1
|
Tamminen LM, Dicksved J, Eriksson E, Keeling LJ, Emanuelson U. Untangling the role of environmental and host-related determinants for on-farm transmission of verotoxin-producing Escherichia coli O157. Infect Ecol Epidemiol 2024; 14:2406852. [PMID: 39386259 PMCID: PMC11463013 DOI: 10.1080/20008686.2024.2406852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 09/17/2024] [Indexed: 10/12/2024] Open
Abstract
Background: Cattle colonised by the zoonotic pathogen verotoxin-producing Escherichia coli of serotype O157 (VTEC O157) can shed high levels of the pathogen in their faeces. A suggested key for controlling VTEC O157 is preventing colonisation of individuals. Aim: In this study the role of individual super-shedders and factors related to susceptibility and environmental exposure in the transmission of VTEC O157 among dairy calves are explored. Methods: The association between sex, age, pen hygiene, pen type and stocking density and colonisation of individual calves, established by recto-anal mucosal swabs, on farms where pathogenic VTEC O157 had been confirmed was investigated. In a follow-up sampling, the consistency of previously identified risk factors and the role of shedding pen mates was assessed by studying the risk of new/re-colonisation. Results: The results suggest an important role of stocking density that decreases with age, possibly due to increased resistance to colonisation following exposure. However, previous colonisation did not influence the risk of being colonised in the second sampling. Super-shedders (shedding >103 colony forming units/g faeces) significantly increased the risk of colonisation in peers (OR = 10, CI 4.2-52). In addition, environmental factors associated with survival of the bacteria, affected risk. Conclusion: The results confirm the suggested importance of super-shedders but also emphasises the importance of considering the combined exposure from peers and the environment.
Collapse
Affiliation(s)
- Lena-Mari Tamminen
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Johan Dicksved
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Linda J. Keeling
- Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ulf Emanuelson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| |
Collapse
|
2
|
Nguyen NTD, Pathak AK, Cattadori IM. Gastrointestinal helminths increase Bordetella bronchiseptica shedding and host variation in supershedding. eLife 2022; 11:e70347. [PMID: 36346138 PMCID: PMC9642997 DOI: 10.7554/elife.70347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/11/2022] [Indexed: 11/09/2022] Open
Abstract
Co-infected hosts, individuals that carry more than one infectious agent at any one time, have been suggested to facilitate pathogen transmission, including the emergence of supershedding events. However, how the host immune response mediates the interactions between co-infecting pathogens and how these affect the dynamics of shedding remains largely unclear. We used laboratory experiments and a modeling approach to examine temporal changes in the shedding of the respiratory bacterium Bordetella bronchiseptica in rabbits with one or two gastrointestinal helminth species. Experimental data showed that rabbits co-infected with one or both helminths shed significantly more B. bronchiseptica, by direct contact with an agar petri dish, than rabbits with bacteria alone. Co-infected hosts generated supershedding events of higher intensity and more frequently than hosts with no helminths. To explain this variation in shedding an infection-immune model was developed and fitted to rabbits of each group. Simulations suggested that differences in the magnitude and duration of shedding could be explained by the effect of the two helminths on the relative contribution of neutrophils and specific IgA and IgG to B. bronchiseptica neutralization in the respiratory tract. However, the interactions between infection and immune response at the scale of analysis that we used could not capture the rapid variation in the intensity of shedding of every rabbit. We suggest that fast and local changes at the level of respiratory tissue probably played a more important role. This study indicates that co-infected hosts are important source of variation in shedding, and provides a quantitative explanation into the role of helminths to the dynamics of respiratory bacterial infections.
Collapse
Affiliation(s)
- Nhat TD Nguyen
- Center for Infectious Disease Dynamics, The Pennsylvania State UniversityUniversity ParkUnited States
- Department of Biology, The Pennsylvania State UniversityUniversity ParkUnited States
| | - Ashutosh K Pathak
- Center for Infectious Disease Dynamics, The Pennsylvania State UniversityUniversity ParkUnited States
- Department of Biology, The Pennsylvania State UniversityUniversity ParkUnited States
- Department of Infectious Diseases, University of GeorgiaAthensUnited States
| | - Isabella M Cattadori
- Center for Infectious Disease Dynamics, The Pennsylvania State UniversityUniversity ParkUnited States
- Department of Biology, The Pennsylvania State UniversityUniversity ParkUnited States
| |
Collapse
|
3
|
Kempf F, La Ragione R, Chirullo B, Schouler C, Velge P. Super Shedding in Enteric Pathogens: A Review. Microorganisms 2022; 10:2101. [PMID: 36363692 PMCID: PMC9692634 DOI: 10.3390/microorganisms10112101] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/24/2024] Open
Abstract
Super shedding occurs when a small number of individuals from a given host population shed high levels of a pathogen. Beyond this general definition, various interpretations of the shedding patterns have been proposed to identify super shedders, leading to the description of the super shedding phenomenon in a wide range of pathogens, in particular enteric pathogens, which are of considerable interest. Several underlying mechanisms may explain this observation, including factors related to the environment, the gut microbiota, the pathogen itself (i.e., genetic polymorphism), and the host (including immune factors). Moreover, data suggest that the interplay of these parameters, in particular at the host-pathogen-gut microbiota interface, is of crucial importance for the determination of the super shedding phenotype in enteric pathogens. As a phenomenon playing an important role in the epidemics of enteric diseases, the evidence of super shedding has highlighted the need to develop various control strategies.
Collapse
Affiliation(s)
- Florent Kempf
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France
| | - Roberto La Ragione
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
- School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Barbara Chirullo
- Department of Food Safety, Nutrition and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 000161 Rome, Italy
| | | | - Philippe Velge
- INRAE, Université de Tours, ISP, F-37380 Nouzilly, France
| |
Collapse
|
4
|
|
5
|
Grover E, Paull S, Kechris K, Buchwald A, James K, Liu Y, Carlton EJ. Predictors of bovine Schistosoma japonicum infection in rural sichuan, china. Int J Parasitol 2022; 52:485-496. [DOI: 10.1016/j.ijpara.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 11/05/2022]
|
6
|
Farthing TS, Dawson DE, Sanderson MW, Seger H, Lanzas C. Combining epidemiological and ecological methods to quantify social effects on Escherichia coli transmission. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210328. [PMID: 34754493 PMCID: PMC8493196 DOI: 10.1098/rsos.210328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Enteric microparasites like Escherichia coli use multiple transmission pathways to propagate within and between host populations. Characterizing the relative transmission risk attributable to host social relationships and direct physical contact between individuals is paramount for understanding how microparasites like E. coli spread within affected communities and estimating colonization rates. To measure these effects, we carried out commensal E. coli transmission experiments in two cattle (Bos taurus) herds, wherein all individuals were equipped with real-time location tracking devices. Following transmission experiments in this model system, we derived temporally dynamic social and contact networks from location data. Estimated social affiliations and dyadic contact frequencies during transmission experiments informed pairwise accelerated failure time models that we used to quantify effects of these sociobehavioural variables on weekly E. coli colonization risk in these populations. We found that sociobehavioural variables alone were ultimately poor predictors of E. coli colonization in feedlot cattle, but can have significant effects on colonization hazard rates (p ≤ 0.05). We show, however, that observed effects were not consistent between similar populations. This work demonstrates that transmission experiments can be combined with real-time location data collection and processing procedures to create an effective framework for quantifying sociobehavioural effects on microparasite transmission.
Collapse
Affiliation(s)
- Trevor S. Farthing
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
| | - Daniel E. Dawson
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
| | - Mike W. Sanderson
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Hannah Seger
- Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Cristina Lanzas
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
| |
Collapse
|
7
|
Touloupou P, Finkenstädt B, Besser TE, French NP, Spencer SEF. Bayesian inference for multistrain epidemics with application to ESCHERICHIA COLI O157:H7 in feedlot cattle. Ann Appl Stat 2020. [DOI: 10.1214/20-aoas1366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
8
|
Socially engaged calves are more likely to be colonised by VTEC O157:H7 than individuals showing signs of poor welfare. Sci Rep 2020; 10:6320. [PMID: 32286399 PMCID: PMC7156447 DOI: 10.1038/s41598-020-63186-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/20/2020] [Indexed: 11/24/2022] Open
Abstract
In cattle herds, the transmission and persistence of VTEC O157:H7 (a serotype of verotoxin-producing Escherichia coli – known for its life threatening complications in humans) is dependent on a small proportion of cattle who become colonised and shed high numbers of the bacteria. Reducing the proportion of these animals is considered key for decreasing the prevalence of VTEC O157:H7. In this study, observations of calf behaviour and animal-based welfare indicators were used to explore individual risk factors and underlying drivers of colonisation in Swedish dairy calves. Interdependencies between variables led to three different approaches being used to visualize and explore the associations. Combining the results of all methods revealed similar patterns and suggest that healthy animals, actively grooming and interacting with others calves in the group have a higher risk of colonisation than small dairy calves in poor condition (diarrhoea, poor ruminal fill, poor body condition score and nasal discharge). This lends no support to the hypothesis that reduced welfare is a risk factor for VTEC O157:H7, but implies that individual differences in calf behaviour affect oral exposure to the bacteria so driving the risk of colonisation. This new finding has important implications for understanding of VTEC O157:H7 transmission within farms.
Collapse
|
9
|
Sites of persistence of Fusobacterium necrophorum and Dichelobacter nodosus: a paradigm shift in understanding the epidemiology of footrot in sheep. Sci Rep 2019; 9:14429. [PMID: 31594981 PMCID: PMC6783547 DOI: 10.1038/s41598-019-50822-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 09/05/2019] [Indexed: 01/09/2023] Open
Abstract
Sites of persistence of bacterial pathogens contribute to disease dynamics of bacterial diseases. Footrot is a globally important bacterial disease that reduces health and productivity of sheep. It is caused by Dichelobacter nodosus, a pathogen apparently highly specialised for feet, while Fusobacterium necrophorum, a secondary pathogen in footrot is reportedly ubiquitous on pasture. Two prospective longitudinal studies were conducted to investigate the persistence of D. nodosus and F. necrophorum in sheep feet, mouths and faeces, and in soil. Molecular tools were used to detect species, strains and communities. In contrast to the existing paradigm, F. necrophorum persisted on footrot diseased feet, and in mouths and faeces; different strains were detected in feet and mouths. D. nodosus persisted in soil and on diseased, but not healthy, feet; similar strains were detected on both healthy and diseased feet of diseased sheep. We conclude that D. nodosus and F. necrophorum depend on sheep for persistence but use different strategies to persist and spread between sheep within and between flocks. Elimination of F. necrophorum would be challenging due to faecal shedding. In contrast D. nodosus could be eliminated if all footrot-affected sheep were removed and fade out of D. nodosus occurred in the environment before re-infection of a foot.
Collapse
|
10
|
Fitzgerald SF, Beckett AE, Palarea-Albaladejo J, McAteer S, Shaaban S, Morgan J, Ahmad NI, Young R, Mabbott NA, Morrison L, Bono JL, Gally DL, McNeilly TN. Shiga toxin sub-type 2a increases the efficiency of Escherichia coli O157 transmission between animals and restricts epithelial regeneration in bovine enteroids. PLoS Pathog 2019; 15:e1008003. [PMID: 31581229 PMCID: PMC6776261 DOI: 10.1371/journal.ppat.1008003] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/25/2019] [Indexed: 02/06/2023] Open
Abstract
Specific Escherichia coli isolates lysogenised with prophages that express Shiga toxin (Stx) can be a threat to human health, with cattle being an important natural reservoir. In many countries the most severe pathology is associated with enterohaemorrhagic E. coli (EHEC) serogroups that express Stx subtype 2a. In the United Kingdom, phage type (PT) 21/28 O157 strains have emerged as the predominant cause of life-threatening EHEC infections and this phage type commonly encodes both Stx2a and Stx2c toxin types. PT21/28 is also epidemiologically linked to super-shedding (>103 cfu/g of faeces) which is significant for inter-animal transmission and human infection as demonstrated using modelling studies. We demonstrate that Stx2a is the main toxin produced by stx2a+/stx2c+ PT21/28 strains induced with mitomycin C and this is associated with more rapid induction of gene expression from the Stx2a-encoding prophage compared to that from the Stx2c-encoding prophage. Bacterial supernatants containing either Stx2a and/or Stx2c were demonstrated to restrict growth of bovine gastrointestinal organoids with no restriction when toxin production was not induced or prevented by mutation. Isogenic strains that differed in their capacity to produce Stx2a were selected for experimental oral colonisation of calves to assess the significance of Stx2a for both super-shedding and transmission between animals. Restoration of Stx2a expression in a PT21/28 background significantly increased animal-to-animal transmission and the number of sentinel animals that became super-shedders. We propose that while both Stx2a and Stx2c can restrict regeneration of the epithelium, it is the relatively rapid and higher levels of Stx2a induction, compared to Stx2c, that have contributed to the successful emergence of Stx2a+ E. coli isolates in cattle in the last 40 years. We propose a model in which Stx2a enhances E. coli O157 colonisation of in-contact animals by restricting regeneration and turnover of the colonised gastrointestinal epithelium. Enterohaemorrhagic E. coli (EHEC) O157 strains are found in cattle where they are asymptomatic, while human exposure can lead to severe symptoms including bloody diarrhoea and kidney damage due to the activity of Shiga toxin (Stx). The most serious symptoms in humans are associated with isolates that encode Stx subtype 2a. The advantage of these toxins in the animal reservoir is still not clear, however there is experimental evidence implicating Stx with increased bacterial adherence, immune modulation and suppression of predatory protozoa. In this study, the hypothesis that Stx2a is important for super-shedding and calf-to-calf transmission was tested by comparing excretion and transmission dynamics of E. coli O157 strains with and without Stx2a. While Stx2a did not alter excretion levels when calfs were orally challenge, it enabled colonisation of more in contact ‘sentinel’ animals in our transmission model. We show that Stx2a is generally induced more rapidly than Stx2c, resulting in increased levels of Stx2a expression. Both Stx2a and Stx2c were able to restrict cellular proliferation of epithelial cells in cultured bovine enteroids. Taken together, we propose that rapid production of Stx2a and its role in establishing E. coli O157 colonisation in the bovine gastrointestinal tract facilitate effective transmission and have led to its expansion in the cattle E. coli O157 population.
Collapse
Affiliation(s)
- Stephen F. Fitzgerald
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- Moredun Research Institute, Penicuik, United Kingdom
| | - Amy E. Beckett
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- Moredun Research Institute, Penicuik, United Kingdom
| | | | - Sean McAteer
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Sharif Shaaban
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Jason Morgan
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- Moredun Research Institute, Penicuik, United Kingdom
| | | | - Rachel Young
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Neil A. Mabbott
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - Liam Morrison
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
| | - James L. Bono
- United States Department of Agriculture, Agricultural Research Service, Nebraska, United States of America
| | - David L. Gally
- Division of Immunity and Infection, The Roslin Institute and R(D)SVS, The University of Edinburgh, Midlothian, United Kingdom
- * E-mail: (DLG); (TNM)
| | - Tom N. McNeilly
- Moredun Research Institute, Penicuik, United Kingdom
- * E-mail: (DLG); (TNM)
| |
Collapse
|
11
|
Touloupou P, Finkenstädt B, Spencer SEF. Scalable Bayesian Inference for Coupled Hidden Markov and Semi-Markov Models. J Comput Graph Stat 2019; 29:238-249. [PMID: 32939192 PMCID: PMC7455056 DOI: 10.1080/10618600.2019.1654880] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 12/28/2018] [Accepted: 07/17/2019] [Indexed: 12/02/2022]
Abstract
Bayesian inference for coupled hidden Markov models frequently relies on data augmentation techniques for imputation of the hidden state processes. Considerable progress has been made on developing such techniques, mainly using Markov chain Monte Carlo (MCMC) methods. However, as the dimensionality and complexity of the hidden processes increase some of these methods become inefficient, either because they produce MCMC chains with high autocorrelation or because they become computationally intractable. Motivated by this fact we developed a novel MCMC algorithm, which is a modification of the forward filtering backward sampling algorithm, that achieves a good balance between computation and mixing properties, and thus can be used to analyze models with large numbers of hidden chains. Even though our approach is developed under the assumption of a Markovian model, we show how this assumption can be relaxed leading to minor modifications in the algorithm. Our approach is particularly well suited to epidemic models, where the hidden Markov chains represent the infection status of an individual through time. The performance of our method is assessed on simulated data on epidemic models for the spread of Escherichia coli O157:H7 in cattle. Supplementary materials for this article are available online.
Collapse
|
12
|
Dawson DE, Keung JH, Napoles MG, Vella MR, Chen S, Sanderson MW, Lanzas C. Investigating behavioral drivers of seasonal Shiga-Toxigenic Escherichia Coli (STEC) patterns in grazing cattle using an agent-based model. PLoS One 2018; 13:e0205418. [PMID: 30304002 PMCID: PMC6179278 DOI: 10.1371/journal.pone.0205418] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/25/2018] [Indexed: 11/18/2022] Open
Abstract
The causes of seasonal variability in pathogen transmission are not well understood, and have not been comprehensively investigated. In an example for enteric pathogens, incidence of Escherichia coli O157 (STEC) colonization in cattle is consistently higher during warmer months compared to cooler months in various cattle production systems. However, actual mechanisms for this seasonality remain elusive. In addition, the influence of host (cattle) behavior on this pattern has not been thoroughly considered. To that end, we constructed a spatially explicit agent-based model that accounted for the effect of temperature fluctuations on cattle behavior (direct contact among cattle and indirect between cattle and environment), as well as its effect on pathogen survival in the environment. We then simulated the model in a factorial approach to evaluate the hypothesis that temperature fluctuations can lead to seasonal STEC transmission dynamics by influencing cattle aggregation, grazing, and drinking behaviors. Simulation results showed that higher temperatures increased the frequency at which cattle aggregated under shade in pasture, resulting in increased direct contact and transmission of STEC between individual cattle, and hence higher incidence over model simulations in the warm season. In contrast, increased drinking behavior during warm season was not an important transmission pathway. Although sensitivity analyses suggested that the relative importance of direct vs. indirect (environmental) pathways depend to upon model parameterization, model simulations indicated that factors influencing cattle aggregation, such as temperature, were likely strong drivers of transmission dynamics of enteric pathogens.
Collapse
Affiliation(s)
- Daniel E. Dawson
- Department of Pathobiology and Population Health, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
| | - Jocelyn H. Keung
- National Institute for Mathematical and Biological Synthesis (NIMBioS), Knoxville, Tennessee, United States of America
| | - Monica G. Napoles
- National Institute for Mathematical and Biological Synthesis (NIMBioS), Knoxville, Tennessee, United States of America
| | - Michael R. Vella
- National Institute for Mathematical and Biological Synthesis (NIMBioS), Knoxville, Tennessee, United States of America
| | - Shi Chen
- Department of Pathobiology and Population Health, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
- Department of Public Health Sciences, College of Health and Human Services, University of North Carolina Charlotte, Charlotte, North Carolina, United States of America
| | - Michael W. Sanderson
- Center for Outcomes Research and Epidemiology, Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | - Cristina Lanzas
- Department of Pathobiology and Population Health, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
| |
Collapse
|
13
|
Chapman LAC, Jewell CP, Spencer SEF, Pellis L, Datta S, Chowdhury R, Bern C, Medley GF, Hollingsworth TD. The role of case proximity in transmission of visceral leishmaniasis in a highly endemic village in Bangladesh. PLoS Negl Trop Dis 2018; 12:e0006453. [PMID: 30296295 PMCID: PMC6175508 DOI: 10.1371/journal.pntd.0006453] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/13/2018] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Visceral leishmaniasis (VL) is characterised by a high degree of spatial clustering at all scales, and this feature remains even with successful control measures. VL is targeted for elimination as a public health problem in the Indian subcontinent by 2020, and incidence has been falling rapidly since 2011. Current control is based on early diagnosis and treatment of clinical cases, and blanket indoor residual spraying of insecticide (IRS) in endemic villages to kill the sandfly vectors. Spatially targeting active case detection and/or IRS to higher risk areas would greatly reduce costs of control, but its effectiveness as a control strategy is unknown. The effectiveness depends on two key unknowns: how quickly transmission risk decreases with distance from a VL case and how much asymptomatically infected individuals contribute to transmission. METHODOLOGY/PRINCIPAL FINDINGS To estimate these key parameters, a spatiotemporal transmission model for VL was developed and fitted to geo-located epidemiological data on 2494 individuals from a highly endemic village in Mymensingh, Bangladesh. A Bayesian inference framework that could account for the unknown infection times of the VL cases, and missing symptom onset and recovery times, was developed to perform the parameter estimation. The parameter estimates obtained suggest that, in a highly endemic setting, VL risk decreases relatively quickly with distance from a case-halving within 90m-and that VL cases contribute significantly more to transmission than asymptomatic individuals. CONCLUSIONS/SIGNIFICANCE These results suggest that spatially-targeted interventions may be effective for limiting transmission. However, the extent to which spatial transmission patterns and the asymptomatic contribution vary with VL endemicity and over time is uncertain. In any event, interventions would need to be performed promptly and in a large radius (≥300m) around a new case to reduce transmission risk.
Collapse
Affiliation(s)
- Lloyd A. C. Chapman
- Zeeman Institute, University of Warwick, Coventry, UK
- School of Life Sciences, University of Warwick, Coventry, UK
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chris P. Jewell
- Centre for Health Informatics, Computing And Statistics, Lancaster University, Lancaster, UK
| | - Simon E. F. Spencer
- Zeeman Institute, University of Warwick, Coventry, UK
- Department of Statistics, University of Warwick, Coventry, UK
| | | | - Samik Datta
- Zeeman Institute, University of Warwick, Coventry, UK
- National Institute of Water and Atmospheric Research, Wellington, New Zealand
| | - Rajib Chowdhury
- National Institute of Preventive and Social Medicine (NIPSOM), Mohakhali, Dhaka, Bangladesh
- International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Caryn Bern
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA
| | - Graham F. Medley
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - T. Déirdre Hollingsworth
- Zeeman Institute, University of Warwick, Coventry, UK
- School of Life Sciences, University of Warwick, Coventry, UK
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| |
Collapse
|
14
|
The effect of transportation and lairage on faecal shedding and carcass contamination with Escherichia coli O157 and O26 in very young calves in New Zealand. Epidemiol Infect 2018; 146:1089-1100. [PMID: 29789035 DOI: 10.1017/s0950268818000973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The effect of transportation and lairage on the faecal shedding and post-slaughter contamination of carcasses with Escherichia coli O157 and O26 in young calves (4-7-day-old) was assessed in a cohort study at a regional calf-processing plant in the North Island of New Zealand, following 60 calves as cohorts from six dairy farms to slaughter. Multiple samples from each animal at pre-slaughter (recto-anal mucosal swab) and carcass at post-slaughter (sponge swab) were collected and screened using real-time PCR and culture isolation methods for the presence of E. coli O157 and O26 (Shiga toxin-producing E. coli (STEC) and non-STEC). Genotype analysis of E. coli O157 and O26 isolates provided little evidence of faecal-oral transmission of infection between calves during transportation and lairage. Increased cross-contamination of hides and carcasses with E. coli O157 and O26 between co-transported calves was confirmed at pre-hide removal and post-evisceration stages but not at pre-boning (at the end of dressing prior to chilling), indicating that good hygiene practices and application of an approved intervention effectively controlled carcass contamination. This study was the first of its kind to assess the impact of transportation and lairage on the faecal carriage and post-harvest contamination of carcasses with E. coli O157 and O26 in very young calves.
Collapse
|
15
|
Newell DG, La Ragione RM. Enterohaemorrhagic and other Shiga toxin-producing Escherichia coli (STEC): Where are we now regarding diagnostics and control strategies? Transbound Emerg Dis 2018; 65 Suppl 1:49-71. [PMID: 29369531 DOI: 10.1111/tbed.12789] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Indexed: 12/24/2022]
Abstract
Escherichia coli comprises a highly diverse group of Gram-negative bacteria and is a common member of the intestinal microflora of humans and animals. Generally, such colonization is asymptomatic; however, some E. coli strains have evolved to become pathogenic and thus cause clinical disease in susceptible hosts. One pathotype, the Shiga toxigenic E. coli (STEC) comprising strains expressing a Shiga-like toxin is an important foodborne pathogen. A subset of STEC are the enterohaemorrhagic E. coli (EHEC), which can cause serious human disease, including haemolytic uraemic syndrome (HUS). The diagnosis of EHEC infections and the surveillance of STEC in the food chain and the environment require accurate, cost-effective and timely tests. In this review, we describe and evaluate tests now in routine use, as well as upcoming test technologies for pathogen detection, including loop-mediated isothermal amplification (LAMP) and whole-genome sequencing (WGS). We have considered the need for improved diagnostic tools in current strategies for the control and prevention of these pathogens in humans, the food chain and the environment. We conclude that although significant progress has been made, STEC still remains an important zoonotic issue worldwide. Substantial reductions in the public health burden due to this infection will require a multipronged approach, including ongoing surveillance with high-resolution diagnostic techniques currently being developed and integrated into the routine investigations of public health laboratories. However, additional research requirements may be needed before such high-resolution diagnostic tools can be used to enable the development of appropriate interventions, such as vaccines and decontamination strategies.
Collapse
Affiliation(s)
- D G Newell
- Department of Pathology and Infectious Diseases, Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - R M La Ragione
- Department of Pathology and Infectious Diseases, Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, UK
| |
Collapse
|
16
|
Ahlstrom C, Muellner P, Lammers G, Jones M, Octavia S, Lan R, Heller J. Shiga Toxin-Producing Escherichia coli O157 Shedding Dynamics in an Australian Beef Herd. Front Vet Sci 2017; 4:200. [PMID: 29230401 PMCID: PMC5711783 DOI: 10.3389/fvets.2017.00200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 11/08/2017] [Indexed: 12/23/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) O157 is an important foodborne pathogen that can be transmitted to humans both directly and indirectly from the feces of beef cattle, its primary reservoir. Numerous studies have investigated the shedding dynamics of E. coli O157 by beef cattle; however, the spatiotemporal trends of shedding are still not well understood. Molecular tools can increase the resolution through the use of strain typing to explore transmission dynamics within and between herds and identify strain-specific characteristics that may influence pathogenicity and spread. Previously, the shedding dynamics and molecular diversity, through the use of multilocus variable number of tandem repeat analysis (MLVA) of STEC O157, were separately investigated in an Australian beef herd over a 9-month study period. Variation in shedding was observed over time, and 33 MLVA types were identified. The study presented here combines the two datasets previously published with an aim to clarify the relationship between epidemiological variables and strain types. Three major genetic clusters (GCs) were identified that were significantly associated with the location of the cattle in different paddocks. No significant association between GCs and individual cow was observed. Results from this molecular epidemiological study provide evidence for herd-level clonal replacement over time that may have been triggered by movement to a new paddock. In conclusion, this study has provided further insight into STEC O157 shedding dynamics and pathogen transmission. Knowledge gaps remain regarding the relationship of strain types and the shedding dynamics of STEC O157 by beef cattle that could be further clarified through the use of whole-genome sequencing.
Collapse
Affiliation(s)
| | | | - Geraldine Lammers
- School of Animal and Veterinary Science, Charles Sturt University, Wagga, NSW, Australia
| | - Meghan Jones
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sophie Octavia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jane Heller
- School of Animal and Veterinary Science, Charles Sturt University, Wagga, NSW, Australia
| |
Collapse
|
17
|
British Escherichia coli O157 in Cattle Study (BECS): to determine the prevalence of E. coli O157 in herds with cattle destined for the food chain. Epidemiol Infect 2017; 145:3168-3179. [PMID: 28925340 PMCID: PMC9148770 DOI: 10.1017/s0950268817002151] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Escherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166-0·325) and England & Wales (0·213, 95% CI 0·156-0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.
Collapse
|
18
|
Plowright RK, Manlove KR, Besser TE, Páez DJ, Andrews KR, Matthews PE, Waits LP, Hudson PJ, Cassirer EF. Age-specific infectious period shapes dynamics of pneumonia in bighorn sheep. Ecol Lett 2017; 20:1325-1336. [PMID: 28871636 DOI: 10.1111/ele.12829] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 04/23/2017] [Accepted: 07/23/2017] [Indexed: 01/21/2023]
Abstract
Superspreading, the phenomenon where a small proportion of individuals contribute disproportionately to new infections, has profound effects on disease dynamics. Superspreading can arise through variation in contacts, infectiousness or infectious periods. The latter has received little attention, yet it drives the dynamics of many diseases of critical public health, livestock health and conservation concern. Here, we present rare evidence of variation in infectious periods underlying a superspreading phenomenon in a free-ranging wildlife system. We detected persistent infections of Mycoplasma ovipneumoniae, the primary causative agent of pneumonia in bighorn sheep (Ovis canadensis), in a small number of older individuals that were homozygous at an immunologically relevant genetic locus. Interactions among age-structure, genetic composition and infectious periods may drive feedbacks in disease dynamics that determine the magnitude of population response to infection. Accordingly, variation in initial conditions may explain divergent population responses to infection that range from recovery to catastrophic decline and extirpation.
Collapse
Affiliation(s)
- Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, 109 Lewis Hall, Bozeman, MT, 59717, USA
| | - Kezia R Manlove
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 99164, USA
| | - Thomas E Besser
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 99164, USA
| | - David J Páez
- Department of Microbiology and Immunology, Montana State University, 109 Lewis Hall, Bozeman, MT, 59717, USA
| | - Kimberly R Andrews
- Department of Fish and Wildlife Sciences, University of Idaho, 875 Perimeter Drive MS 1136, Moscow, ID, 83844, USA
| | - Patrick E Matthews
- Oregon Department of Fish and Wildlife, 65495 Alder Slope Road, Enterprise, OR, 97828, USA
| | - Lisette P Waits
- Department of Fish and Wildlife Sciences, University of Idaho, 875 Perimeter Drive MS 1136, Moscow, ID, 83844, USA
| | - Peter J Hudson
- Center for Infectious Disease Dynamics, 201, Life Sciences Building, Pennsylvania State University, University Park, PA, 16802, USA
| | - E Frances Cassirer
- Idaho Department of Fish and Game, 3316 16th Street, Lewiston, ID, 83501, USA
| |
Collapse
|
19
|
Plowright RK, Parrish CR, McCallum H, Hudson PJ, Ko AI, Graham AL, Lloyd-Smith JO. Pathways to zoonotic spillover. Nat Rev Microbiol 2017; 15:502-510. [PMID: 28555073 PMCID: PMC5791534 DOI: 10.1038/nrmicro.2017.45] [Citation(s) in RCA: 533] [Impact Index Per Article: 76.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Zoonotic spillover, which is the transmission of a pathogen from a vertebrate animal to a human, presents a global public health burden but is a poorly understood phenomenon. Zoonotic spillover requires several factors to align, including the ecological, epidemiological and behavioural determinants of pathogen exposure, and the within-human factors that affect susceptibility to infection. In this Opinion article, we propose a synthetic framework for animal-to-human transmission that integrates the relevant mechanisms. This framework reveals that all zoonotic pathogens must overcome a hierarchical series of barriers to cause spillover infections in humans. Understanding how these barriers are functionally and quantitatively linked, and how they interact in space and time, will substantially improve our ability to predict or prevent spillover events. This work provides a foundation for transdisciplinary investigation of spillover and synthetic theory on zoonotic transmission.
Collapse
Affiliation(s)
- Raina K Plowright
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana 59717, USA
| | - Colin R Parrish
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA
| | - Hamish McCallum
- Griffith School of Environment, Griffith University, Brisbane, Queensland 4111, Australia
| | - Peter J Hudson
- Center for Infectious Disease Dynamics, Pennsylvania State University, State College, Pennsylvania 16802, USA
| | - Albert I Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut 06520-8034, USA
| | - Andrea L Graham
- Department of Ecology &Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA
| | - James O Lloyd-Smith
- Department of Ecology &Evolutionary Biology, University of California, Los Angeles, Los Angeles, California 90095-7239, USA; and at Fogarty International Center, National Institutes of Health, Bethesda, Maryland 20892-2220, USA
| |
Collapse
|
20
|
Haley BJ, Pettengill J, Gorham S, Ottesen A, Karns JS, Van Kessel JAS. Comparison of Microbial Communities Isolated from Feces of Asymptomatic Salmonella-Shedding and Non-Salmonella Shedding Dairy Cows. Front Microbiol 2016; 7:691. [PMID: 27313565 PMCID: PMC4887466 DOI: 10.3389/fmicb.2016.00691] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 04/26/2016] [Indexed: 01/06/2023] Open
Abstract
In the United States Salmonella enterica subsp. enterica serotypes Kentucky and Cerro are frequently isolated from asymptomatic dairy cows. However, factors that contribute to colonization of the bovine gut by these two serotypes have not been identified. To investigate associations between Salmonella status and bacterial diversity, as well as the diversity of the microbial community in the dairy cow hindgut, the bacterial and archaeal communities of fecal samples from cows on a single dairy farm were determined by high-throughput sequencing of 16S rRNA gene amplicons. Fecal grab samples were collected from two Salmonella-positive cows and two Salmonella-negative cows on five sampling dates (n = 20 cows), and 16S rRNA gene amplicons from these samples were sequenced on the Illumina MiSeq platform. A high level of alpha (within) and beta diversity (between) samples demonstrated that microbial profiles of dairy cow hindguts are quite diverse. To determine whether Salmonella presence, sampling year, or sampling date explained a significant amount of the variation in microbial diversity, we performed constrained ordination analyses (distance based RDA) on the unifrac distance matrix produced with QIIME. Results indicated that there was not a significant difference in the microbial diversity associated with Salmonella presence (P > 0.05), but there were significant differences between sampling dates and years (Pseudo-F = 2.157 to 4.385, P < 0.05). Based on these data, it appears that commensal Salmonella infections with serotypes Cerro and Kentucky in dairy cows have little or no association with changes in the abundance of major bacterial groups in the hindgut. Rather, our results indicated that temporal dynamics and other undescribed parameters associated with them were the most influential drivers of the differences in microbial diversity and community structure in the dairy cow hindgut.
Collapse
Affiliation(s)
- Bradd J Haley
- Environmental Microbial and Food Safety Laboratory, Beltsville Agricultural Research Center, U.S. Department of Agriculture, Agricultural Research Service Beltsville, MD, USA
| | - James Pettengill
- Division of Public Health Informatics and Analytics, Center for Food Safety and Nutrition, Office of Analytics and Outreach, U.S. Food and Drug Administration College Park, MD, USA
| | - Sasha Gorham
- Division of Microbiology, Center for Food Safety and Nutrition, Office of Regulatory Science, U.S. Food and Drug Administration College Park, MD, USA
| | - Andrea Ottesen
- Division of Microbiology, Center for Food Safety and Nutrition, Office of Regulatory Science, U.S. Food and Drug Administration College Park, MD, USA
| | - Jeffrey S Karns
- Environmental Microbial and Food Safety Laboratory, Beltsville Agricultural Research Center, U.S. Department of Agriculture, Agricultural Research Service Beltsville, MD, USA
| | - Jo Ann S Van Kessel
- Environmental Microbial and Food Safety Laboratory, Beltsville Agricultural Research Center, U.S. Department of Agriculture, Agricultural Research Service Beltsville, MD, USA
| |
Collapse
|
21
|
Slater N, Mitchell RM, Whitlock RH, Fyock T, Pradhan AK, Knupfer E, Schukken YH, Louzoun Y. Impact of the shedding level on transmission of persistent infections in Mycobacterium avium subspecies paratuberculosis (MAP). Vet Res 2016; 47:38. [PMID: 26925966 PMCID: PMC4772324 DOI: 10.1186/s13567-016-0323-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 02/01/2016] [Indexed: 11/21/2022] Open
Abstract
Super-shedders are infectious individuals that contribute a disproportionate amount of infectious pathogen load to the environment. A super-shedder host may produce up to 10,000 times more pathogens than other infectious hosts. Super-shedders have been reported for multiple human and animal diseases. If their contribution to infection dynamics was linear to the pathogen load, they would dominate infection dynamics. We here focus on quantifying the effect of super-shedders on the spread of infection in natural environments to test if such an effect actually occurs in Mycobacterium avium subspecies paratuberculosis (MAP). We study a case where the infection dynamics and the bacterial load shed by each host at every point in time are known. Using a maximum likelihood approach, we estimate the parameters of a model with multiple transmission routes, including direct contact, indirect contact and a background infection risk. We use longitudinal data from persistent infections (MAP), where infectious individuals have a wide distribution of infectious loads, ranging upward of three orders of magnitude. We show based on these parameters that the effect of super-shedders for MAP is limited and that the effect of the individual bacterial load is limited and the relationship between bacterial load and the infectiousness is highly concave. A 1000-fold increase in the bacterial contribution is equivalent to up to a 2-3 fold increase in infectiousness.
Collapse
Affiliation(s)
- Noa Slater
- Gonda Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
| | - Rebecca Mans Mitchell
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA.
- Department of Mathematics and Computer Science, Emory University, Atlanta, GA, USA.
| | - Robert H Whitlock
- New Bolton Center, University of Pennsylvania, Kennett Square, Philadelphia, PA, USA.
| | - Terry Fyock
- New Bolton Center, University of Pennsylvania, Kennett Square, Philadelphia, PA, USA.
| | - Abani Kumar Pradhan
- Department of Nutrition and Food Science, Center for Food Safety and Security Systems, University of Maryland, College Park, College Park, MD, USA.
| | | | - Ynte Hein Schukken
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA.
- GD Animal Health, Deventer, The Netherlands.
- Department of Animal Sciences, Wageningen University, Wageningen, The Netherlands.
| | - Yoram Louzoun
- Gonda Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.
- Department of Mathematics, Bar-Ilan University, Ramat Gan, Israel.
| |
Collapse
|