scholarly journals The phylogenetic range of bacterial and viral pathogens of vertebrates

2019 ◽  
Author(s):  
Liam P. Shaw ◽  
Alethea D. Wang ◽  
David Dylus ◽  
Magda Meier ◽  
Grega Pogacnik ◽  
...  
Keyword(s):  
Host Range ◽  
Host Species ◽  
Research Effort ◽  
Quantitative Measure ◽  
Zoonotic Potential ◽  
Phylogenetic Distance ◽  
Human Pathogens ◽  
Viral Pathogens ◽  
Host Pathogen ◽  
Single Host

AbstractMany major human pathogens are multi-host pathogens, able to infect other vertebrate species. Describing the general patterns of host-pathogen associations across pathogen taxa is therefore important to understand risk factors for human disease emergence. However, there is a lack of comprehensive curated databases for this purpose, with most previous efforts focusing on viruses. Here, we report the largest manually compiled host-pathogen association database, covering 2,595 bacteria and viruses infecting 2,656 vertebrate hosts. We also build a tree for host species using nine mitochondrial genes, giving a quantitative measure of the phylogenetic similarity of hosts. We find that the majority of bacteria and viruses are specialists infecting only a single host species, with bacteria having a significantly higher proportion of specialists compared to viruses. Conversely, multi-host viruses have a more restricted host range than multi-host bacteria. We perform multiple analyses of factors associated with pathogen richness per host species and the pathogen traits associated with greater host range and zoonotic potential. We show that factors previously identified as important for zoonotic potential in viruses—such as phylogenetic range, research effort, and being vector-borne—are also predictive in bacteria. We find that the fraction of pathogens shared between two hosts decreases with the phylogenetic distance between them. Our results suggest that host phylogenetic similarity is the primary factor for host-switching in pathogens.

scholarly journals Phylogenetic aggregation increases zoonotic potential of mammalian viruses

2019 ◽  
Vol 15 (12) ◽  
pp. 20190668 ◽  
Author(s):  
Andrew W. Park
Keyword(s):  
Host Range ◽  
Host Species ◽  
Phylogenetic Relationships ◽  
Zoonotic Potential ◽  
Phylogenetic Distance ◽  
Wild Mammals ◽  
High Fitness

While many viruses of wild mammals are capable of infecting humans, our understanding of zoonotic potential is incomplete. Viruses vary in their degree of generalism, characterized by the phylogenetic relationships of their hosts. Among the dimensions of this phylogenetic landscape, phylogenetic aggregation, which is largely overlooked in studies of parasite host range, emerges in this study as a key predictor of zoonotic status of viruses. Plausibly, viruses that exhibit aggregation, typified by discrete clusters of related host species, may (i) have been able to close the phylogenetic distance to humans, (ii) have subsequently acquired an epidemiologically relevant host and (iii) exhibit relatively high fitness in realized host communities, which are frequently phylogenetically aggregated. These mechanisms associated with phylogenetic aggregation may help explain why correlated fundamental traits, such as the ability of viruses to replicate in the cytoplasm, are associated with zoonoses.

Specificity

2021 ◽  
pp. 159-182
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Host Range ◽  
Host Species ◽  
Cross Reactivity ◽  
Geographical Range ◽  
Immune Memory ◽  
Phylogenetic Distance ◽  
Immune Priming ◽  
Number Of Factors ◽  
Ecological Filter ◽  
Immune Defences

infect a number of host species. This host range is given by an ecological filter (the possibility of encounter) and a physiological one (the capacity of establishing an infection). Host ranges typically are right-skewed, with most parasites infecting only a few, but few infecting very many hosts. There is no universally valid hypothesis that explains host range. However, a number of factors contribute to host range, such as geographical range, phylogenetic distance, host predictability, and parasite virulence. Specificity and cross-reactivity of immune defences are important mechanisms. Moreover, immune memory is based on specificity; transgenerational immune priming protects offspring when parents have already been exposed to the same or similar parasites.

Single-host pathogen effects on mortality and behavioral responses to predators in salamanders (Urodela: Ambystomatidae)

2004 ◽  
Vol 82 (9) ◽  
pp. 1477-1483 ◽  
Author(s):  
Matthew J Parris ◽  
Alison Davis ◽  
James P Collins
Keyword(s):  
Activity Level ◽  
Ambystoma Tigrinum ◽  
Predator Prey ◽  
Host Behavior ◽  
Anax Junius ◽  
Tiger Salamanders ◽  
Thermal Maximum ◽  
Antipredator Responses ◽  
Host Pathogen ◽  
Single Host

Pathogens can alter host behavior and affect the outcome of predator-prey interactions. Acute phase responses of hosts (e.g., a change in activity level or behavioral fever) often signal an infection, but the ecological consequences of host behavioral changes largely are unexplored, particularly for directly transmitted (i.e., single-host) pathogens. We performed three experiments to test the hypothesis that a pathogen, Ambystoma tigrinum virus (ATV), alters host behavior of Sonoran tiger salamanders (Ambystoma tigrinum stebbinsi Lowe, 1954) and enhances predation. In the first experiment, salamander larvae exposed to ATV experienced 48% lower mortality from dragonfly Anax junius (Drury, 1773) larvae than those in controls. Second, uninfected and infected larvae exposed to the nonlethal (caged) presence of predators did not significantly differ in their distance from the predator. Infected salamanders significantly increased their activity level relative to those in controls in predator-free conditions. Finally, ATV-infected larvae preferred significantly warmer temperatures than uninfected larvae, but larvae reared at the thermal maximum for the virus all died. High host activity level yet retention of effective antipredator responses likely benefits ATV because this single-host pathogen relies on host survival for transmission. Preference for warmer temperatures may be associated with the host response to pathogens and may help fight infection.

scholarly journals AFM-Based Correlative Microscopy Illuminates Human Pathogens

2021 ◽  
Vol 11 ◽  
Author(s):  
Supriya V. Bhat ◽  
Jared D. W. Price ◽  
Tanya E. S. Dahms
Keyword(s):  
Optical Microscopy ◽  
Disease Transmission ◽  
Fitness Landscape ◽  
Host Cells ◽  
Full Potential ◽  
Correlative Microscopy ◽  
Human Pathogens ◽  
Host Pathogen Interactions ◽  
Host Pathogen ◽  
The Many

Microbes have an arsenal of virulence factors that contribute to their pathogenicity. A number of challenges remain to fully understand disease transmission, fitness landscape, antimicrobial resistance and host heterogeneity. A variety of tools have been used to address diverse aspects of pathogenicity, from molecular host-pathogen interactions to the mechanisms of disease acquisition and transmission. Current gaps in our knowledge include a more direct understanding of host-pathogen interactions, including signaling at interfaces, and direct phenotypic confirmation of pathogenicity. Correlative microscopy has been gaining traction to address the many challenges currently faced in biomedicine, in particular the combination of optical and atomic force microscopy (AFM). AFM, generates high-resolution surface topographical images, and quantifies mechanical properties at the pN scale under physiologically relevant conditions. When combined with optical microscopy, AFM probes pathogen surfaces and their physical and molecular interaction with host cells, while the various modes of optical microscopy view internal cellular responses of the pathogen and host. Here we review the most recent advances in our understanding of pathogens, recent applications of AFM to the field, how correlative AFM-optical microspectroscopy and microscopy have been used to illuminate pathogenicity and how these methods can reach their full potential for studying host-pathogen interactions.

Host Range of Some Eucalypt Mycorrhizal Fungi

1973 ◽  
Vol 21 (1) ◽  
pp. 103 ◽  
Author(s):  
GA Chilvers
Keyword(s):  
Host Range ◽  
Host Species ◽  
Mycorrhizal Fungi ◽  
Wide Range ◽  
Genus Eucalyptus

Various fungi are shown to form mycorrhizas with a wide range of host species within the genus Eucalyptus. In general, the same fungi do not appear to be capable of forming mycorrhizas with Pinus.

Genetic variation in the mitochondrial cytochrome c oxidase subunit 1 within Progamotaenia festiva (Cestoda: Anoplocephalidae) from macropodid marsupials

Parasitology ◽  
2007 ◽  
Vol 134 (10) ◽  
pp. 1465-1476 ◽  
Author(s):  
I. BEVERIDGE ◽  
S. SHAMSI ◽  
M. HU ◽  
N. B. CHILTON ◽  
R. B. GASSER
Keyword(s):  
Genetic Variation ◽  
Host Species ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Enzyme Electrophoresis ◽  
Single Strand Conformational Polymorphism ◽  
Oxidase Subunit ◽  
Single Host ◽  
Distinct Sequence ◽  
Sequence Types

SUMMARYGenetic variation was examined in the anoplocephalid cestode Progamotaenia festiva, from Australian marsupials, in order to test the hypothesis that P. festiva, is a complex of sibling species and to assess the extent of host switching reported previously based on multilocus enzyme electrophoresis (MEE). Polymerase chain reaction (PCR)-based single-strand conformational polymorphism (SSCP) was used for the analysis of sequence variation in the cytochrome c oxidase subunit 1 (cox1) gene among 179 specimens of P. festiva (identified based on morphology and predilection site in the host) from 13 different host species, followed by selective DNA sequencing. Fifty-three distinct sequence types (haplotypes) representing all specimens were defined. Phylogenetic analyses of these sequence data (utilizing maximum parsimony and neighbour-joining methods) revealed 12 distinct clades. Other heterologous species, P. ewersi and P. macropodis, were used as outgroups and the remaining bile-duct inhabiting species, P. diaphana and P. effigia, were included in the analysis for comparative purposes. The latter 2 species were nested within the clades representing P. festiva. Most clades of P. festiva identified were restricted to a single host species; one clade primarily in Macropus robustus was also found in the related host species M. antilopinus in an area of host sympatry; another clade occurring primarily in M. robustus occurred also in additional kangaroo species, M. rufus and M. dorsalis. High levels of genetic divergence, the existence of distinct clades and their occurrence in sympatry provide support for the hypothesis that P. festiva represents a complex of numerous species, most of which, but not all, are host specific. Three distinct clades of cestodes were found within a single host, M. robustus, but there was no evidence of within-host speciation.

scholarly journals Evidence for Multiple Recent Host Species Shifts among the Ranaviruses (Family Iridoviridae)

2009 ◽  
Vol 84 (6) ◽  
pp. 2636-2647 ◽  
Author(s):  
James K. Jancovich ◽  
Michel Bremont ◽  
Jeffrey W. Touchman ◽  
Bertram L. Jacobs
Keyword(s):  
Host Species ◽  
Fish Pathogen ◽  
Necrosis Virus ◽  
Viral Pathogens ◽  
Host Shifts ◽  
Fish Virus ◽  
New Hosts ◽  
Australian Fish ◽  
Species Shifts

ABSTRACT Members of the genus Ranavirus (family Iridoviridae) have been recognized as major viral pathogens of cold-blooded vertebrates. Ranaviruses have been associated with amphibians, fish, and reptiles. At this time, the relationships between ranavirus species are still unclear. Previous studies suggested that ranaviruses from salamanders are more closely related to ranaviruses from fish than they are to ranaviruses from other amphibians, such as frogs. Therefore, to gain a better understanding of the relationships among ranavirus isolates, the genome of epizootic hematopoietic necrosis virus (EHNV), an Australian fish pathogen, was sequenced. Our findings suggest that the ancestral ranavirus was a fish virus and that several recent host shifts have taken place, with subsequent speciation of viruses in their new hosts. The data suggesting several recent host shifts among ranavirus species increase concern that these pathogens of cold-blooded vertebrates may have the capacity to cross numerous poikilothermic species barriers and the potential to cause devastating disease in their new hosts.

Flaviviruses excluding dengue

2020 ◽  
pp. 830-845
Author(s):  
Shannan Lee Rossi ◽  
Nikos Vasilakis
Keyword(s):  
Japanese Encephalitis Virus ◽  
Host Range ◽  
Yellow Fever ◽  
Japanese Encephalitis ◽  
Human Infection ◽  
Virus Species ◽  
Human Pathogens ◽  
West Nile ◽  
The Family ◽  
Large Host

The family Flaviviridae currently consists of four recognized genera: Flavivirus, Pestivirus, Hepacivirus, and Pegivirus. Although members of the family have a large host range that includes both vertebrates and invertebrates, only members of the genus Flavivirus are known as arboviruses, vectored either by mosquitoes or ticks. The remaining genera in the family are exclusively found in mammals, and their diversity has greatly expanded with recent virus discoveries. The genus Flavivirus comprises 92 virus species, of which over 40 can cause human infection. Many of these include important human pathogens such as Zika, dengue, yellow fever, West Nile, and Japanese encephalitis virus.

scholarly journals Application of Game Theory to Explore the Dynamics of Host−Pathogen Association in Phytobiomes

2018 ◽  
Vol 2 (3) ◽  
pp. 111-116 ◽  
Author(s):  
Man S. Kim ◽  
Huan Zhang ◽  
Won Bo Shim
Keyword(s):  
Game Theory ◽  
Big Data Analytics ◽  
Model Systems ◽  
Complex Nature ◽  
New Era ◽  
Host Pathogen ◽  
Single Host ◽  
Experimental Approaches ◽  
Improved Technology ◽  
Open Access Article

Recent advances in sequencing technology and big data analytics are moving plant pathology into a new era where we are now pursuing a deeper systems-level understanding of host–pathogen associations. For past several decades, scientists have predominantly tried to delineate and streamline these interactions into single pathogen–single host model systems, using reductionist experimental approaches. As many of us are aware, there have been several significant proposed ideas and models to help simplify and conceptualize the complex nature of associations that occur between plants and pathogens. However, equipped with vastly improved technology we now have opportunities to further explore multicomponent host–pathogen associations as well as microbe–microbe associations in phytobiomes and agroecosystems. Here, we would like to share our perspective on how game theory concepts could be adopted to study the dynamics of complex phytobiomes and to help us gain fresh and transformative insight. [Formula: see text] Copyright © 2018 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .

Nematodes and cestodes of rodents in South Africa: baseline data on diversity and geographic distribution

2019 ◽  
Vol 94 ◽  
Author(s):  
A. Spickett ◽  
K. Junker ◽  
G. Froeschke ◽  
V. Haukisalmi ◽  
S. Matthee
Keyword(s):  
South Africa ◽  
Host Range ◽  
Geographic Distribution ◽  
Host Species ◽  
Baseline Data ◽  
Helminth Species ◽  
Rodent Species ◽  
Helminth Parasites ◽  
Gastrointestinal Helminths ◽  
Naturally Occurring

Abstract Currently, descriptive information on the host range and geographic distribution of helminth parasites associated with naturally occurring rodents in South and southern Africa is scant. Therefore, we embarked on a countrywide study to: (1) identify gastrointestinal helminths and their host range, and (2) provide baseline data on the geographic distribution of helminths across the country. Altogether, 55 helminth taxa were recovered from at least 13 rodent species (n = 1030) at 26 localities across South Africa. The helminth taxa represented 25 genera (15 nematodes, nine cestodes and one acanthocephalan). Monoxenous nematodes were the most abundant and prevalent group, while the occurrence of heteroxenous nematodes and cestodes was generally lower. The study recorded several novel helminth–host associations. Single-host-species infections were common, although multiple-host-species infections by helminth species were also recorded. Monoxenous nematodes and some cestodes were recovered countrywide, whereas heteroxenous nematodes were restricted to the eastern regions of South Africa. The study highlights the as yet unexplored diversity of helminth species associated with naturally occurring rodent species and provides initial data on their geographical distribution in South Africa.

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