Gastrointestinal Helminth Communities Research Articles

Helminths of captive and free-ranging populations of the mountain gazelle (Gazella gazella): Evidence from faecal examination.

Understanding parasite diversity in wild and captive animal populations has critical implications for both individual animal health and ecosystem dynamics in a broader sense. In mountain gazelles (Gazella gazella), the gastrointestinal helminth community is poorly understood, limiting our efforts in the conservation of this endangered bovid species. This species has only two remaining populations in the world, including the isolated northernmost population in Türkiye. To identify and compare the diversity and prevalence of gastrointestinal helminths in captive and free-ranging populations of mountain gazelles in Hatay, Türkiye, and to assess potential zoonotic risks. In total, 105 fresh faecal samples, 45 individual samples and 60 faecal samples, representing 16 pools, from both captive and free-ranging populations were collected and analysed using Fulleborn flotation, Benedek sedimentation and Bearman-Wetzel methods faecal flotation methods, including the McMaster technique to determine the severity of infection. We detected 12 helminth taxa in our examination of faecal samples, including gastrointestinal nematodes, lungworms and trematodes. Parasites from the Trichostrongyloidea family demonstrated variable hatching stages and rates, potentially influenced by ambient conditions. We also detected one protozoan among the samples. Our results revealed a higher diversity of parasites in free-ranging populations compared to captive ones. This study underscores the necessity for regular parasitological surveillance in both captive and free-ranging wildlife populations for effective conservation management. It also contributes to the 'One Health' perspective by highlighting the potential zoonotic risks posed by parasites in wild ruminants. Our results have implications for the conservation and management of the mountain gazelle.

Nestedness and beta diversity of gastrointestinal helminth communities in common warthogs, Phacochoerus africanus (Suidae), at 2 localities in South Africa.

Few studies have investigated the ecological interactions between wild species of Suidae and their parasites, leaving our knowledge concerning this host–parasite system fragmented. In the present study, we applied network studies to analyse community nestedness in helminth assemblages of common warthogs, Phacochoerus africanus (Gmelin) (Suidae). Helminth data were compiled from 95 warthogs, including young and adult males and females, from 2 different conservation areas in Mpumalanga and Limpopo Provinces, South Africa, collected monthly over a period of 1 year each. The aim was to study the effect of host sex, age and season of sampling on the structure of helminth infracommunities harboured by the warthogs and to search for non-random structural patterns in the warthog–helminth interaction networks. Furthermore, we investigated the influence of a warthog's age, sex and season of sampling on beta diversity and dark diversity of their helminth infracommunities. Lastly, we asked whether the effects of host sex, age and sampling season on helminth communities differed between the 2 localities. We found that helminth communities of warthogs were nested and host–parasite interactions were influenced by all 3 factors as well as combinations thereof. However, the resulting patterns differed at the 2 localities, indicating that local environmental processes are important drivers of community structure.

Linking Behavior, Co-infection Patterns, and Viral Infection Risk With the Whole Gastrointestinal Helminth Community Structure in Mastomys natalensis.

Infection probability, load, and community structure of helminths varies strongly between and within animal populations. This can be ascribed to environmental stochasticity or due to individual characteristics of the host such as their age or sex. Other, but understudied, factors are the hosts' behavior and co-infection patterns. In this study, we used the multimammate mouse (Mastomys natalensis) as a model system to investigate how the hosts' sex, age, exploration behavior, and viral infection history affects their infection risk, parasitic load, and community structure of gastrointestinal helminths. We hypothesized that the hosts' exploration behavior would play a key role in the risk for infection by different gastrointestinal helminths, whereby highly explorative individuals would have a higher infection risk leading to a wider diversity of helminths and a larger load compared to less explorative individuals. Fieldwork was performed in Morogoro, Tanzania, where we trapped a total of 214 individual mice. Their exploratory behavior was characterized using a hole-board test after which we collected the helminths inside their gastrointestinal tract. During our study, we found helminths belonging to eight different genera: Hymenolepis sp., Protospirura muricola, Syphacia sp., Trichuris mastomysi, Gongylonema sp., Pterygodermatites sp., Raillietina sp., and Inermicapsifer sp. and one family: Trichostrongylidae. Hierarchical modeling of species communities (HMSC) was used to investigate the effect of the different host-related factors on the infection probability, parasite load, and community structure of these helminths. Our results show that species richness was higher in adults and in females compared to juveniles and males, respectively. Contrary to our expectations, we found that less explorative individuals had higher infection probability with different helminths resulting in a higher diversity, which could be due to a higher exposure rate to these helminths and/or behavioral modification due to the infection.

Food chain, parasites and climate changes in the high Arctic: a case study on trophically transmitted parasites of common eider Somateria mollissima at Franz Josef Land

Assessment of the impact of climate change on the Arctic nearshore ecosystems requires knowledge of the “reference points”, that is, the state of things before the effects of the warming become pronounced. For parasites, which play an essential role in the nearshore ecosystems, this knowledge is scarce and fragmentary. This study, based on the materials collected at Franz Josef Land (FJL) in 1990–1993, partly fills this gap. We present the first data on the diet of the common eider Somateria mollissima at FJL, the transmission of helminths in its population and the infection of nearshore invertebrates with helminth larvae. We found that gastrointestinal helminth communities were impoverished (only ten species) and dominated by cestodes and acanthocephalans. This is associated with the prevalence of nearshore crustaceans, the intermediate hosts of these helminths, in the diet of the eiders. The absence of the vulnerable free-living larvae also facilitates transmission of helminths parasitizing eiders at FJL. Infection with helminths and the diet were different in ducklings and in adult birds as well as in eiders from different parts of the archipelago. The infection distribution of molluscs and crustaceans with helminth larvae was patchy and higher in the vicinity of the eider colonies. A high-infection intensity of FJL eiders with cestodes and acanthocephalans recorded in our study seems to have a certain negative effect on the bird population. Its significance is likely to grow considering that the transmission of helminths is promoted by the climate warming in the Arctic.

First Record of the Nematode Physaloptera squamatae in the Helminth Community of the Introduced Anole Anolis grahami (Polychrotidae) on Bermuda

The gastrointestinal helminth communities of five populations of Anolis grahami, an introduced anole on Bermuda, were surveyed to determine the prevalence, abundance, and species diversity of parasites in these reptiles. Only three nematode species were found, Atractis scelopori, Parapharyngodon cubensis, and Physaloptera squamatae. This species, P. squamatae, is recorded for the first time in Anolis grahami on Bermuda, probably introduced through its arthropod intermediate host. The role of the host A. grahami as a “spillover” agent for these parasites is discussed.

Review of metazoan parasites of the northern fur seal (Callorhinus ursinus) and the analysis of the gastrointestinal helminth community of the population on St. Paul Island, Alaska.

The northern fur seal (NFS), Callorhinus ursinus (Mammalia: Otariidae), is a marine mammal species included into the IUCN Red List as the vulnerable species which population is dramatically declining. A significant amount of parasitological data collected previously and our recent data allowed us to clarify the list of NFS metazoan parasites and to perform a comprehensive analysis of the gastrointestinal helminth community. Gastrointestinal tracts from 756 NFSs (3- to 4-year-old males) were collected during the annual Aleut subsistence harvests in July-August of 2011-2014 from five separate rookeries on St. Paul Island, Alaska. Totally, 27,625 specimens of helminths and approximately 1000 nasal mites were collected and identified. Detailed analysis of the previously published and newly obtained data revealed 32 species of metazoan parasites, including trematodes (6 species), cestodes (4), nematodes (9), acanthocephalans (9) and arthropods (4). The gastrointestinal helminth community of newly studied NFSs comprised 19 species including trematodes (4), cestodes (3), nematodes (5) and acanthocephalans (7). Temporal changes in the helminth community structure were small but statistically significant. Gastrointestinal helminth infracommunities comprised from 1 to 10 species (average of 4). Small but significant correlation was found between the abundances of acanthocephalans (Corynosoma similis and C. strumosum), nematodes (Contracaecum osculatum, Pseudoterranova spp.) and cestode Diphyllobothrium tetrapterum.

Gastrointestinal helminth fauna and helminth communities of bleak (Alburnus alburnus, L. 1758) from lower section of Danube River

The present study presents the results from examinations of bleak’s endohelminth species and structure of helminth communities from the Bulgarian part of the Lower Danube River. In 2015 and 2016, on a seasonal manner, 91 specimens of Alburnus alburnus (Linnaeus, 1758) (bleak) were examined with standard techniques for parasites. Five species of parasites: Nicolla skrjabini (Ivanitzky, 1928), Ligula intestinalis (Linnaeus, 1758), Acanthocephalus lucii (Müller, 1776), Pomphorhynchus laevis (Müller, 1776) and Contracoecum microcephalum (Stossich, 1890), larvae were identified. The analysis of the dominant structure of the found parasite species is presented to the component and infracommunities levels. All parasite species were accidental for the parasitic communities of examined fish with the exception of P. laevis and N. skrjabini. P. laevis was a core parasite species and N. skrjabini was a component parasite species for the helminth communities of bleak. The parasite communities of A. alburnus were discussed and compared with previous research data on parasite communities of bleak from River Danube in Bulgaria. New data for helminths and helminth communities of A. alburnus from Danube River (biotope Vetren) and their seasonal occurrence are presented.

Gastrointestinal Helminths of Rattus steini (Rodentia: Muridae) from Papua New Guinea

Abstract Helminth specimens representing 3 cestode species, an acanthocephalan, and 15 nematode species were collected from the digestive tracts of 30 individuals of Rattus steini (Muridae) from Papua New Guinea. Of the nematode morphotypes, 7 could be identified to species level and there was insufficient material to fully identify the remainder. All were new host records. A bootstrap estimator of species richness indicated that 83.6% of the expected species in the gastrointestinal helminth community of R. steini were recovered. A comparison of the gastrointestinal communities of Rattus leucopus, Rattus giluwensis, Rattus novaeguineae, and Rattus niobe with R. steini found that the dominant elements in each case were heterakids, oxyurids, and spirurids, with heligmonellids at low prevalences and intensities.

Gastrointestinal helminths of Emperor Penguin (Aptenodytes forsteri) from Antarctica

Although research on parasitic diseases in Antarctic birds is scarce and the information largely fragmented, an increasing number of studies are currently in progress in this area. The host/parasite relationship is very important for understanding the impact of parasitism on the seabirds’ feeding ecology, especially in those isolated regions where the host is extremely sensitive to new diseases. Penguins are a big favorite for these studies because of their importance as indicators of change in the Antarctic ecosystem. This study aims at adding information on gastrointestinal parasites of the Emperor Penguin Aptenodytes forsteri from Snow Hill colony. Based on a sample of 43 individuals found freshly dead (3 adults and 40 chicks) from predation or starvation, the gastrointestinal helminth community in Emperor penguins was composed of two species of cestodes (Parorchites zederi and Tetrabothrius sp.) and three species of nematodes (Stegophorus macronectes, Tetrameres sp. and Contracaecum osculatum). This is the first record of S. macronectes in the Emperor Penguin. The low parasite richness observed might be related to the stenophagic and pelagic diet of this host.

Gastrointestinal helminths of two populations of wild pigeons (Columba livia) in Brazil

Abstract The present study analyzed gastrointestinal helminth communities in 265 wild pigeons (Columba livia) living in the municipalities of São Paulo and Tatuí, state of São Paulo, Brazil, over a one-year period. The birds were caught next to grain storage warehouses and were necropsied. A total of 790 parasites comprising one nematode species and one cestode genus were recovered from 110 pigeons, thus yielding an overall prevalence of 41.5%, mean intensity of infection of 7.2 ± 1.6 (range 1-144) and discrepancy index of 0.855. Only 15 pigeons (5.7%) presented mixed infection. The helminths isolated from the birds were Ascaridia columbae (Ascaridiidae) and Raillietina sp. (Davaineidae). The birds’ weights differed according to sex but this did not influence the intensity of infection. The overall prevalence and intensity of infection did not differ between the sexes, but the prevalence was higher among the birds from Tatuí (47.8%). The gastrointestinal helminth community of C. livia was characterized in the two areas studied and parasite homogeneity was observed over the 12 months analyzed at both locations. These results make contributions to the current literature on health aspects of wild C. livia populations.

Ecologia da comunidade de helmintos gastrointestinais de tartarugas-verdes ( Chelonia mydas ) recolhidas no litoral do Espírito Santo

RESUMO A tartaruga-verde, Chelonia mydas, apresenta distribuição cosmopolita. No Brasil, ocorre na costa, porém desova em ilhas oceânicas. A helmintofauna de tartarugas-verdes é diversificada, podendo-se dizer que tem a maior diversidade comparada com outras espécies de tartarugas. Objetivou-se avaliar aspectos ecológicos da comunidade de helmintos gastrointestinais e relacionar com a condição corporal de tartarugas-verdes recolhidas no litoral do Espírito Santo. Foram utilizados 36 exemplares juvenis da espécie C. mydas. O trato gastrointestinal foi separado e dividido em porções: esôfago/estômago, intestino delgado e intestino grosso. Cada porção foi inspecionada à procura de parasitos, e os exemplares encontrados foram separados para posterior identificação. Das 36 tartarugas avaliadas, 34 estavam parasitadas por helmintos (94,44%), com um total de 10.734 helmintos. Foram encontradas 18 espécies de trematodas pertencentes a quatro famílias. A riqueza de espécies encontrada foi de 4,29±2,19 (1-10) e a intensidade média de infecção foi de 315,64±281,83 (2-994) helmintos. Os parasitos mais prevalentes foram Cricocephalus albus, Metacetabulum invaginatum e Neoctangium travassosi, ambos com 61,11% (22/36), Pronocephalus obliquus com 33,33% (12/36), e Glyphicephalus lobatus com 30,55% (11/36). O helminto mais abundante foi M. invaginatum com 70,63 helmintos/animal, seguido de C. albus com 58,77 helmintos/animal e N. travassosi com 41,75 helmintos/animal.

Parasites and invasions: changes in gastrointestinal helminth assemblages in invasive and native rodents in Senegal

Understanding why some exotic species become widespread and abundant in their colonised range is a fundamental issue that still needs to be addressed. Among many hypotheses, newly established host populations may benefit from a parasite loss (“enemy release” hypothesis) through impoverishment of their original parasite communities or reduced infection levels. Moreover, the fitness of competing native hosts may be negatively affected by the acquisition of exotic taxa from invaders (“parasite spillover”) and/or by an increased transmission risk of native parasites due to their amplification by invaders (“parasite spillback”). We focused on gastrointestinal helminth communities to determine whether these predictions could explain the ongoing invasion success of the commensal house mouse (Mus musculus domesticus) and black rat (Rattus rattus), as well as the associated decrease in native Mastomys spp., in Senegal. For both invasive species, our results were consistent with the predictions of the enemy release hypothesis. A decrease in overall gastrointestinal helminth prevalence and infracommunity species richness was observed along the invasion gradients as well as lower specific prevalence/abundance (Aspiculuris tetraptera in Mus musculus domesticus, Hymenolepis diminuta in Rattus rattus) on the invasion fronts. Conversely, we did not find strong evidence of GIH spillover or spillback in invasion fronts, where native and invasive rodents co-occurred. Further experimental research is needed to determine whether and how the loss of gastrointestinal helminths and reduced infection levels along invasion routes may result in any advantageous effects on invader fitness and competitive advantage.

Trophic ecology shapes gastrointestinal helminth communities of two sympatric mesopredatory sharks in the Adriatic Sea

AbstractWe investigated and compared the structure of parasite communities in two sympatric, commercially exploited sharks. We analysed 188 gastrointestinal tracts from a crustacean feeder Mustelus punctulatus and 157 gastrointestinal tracts from a piscivorous Squalus acanthias. The overall prevalence of helminth parasites was very high (84.0%) for M. punctulatus with nematode Cucullanus micropapillatus as the most abundant species (mean abundance 13.96) and Anisakis spp. larvae as the most prevalent taxa (47.9%). In contrast, only 21.7% of S. acanthias specimens were infected, showing Anisakis spp. larvae as the most prevalent (17.8%) and abundant taxa (mean abundance 0.39). The subsample of Anisakis spp. larvae, isolated from both hosts, was molecularly identified at ITS locus as A. pegreffii. Significant variations among size classes were recorded for M. punctulatus, mainly as a consequence of higher C. micropapillatus loads in larger sharks. Seasonal patterns in prevalence and abundance of C. micropapillatus were recorded for M. punctulatus, with peaks in autumn, whereas Anisakis spp. larvae prevailed during spring, for both sharks. Sex contributed little to the observed parasite abundances, although female spiny dogfish were more prone to infections than males, and higher helminth diversity was recorded in females in both shark species. The differences in infection parameters between the two shark species likely reflect the variations in foraging strategies and availability of intermediate hosts. Our findings suggest that crustacean feeder M. punctulatus is more susceptible to helminth infections in the Adriatic Sea, which may affect the health status of local shark populations.

Biodiversity threats from outside to inside: effects of alien grey squirrel (Sciurus carolinensis) on helminth community of native red squirrel (Sciurus vulgaris)

Biological invasions are among the major causes of biodiversity loss worldwide, and parasites carried or acquired by invaders may represent an added threat to native species. We compared gastrointestinal helminth communities of native Eurasian red squirrels (Sciurus vulgaris) in the presence and absence of introduced Eastern grey squirrels (Sciurus carolinensis) to detect alterations induced by the alien species. In particular, we investigated whether spillover of a North American nematode Strongyloides robustus occurs and whether prevalence of a local parasite Trypanoxyuris sciuri in red squirrels is affected by grey squirrel presence. The probability of being infected by both parasites was significantly higher in areas co-inhabited by the alien species, where 61% of examined red squirrels (n = 49) were infected by S. robustus and 90% by T. sciuri. Conversely, in red-only areas, the two parasites infected only 5 and 70% of individuals (n = 60). Overall, our findings support the hypothesis that red squirrels acquire S. robustus via spillover from the alien congener and suggest that invaders' presence may also indirectly affect infection by local parasites through mechanisms diverse than spill-back and linked to the increased competitive pressure to which red squirrels are subjected. These results indicate that the impact of grey squirrel on red squirrels may have been underestimated and highlight the importance of investigating variation in macroparasite communities of native species threatened by alien competitors.

Network transmission inference: Host behavior and parasite life cycle make social networks meaningful in disease ecology

The process of disease transmission is determined by the interaction of host susceptibility and exposure to parasite infectious stages. Host behavior is an important determinant of the likelihood of exposure to infectious stages but is difficult to measure and often assumed to be homogenous in models of disease spread. We evaluated the importance of precisely defining host contact when using networks that estimate exposure and predict infection prevalence in a replicated, empirical system. In particular, we hypothesized that infection patterns would be predicted only by a contact network that is defined according to host behavior and parasite life cycle. Two competing host contact criteria were used to construct networks defined by parasite life cycle and social contacts. First, parasite-defined contacts were based on shared space with a time delay corresponding to the environmental development time of nematode parasites with a direct fecal-oral life cycle. Second, social contacts were defined by shared space in the same time period. To quantify the competing networks of exposure and infection, we sampled natural populations of the eastern chipmunk (Tamias striatus) and infection of their gastrointestinal helminth community using replicated longitudinal capture-mark-recapture techniques. We predicted that (1) infection with parasites with direct fecal-oral life cycles would be explained by the time delay contact network, but not the social contact network; (2) infection with parasites with trophic life cycles (via a mobile intermediate host; thus, spatially decoupling transmission from host contact) would not be explained by either contact network. The prevalence of fecal-oral life cycle nematode parasites was strongly correlated to the number and strength of network connections from the parasite-defined network (including the time delay), while the prevalence of trophic life cycle parasites was not correlated with any network metrics. We concluded that incorporating the parasite life cycle, relative to the way that exposure is measured, is key to inferring transmission and can be empirically quantified using network techniques. In addition, appropriately defining and measuring contacts according the life history of the parasite and relevant behaviors of the host is a crucial step in applying network analyses to empirical systems.

Macroparasite community of the Eurasian red squirrel (Sciurus vulgaris): poor species richness and diversity

The Eurasian red squirrel (Sciurus vulgaris) is the only naturally occurring tree squirrel throughout its range. We aim at improving current knowledge on its macroparasite fauna, expecting that it will have a poor parasite diversity because in species that have no sympatric congeners parasite richness should be lower than in hosts sharing their range with several closely related species, where host-switching events and lateral transmission are promoted. We examined gastro-intestinal helminth and ectoparasite communities (excluding mites) of, respectively, 147 and 311 red squirrel roadkills collected in four biogeographic regions in Italy and France. As expected, the macroparasite fauna was poor: we found five species of nematodes and some unidentified cestodes, three fleas, two sucking lice and two hard ticks. The helminth community was dominated by a single species, the oxyurid Trypanoxyuris (Rodentoxyuris) sciuri (prevalence, 87%; mean abundance, 373 ± 65 worms/host). Its abundance varied among seasons and biogeographic regions and increased with body mass in male hosts while decreased in females. The most prevalent ectoparasites were the flea Ceratophyllus (Monopsyllus) sciurorum (28%), whose presence was affected by season, and the generalist tick Ixodes (Ixodes) ricinus that was found only in France (34%). All the other helminths and arthropod species were rare, with prevalence below 10%. However, the first record of Strongyloides robustus, a common nematode of North American Eastern grey squirrels (S. carolinensis), in two red squirrels living in areas where this alien species co-inhabits, deserves further attention, since low parasite richness could result in native red squirrels being particularly vulnerable to parasite spillover.

Gastrointestinal helminth communities of the blackspot seabreamPagellus bogaraveo(Teleostei: Sparidae) from Portuguese north-east Atlantic waters

A study was carried out on the gastrointestinal helminth communities of blackspot seabream, Pagellus bogaraveo, from the Portuguese mainland and island waters. Fifteen helminth parasite species were detected, including the following new records in this host: the digeneans Accacladocoelium petasiporum, Brachyenteron helicoleni, Glomericirrus macrouri, Lecithocladium excisum, Lepocreadium album and Pachycreadium carnosum; the nematode Camallanus sp. and the acanthocephalan Rhadinorhynchus pristis. Infection levels were generally low. Samples from mainland waters had a significantly higher prevalence of digeneans than those from the islands, probably due to the greater availability of invertebrate intermediate hosts on the continental slope. The helminth community of P. bogaraveo from Azores was diverse but mostly composed of species that infected no more than a single host, whereas in Madeira the helminth community was very depauperate. Most helminth species exhibited niche preferences within the gastrointestinal tract of the host. Higher functional richness and evenness were obtained in helminth communities of P. bogaraveo from mainland waters, indicating a balanced use of available resources, which is suggestive of more stable gastrointestinal helminth communities in these waters.

Gastrointestinal helminth community of loggerhead sea turtle Caretta caretta in the Adriatic Sea

We analysed the intestinal helminth community of 70 loggerhead sea turtles Caretta caretta with a curved carapace length ranging from 25 to 85.4 cm, recovered dead in neritic foraging habitats in the Adriatic Sea in 1995 to 2004. The overall prevalence of infection was high (70.0%), with a mean abundance of 36.8 helminth parasites per turtle. Helminth fauna comprised 5 trematodes (Calycodes anthos, Enodiotrema megachondrus, Orchidasma amphiorchis, Pachypsolus irroratus, Rhytidodes gelatinosus) and 3 nematodes (Sulcascaris sulcata, Anisakis spp., Hysterothylacium sp.), with 6 taxa specific for marine turtles. In terms of infection intensity and parasite abundance, O. amphiorchis was the dominant species (mean intensity: 49.8; mean abundance: 12.8), followed by R. gelatinosus (30.5 and 8.3, respectively) and P. irroratus (23.5 and 7.0, respectively), while larval Anisakis spp. exhibited the highest prevalence (34.3%). The intensity of helminth infection ranged from 1 to 302 (mean: 52.6 ± 69.1) and was not correlated with the size of turtles; this relationship held for all species, except R. gelatinosus (rS = 0.556, p < 0.05). In comparison to other marine habitats, the helminth community of Adriatic loggerheads is characterised by higher species diversity (Shannon-Wiener H' = 1.58) and evenness (E = 0.76), and lower dominance values (Berger-Parker d = 0.35), which can be attributed to the life history and feeding ecology of sea turtles in recruited neritic grounds and the diversity of their benthic prey.

Gastrointestinal helminth communities of two gekkonid lizard species, Nactus multicarinatus and Nactus pelagicus (Squamata: Gekkonidae), from the Republic of Vanuatu, Oceania

Gastrointestinal helminth communities of two gekkonid species, Nactus multicarinatus and Nactus pelagicus, from the Vanuatu Archipelago were examined. Both helminth communities were depauperate: N. multicarinatus harboured one species of Digenea, Mesocoelium monas, one species of Cestoda, Oochoristica javaensis, four species of Nematoda, Hedruris hanleyae, Parapharyngodon maplestoni, Physocephalus sp. (larvae in cysts), Filarioidea gen. sp. (juvenile); N. pelagicus harboured one species of Cestoda, O. javaensis, four species of Nematoda, H. hanleyae, Falcaustra tannaensis, P. maplestoni, Physocephalus sp. (larvae in cysts). In each helminth community P. maplestoni represented a core species and H. hanleyae was a secondary species. It is postulated that the helminth fauna infecting lizards of the Vanuatu Archipelago originated in Australia and Papua New Guinea and reached the archipelago by rafting; their establishment in Vanuatu was fortuitous.

The helminth community of the skink Chalcides sexlineatus from Gran Canaria (Canary Islands)

A survey of the gastrointestinal helminth communities of a population of Chalcides sexlineatus Steindachner, a small skink endemic to Gran Canaria island (Canary Archipelago, Spain), was conducted to determine the prevalence, abundance and species diversity of intestinal parasites in these reptiles. Only three parasite species were found, one cestode, Oochoristica agamae Baylis, 1919 and two nematodes, Parapharyngodon micipsae (Seurat, 1917) and Pharyngodonidae gen. sp. Helminth infracommunities of C. sexlineatus showed low values of abundance and species richness and diversity, being more similar to the helminth community of Tarentola boettgeri boettgeri (Steindachner) rather than those of Gallotia stehlini (Schenkel), both syntopic with the sampled host.