scholarly journals First study on the helminth community structure of the neotropical marsupial Metachirus myosuros (Didelphimorphia, Didelphidae)

Author(s):  
Bruna Silva Cirino ◽  
Sócrates Fraga da Costa Neto ◽  
Arnaldo Maldonado Júnior ◽  
Rosana Gentile

Abstract Metachirus myosuros is a marsupial species widely distributed in South America. Despite this, there is a lack of knowledge about its helminth parasites and helminth community structure. The aims of this study were to describe the species composition and determine the parasitological parameters of helminth communities of M. myosuros in preserved areas of the Atlantic Forest, Igrapiúna, Bahia state, northeastern Brazil. Parasites were searched from 19 specimens of this marsupial (18 were infected with at least one species), counted and identified. Ten species of helminth parasites were obtained: 7 nematodes, 2 platyhelminths and 1 acanthocephalan. The most abundant species were Aspidodera raillieti, Cruzia tentaculata, Physaloptera mirandai and Viannaia conspicua (Nematoda). These species were also the only dominant ones in the component community. Male hosts had higher prevalence of P. mirandai and greater abundance of V. conspicua. We observed a relationship between host body size and helminth abundance in both male and female hosts, and between host body size and helminth species richness in female hosts. This was the first study to analyze the helminth fauna and helminth community structure of M. myosuros. This was the first report of occurrences of A. raillieti and Didelphonema longispiculata in M. myosuros.

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.


2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Monika Hamann ◽  
Cynthya González ◽  
Arturo Kehr

AbstractA total of 36 adult individuals of Leptodactylus latinasus were collected near the city of Corrientes, Province of Corrientes in Argentina. The main goals of this study were: (1) to determine the helminth parasite fauna of L. latinasus; (2) to determine the richness and diversity of parasites at the component and infracommunity levels; (3) to analyze the relationships between helminth, frog body size and sex, and (4) to identify and examine species affinity of helminth communities. The helminth component community of this frog’s population consisted of 17 species. The predominant groups of parasites were the trematodes (adults: Glypthelmins repandum, Catadiscus inopinatus and Haematoloechus longiplexus; larvae: Travtrema aff. stenocotyle, Bursotrema aff. tetracotyloides, Styphlodora sp., unknown opisthogonimid species, Petasiger sp. and unknown strigeid species), followed by the nematodes (Cosmocerca podicipinus, C. parva, C. rara, C. cruzi, Schrankiana schranki and Aplectana hylambatis); other groups of parasites were represented by only one species (unknown larval cestode species and Centrorhynchus sp.). All parasite helminth species showed an aggregated pattern of distribution. The most infected organs were kidneys, small intestine, large intestine and pharyngeal zone. The host body size was important in determining the parasites abundance of G. repandum. At the level of component community G. repandum was the species with highest prevalence of infection and Bursotrema aff. tetracotyloides was the dominant species. Helminth species showed four significant pairs of covariation and two significant pairs of association in the infracommunities of Leptodactylus latinasus.


Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Monika Hamann ◽  
Arturo Kehr ◽  
Cynthya González

AbstractThe main goals of this study were to determine the richness and diversity of helminth parasites of Rhinella fernandezae at the component and infracommunity levels and determine the ecological implications of different biotic and abiotic factors. Specimens were collected near the city of Corrientes, Corrientes Province, Argentina. Prevalence of infection was 94% in the specimens examined (n = 65). The helminth component community in R. fernandezae in this area was comprised a total of 22 species. Of all helminth species, only three (Catadiscus inopinatus, Cosmocerca podicipinus and C. parva) were dominant (importance value: I > 1.0) in the community. The most abundant species were B. tetracotyloides (d = 0.43) among the larvae and C. podicipinus (d = 0.09) among adult worms. At the infracommunity level, the mean individual species richness (2.28 ± 1.48) (mean ± SD) was no more than 3 helminth species per infected host; the diversity and equitability of helminths were 0.23 ± 0.21 and 0.48 ± 0.38, respectively. The host body size was the main factor in determining the parasite abundance. Species richness was significantly and positively correlated with host body size. The parasite helminth species predominantly showed an overdispersed pattern of distribution. Helminth species showed two negative and significant pairs of covariation and one significant pair of association (P < 0.05). R. fernandezae has a wide variety of parasites relating to the host microhabitat, mobility and feeding habits.


Author(s):  
Amber J. Brace ◽  
Marc J. Lajeunesse ◽  
Daniel R. Ardia ◽  
Dana M. Hawley ◽  
James S. Adelman ◽  
...  

Parasitology ◽  
1993 ◽  
Vol 107 (1) ◽  
pp. 71-78 ◽  
Author(s):  
C. R. Kennedy

SummaryThe prediction that species richness and diversity of intestinal helminth communities in eels would change over time in response to habitat changes was tested over a period of 13 years in a small stream subjected to extensive human management. Nearly all measures of helminth community structure adopted indicated a decline in richness and diversity over the first 6 years followed by a recovery over the last few years to levels unexpectedly close to those at the start of the investigation. Changes in total number of species suggested that the component community was far richer (from 3–9 species) at the end of the period. By contrast, changes in diversity and dominance measures revealed less variation than expected and suggested that there was an underlying stability of community structure characterized by high dominance by a single species, although the identity of this changed, low diversity and a large proportion of the eel population harbouring 0 or only 1 species. A similar pattern of changes was recorded in the infra-communities, where values of species richness and diversity were very similar at the commencement and termination of the study. It appeared that those helminths that colonized in the recovery period contributed to community richness but had little impact on community structure. The helminth communities clearly did change in response to habitat changes, and the evidence for a fixed number of niches and an underlying constancy in helminth community structure in eels is evaluated.


2018 ◽  
Vol 10 (9) ◽  
pp. 504
Author(s):  
Jesús Montoya-Mendoza ◽  
Sandra Edith Badillo-López ◽  
Isabel Araceli Amaro-Espejo ◽  
María del Refugio Castañeda-Chávez ◽  
Fabiola Lango-Reynoso ◽  
...  

Scorpaena brasiliensis and S. plumieri are relevant fish species in reef systems, but little is known about their parasitic helminth communities and their structure. This paper describes such community in terms of species richness and diversity. A helminthological study was conducted on 33 specimens of S. brasiliensis and 36 S. plumieri, captured in the Pajaros and Cabezo Reefs, in the Veracruz Reef System National Park (VRSNP), Veracruz, Mexico. The helminth community structure was analyzed in both host species. A total of 10 parasitic species was registered in S. brasiliensis (5 digeneans, 1 cestode, 3 nematodes, 1 acanthocephalan), while S. plumieri hosted 11 species (4 digeneans, 1 monogenean, 1 cestode, 4 nematodes, 1 acanthocephalan), with 8 common species. The species with the highest prevalence were Pseudocapillaria (Icthyocapillaria) sp., with 18.2% and 19.4% in S. brasiliensis and S. plumieri, respectively. Component community richness for S. brasiliensis was S = 10, with Shannon index diversity value of H’ = 2.08. For S. plumieri, such values were of S = 11 and H’ = 1.91. Richness and diversity in the component and infracommunity levels for both hosts are lower than in other parasite communities of marine fishes in the southern Gulf of Mexico.


Author(s):  
Helen J. Esser ◽  
Janet E. Foley ◽  
Frans Bongers ◽  
Edward Allen Herre ◽  
Matthew J. Miller ◽  
...  
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