Modelling Marek's Disease Virus (MDV) infection: parameter estimates for mortality rate and infectiousness

Atkins, Katherine E.; Read, Andrew F.; Savill, Nicholas J.; Renz, Katrin; Walkden‐Brown, Stephen W.; Woolhouse, Mark

doi:10.1186/1746-6148-7-70

Cited by 26 publications

(44 citation statements)

References 31 publications

(49 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Several of our model parameters are already known from previous experiments. These include the rate of dust production as a function of bird age d ( τ ) (Atkins et al, 2013a), the incubation period of the virus (Islam and Walkden-Brown, 2007; Read et al, 2015), which is determined by β , and the mean transmission rate of the virus μ α (Atkins et al, 2011, 2013b). Placement dates, load out dates, and flock sizes were fixed at known values from the respective datasets being modeled.…”

Section: Methodsmentioning

confidence: 99%

Modeling Marek's disease virus transmission: A framework for evaluating the impact of farming practices and evolution

2018

View full text Add to dashboard Cite

Marek’s disease virus (MDV) is a pathogen of chickens whose control has twice been undermined by pathogen evolution. Disease ecology is believed to be the main driver of this evolution, yet mathematical models of MDV disease ecology have never been confronted with data to test their reliability. Here, we develop a suite of MDV models that differ in the ecological mechanisms they include. We fit these models with maximum likelihood using iterated filtering in ‘pomp’ to data on MDV concentration in dust collected from two commercial broiler farms. We find that virus dynamics are influenced by between-flock variation in host susceptibility to virus, shedding rate from infectious birds, and cleanout efficiency. We also find evidence that virus is reintroduced to farms approximately once per month, but we do not find evidence that virus sanitization rates vary between flocks. Of the models that survive model selection, we find agreement between parameter estimates and previous experimental data, as well as agreement between field data and the predictions of these models. Using the set of surviving models, we explore how changes to farming practices are predicted to influence MDV-associated condemnation risk (production losses at slaughter). By quantitatively capturing the mechanisms of disease ecology, we have laid the groundwork to explore the future trajectory of virus evolution.

show abstract

Section: Methodsmentioning

confidence: 99%

Modeling Marek's disease virus transmission: A framework for evaluating the impact of farming practices and evolution

2018

View full text Add to dashboard Cite

show abstract

“…We assume that there is a positive relationship between the transmission rate ðβÞ of the parasite and the extent of damage caused to the host, resulting in a loss of fecundity for infected individuals. Such relationships are typically used to study the evolution of virulence in lethal infections (29)(30)(31), and are supported by strong evidence from a number of systems (32,33). Few studies have directly looked for transmission-virulence relationships among parasites that reduce host fecundity rather than increase mortality, although Ebert et al (34) found a negative relationship between reproduction by a bacterial parasite (Pasteuria ramosa) and the fecundity of its host (Daphnia magna).…”

Section: Significancementioning

confidence: 99%

Coevolution of parasite virulence and host mating strategies

Ashby

Boots

2015

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Parasites are thought to play an important role in sexual selection and the evolution of mating strategies, which in turn are likely to be critical to the transmission and therefore the evolution of parasites. Despite this clear interdependence we have little understanding of parasite-mediated sexual selection in the context of reciprocal parasite evolution. Here we develop a general coevolutionary model between host mate preference and the virulence of a sexually transmitted parasite. We show when the characteristics of both the host and parasite lead to coevolutionarily stable strategies or runaway selection, and when coevolutionary cycling between high and low levels of host mate choosiness and virulence is possible. A prominent argument against parasites being involved in sexual selection is that they should evolve to become less virulent when transmission depends on host mating success. The present study, however, demonstrates that coevolution can maintain stable host mate choosiness and parasite virulence or indeed coevolutionary cycling of both traits. We predict that choosiness should vary inversely with parasite virulence and that both relatively long and short life spans select against choosy behavior in the host. The model also reveals that hosts can evolve different behavioral responses from the same initial conditions, which highlights difficulties in using comparative analysis to detect parasitemediated sexual selection. Taken as a whole, our results emphasize the importance of viewing parasite-mediated sexual selection in the context of coevolution.host-parasite coevolution | mate choice | virulence | transmission avoidance | sexually transmitted infection S ince Hamilton and Zuk (1) first proposed that parasitism may explain the existence of secondary sex traits such as the peacock's tail, there has been considerable interest in the role that parasites play in sexual selection and the evolution of mating strategies (2-19). A prominent theory, known as the transmissionavoidance hypothesis, posits that secondary sex traits, and more generally, mating strategies, have evolved to limit the risk of contracting an infection (10). Although this theory emphasizes the importance of parasites in determining mating strategies, it is clear that different mating strategies will have an impact on infectious disease transmission and therefore influence parasite evolution. However, despite this clear interdependence we lack a coevolutionary theory of mating strategies that captures reciprocal adaptations by both species.Sex can leave individuals at risk of infection due to sustained close contact with sexual partners or through the transfer of genetic material (20). Hence, sexually transmitted infections, which are common in both plants (21) and animals (22), are likely to be a key factor in the evolution of mating strategies. Furthermore, sexually transmitted infections typically exhibit different epidemiological dynamics (17, 23) and disease outcomes (e.g., sterility rather than mortality; ref. 22) to other in...

show abstract

“…Estas lesiones están influenciadas por la presencia de infiltrado linfocitario lo que ha demostrado que a medida que la cepa se hace más virulenta el infiltrado linfocitario es mayor lo que puede conducir a la atrofia del timo y la bursa; esta característica ha servido para prever que todas estas cepas han tenido una evolución continua en el tiempo para cambiar su virulencia 30,50,54,61 , lo que sugiere que los tres serotipos pueden desarrollar rápidamente características biológicas y moleculares alteradas, indicando que pueden existir mutaciones espontáneas en su genoma 15,16,17 .…”

Section: Virus De La Enfermedad De Marek Y Clasificación Patotípicaunclassified

“…El virus de la Enfermedad de Marek (VEM) es uno de los agentes infecciosos aviares con mayor impacto en la producción de pollo de engorde y gallina ponedora, la Enfermedad de Marek (EM) es causada por este agente y tiene gran importancia en muchos países ya que se pueden presentar decomisos y mortalidad que afectan la economía de la industria avícola 30 Las características genéticas y moleculares del VEM han sido evaluadas y documentadas a través publicaciones científicas, las cuales reportan en consenso la diversidad genética que poseen cada uno de los serotipos del virus, las características genéticas hacen que este virus tenga singulares estrategias en su replicación, las cuales afectan considerablemente la respuesta inmune del ave a la infección y la efectividad en controlar su infección y diseminación debido principalmente a la producción de interferones que actúan directamente sobre la respuesta inmune innata contra el virus 29,30 . Esto permite que el virus evolucione en el tiempo evitando su exposición al sistema inmune, impidiendo su eliminación del hospedero e incrementado su patogénesis 46,50 .…”

Section: Introductionunclassified

Virus de la Enfermedad de Marek: aproximación molecular al virus y respuesta inmune del hospedero

Toro

Rodríguez-Lecompte

2016

Ces. Med. Vet. Zootec.

View full text Add to dashboard Cite

Marek's disease virus affects dramatically the production of broiler chicken, hens breeding and commercial due to lost causes for carcass condemnation, presence of tumors and high mortality. Give them us derivatives by the VEM they affect significant economic losses in the poultry industry worldwide and impact the comprehensive management of poultry health and health in general. The genetic and molecular characteristics of the VEM highlight the diversity of the genome in each of the 3 serotypes of the virus; genes involved in pathogenicity, evasion of the immune response and replication strategies are consistent with the difficulty of their infection control. Viral latency and the pump of the immune response of the host, particularly the control of type I interferons, are the mechanism to help the perpetuation in the poultry and thus hamper their effective environmental control. All those conditions have allowed that the virus evolves to forms more virulent that with the use of the vaccines current does not provide a protection adequate against these; for this reason, it is necessary to reconsider current vaccination plans to improve the immune response of active type, particularly involving cell type, to control his evasion and control on the immune system. Keywords: Gallid Herpesvirus 2, Immune system, Interferon type 1, Marek's disease, Viral latency, Virulence. ResumenEl virus de la enfermedad de Marek afecta dramaticamente la producción de pollo de engorde, gallinas comerciales y reproductoras debido a las perdidas causas por decomisos en mataderos, presencia de tumores y alta mortalidad. Las daños derivados por el VEM repercuten en pérdidas económicas significativas en la industria avícola mundial e impactan el manejo integral de la sanidad y salud avícola en general. Las característi-cas genéticas y moleculares del VEM resaltan la diversidad genómica en cada uno de los tres serotipos del virus; genes involucrados en sus estrategias de replicación, patogenicidad y evasión de la respuesta inmune son consistentes con la dificultad del control de su infección. La latencia viral

show abstract

Modelling Marek's Disease Virus (MDV) infection: parameter estimates for mortality rate and infectiousness

Cited by 26 publications

References 31 publications

Modeling Marek's disease virus transmission: A framework for evaluating the impact of farming practices and evolution

Modeling Marek's disease virus transmission: A framework for evaluating the impact of farming practices and evolution

Coevolution of parasite virulence and host mating strategies

Virus de la Enfermedad de Marek: aproximación molecular al virus y respuesta inmune del hospedero

Contact Info

Product

Resources

About