Yrjo Grohn

Cornell University | CU · Department of Population Medicine and Diagnostic Sciences

Dogs are a potential source of drug-resistant Escherichia coli, but very few large-scale antimicrobial resistance surveillance studies have been conducted in the canine population. Here, we assess the antimicrobial susceptibility patterns, identify temporal resistance and minimum inhibitory concentration (MIC) trends, and describe associations betw...

The increased accessibility of next generation sequencing has allowed enough genomes from a given bacterial species to be sequenced to describe the distribution of genes in the pangenome, without limiting analyses to genes present in reference strains. Although some taxa have thousands of whole genome sequences available on public databases, most g...

Background Salmonella enterica in cattle has long been problematic and suspected to be transmitted by wildlife in Tokachi, Hokkaido, a major cattle farming area in Japan. Understanding the role of wildlife in S. enterica transmission would be helpful for developing control strategies of bovine salmonellosis. Objectives We aimed to elucidate the po...

Trypanosoma theileri is considered a non- or low-pathogenic trypanosome that generally causes latent infection in apparently healthy cattle; however, T. theileri propagates in the bloodstream and may cause clinical disease in pregnant animals or co-infection with bovine leukemia virus or Theileria orientalis. In the current study, a monthly survey...

We formulate and investigate a compartmental model for a multi-strain SIR disease with complete cross immunity and nonlinear force of infection. More specifically we consider a hyperbolic force of infection with saturation effects. Using a combination of analytical and computational methods, we find that under such a nonlinear force of infection in...

Recent evidence of circulation of multiple strains within herds and mixed infections of cows marks the beginning of a rethink of our knowledge on Mycobacterium avium ssp. paratuberculosis (MAP) epidemiology. Strain typing opens new ways to investigate MAP transmission. This work presents a method for reconstructing infection chains in a setting of...

Antimicrobial resistance (AMR) is a recognized global public health concern. Although the link between antimicrobial usage in food animals and AMR in humans is established, the detailed interactions are unclear. Antimicrobial stewardship (AMS) in livestock was first implemented in Europe with Sweden as the pioneer in 1986. Despite this head start,...

There is consumer pressure on the US beef cattle industry to minimize antibiotic use (ABU) in order to aid in the global antimicrobial resistance mitigation efforts. Our objective was to estimate the economic costs of ABU constraints in a conceptual US integrated beef supply chain (IBSC) to aid the beef industry in mitigating the ever-increasing ri...

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne's disease in ruminants, which has important health consequences for dairy cattle. The Regional Dairy Quality Management Alliance (RDQMA) project is a multistate research program involving MAP isolates taken from three intensively studied commercial dairy farms in the...

Recent evidence of circulation of multiple strains within herds and mixed infections of cows marks the beginning of a rethink of our knowledge on Mycobacterium avium ssp. paratuberculosis (MAP) epidemiology. Strain typing opens new ways to investigate MAP transmission. This work presents a method for reconstructing infection chains in a setting of...

Multidrug resistance (MDR) surveillance consists of reporting MDR prevalence and MDR phenotypes. Detailed knowledge of the specific associations underlying MDR patterns can allow antimicrobial stewardship programs to accurately identify clinically relevant resistance patterns. We applied machine learning and graphical networks to quantify and visua...

Infectious disease management relies on accurate characterization of disease progression so that transmission can be prevented. Slowly progressing infectious diseases can be difficult to characterize because of a latency period between the time an individual is infected and when they show clinical signs of disease. The introduction of Mycobacterium...

Tylosin phosphate (TYL) is administered to more than 50% of U.S. beef cattle to reduce the incidence of liver abscesses but may increase the risk of macrolide-lincosamide-streptogramin-resistant bacteria disseminating from the feedlot. Limited evidence has been collected to understand how TYL affects the proportion of resistant bacteria in cattle o...

The rising public health threat of antimicrobial resistance, the influence of food service companies, as well as the overall lack of positive image of using medical products in intensive farming are major drivers curbing antimicrobial use. In the future, government policies may affect practices of antimicrobial use in beef production in feedlots, a...

[This corrects the article DOI: 10.3389/fmicb.2019.00687.].

Epidemiological data establish that lameness is second only to mastitis as the dairy industry’s most prevalent and costly animal welfare issue. Using an automatic lameness detection (ALD) system in which continuous, accurate detection is coupled with proper treatment, is key for reducing economic losses due to lameness. It is reasonable to assume t...

Development of new biocides has dominated human responses to evolution of antibiotic and pesticide resistance. Increasing and uniform biocide use, the spread of resistance genes, and the lack of new classes of compounds indicate the importance of navigating toward more sustainable coevolutionary dynamics between human culture and species that evolv...

This paper explains how the methodologies of first and second order stochastic dominance, and expected utility using specific risk preferences, can be applied to epidemiology when choosing among control strategies that have stochastic outcomes. We provide a step-by-step guide on how epidemiologists can rank a number of control strategies based on t...

The risk of a zoonotic pandemic disease threatens hundreds of millions of people. Emerging infectious diseases also threaten livestock and wildlife populations around the world and can lead to devastating economic damages. China and the USA—due to their unparalleled resources, widespread engagement in activities driving emerging infectious diseases...

Background: Tylosin is a commonly used in-feed antimicrobial and is approved in several countries to reduce the incidence of liver abscesses in beef cattle. Macrolides are critically important antimicrobials in human health and used to treat some foodborne bacterial diseases, such as Campylobacter jejuni and Salmonella. Feeding tylosin could selec...

Background: In animal agriculture, antimicrobials (AM) are used to control infectious diseases whose incidence and severity vary across production systems, but may contribute to select AM resistant bacteria, potentially disseminating in humans. Antimicrobial resistance (AMR) represents a public threat, leading policymakers to implement measures to...

Considerable effort has been directed toward controlling Johne’s disease (JD), a chronic granulomatous intestinal inflammatory disease caused by Mycobacterium avium subsp. paratuberculosis (MAP) in cattle and other ruminants. However, progress in controlling the spread of MAP infection has been impeded by the lack of reliable diagnostic tests that...

Antibiotics use (ABU) in animal agriculture has been implicated in the emergence of antibiotic resistance, a global public health threat. Economically justifiable antibiotic reduction strategies can motivate farmers to reduce ABU for clinical mastitis (CM) and metritis, the most common reasons for ABU on dairy farms. Our objective was to quantify t...

The benefits and efficacy of control programs for herds infected with Mycobacterium avium subsp. paratuberculosis (MAP) have been investigated under various contexts. However, most previous research investigated paratuberculosis control programs in isolation, without modeling the potential association with other dairy diseases. This paper evaluated...

Antimicrobial use (AMU) in animal agriculture contributes to select resistant bacteria potentially transferred to humans directly or indirectly via the food chain, representing a public health hazard. Yet, a major difference triggering AMU in food animal production is that in addition to therapeutic cure, farmers use antimicrobials to keep their he...

Antimicrobial use (AMU) in animal agriculture contributes to the selection of resistant bacteria, potentially constituting a public health threat. To address antimicrobial resistance, public policies set by governments, as well as intra-sectoral approaches, can be implemented. In this paper, we explore how common policy instruments such as regulati...

Average cost estimates of lameness in dairy cows range from $120 to $216. Costs increase with severity and prevalence Early detection is a key to decrease prevalence. 6 years are needed to reach the break-even point with Automated Lameness Detection System (ALDS) for a 100 cow herd with medium or high prevalence, with a $10,000 ALDS machine at 25%...

The benefits and efficacy of control programs for herds infected with Mycobacterium avium subsp. paratuberculosis (MAP) have been investigated under various contexts. However, most previous research investigated paratuberculosis control programs in isolation, without modeling the potential association with other dairy diseases. This paper evaluated...

Appendix to the article: Global resistance to antimicrobials and their sustainable use in agriculture. Guillaume Lhermie, Didier Wernli, Peter Søgaard Jørgensen, Donald Kenkel, Loren William Tauer, Yrjo Tapio Gröhn The Lancet Planetary Health, Volume 3, ISSUE 3, Pe109-e110, March 01, 2019 Open AccessPublished:March, 2019DOI:https://doi.org/10.101...

In this study, we analyzed the performance of the USDA's bovine tuberculosis (bTB) elimination protocol in a 1,000-cow closed dairy herd using an agent-based simulation model under different levels of initial bTB infection. We followed the bTB test sensitivity and specificity values used by the USDA in its model assessment. We estimated the net pre...

Multidrug resistance is a serious problem raising the specter of infections for which there is no treatment. One of the most important tools in combating multidrug resistance is large scale monitoring programs, because they track resistance over large geographic areas and time scales. This large scope, however, can also introduce variability into t...

The role of wildlife in the persistence and spread of livestock diseases is difficult to quantify and control. These difficulties are exacerbated when several wildlife species are potentially involved. Bovine tuberculosis (bTB), caused by Mycobacterium bovis, has experienced an ecological shift in Michigan, with spillover from cattle leading to an...

Chronic livestock diseases cause large financial loss and affect animal health and welfare. Controlling these diseases mostly requires precise information on both individual animal and population dynamics to inform the farmer’s decisions, but even successful control programmes do by no means assure elimination. Mathematical models provide opportuni...

The model predicted fitted to the observed milk yield for 360 days in milk for farm A, B, and C. The milk yield was calculated using equation shown in the method section. (TIF)

The best 1% parameter sets were ranked from the parameter searching space. (DOCX)

The model predicted median number of years to reduce the apparent prevalence by 25% (top panel) and 5% (bottom panel) calculated from top 1% simulations with best set of parameters while implementing two control scheme I: Aggressive culling and control II: Delayed culling after the pre-intervention fit for the farms A, B, and C. (TIF)

Background: Sensitivity analysis is an essential step in mathematical modeling because it identifies parameters with a strong influence on model output, due to natural variation or uncertainty in the parameter values. Recently behavior pattern sensitivity analysis has been suggested as a method for sensitivity analyses on models with more than one...

Antimicrobial resistance is a public threat for humans, generated by the use of antimicrobials in human medicine as well as animal agriculture. Consequently, governments set public policies aim at curbing antimicrobial use (AMU). In dairy production, the occurrence of diseases triggers AMU to limit the costs associated with these afflictions. There...

Chronic livestock diseases cause large financial loss and affect the animal health and welfare. Controlling these diseases mostly requires precise information on both individual animal and population dynamics to inform farmer’s decision. Mathematical models provide opportunities to test different control and elimination options rather implementing...

The aim of this study was to estimate the associations of the first occurrence of pathogen-specific clinical mastitis (CM) with milk yield and milk composition (somatic cell count (SCC), lactose, fat, protein content in milk and milk urea nitrogen (MUN)). We studied 3149 dairy cows in 31 Hokkaido dairy farms in Japan. Five pathogen groups were stud...

This observational retrospective cohort study provides benchmarking information on recent sow productivity development in Finnish herds. It focuses on parity cycle specific trends in sow removal patterns, and especially on the role of litter performance (size and piglet survival) in sow removal. In addition, the generated models offer a tool for ca...

Fresh produce supply chains present variable and diverse conditions that are relevant to food quality and safety because they may favor microbial growth and survival following contamination. This study presents the development of a simulation and visualization framework to model microbial dynamics on fresh produce moving through postharvest supply...

[This corrects the article on p. 1753 in vol. 8, PMID: 29033901.].

Antimicrobials play a critical role in treating cases of invasive non-typhoidal salmonellosis (iNTS) and other diseases, but efficacy is hindered by resistant pathogens. Selection for phenotypical resistance may occur via several mechanisms. The current study aims to identify correlations that would allow indirect selection of increased resistance...

This paper analyses the performance of the USDA bovine tuberculosis (bTB) eradication protocol in a positive bovine Tb infected dairy herd using an agent-based simulation model under different levels of initial infection. We estimate the net present value over a 20-year horizon for a bTB-free milking herd, and bTB infected herds following the USDA,...

This paper uses an agent-based simulation model to estimate the costs associated with Mycobacterium avium ssp. paratuberculosis (MAP), or Johne's disease, in a milking herd, and to determine the net benefits of implementing various control strategies. The net present value (NPV) of a 1,000-cow milking herd is calculated over 20 yr, parametrized to...

Antimicrobials are used in animal agriculture to cure bacterial infectious diseases. However, antimicrobial use (AMU) inevitably leads to the selection of resistant bacteria, potentially infecting humans. As a global public threat, antimicrobial resistance has led policy makers to implement regulations supervising AMU. The objective of our research...

The growth of antimicrobial resistance presents a significant threat to human and animal health. Of particular concern is multi-drug resistance, as this increases the chances an infection will be untreatable by any antibiotic. In order to understand multi-drug resistance, it is essential to understand the association between drug resistances. Pairw...

Johne’s Disease (JD), caused by Mycobacterium avium subspecies paratuberculosis (MAP), results in significant economic loss to livestock production. The early detection of MAP infection in animals with extant serological assays has remained challenging due to the low sensitivity of commercially available ELISA tests, a fact that has hampered the de...

AUC, cut-off, sensitivity, and specificity values for each of the six MAP recombinant proteins, individually and in combination in serum and milk. (XLSX)

ROC curves depicting reactivity for each antigen with both serum and milk samples. (A) Serum (n = 180, 60 each group), (B) Milk (n = 90, 30 each group). Group All represents 180 samples in serum and 90 in milk; F+E+/NL includes group NL and F+E+ (n = 120 in serum; n = 90 in milk); F+E-/NL includes group NL and F+E+ (n = 120 in serum; n = 90 in milk...

The objectives of this study were to estimate the direct effects of clinical mastitis (CM) occurring in early productive life (defined as the first 100 d of the first lactation) of Holstein dairy cows on the future rate of CM occurrence and on the length of total productive lifetime. Information on CM cases and other data occurring in 55,144 lactat...

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of Johne’s disease in ruminants causing chronic diarrhea, malnutrition, and muscular wasting. Neonates and young animals are infected primarily by the fecal–oral route. MAP attaches to, translocates via the intestinal mucosa, and is phagocytosed by macrophages. The ensuing hos...

Veterinary Precision Medicine (VPM), defined as an optimized preventive or curative therapeutic approach (right animal, right drug, right dose, right time) based on identification of biomarkers of disease and use of technologies of disease monitoring. The emergence of such technology may modify the role of field veterinarians in the future.

Antimicrobial use (AMU) fulfills therapeutic as well as economic objectives, but generates a negative externality, i.e., antimicrobial resistance (AMR). The consideration of socio-economic and behavioral determinants of AMU is necessary to frame adequate public policies tackling AMR. Our aim was to model the dynamics of AMU, the relationship betwee...

The development of reliable models for transmission of intramammary infections (IMI) is the subject of extensive research. Such models are useful to enhance the identification and understanding of factors that affect pathogen-specific IMI dynamics. Longitudinal transmission models are valuable for predicting infection outbreak risks, quantifying th...

Johne’s disease (JD) is a chronic enteric disease in cattle caused by Mycobacterium avian subsp. paratuberculosis (MAP). Eradicating JD is a difficult task due to the long incubation period of MAP, inefficient diagnostic tests, and delayed clinical signs. Effective control strategies can help farmers to reduce prevalence, but those most acceptable...

Endemic diseases can be counted among the most serious sources of losses for livestock production. In dairy farms in particular, one of the most common diseases is Johne's disease, caused by Mycobacterium avium ssp. paratuberculosis (MAP). Infection with MAP causes direct costs because it affects milk production, but it has also been suspected to i...

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne's disease (JD), a chronic intestinal inflammatory disease of cattle and other ruminants. JD has a high herd prevalence and causes serious animal health problems and significant economic loss in domesticated ruminants throughout the world. Since serological detection o...

Serum samples used in the study. (XLSX)

MAP orthologs of MTB proteins identified as significantly reactive antigens. (XLSX)

Sensitivity and specificity for each antigen. (XLSX)

Different profiles of comparison of infected groups with NL and NH as a reference. A. Number of significantly reactive proteins identified in F+E- group in comparison with NL and NH. The large circle represents the number of significantly reactive proteins in comparison with NL and the smaller circle represents the number of identified proteins in...

Proteins identified in NH, F+E-, and F+E+ group. Unique proteins represents proteins the proteins are significantly reactive (P<0.05) proteins identified only in the specific group (NH, F+E-, or F+E+). Shared proteins represent proteins are significantly reactive (P<0.05) proteins identified in two or three groups. (TIFF)

Comparison of MAP3939c with 5 MTB orthologues. Upper: multiple alignment of MAP3939c with 5 MTB orthologue. As showed in the alignment, there is the highest identity between MAP3939c and Rv0442c. Bottom: similar structure characters between MAP3939c and Rv0442c (Protean of Lasergene, DNAstar, Madison, Wisconsin). (TIFF)

Antimicrobial use in beef cattle can increase antimicrobial resistance prevalence in their enteric bacteria, including potential pathogens such as Escherichia coli. These bacteria can contaminate animal products at slaughterhouses and cause food-borne illness, which can be difficult to treat if it is due to antimicrobial resistant bacteria. One pot...

Mycobacterium avium ssp. paratuberculosis (MAP), the causative agent of ruminant Johne's disease, presents a particular challenge with regard to infection mitigation on dairy farms. Diagnostic testing strategies to identify and quantify MAP and associated antibodies are imperfect, and certain facets of the relationship between diagnostic tests rema...