Gastric Nematode Communities in Lizards From the Great Victoria Desert, and an Hypothesis for Their Evolution

1995 ◽  
Vol 43 (2) ◽  
pp. 141 ◽  
Author(s):  
HI Jones
Keyword(s):  
Host Species ◽  
Species Abundance ◽  
Nematode Species ◽  
Geographical Range ◽  
Infection Prevalence ◽  
Intermediate Hosts ◽  
Epidemiological Evidence ◽  
Lizard Species ◽  
Evolutionary Phase ◽  
Paratenic Hosts

This study examines the biology of gastric nematodes in two communities of lizards from the Great Victoria Desert, and develops an hypothesis for their evolution. Abbreviata antarctica A. hastaspicula, A, levicauda, A. tumidocapitis, Skrjabinoptera goldmanae, Kreisiella chrysocampa, Physalopteroides filicauda, Wanaristrongylus ctenoti and W. papangawurpae were recovered from 3023 lizards of 45 species from two different habitats. Genera in the Physalopterinae (Abbreviata, Skrjabinoptera and Kreisiella) exhibited narrow host specificities, Abbreviara and Skrjabinoptera occurring as adults only in larger host species (Varanus gouldii, V. tristis and Pogona minor). P. filicauda and encysted larvae of Physalopterinae occurred widely in the smaller lizard species in all five families represented. Eight of the nine nematode species were recovered from both lizard populations, and differences in prevalence and number of host species infected are discussed in terms of core hosts providing an infective pool. Associations were derived between parameters of infection (prevalence, intensity and abundance) and host size across and within species; abundance of nematodes in Ctenotus skinks correlated with host geographical range. Epidemiological evidence is presented that suggests that termites are intermediate hosts to species of Physalopterinae, and that Orthoptera may be intermediate hosts to P.filicauda. It is suggested that species in the Physalopterinae arose in smaller lizards (where they are now represented by the morphologically primitive Kreisiella), and that they were acquired by large predatory species by host capture, and in which they are now speciating. The small lizards now act as paratenic hosts to their larvae, and the niches left vacant have been occupied by P. filicauda. It is concluded that P.filicauda is at an early non-interactive phase and that Abbreviata and Skrjabinoptera are at an evolutionary phase, and are evolving along with their hosts. Thus, the two principal nematode groups arose at different times in response to the radiation and ecology of their hosts, and are at different stages in their own evolution.

Niche restriction in parasites: proximate and ultimate causes

Parasitology ◽  
1994 ◽  
Vol 109 (S1) ◽  
pp. S69-S84 ◽  
Author(s):  
K. Rohde
Keyword(s):  
Interspecific Competition ◽  
Host Species ◽  
Feeding Habits ◽  
Geographical Range ◽  
Physical Factors ◽  
Reproductive Barriers ◽  
Intermediate Hosts ◽  
Specific Chemical ◽  
Morphological Adaptations ◽  
Marine Parasites

SUMMARYHutchinson's (1957) definition of an ecological niche as a multidimensional hypervolume determined by a number of physical and biotic variables is adopted. The number of niche dimensions is very great, but as a working hypothesis it is assumed that a few are sufficient to characterize the niche of a parasite species to a high degree of accuracy. They are host species, microhabitat(s), macrohabitat(s), geographical range, sex and age of host, season, food and hyperparasites. Methods to measure niche width, in particular specificity indices, are discussed, and some examples of niche restriction are described. Proximate and ultimate causes of niche restriction are discussed, mainly using marine parasites as examples. Among proximate causes of one niche dimension, host specificity, are ecological factors restricting exposure to infection to certain host species; host-specific chemical factors that induce hatching, direct infective stages to a host and bring about settlement of a parasite; factors that lead to mortality in or on the wrong host; morphological adaptations that guarantee survival in or on the ‘correct’ host; and availability of suitable hosts. Many factors are likely to be responsible for microhabitat specificity, but have been little studied, except for some physiological and morphological adaptations to particular microhabitats. Macrohabitats and geographical range may be determined by the distribution of intermediate hosts and certain food items, and by a variety of chemical and physical factors. Hosts of different sexes may differ in feeding habits and the composition of the skin, and thus acquire parasites differentially. Hosts of different age may be differentially infected due to accumulation of parasites with age, loss of parasites due to developing resistance (or immunity), and different size and feeding habits. Among ultimate causes of niche restriction and segregation are avoidance of competition, predation and hyperparasites; facilitation of mating; reinforcement of reproductive barriers; and adaptations to environmental complexity. Few studies permit a decision on which factor or factors are responsible in particular cases. Interspecific competition may play a greater role in helminth communities of some host groups than of others, but it seems that, overall, its role has been exaggerated at least for marine parasites. Some ‘classical’ examples of microhabitat segregation explained by interspecific competition can also be explained by reinforcement of reproductive barriers. There is evidence for the importance of facilitation of mating in microhabitat restriction, and the availability of many vacant niches indicates that competition, overall, is not of great importance.

scholarly journals Non-random biodiversity loss underlies predictable increases in viral disease prevalence

2014 ◽  
Vol 11 (92) ◽  
pp. 20130947 ◽  
Author(s):  
Christelle Lacroix ◽  
Anna Jolles ◽  
Eric W. Seabloom ◽  
Alison G. Power ◽  
Charles E. Mitchell ◽  
...  
Keyword(s):  
Host Species ◽  
Species Abundance ◽  
Virus Transmission ◽  
Biodiversity Loss ◽  
Viral Disease ◽  
Field Trials ◽  
Disease Prevalence ◽  
Infection Prevalence ◽  
Virus Prevalence ◽  
Local Host

Disease dilution (reduced disease prevalence with increasing biodiversity) has been described for many different pathogens. Although the mechanisms causing this phenomenon remain unclear, the disassembly of communities to predictable subsets of species, which can be caused by changing climate, land use or invasive species, underlies one important hypothesis. In this case, infection prevalence could reflect the competence of the remaining hosts. To test this hypothesis, we measured local host species abundance and prevalence of four generalist aphid-vectored pathogens (barley and cereal yellow dwarf viruses) in a ubiquitous annual grass host at 10 sites spanning 2000 km along the North American West Coast. In laboratory and field trials, we measured viral infection as well as aphid fecundity and feeding preference on several host species. Virus prevalence increased as local host richness declined. Community disassembly was non-random: ubiquitous hosts dominating species-poor assemblages were among the most competent for vector production and virus transmission. This suggests that non-random biodiversity loss led to increased virus prevalence. Because diversity loss is occurring globally in response to anthropogenic changes, such work can inform medical, agricultural and veterinary disease research by providing insights into the dynamics of pathogens nested within a complex web of environmental forces.

scholarly journals Morphometric and Molecular Analyses of Ostertagia leptospicularis Assadov, 1953 from Ruminants: Species Diversity or Host Influence?

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 182
Author(s):  
Anna Wyrobisz-Papiewska ◽  
Jerzy Kowal ◽  
Elżbieta Łopieńska-Biernat ◽  
Paweł Nosal ◽  
Iwona Polak ◽  
...  
Keyword(s):  
Host Species ◽  
Roe Deer ◽  
Bos Taurus ◽  
Capreolus Capreolus ◽  
Nematode Species ◽  
Molecular Techniques ◽  
Systematic Classification ◽  
Morphological Variations ◽  
Wide Range ◽  
Induced Changes

Ostertagia leptospicularis Assadov, 1953 was formally described in roe deer Capreolus capreolus and has been reported in a wide range of ruminants, including other Cervidae, as well as Bovidae. Nematode specimens derived from various host species exhibit morphological similarity; however, some differences can be observed. It is unclear if this is due to the differential reaction of one nematode species in different host species (i.e., host-induced changes) or because of distinct nematode species in these hosts (i.e., species complex). This paper focuses on specimens resembling O. leptospicularis f. leptospicularis and its closely related species (Ostertagia ostertagi f. ostertagi) collected from various hosts. Morphometric and molecular techniques were applied to assess host-induced changes in nematode morphology and to clarify its systematic classification. There was an overall effect of host species on measurements of nematodes resembling O. leptospicularis (both males and females), but the distinctiveness of the specimens from cattle Bos taurus were highlighted. The results obtained may suggest that the specimens of O. leptospicularis from cattle in Germany and cervids in central Europe belong to different strains. Furthermore, nematodes from the cervid strain appear to circulate within particular host species, which can be seen in the stated morphological variations.

Revision of Coronostrongylus (Nematoda : Strongyloidea) parasitic in the stomachs of macropodid marsupials

2002 ◽  
Vol 16 (6) ◽  
pp. 893 ◽  
Author(s):  
I. Beveridge
Keyword(s):  
Papua New Guinea ◽  
Host Species ◽  
Related Species ◽  
New Guinea ◽  
Nematode Species ◽  
Closely Related Species ◽  
Nematode Genus ◽  
Eastern Australia ◽  
Wide Range ◽  
Species Occurrences

The monotypic nematode genus Coronostrongylus Johnston & Mawson, 1939 from the stomachs of macropodid marsupials was reviewed and was found to consist of a least seven closely related species. Coronostrongylus coronatus Johnston & Mawson, 1939 is found most commonly in Macropus rufogriseus, but occurs occasionally in M. dorsalis, M. parryi and Petrogale inornata. Coronostrongylus johnsoni, sp. nov. is most commonly found in M. dorsalis, but occurs also in M. rufogriseus, M. parma, Thylogale stigmatica, Petrogale godmani and P. brachyotis. Coronostrongylus barkeri, sp. nov. is most prevalent in Onychogalea unguifera, but occurs also in M. rufus, M. robustus and P. brachyotis. Coronostrongylus closei, sp. nov. is restricted to Petrogale persephone. Coronostrongylus sharmani, sp. nov. occurs only in rock wallabies from eastern Australia: P.�coenensis, P. godmani and P. mareeba; C. spratti, sp. nov. occurs in P. inornata and P. assimilis. Coronostrongylus spearei, sp. nov. is restricted to Papua New Guinea where it is found in Dorcopsulus vanhearni, Dorcopsis hageni and D. muelleri. Although all of the nematode species occur in one principal host species or a series of closely related host species, occurrences in geographically disjunct areas and in phylogenetically distant hosts are features of C. coronatus, C. barkeri, sp. nov. and C. johnsoni, sp. nov. The occurrence of seven closely related nematode species found in a wide range of macropodid host species is more readily accounted for by a hypothesis involving multiple colonisations of hosts than by the hypothesis of co-speciation.

scholarly journals Do parasites adopt different strategies in different intermediate hosts? Host size, not host species, influences Coitocaecum parvum (Trematoda) life history strategy, size and egg production

Parasitology ◽  
2012 ◽  
Vol 140 (2) ◽  
pp. 275-283 ◽  
Author(s):  
R. RUIZ DANIELS ◽  
S. BELTRAN ◽  
R. POULIN ◽  
C. LAGRUE
Keyword(s):  
Host Species ◽  
Egg Production ◽  
Life History Strategy ◽  
Host Size ◽  
Life Strategy ◽  
Amphipod Species ◽  
Intermediate Hosts ◽  
Host Interactions ◽  
Resource Limitations ◽  
Coitocaecum Parvum

SUMMARYHost exploitation induces host defence responses and competition between parasites, resulting in individual parasites facing highly variable environments. Alternative life strategies may thus be expressed in context-dependent ways, depending on which host species is used and intra-host competition between parasites. Coitocaecum parvum (Trematode) can use facultative progenesis in amphipod intermediate hosts, Paracalliope fluviatilis, to abbreviate its life cycle in response to such environmental factors. Coitocaecum parvum also uses another amphipod host, Paracorophium excavatum, a species widely different in size and ecology from P. fluviatilis. In this study, parasite infection levels and strategies in the two amphipod species were compared to determine whether the adoption of progenesis by C. parvum varied between these two hosts. Potential differences in size and/or egg production between C. parvum individuals according to amphipod host species were also investigated. Results show that C. parvum life strategy was not influenced by host species. In contrast, host size significantly affected C. parvum strategy, size and egg production. Since intra-host interactions between co-infecting parasites also influenced C. parvum strategy, size and fecundity, it is highly likely that within-host resource limitations affect C. parvum life strategy and overall fitness regardless of host species.

scholarly journals Nematofauna of bank vole: Clethrionomys glareolus (Schreber, 1780) from Mt. Fruska gora (Serbia)

2009 ◽  
Vol 61 (3) ◽  
pp. 555-561 ◽  
Author(s):  
Olivera Bjelic-Cabrilo ◽  
Ester Popovic ◽  
Smiljka Simic ◽  
Desanka Kostic
Keyword(s):  
Bank Vole ◽  
Host Species ◽  
National Park ◽  
Nematode Species ◽  
Clethrionomys Glareolus ◽  
Parasite Invasion ◽  
Mean Intensity ◽  
Aspiculuris Tetraptera ◽  
First Time

The nematofauna of bank vole (Clethrionomys glareolus) was analyzed for the first time from samples collected in our country. The specimens were collected in Fruska Gora National Park (locality of Brankovac). The number of collected specimens was 138, and infestation with seven nematode species was determined: Heligmosomum mixtum (Schulz, 1954), Heligmosomoides glareoli (Baylis, 1928), Syphacia petrusewiczi (Bernard, 1966), S. stroma (Linstow, 1884), Capillaria murissylvatici (Dieseng, 1851), Trichocephalus muris Schrank, 1788, and Aspiculuris tetraptera (Nitzsch, 1821). The species Heligmosomum mixtum, Heligmosomoides glareoli, and Syphacia petrusewiczi represent the first records for the territory of our country. The species best represented in the sample were H. glareoli and S. petrusewiczi. There were no statistically significant differences between the sexes of host species regarding the prevalence, mean intensity, or mean abundance of parasite invasion.

The influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum

1999 ◽  
Vol 73 (2) ◽  
pp. 143-145 ◽  
Author(s):  
A.M. McCarthy
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Host Species ◽  
Post Infection ◽  
Rana Temporaria ◽  
Biomphalaria Glabrata ◽  
Reproductive Status ◽  
Intermediate Hosts ◽  
Potential Influence ◽  
Second Intermediate Host

The potential influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum to the definitive host Anas platyrhynchos was examined experimentally. Echinoparyphium recurvatum metacercarial cysts were obtained from the following experimentally infected second intermediate hosts 14 days post expsoure to cercariae: Lymnaea peregra; Physa fontinalis; L. stagnalis;Planorbis planorbis; Biomphalaria glabrata; tadpoles of the amphibian Rana temporaria. Metacercarial cysts from each of these hosts were fed, in doses of 50 cysts per individual, to separate groups composed of between four and eight, 3-day-old A. platyrhynchos ducklings. All A. platyrhynchos were necropsied 15 days post-infection and the number, size, and reproductive status of E. recurvatum worms in the intestine was recorded. Analyses of variance on the number (transformed log (x + 1)) and size of worms revealed no significant differences in worms originating from metacercariae formed in the different second intermediate hosts (worm number P > 0.05, and worm size P > 0.05). All worms recovered were found to be gravid. It is therefore concluded that the species of second intermediate host utilized does not influence the infectivity of the metacercarial cyst of E. recurvatum, nor the subsequent establishment and reproductive status of the parasite in A. platyrhynchos.

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.

scholarly journals DNA Footprints: Using Parasites to Detect Elusive Animals, Proof of Principle in Hedgehogs

Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1420
Author(s):  
Simon Allen ◽  
Carolyn Greig ◽  
Ben Rowson ◽  
Robin B. Gasser ◽  
Abdul Jabbar ◽  
...  
Keyword(s):  
Parasitic Nematode ◽  
Survey Methods ◽  
Nematode Species ◽  
Molecular Test ◽  
Intermediate Hosts ◽  
European Hedgehog ◽  
Second Internal Transcribed Spacer ◽  
Specific Parasite ◽  
Objective Tool ◽  
Proof Of Principle

The Western European Hedgehog (Erinaceous europaeus) is a nocturnal animal that is in decline in much of Europe, but the monitoring of this species is subjective, prone to error, and an inadequate basis for estimating population trends. Here, we report the use of Crenosoma striatum, a parasitic nematode specific to hedgehogs as definitive hosts, to detect hedgehog presence in the natural environment. This is achieved through collecting and sampling the parasites within their intermediate hosts, gastropoda, a group much simpler to locate and sample in both urban and rural habitats. C. striatum and Crenosoma vulpis were collected post-mortem from the lungs of hedgehogs and foxes, respectively. Slugs were collected in two sessions, during spring and autumn, from Skomer Island (n = 21), which is known to be free of hedgehogs (and foxes); and Pennard, Swansea (n = 42), known to have a healthy hedgehog population. The second internal transcribed spacer of parasite ribosomal DNA was used to develop a highly specific, novel, PCR based multiplex assay. Crenosoma striatum was found only at the site known to be inhabited by hedgehogs, at an average prevalence in gastropods of 10% in spring and autumn. The molecular test was highly specific: One mollusc was positive for both C. striatum and C. vulpis, and differentiation between the two nematode species was clear. This study demonstrates proof of principle for using detection of specific parasite DNA in easily sampled intermediate hosts to confirm the presence of an elusive nocturnal definitive host species. The approach has great potential as an adaptable, objective tool to supplement and support existing ecological survey methods.

Extraintestinal Acanthocephalan Oncicola venezuelensis (Oligacanthorhynchidae) in Small Indian Mongooses (Herpestes auropunctatus) and African Green Monkeys (Chlorocebus aethiops sabaeus)

2019 ◽  
Vol 56 (5) ◽  
pp. 794-798
Author(s):  
Anne A. M. J. Becker ◽  
Sreekumari Rajeev ◽  
Mark A. Freeman ◽  
Amy Beierschmitt ◽  
Victoria Savinon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Subcutaneous Tissue ◽  
Intermediate Hosts ◽  
Feral Cat ◽  
Chlorocebus Aethiops ◽  
Herpestes Auropunctatus ◽  
Paratenic Hosts ◽  
Green Monkeys ◽  
Small Indian Mongoose

We identified multiple extraintestinal cystacanths during routine postmortem examination of 3 small Indian mongooses and 2 African green monkeys from the Caribbean island of St. Kitts. In mongooses, cystacanths were encysted or free in the subcutaneous tissue, skeletal muscle, or peritoneal or pericardial cavities, whereas in the monkeys, they were in the cavity and parietal layer of the, tunica vaginalis, skeletal muscle, and peritoneal cavity. Morphological, histological, and molecular characterization identified these cystacanths as Oncicola venezuelensis (Acanthocephala: Oligacanthorhynchidae). There was minimal to mild lymphoplasmacytic inflammation associated with the parasite in the mongooses and moderate inflammation, mineralization, hemorrhage, and fibrosis in the connective tissue between the testis and epididymis in 1 monkey. We identified a mature male O. venezuelensis attached in the aboral jejunum of a feral cat, confirming it as the definitive host. Termites serve as intermediate hosts and lizards as paratenic hosts. This report emphasizes the role of the small Indian mongoose and African green monkey as paratenic hosts for O. venezuelensis.

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