosis in humans, as well.

EMA and EFSA Joint Scientific Opinion on measures to reduce the need to use antimicrobial agents in animal husbandry in the European Union, and the resulting impacts on food safety (RONAFA)

Abstract: EFSA and EMA have jointly reviewed measures taken in the EU to reduce the need for and use of antimicrobials in food-producing animals, and the resultant impacts on antimicrobial resistance (AMR). Reduction strategies have been implemented successfully in some Member States. Such strategies include national reduction targets, benchmarking of antimicrobial use, controls on prescribing and restrictions on use of specific critically important antimicrobials, together with improvements to animal husbandry and disease prevention and control measures. Due to the multiplicity of factors contributing to AMR, the impact of any single measure is difficult to quantify, although there is evidence of an association between reduction in antimicrobial use and reduced AMR. To minimise antimicrobial use, a multifaceted integrated approach should be implemented, adapted to local circumstances. Recommended options (non-prioritised) include: development of national strategies; harmonised systems for monitoring antimicrobial use and AMR development; establishing national targets for antimicrobial use reduction; use of on-farm health plans; increasing the responsibility of veterinarians for antimicrobial prescribing; training, education and raising public awareness; increasing the availability of rapid and reliable diagnostics; improving husbandry and management procedures for disease prevention and control; rethinking livestock production systems to reduce inherent disease risk. A limited number of studies provide robust evidence of alternatives to antimicrobials that positively influence health parameters. Possible alternatives include probiotics and prebiotics, competitive exclusion, bacteriophages, immunomodulators, organic acids and teat sealants. Development of a legislative framework that permits the use of specific products as alternatives should be considered. Further research to evaluate the potential of alternative farming systems on reducing AMR is also recommended. Animals suffering from bacterial infections should only be treated with antimicrobials based on veterinary diagnosis and prescription. Options should be reviewed to phase out most preventive use of antimicrobials and to reduce and refine metaphylaxis by applying recognised alternative measures.

Relationship between biosecurity and production/antimicrobial treatment characteristics in pig herds

Abstract: The biosecurity status of 95 breeder-finisher pig herds was quantified using a risk-based weighted scoring system. Data relating to herd-, farmer- and production-characteristics and to the prophylactic use of antimicrobials were also collected. The average external biosecurity score (measures to prevent pathogens from entering a herd) was 65 (range, 45-89) and the average internal score (measures to reduce the within-herd spread of pathogens) was 52 (range, 18-87). External scores were positively associated with herd size, while internal scores were negatively associated with both 'age of buildings' and 'years of experience of the farmer', indicating that biosecurity is generally better implemented in larger herds, in more modern facilities and by younger farmers. External and internal biosecurity scores were positively associated with daily weight gain and negatively associated with feed conversion ratio of fattening pigs. Internal scores were negatively associated with disease treatment incidence, suggesting that improved biosecurity might help in reducing the amount of antimicrobials used prophylactically. This study demonstrates and quantifies a clear link between biosecurity and both production- and antimicrobial treatment-related criteria in pig herds.

Update on Mycoplasma hyopneumoniae infections in pigs: Knowledge gaps for improved disease control.

Abstract: Mycoplasma hyopneumoniae (M. hyopneumoniae) is the primary pathogen of enzootic pneumonia, a chronic respiratory disease in pigs. Infections occur worldwide and cause major economic losses to the pig industry. The present paper reviews the current knowledge on M. hyopneumoniae infections, with emphasis on identification and analysis of knowledge gaps for optimizing control of the disease. Close contact between infected and susceptible pigs is the main route of M. hyopneumoniae transmission. Management and housing conditions predisposing for infection or disease are known, but further research is needed to better understand M. hyopneumoniae transmission patterns in modern pig production systems, and to assess the importance of the breeding population for downstream disease control. The organism is primarily found on the mucosal surface of the trachea, bronchi and bronchioles. Different adhesins and lipoproteins are involved in the adherence process. However, a clear picture of the virulence and pathogenicity of M. hyopneumoniae is still missing. The role of glycerol metabolism, myoinositol metabolism and the Mycoplasma Ig binding protein-Mycoplasma Ig protease system should be further investigated for their contribution to virulence. The destruction of the mucociliary apparatus, together with modulating the immune response, enhances the susceptibility of infected pigs to secondary pathogens. Clinical signs and severity of lesions depend on different factors, such as management, environmental conditions and likely also M. hyopneumoniae strain. The potential impact of strain variability on disease severity is not well defined. Diagnostics could be improved by developing tests that may detect virulent strains, by improving sampling in live animals and by designing ELISAs allowing discrimination between infected and vaccinated pigs. The currently available vaccines are often cost-efficient, but the ongoing research on developing new vaccines that confer protective immunity and reduce transmission should be continued, as well as optimization of protocols to eliminate M. hyopneumoniae from pig herds.

Risk factors associated with pleuritis and cranio-ventral pulmonary consolidation in slaughter-aged pigs.

Abstract: Examination of lung lesions at the slaughterhouse is a useful tool to estimate the importance of respiratory disease at farm, regional or national level. The objective of the present work was to describe the prevalence of gross lung lesions at slaughter, with a special focus on pleuritis and cranio-ventral pulmonary consolidation, and to identify major risk factors for these lesions. Data from 107 farms involving approximately 11,000 pigs enabled gross lung lesions to be correlated with serology to different swine respiratory pathogens as well as with production system characteristics and vaccination schedules. Pleuritis and cranio-ventral pulmonary consolidation lesions were recorded in 26.8% and 55.7% of slaughter-aged pigs, respectively. Among lungs with pleuritis, 50.1% had lesions compatible with Actinobacillus pleuropneumoniae (App) infection. Antibodies to porcine reproductive and respiratory syndrome (PRRSV), three subtypes (H1N1, H1N2 and H3N2) of swine influenza virus (SIV), App and Mycoplasma hyopneumoniae (Mhyo) were highly prevalent (>82%) in most of the farms. In a multivariable analysis, it was estimated (R2 = 0.40) that the percentage of animals with pleuritis compatible with App infection depended on the existence of an all in-all out by room management system and App and PRRSV herd seroprevalence. Moreover, it was possible to foresee (R2 = 0.59) that cranio-ventral pulmonary consolidation lesions (EP-like lesions) were affected by the type of farm ventilation, the presence of respiratory symptoms during the fattening period and Mhyo and SIV H1N2 herd seroprevalence.