scholarly journals Phylogenetic aggregation increases zoonotic potential of mammalian viruses

2019 ◽  
Vol 15 (12) ◽  
pp. 20190668 ◽  
Author(s):  
Andrew W. Park

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.

2019 ◽  
Author(s):  
Liam P. Shaw ◽  
Alethea D. Wang ◽  
David Dylus ◽  
Magda Meier ◽  
Grega Pogacnik ◽  
...  

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.


2021 ◽  
pp. 159-182
Author(s):  
Paul Schmid-Hempel

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.


2011 ◽  
Vol 11 (8) ◽  
pp. 1049-1055 ◽  
Author(s):  
Relja Beck ◽  
Hein Sprong ◽  
Snjezana Lucinger ◽  
Edoardo Pozio ◽  
Simone M. Cacciò

1973 ◽  
Vol 21 (1) ◽  
pp. 103 ◽  
Author(s):  
GA Chilvers

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.


2019 ◽  
Vol 94 ◽  
Author(s):  
A. Spickett ◽  
K. Junker ◽  
G. Froeschke ◽  
V. Haukisalmi ◽  
S. Matthee

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.


Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 731
Author(s):  
Anahí G. Díaz ◽  
Paula G. Ragone ◽  
Fanny Rusman ◽  
Noelia Floridia-Yapur ◽  
Rubén M. Barquez ◽  
...  

Trypanosomes are a group of parasitic flagellates with medical and veterinary importance. Despite many species having been described in this genus, little is known about many of them. Here, we report a genetic and morphological characterization of trypanosomatids isolated from wild mammals from the Argentine Chaco region. Parasites were morphologically and ultrastructurally characterized by light microscopy and transmission electron microscopy. Additionally, 18s rRNA and gGAPDH genes were sequenced and analyzed using maximum likelihood and Bayesian inference. Morphological characterization showed clear characteristics associated with the Trypanosoma genus. The genetic characterization demonstrates that the studied isolates have identical sequences and a pairwise identity of 99% with Trypanosoma lainsoni, which belongs to the clade of lizards and snakes/rodents and marsupials. To date, this species had only been found in the Amazon region. Our finding represents the second report of T. lainsoni and the first record for the Chaco region. Furthermore, we ultrastructurally described for the first time the species. Finally, the host range of T. lainsoni was expanded (Leopardus geoffroyi, Carenivora, Felidae; and Calomys sp., Rodentia, Cricetidae), showing a wide host range for this species.


1990 ◽  
Vol 20 (12) ◽  
pp. 1859-1863 ◽  
Author(s):  
K. I. Mallett

A survey to identify Armillaria root rot pathogens, their host range, and geographic distribution was conducted in the Canadian prairie provinces. Collections of basidiocarps and isolates from the wood of gymptomatic or dead trees were made. Armillaria species were identified by interfertility testing and by the L-DOPA method. Three Armillaria species, A. ostoyae (Romagn.) Herink, A. sinapina Bérubé & Dessureault, and A. calvescens Bérubé & Dessureault, were identified. Armillariaostoyae was the most common species in both the subalpine and boreal forests and was found on a wide variety of coniferous and deciduous host species. Armillariasinapina was in both the boreal and subalpine forests but occurred primarily on deciduous host species. Armillariacalvescens was rare and was found only in the boreal forest on both coniferous and deciduous host species.


2010 ◽  
Vol 79 (2) ◽  
pp. 69-78 ◽  
Author(s):  
Bastian T. Reijnen ◽  
Bert W. Hoeksema ◽  
Edmund Gittenberger

Ovulid gastropods and their octocoral hosts were collected along the leeward coast of Curaçao, Netherlands Antilles. New molecular data of Caribbean and a single Atlantic species were combined with comparable data of Indo-Pacific Ovulidae and a single East-Pacific species from GenBank. Based on two DNA markers, viz. CO-I and 16S, the phylogenetic relationships among all ovulid species of which these data are available are reconstructed. The provisional results suggest a dichotomy between the Atlantic and the Indo-Pacific taxa. Fully grown Simnialena uniplicata closely resembles juvenile Cyphoma gibbosum conchologically. Cymbovula acicularis and C. bahamaensis might be synonyms. The assignments of Caribbean host species for Cyphoma gibbosum, C. signatum, Cymbovula acicularis and Simnialena uniplicata are revised.


2014 ◽  
Vol 15 (3) ◽  
pp. 105-111
Author(s):  
Robert M. Harveson

Sugar beet seedling rust, caused by Puccinia subnitens, is a rarely occurring but essentially harmless disease in sugar beet production. However, it has caused substantial but sporadic losses to commercial spinach growers. It has the typically complex life cycle of a macrocyclic rust pathogen, but is also unusual because it is one of the few documented heteroecious rust diseases where the early spore stages (pycnial and aecial) occur on the economic host while the normally damaging, repeating, uredial stage is found on the feral, noneconomic host. Most significantly, it was one of the first heteroecious rust diseases recognized to have the ability to infect numerous, distinct host species with the aecial stage while maintaining a relatively narrow host range for its uredial and telial stages. Accepted 6 June 2014. Published 25 July 2014.


1999 ◽  
Vol 354 (1383) ◽  
pp. 593-602 ◽  
Author(s):  
Adrian Gibbs

More than a dozen tobamoviruses are known. In nature, each species probably survives by moving between several closely related host species. Each infected plant contains a population of variants, but in most host populations the tobamovirus population is stable. The phylogenetic relationships of tobamovirus species broadly correlate with those of their angiosperm hosts. The simplest explanation for this correlation is that they have coevolved with the angiosperms, and hence, like them, are about 120–140 million years old. Gene sequence differences between species also indicate that the tobamoviruses are an ancient genus. Their gene sequences, and the protein motifs they encode, link them to tobraviruses, hordeiviruses and soil–borne wheat mosaic virus, more distantly to the tricornaviruses, and even to hepatitis virus E and other furoviruses, rubiviruses and alphaviruses. Their progenitors may have been associated with charophycean algae, and perhaps also plasmodiophoromycete fungi.


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