Adult Parasite Species Research Articles

Genetic characterization and phylogenetic relationships of Phyllodistomum parasites in Indian subcontinent: insights from freshwater fish and shrimp hosts

Phyllodistomum is the large digenean group of fish parasites, with 25 species described so far in the Indian subcontinent. Here, we redescribed two adult species of Phyllodistomum (P. srivastava Rai 1964 and P. parorchium Jaiswal 1957) collected from freshwater fish Heteropneustes fossilis Bloch, 1974 and Glossogobius giuris Ham, 1822, respectively, and an unknown Phyllodistomum metacercaria from shrimp (Macrobrachium dayanum Henderson, 1893). These parasites were genetically characterized using 28S and first and second internal transcribed spacers (ITS1 and ITS2) regions of the nuclear ribosomal DNA and CoxI region of the mitochondrial (mt) DNA to establish the link between metacercaria and adult. Morphologically, both the unknown metacercaria in shrimp and adult Phyllodistomum srivastava in fish, resembled in terms of crenulated margin of hind body, arrangement of diagonal testes, bipartite seminal vesicle, and compact paired vitelline masses. The two adult parasite species, P. srivastava from P. parorchium, were different in terms of shape and size of the body, ratio of suckers, the absence of crenulated margin of hind body, a single chambered seminal vesicle, and deeply lobed paired vitelline masses, in the former species. Comparison of the 28S, ITS, and mtCoxI sequence data suggested P. srivastava and Phyllodistomum metacercaria belong to the same species, and supported the distinction between P. srivastava and P. parorchium. Exploring the potential impact of Phyllodistomum infection on host behaviour and health would be prospective areas for future research.

Helminth endoparasites of black drongo, Dicrurus macrocercus (Passeriformes: Dicruridae) from Chattogram, Bangladesh

The common passerine bird species of Bangladesh, the Black Drongo (Dicrurus macrocercus), was collected between November 2013 and March 2014 from paddy fields around the Chittagong University campus to study endohelminth parasites. In total, four helminth adult parasite species, one trematoda (Eumegacetes triangularis), one cestoda (Notopentorchis sp.), two nematoda (Viguiera dicrurusi and Diplotriaena bargusinica) and single unidentified pleurocercoid larva were evident from the body cavity and digestive tracts of the sampled birds. With prevalence, mean intensity and abundance of 52.94%, 3.33 ± 3.04 and 1.76, respectively. It was apparent that the nematodes were the most prevalent (41.18%) species and the male (60%) hosts were found to be more susceptible to infection with the helminths. The mean intensity and the abundance of male also followed the same trend. However, the maximum (100%) prevalence was in February 2014. Parasitic abundance was found to be dependent with total length (t = 40.19, p = 0.000), body length (t = 31.97, p = 0.000) and body weight (t = 39.88, p = 0.000) of the host. Among the identified helminths E. triangularis, Notopentorchis sp. and Diplotriaena bargusinica are the new records for Bangladesh and from the present host. Stomach contents showed that the bird is affirmed as insectivorous, predominant abundance of insect (97-100%) having an abundance gradient of lepidopteran > odonates > dipteran > coleopterans > hemipterans > hymenopterans. The present study coincided with the winter and spring season of an isolated study area, i.e. Chittagong University campus only. Therefore, a detailed study is expected to have a complete helminth profile and epidemiological aspects of the present host at different ecological areas of the country.
 Bangladesh J. Zool. 47(1): 159-171, 2019

Gastrointestinal helminths of Adélie penguins (Pygoscelis adeliae) from Antarctica

Knowledge about parasitic organisms in Antarctica is scarce and fragmentary. The study reported here adds to the knowledge of gastrointestinal parasites of the Adelie penguin ( Pygoscelis adeliae ) (Sphenisciformes), from 25 de Mayo/King George Island (South Shetlands), Bahia Esperanza (Hope Bay) and Avian Island (Antarctica). Thirty-five freshly dead specimens (20 chicks and 15 adults) were collected from December 2007 to December 2014 and examined for internal macroparasites. Three adult parasite species were found: one Cestoda, Parorchites zederi , and two Nematoda, Stegophorus macronectes and Tetrameres sp. Immature Tetrabothrius sp. were found in hosts from Avian Island. Helminth communities are known to be related to host feeding behaviours. Low parasite richness observed in Adelie penguins could be related to the stenophagic and pelagic diet of this host species, which feeds almost exclusively on krill. Keywords: Parorchites zederi ; Stegophorus macronectes ; Tetrameres sp.; parasites; ecosystem health. (Published: 16 June 2016) Citation: Polar Research 2016, 35 , 28516,http://dx.doi.org/10.3402/polar.v35.28516

Gastrointestinal helminths of Gentoo penguins (Pygoscelis papua) from Stranger Point, 25 de Mayo/King George Island, Antarctica

The aim of this work is to contribute to the knowledge of gastrointestinal parasites of the Gentoo penguin (Pygoscelis papua) from 25 de Mayo/King George Island (South Shetlands, Antarctica). Gastrointestinal tracts of 37 fresh dead individuals (21 chicks, 10 juveniles, and 6 adults) were collected from December 2006 to February 2012 and examined for macroparasites. Four adult parasite species were found: one Cestoda species (Parorchites zederi), two Nematoda species (Stegophorus macronectes and Tetrameres wetzeli), and one Acanthocephalan (Corynosoma shackletoni). Two species of immature acanthocephalans, Corynosoma hamanni and Corynosoma bullosum, were found in a single host. This is the first record of Tetrameres wetzeli in Gentoo penguins. The low parasite richness observed could be related to the stenophagic and pelagic diet of this host species which feeds almost exclusively on krill.

Gastrointestinal parasites in Chinstrap Penguins from Deception Island, South Shetlands, Antarctica

Knowledge about parasites of Antarctic birds is fragmented and scarce. The aim of this work is to contribute to the knowledge of gastrointestinal parasites of the Chinstrap Penguin (Pygoscelis antarctica) from Deception Island (South Shetlands, Antarctica). Gastrointestinal tracts of 64 fresh dead individuals (61 chicks and three adults) were collected from December 2006 to February 2009 and examined for macroparasites. Three adult parasite species were found: two Cestoda species (Parorchites zederi and Tetrabothrius pauliani) and one Nematoda species (Stegophorus macronectes). Also, immature acanthocephalans (Corynosoma sp.) were found in one penguin. The low parasite richness observed could be related to the stenophagic and pelagic diet of the host species. False negatives were found in coprological studies.

Spatial niche competition among helminth parasites in horse's large intestine

The spatial distribution of large intestinal helminth parasites of 50 horses was studied. Both adult and mucosal larval stages were examined and counted within the ventral colon, dorsal colon and caecum. Thirty-three species of adult parasites were identified and their distribution in the three large intestinal regions reported, together with the localization of cyathostome encysted larvae and of empty mucosal cysts. In order to highlight interspecific interactions, both Spearman pairwise correlation (among all parasites) and multivariable negative binomial regression (among the most abundant parasites) were performed. Interactions among parasite species are very important from the ecological and parasitological point of view as they can modulate the abundance and the spatial distribution of parasites, as well as the composition of the infracommunity. The main results were: the selection of preferred sites of horse's large intestinal helminths has been confirmed; all statistically significant pairwise correlation coefficients (359 out of 666) were positive; the build up of multivariable regression models brought to light both negative and positive interactions; the most interesting competitive interactions have been observed between the most abundant and relatively large strongyle species: Strongylus edentatus and Strongylus vulgaris in the caecum and ventral colon. When S. edentatus is in the caecum, the favourite site of S. vulgaris, the latter decreases especially in the caecum. On the other hand, when S. edentatus is in the ventral colon, its favourite site, there is no negative relationship with S. vulgaris in the ventral colon and the positive correlation observed with bivariate analysis is maintained. The common belief that the horse large intestinal parasite community is isolationist, due to the absence of negative pairwise interaction, is therefore contradicted by the present study.

Parasite diversity\\host age and size relationship in three coral-reef fishes from French Polynesia

The parasite communities of three coral-reef fish species ( Stegastes nigricans, Dascyllus aruanus and Cephalopholis argus) were on Tiahura reef, French Polynesia. The age and growth of each fish was analysed by otolith increment counts and a significant correlation between these variables was found. Stegastes nigricans was parasitised by six adult parasite species, D. aruanus by two adult parasite species and C. argus by five adult parasite species. The most common parasite species were found in all fish size classes. Ectoparasites showed a positive relationship between their abundance and host body length for all three reef fish species. A positive relationship was found only between host size and parasite abundance for common endoparasite species. Parasite species richness, Brillouins diversity index, and host size and age were positively related. Finally, we discuss the influence of different biological (host diet, host immune response, parasite life-cycle) and ecological factors on parasite community structure in these three reef fishes. Host diet quality seems to be one of the major factors affecting the endoparasite community structure in these reef fishes. Ectoparasite communities seem to be influenced more by biological factors such as, for example, host immunity for the caligid larvae or parasite life-cycle for the gnathiid praniza larvae. In addition, the effect of ecological factors such as cleaning symbiosis on these ectoparasites cannot be dismissed.

Parasitism of Gobius bucchichii Steindachner, 1870 (Teleostei, Gobiidae) in protected and unprotected marine environments.

We collected 396 Gobius bucchichii, Steindachner, 1870 (Teleostei, Gobiidae) in and around the marine reserve of Cerbère-Banyuls, in the southeast of France, between March and July 1994. Five species of adult parasites were found: one acanthocephalan, Acanthocephaloides propinquus Dujardin, 1845 (Acanthocephala, Arhythmacanthidae); one nematode, Cucullanus sp. (Nematoda, Cucullanidae); and three species of digenetic trematodes, Helicometra sp. (Digenea, Opecoelidae), Derogenes sp. (Digenea, Hemiuridae) and Deretrema scorpaenicola Bartoli, 1990 (Digenea, Zoogonidae). Fishes collected in a protected area were on average, larger, older, had a higher percentage of regenerated scales, and harbored more parasites.

Impact of Ecological Succession on the Parasite Fauna in Centrarchids from Oligotrophic and Eutrophic Ecosystems

Approximately 30 species of larval and adult parasites were collected from 549 centrarchid fish and 7718 gastropod molluscs from an oligotrophic and two eutrophic lakes in southwestern Michigan. The distribution pattern indicates that centrarchids from the oligotrophic lake harbor a wide range of species of adult parasites and a comparatively smaller number of larval forms, many of which complete their life cycles in predatory fish. On the other hand, bass and sunfish from the two eutrophic lakes harbor a proportionately larger number of larval parasites, most of which culminate their life cycles in fish-eating birds and mammals. A trophic hypothesis, based on the nature of predatorprey relationships in each of the two types of ecosystem, is proposed to explain the distribution patterns of parasites.