scholarly journals Integrating ecology and epidemiology using individual-based multi-species networks

2014 ◽  
Author(s):  
Shai Pilosof ◽  
Serge Morand ◽  
Boris R Krasnov ◽  
Charles L Nunn
Keyword(s):  
Ecological Factors ◽  
Single Species ◽  
Parasite Transmission ◽  
Species Identity ◽  
Interaction Structure ◽  
Relative Contribution ◽  
Contact Patterns ◽  
Individual Traits ◽  
Individual Contact ◽  
Host Parasite

Parasite transmission in host communities is a function of ecological factors that influence interspecific contacts and contact patterns within species. These two levels are studied with different kinds of networks – ecological networks and individual contact networks – and the integration of these levels is essential for effective understanding of parasite transmission. We combined these approaches by creating epidemiological networks based on parasite sharing from individual-based ecological host-parasite networks. We compared multi- to single-species networks to investigate the drivers of helminth infection in wild individual rodents of South-east Asia. Network modularity was higher in the multi-species than in the single-species networks. Phylogeny affected affiliation of individuals to modules. The importance of individuals differed between multi- and single-species networks, with species identity and individual traits influencing their position in the networks. Simulations revealed that a novel parasite spreads more slowly in multi- than in single-species networks and that this depended on network structure. Although the relative contribution of within- vs. between-species transmission rates to disease dynamics is important, using multi-host epidemiological networks improves our understanding of parasite dynamics as it further considers interaction structure between individuals.

scholarly journals Potential parasite transmission in multi-host networks based on parasite sharing

2014 ◽  
Author(s):  
Shai Pilosof ◽  
Serge Morand ◽  
Boris R Krasnov ◽  
Charles L Nunn
Keyword(s):  
Host Species ◽  
Single Species ◽  
Individual Characteristics ◽  
Parasite Transmission ◽  
Species Identity ◽  
Transmission Networks ◽  
Single Host ◽  
Transmission Pathways ◽  
Host Parasite ◽  
Parasite Dynamics

Epidemiological networks are commonly used to explore dynamics of parasite transmission among individuals in a population of a given host species. However, many parasites infect multiple host species, and thus multi-host networks may offer a better framework for investigating parasite dynamics. We investigated the factors that influence parasite sharing – and thus potential transmission pathways – among rodent hosts in Southeast Asia. We focused on differences between networks of a single host species and networks that involve multiple host species. In host-parasite networks, modularity (the extent to which the network is divided to subgroups composed of individuals that interact more among themselves than with individuals outside the subgroup) was higher in the multi-species than in the single-species networks. This suggests that phylogeny affects patterns of parasite sharing, which was confirmed in analyses showing that it predicted affiliation of individuals to modules. We then constructed “potential transmission networks” based on the host-parasite networks, in which edges depict the number of parasites shared between a pair of individuals. The centrality of individuals in these networks differed between multi- and single-species networks, with species identity and individual characteristics influencing their position in the networks. Simulations further revealed that parasite dynamics differed between multi- and single-species networks. We conclude that multi-host networks based on parasite sharing can provide new insights into the potential for transmission among hosts in an ecological community. In addition, the factors that determine the nature of parasite sharing (i.e. structure of the host-parasite network) may impact transmission patterns.

scholarly journals Potential parasite transmission in multi-host networks based on parasite sharing

2014 ◽  
Author(s):  
Shai Pilosof ◽  
Serge Morand ◽  
Boris R Krasnov ◽  
Charles L Nunn
Keyword(s):  
Host Species ◽  
Single Species ◽  
Individual Characteristics ◽  
Parasite Transmission ◽  
Species Identity ◽  
Transmission Networks ◽  
Single Host ◽  
Transmission Pathways ◽  
Host Parasite ◽  
Parasite Dynamics

Epidemiological networks are commonly used to explore dynamics of parasite transmission among individuals in a population of a given host species. However, many parasites infect multiple host species, and thus multi-host networks may offer a better framework for investigating parasite dynamics. We investigated the factors that influence parasite sharing – and thus potential transmission pathways – among rodent hosts in Southeast Asia. We focused on differences between networks of a single host species and networks that involve multiple host species. In host-parasite networks, modularity (the extent to which the network is divided to subgroups composed of individuals that interact more among themselves than with individuals outside the subgroup) was higher in the multi-species than in the single-species networks. This suggests that phylogeny affects patterns of parasite sharing, which was confirmed in analyses showing that it predicted affiliation of individuals to modules. We then constructed “potential transmission networks” based on the host-parasite networks, in which edges depict the number of parasites shared between a pair of individuals. The centrality of individuals in these networks differed between multi- and single-species networks, with species identity and individual characteristics influencing their position in the networks. Simulations further revealed that parasite dynamics differed between multi- and single-species networks. We conclude that multi-host networks based on parasite sharing can provide new insights into the potential for transmission among hosts in an ecological community. In addition, the factors that determine the nature of parasite sharing (i.e. structure of the host-parasite network) may impact transmission patterns.

Syntaxonomic changes in the plant cover of meadow steppe in the «Mikhailovskaya Tselina» reserve (Sumy Region, Ukraine)

2006 ◽  
pp. 43-57 ◽  
Author(s):  
H. N. Lysenko ◽  
I. A. Korotchenko
Keyword(s):  
Nature Reserve ◽  
Plant Cover ◽  
Ecological Factors ◽  
Single Species ◽  
Meadow Steppe ◽  
Total Species

Changes in the set of syntaxa have been traced for the plant cover of the «Mikhaylovskaya Tselina» meadow-steppe (an isolated part of the Ukrainian Steppe Nature Reserve, Sumy Region, Ukraine) with the help of the Braun-Blanquet approach. The area vegetation syntaxa prodromus includes 2 classes, 2 rders, 3 alliances, 9 associations, and 6 subasso­ciations, 2 of the latter described anew. The plant cover is highly dynamic and undergoes expressed meso­phytization, especially within the area where strict protection has been maintained since 1961. Amplitudes of the principal ecological factors and also peculiarities of their shift under exogenic regulation are determined with the help of the method of synecological phyto­indication (i. e. not single species but total species sets of communities serve as indicators). The essential transformations of the reserve meadow steppes are probably caused by the «insular» character of the reserve, its small size, also by the poorness of the set of natural grazers and hence the inadequacy of regulation by means of mowing.

Further Studies of Lung Parasites (Nematoda) From Australian Marsupials.

1984 ◽  
Vol 32 (2) ◽  
pp. 283 ◽  
Author(s):  
DM Spratt
Keyword(s):  
New South ◽  
Single Species ◽  
Northern Territory ◽  
Trichosurus Vulpecula ◽  
Monotypic Genus ◽  
New Host ◽  
Phascolarctos Cinereus ◽  
Histological Sections ◽  
South Wales ◽  
Host Parasite

Seven new taxa in two families of metastrongyloid nematodes are described from the lungs of five host species belonging to the Dasyuridae, Phalangeridae and Macropodidae. Filaroides (Filaroides) athertonensis, sp. nov., (Filaroididae) is described from Thylogale stigmatica Gould in north Queensland. The following species of Marsupostrongylus Mackerras & Sandars, 1953, (Angiostrongylidae) are described as new: M. parallelus, sp. nov., from Satanellus hallucatus (Could) in the Northern Territory; M. pseudominesi, sp. nov., from Trichosurus vulpecula johnstonii (Ramsay) in north Queensland; M. vandiemeni, sp. nov., from macro pus rufogriseus rufogriseus (Desmarest) in Tasmania; and M. wallabiae, sp. nov., from Wallabia bicolor (Desmarest) and Macropus rufogriseus banksianus (Quoy & Gaimard) in New South Wales. To the formerly monotypic genus Filostrongylus Mackenas, 1955, (Angiostrongylidae) is added F. tridendriticus, sp. nov., described from Trichosurus vulpecula (Kerr) in Tasmania. The genus Cosmostrongylus (Angiostrongylidae) is described as new, with a single species C. conspectus, sp. nov., from Thylogale stigmatica Gould in north Queensland. Durikainema sp. (Muspiceoidea: Robertdollfusidae) is diagnosed in histological sections of the lungs of Phascolarctos cinereus (Goldfuss), Macropus agilis (Could) and M. giganteus Shaw. Keys to the genera of lung parasites and to all species of Filaroides, Marsupostrongylus and Filostrongylus known from Australian marsupials, new host and new geographic records of known taxa, and a host-parasite list of lung parasites of Australian marsupials, including those known only from histological sections of lung tissue, are provided.

scholarly journals Gene by environmental interactions affecting oxidative phosphorylation and thermal sensitivity

2016 ◽  
Vol 311 (1) ◽  
pp. R157-R165 ◽  
Author(s):  
Tara Z. Baris ◽  
Pierre U. Blier ◽  
Nicolas Pichaud ◽  
Douglas L. Crawford ◽  
Marjorie F. Oleksiak
Keyword(s):  
Oxidative Phosphorylation ◽  
Complex I ◽  
Thermal Sensitivity ◽  
Single Species ◽  
Mitochondrial Haplotype ◽  
Acclimation Temperature ◽  
Atp Production ◽  
Acute Response ◽  
Relative Contribution ◽  
Mitochondrial Genotype

The oxidative phosphorylation (OxPhos) pathway is responsible for most aerobic ATP production and is the only metabolic pathway with proteins encoded by both nuclear and mitochondrial genomes. In studies examining mitonuclear interactions among distant populations within a species or across species, the interactions between these two genomes can affect metabolism, growth, and fitness, depending on the environment. However, there is little data on whether these interactions impact natural populations within a single species. In an admixed Fundulus heteroclitus population with northern and southern mitochondrial haplotypes, there are significant differences in allele frequencies associated with mitochondrial haplotype. In this study, we investigate how mitochondrial haplotype and any associated nuclear differences affect six OxPhos parameters within a population. The data demonstrate significant OxPhos functional differences between the two mitochondrial genotypes. These differences are most apparent when individuals are acclimated to high temperatures with the southern mitochondrial genotype having a large acute response and the northern mitochondrial genotype having little, if any acute response. Furthermore, acute temperature effects and the relative contribution of Complex I and II depend on acclimation temperature: when individuals are acclimated to 12°C, the relative contribution of Complex I increases with higher acute temperatures, whereas at 28°C acclimation, the relative contribution of Complex I is unaffected by acute temperature change. These data demonstrate a complex gene by environmental interaction affecting the OxPhos pathway.

scholarly journals The role of host phenology for parasite transmission

2020 ◽  
Author(s):  
Hannelore MacDonald ◽  
Erol Akçay ◽  
Dustin Brisson
Keyword(s):  
Species Interactions ◽  
Activity Period ◽  
Parasite Transmission ◽  
Nymphal Stage ◽  
Mouse Population ◽  
Tick Activity ◽  
Contact Rates ◽  
Wide Range ◽  
Host Phenology ◽  
Host Parasite

Abstract Phenology is a fundamental determinant of species distributions, abundances, and interactions. In host–parasite interactions, host phenology can affect parasite fitness due to the temporal constraints it imposes on host contact rates. However, it remains unclear how parasite transmission is shaped by the wide range of phenological patterns observed in nature. We develop a mathematical model of the Lyme disease system to study the consequences of differential tick developmental-stage phenology for the transmission of B. burgdorferi. Incorporating seasonal tick activity can increase B. burgdorferi fitness compared to continuous tick activity but can also prevent transmission completely. B. burgdorferi fitness is greatest when the activity period of the infectious nymphal stage slightly precedes the larval activity period. Surprisingly, B. burgdorferi is eradicated if the larval activity period begins long after the end of nymphal activity due to a feedback with mouse population dynamics. These results highlight the importance of phenology, a common driver of species interactions, for the fitness of a parasite.

Heterogeneities in water contact patterns and the epidemiology of schistosoma haematobium

Parasitology ◽  
1991 ◽  
Vol 103 (3) ◽  
pp. 363-370 ◽  
Author(s):  
S. K. Chandiwana ◽  
M. E. J. Woolhouse
Keyword(s):  
Time Of Day ◽  
Limited Information ◽  
Water Contact ◽  
Contact Rates ◽  
Contact Patterns ◽  
Contact Behaviour ◽  
Control Programmes ◽  
The Mean ◽  
Individual Contact ◽  
Age And Sex

Variations in the amount of water contact made by individuals and in the amount of water contact made at different sites may have significant impacts on patterns of human schistosome infection. Previous studies have reported variations in the rate of water contact and differences in the sites used between age/sex classes, but there is limited information on variations in individual water contact behaviour. In this paper we report and analyse observations of essentially all water contacts made over a two week period by all individuals in a rural community in eastern Zimbabwe. The mean rate of water contact was 0.43 contacts/person/day. These data were over-dispersed, ranging from zero to 3.3 contacts/person/day; 90% of contacts were made by only 37% of the population. Contact rates were related to age (highest in 8 to 10-year-olds) but not sex, with substantial variation unaccounted for by these variables. Age and sex classes differed in types of water-related activities and the time of day of contact. A greater diversity of sites was used by children than by adults and by males than by females. Individual contact rates were correlated with intensities of infection, although the risk of infection per contact was estimated to be highest in 2 to 4-year-old children and higher for males than females. Five contact sites were used during the study period, with more than 50% of contacts occurring at just 2 sites. Different age and sex classes used different sites and there were additional site-related differences in types of activity and the time of day of use. The implications of these water contact patterns for schistosome epidemiology are discussed. In particular the results provide strong quantitative support for control programmes aimed at heavily used sites (e.g. focal mollusciciding) or at the minority of individuals making most water contacts (e.g. targeted chemotherapy).

Synchronization of host-parasite cycles by means of diapause: host influence and parasite response to involuntary host shifting

Parasitology ◽  
2008 ◽  
Vol 135 (11) ◽  
pp. 1343-1352 ◽  
Author(s):  
M. A. CALERO-TORRALBO ◽  
F. VALERA
Keyword(s):  
Ecological Factors ◽  
Susceptible Host ◽  
Incubation Periods ◽  
Carnus Hemapterus ◽  
Merops Apiaster ◽  
The Mean ◽  
Rate Of Emergence ◽  
The One ◽  
Host Parasite ◽  
Host Influence

SUMMARYMany parasites require synchronization of their infective phases with the appearance of susceptible host individuals and, for many species, diapause is one of the mechanisms contributing to such coincidence. A variety of ecological factors, like changes in host temperature produced by involuntary host shifting (substitution of the usual host by an infrequent one), can modify host-parasite synchronization of diapausing ectoparasites of endothermic species. To understand the influence of host shifting on the mechanisms of parasite synchronization, we conducted experiments using the system formed by the ectoparasitic fly Carnus hemapterus and its avian hosts. We simulated the occurrence of the usual host and natural cases of host shifting by exposing overwintering carnid pupae from Bee-eater nests (Merops apiaster) to the earlier incubation periods of two Carnus host species that frequently reoccupy Bee-eater nests. Pupae exposed to host shifting treatments advanced the mean date of emergence and produced an earlier and faster rate of emergence in comparison with pupae exposed both to the control (absence of any host) and Bee-eater treatments. The effect was more evident for the treatment resembling the host with the most dissimilar phenology to the one of the usual host. Our results show that host temperature is an environmental cue used by this nest-dwelling haematophagous ectoparasite and reveal that Carnus hemapterus has some potential to react to involuntary host shifting by means of plasticity in the termination of diapause.

Contrasting and complex evolutionary histories within the terapontid grunter genus Hephaestus revealed by nuclear and mitochondrial genes

2016 ◽  
Vol 67 (12) ◽  
pp. 1813 ◽  
Author(s):  
Bradley J. Pusey ◽  
Andrew Bentley ◽  
Damien Burrows ◽  
Colton Perna ◽  
Aaron Davis ◽  
...  
Keyword(s):  
Nuclear Gene ◽  
Single Species ◽  
Eastern Coast ◽  
Cryptic Speciation ◽  
Species Identity ◽  
Systematic Revision ◽  
Widespread Species ◽  
Mitochondrial Data ◽  
Wet Tropics ◽  
Gene Data

Contrasting evolutionary histories may be revealed by mitochondrial and nuclear information. Divergent New Guinean and eastern and western Australian lineages of Hephaestus fuliginosus (sooty grunter) were detected using mitochondrial data, with the extent of divergence consistent with cryptic speciation events. However, this phylogeographic pattern was not supported by nuclear gene data, and evidence for cryptic speciation appears driven almost entirely by introgression between H. fuliginosus and congeners on the periphery of its distribution (e.g. with H. tulliensis, H. jenkinsi or H. roemeri). Hephaestus fuliginosus is a single species with a complex evolutionary history. Introgression on the eastern coast is consistent with transfer of the mitochondrial genome of the resident species (H. tulliensis) to the invading species (H. fuliginosus) and may have provided the metabolic capacity for H. fuliginosus to spread into the cooler rainforest environment of the Wet Tropics region. Mitochondrial and nuclear analyses both identified the genus Hephaestus as polyphyletic with H. carbo and H. habbemai placed in a clade with Leiopotherapon unicolor and Amniataba percoides. The present study demonstrated the need to consider a variety of genetic information when assessing species identity in a widespread species and the need for a systematic revision of the genus and family as a whole.

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