Group Of Helminths Research Articles

HELMINTHS OF WOLF IN THE VORONEZH RESERVE AND ADJACENT TERRITORIES

The wolf is the largest predatory mammal in the Central Black Soil region of Russia. The close trophic relationships of the wolf with wild ungulates and other animals play an important role in the formation of the modern predator helminth fauna. Helminthological materials from the wolf have been collected in the Voronezh Reserve and in adjacent natural areas for a long-term period (1981–2018). The modern fauna of the helminths of the wolf of the Voronezh Reserve contains 16 species. The main taxonomic groups of helminths (trematodes, cestodes, and nematodes) in the wolf are represented unevenly. The maximum number of helminth species is registered among nematodes – 12 species (Aonchothe caputorii, Eucoleus aerophilus, E. boehmi, Pearsonema plica, Calodium hepaticum, Trichinella nativa, Toxocara canis, Toxaskaris leonina, Uncinaria stenocephala, Crenosoma vulpis, Molineus patens, Dirofilaria repens). We have identified three species of cestodes (Dypilidium caninum, Taenia hydatigena, T. krabbei) and one species of trematodes (Alaria alata). The highest infection rates were registered for A. alata: the extensiveness of invasion (EI) is 92.3%, the intensity of invasion is 149.7 specimens, an abundance index is 138.2 specimens. High rates of wolf invasion by certain nematode species were revealed: E. boehmi (69.2%); P. plica (46.2%); E. aerophilus (38.5%); C. hepaticum (15.4%) and nematode T. nativa (27.9%). More than ten species of helminths of the wolf are of significant epidemiological and epizootological importance for this area.

Micro- and macroparasite species richness in birds: The role of host life history and ecology.

Identifying the factors shaping variation in parasite diversity among host species is crucial to understand wildlife diseases. Although micro- and macroparasites may exert different selective pressures on their hosts, studies investigating the determinants of parasite species richness in animals have rarely considered this divide. Here, we investigated the role of host life history and ecology in explaining the species richness of helminths (macroparasites) and haemosporidians (microparasites) in birds world-wide. We collated data from multiple global datasets on diverse bird traits (longevity, body mass, coloniality, migration distance/tendency, geographic range size and dietary and habitat breadths) and the species richness of their helminth and haemosporidian parasites. We tested predictors of helminth and haemosporidian parasite richness using phylogenetic generalized linear mixed models in a Bayesian framework. We found that, after controlling for research effort and host phylogeny, the richness of helminths, but not of haemosporidians, increased with host longevity, range size, migration distance and dietary breadth. Overall, these correlates were also important across different helminth groups (acanthocephalans, cestodes, nematodes and trematodes), and two additional ones (body mass, coloniality) emerged as important for cestodes and acanthocephalans. We propose that long life spans may promote the diversity of helminth parasite assemblages over evolutionary time, thus resulting in richer helminth faunas. Similarly, longer-distance migrations, larger ranges and broader dietary breadths are likely to lead to greater encounter rates and the accumulation of trophically transmitted helminths. In contrast, vector-borne haemosporidians may be influenced more by factors related to vector ecology than by the host traits included in the analyses. The lack of strong associations between haemosporidian species richness and host characteristics emphasizes the need to find appropriate traits to model the distribution and diversity of parasites with different environmental preferences in order to anticipate disease emergence risks associated with global change.

Worldwide paleodistribution of capillariid parasites: Paleoparasitology, current status of phylogeny and taxonomic perspectives.

IntroductionPaleoparasitology, the study of parasites in the past, brings the knowledge of where and when they occurred in preterit populations. Some groups of parasites, as capillariids, have a complex and controversial systematic, hindering the paleoparasitological diagnosis. In this article, we synthesized the occurrence of capillariids in both the New and the Old World in ancient times, and discussed the difficulty of the diagnosis of species and the strategies for identification. The present review also shows the current status of the phylogeny in capillariids and indicates the necessity to try new approaches for a better understanding of capillariid paleodistribution.MethodsFor the systematic review, a predefined guideline defined by PRISMA was used. The articles collected were identified, screened, and included in the review following criteria for eligibility. The current status of the phylogeny of capillariids was accessed using MUSCLE, Bioedit v.7.0.5 and MEGA v. 7.0.21 programs.ResultsThe review discussed 38 articles that presented information about capillariids in past populations. Most of capillariid eggs found in the New and Old World were not identified. However, Calodium hepaticum eggs were the most identified, as some from Eucoleus genus. It was observed that sites from the New World had a better chance for capillariid egg identification, due to previous knowledge of its host, when compared to the Old World. In the 18S rDNA phylogenetic analyses, two datasets were constructed, one including sequences from 7 Moravec’s genera, where 3 genus-specific clusters, with high bootstrap values, could be observed for Capillaria (ML = 99%, NJ = 96%), Eucoleus (ML / NJ = 100%) and Paratrichosoma (ML / NJ = 100%). A fourth cluster of 18S rDNA dataset I revealed lack of definition of Pearsonema and Aonchotheca genera. The 18S rDNA dataset II comprised 8 Moravec’s genera and defined 3 clusters, 2 genus-specific for Eucoleus (ML = 99%, NJ = 100%) and Capillaria (ML / NJ = 98%). The third 18S rDNA dataset II cluster included 6 genera and exhibited, once again, Pearsonema and Aonchotheca poor discrimination. The cox1 gene data consist of 4 Moravec’s genera, and in spite of grouping some species-specific clusters, did not show genera-specific definition.ConclusionsDespite the numerous archaeological findings, both in the New and the Old Worlds, the identification of capillariid species based on the morphology and morphometry of eggs remains imprecise, often resulting in a generic diagnosis of a group or morphotype of capillariid. Capillariid is one of the most diverse group of helminths recovered in archaeological sites. The phylogenetic trees produced in this study showed limited genetic information available, unresolved genera and incongruence with the classical taxonomy. The elucidation of the paleodistribution of capillariids can give insights of the ancient host-parasite associations but also in modern sceneries.

Trematode Genomics and Proteomics.

Trematode infections are among the most neglected tropical diseases despite their worldwide distribution and extraordinary ability to parasitise many different host species and host tissues. Furthermore, these parasites are of great socioeconomic, medical, veterinary and agricultural importance. During the last 10years, there have been increasing efforts to overcome the lack of information on different "omic" resources such as proteomics and genomics. Herein, we focus on the recent advances in genomics and proteomics from trematodes of human importance, including liver, blood, intestinal and lung flukes. We also provide information on the latest technologies applied to study the biology of trematodes as well as on the resources available for the study of the molecular aspects of this group of helminths.

Socio-demographic factors facilitating intestinal helminth infestation and impact of single dose of mebendazole administration among the street children of Karwan Bazar, Tejgaon, Dhaka

A total of eighty stool samples from forty street children living in Karwan Bazar, Tejgaon area were collected to study the prevalence of intestinal helminths during February 2017 to May 2017. The highest prevalence of Ascaris lumbricoides and Trichuiris trichiura was observed among the children aged 13-15 (70%) years old followed by the age group 7-9. Male children were more A. lumbricoides prevalent (53.57%) followed by T. trichiura (46.43%) than the female children (41.67%; for both the A. lumbricoides and T. trichiura). Except Enterobius vermicularis and hookworm, heavy infestation with other worms was reduced; esspecially A. lumbricoides (50% to 12.5%) and T. trichiura (45% to 15%), after administering Mebendazole (Vermox 500mg, single dose). Children who collected waste material from dustbin were highly helminth prevalent group (91.67%) followed by vegetable shop worker (66.67%). In February 2017, double infection showed the highest occurrence (32.5%). After administering single dose of mebendazole, in May 2017, single infection was at the peak (55%). With the initiation of broad-spectrum anthelminthic drugs that are low-priced, non-hazardous and simple to deliver, further control programs should include health education, public and good personal hygiene practices among the street children.Asian J. Med. Biol. Res. June 2018, 4(2): 172-177

Co-infection patterns of intestinal parasites in arboreal primates (proboscis monkeys, Nasalis larvatus) in Borneo.

Non-human primates of South-East Asia remain under-studied concerning parasite epidemiology and co-infection patterns. Simultaneously, efforts in conservation demand knowledge of parasite abundance and biodiversity in threatened species. The Endangered proboscis monkey, Nasalis larvatus, a primate flagship species for conservation in Borneo, was investigated in the present study. Habitat loss and fragmentation are among the greatest threats to bachelor and harem groups of this folivorous colobine. Designed as a follow-up study, prevalence and co-infection status of intestinal parasites from N. larvatus in a protected area in Malaysian Borneo were analyzed from fecal samples using a flotation method. For the first time, the intestinal parasite co-infection patterns were examined using quantitative analyses. Overall, 92.3% of fecal samples (N = 652) were positive for helminth eggs. Five helminth groups were detected: (1) trichurids (82.7% prevalence) including Trichuris spp. (82.1%) and Anatrichosoma spp. (1.4%), (2) strongyles (58.9%) including Trichostrongylus spp. (48.5%) and Oesophagostomum/Ternidens spp. (22.8%), (3) Strongyloides fuelleborni (32.7%), (4) Ascaris lumbricoides (8.6%), and (5) Enterobius spp. (5.5%). On average, an individual was co-infected with two different groups. Significant positive associations were found for co-infections of trichurids with strongyles and S. fuelleborni as well as S. fuelleborni with A. lumbricoides and strongyles. This study shows a high prevalence of various gastrointestinal helminths with potential transmission pathways primarily related to soil and with zoonotic relevance in wild proboscis monkeys in their remaining natural habitats. Observed positive associations of trichurids with strongyles and Strongyloides spp. may result from the high prevalence of trichurids. Similarly, positive associations between Strongyloides and Ascaris were found, both of which typically occur predominantly in juvenile hosts. These findings should be considered when proposing conservation actions in altered habitats nearby human settlements and when managing captive populations.

Gastrointestinal trichostrongylosis can predispose ewes to clinical mastitis after experimental mammary infection

Objective was to study, in an experimental model, the possible role of gastrointestinal nematode infection in predisposing ewes to mastitis during the lactation period. Twenty-four ewes (A or B [n=12]), free from nematode and trematode helminths, were used. Group A animals received 5000 third-stage larvae of a trichostrongylid helminth cocktail and group B ewes were unparasitised controls. Animals in group A developed gastrointestinal trichostrongylosis confirmed by >500epg in faecal samples; mean epg of group B ewes were <20 (P<0.001). Ewes were challenged by deposition of Mannheimia haemolytica into the teat duct. In group A, 7 ewes developed clinical and 5 subclinical mastitis; no ewe in group B developed clinical mastitis, but only subclinical (12 ewes) (P=0.002). M. haemolytica was isolated from 132/132 and 121/132 udder samples from group A or B, respectively (P<0.015); increased leucocyte numbers were recorded in 66/66 and 61/66 samples, respectively (P=0.023). During post-mortem examination, mean number of helminths in gastrointestinal content was 2523 and 7.5 in group A or B, respectively (P<0.001); within group A, proportions of Teladorsagia and Haemonchus were significantly greater in ewes that developed clinical mastitis than in others which did not (0.709 and 0.162 versus 0.662 and 0.136, respectively; P<0.035). M. haemolytica was isolated from 36/36 and 19/36 udder tissue samples from group A or B, respectively (P<0.001). In ewes with subclinical mastitis (in group A or B), inducible-lymphoid-follicles were observed in the teat, which were not observed in ewes with clinical disease. Total pathology scores summed over all days were 127 and 73 for group A or B ewes, respectively (maximum possible 192; P<0.05). In general, there was positive correlation between intestinal helminth counts and pathology score (P<0.001) and between Teladorsagia counts and pathology score (P=0.002) in ewes that developed clinical mastitis. It is concluded that, in view of bacterial challenge, gastrointestinal trichostrongylosis and particularly Teladorsagia infection, might lead to clinical mastitis, through various pathogenetic pathways.

The importance of patient compliance in repeated rounds of mass drug administration (MDA) for the elimination of intestinal helminth transmission

BackgroundSystematic non-compliance to chemotherapeutic treatment among a portion of the eligible population is thought to be a major obstacle to the elimination of helminth infections by mass drug administration (MDA). MDA for helminths is repeated at defined intervals such as yearly or every 2 years, as a consequence of the inability of the human host to develop fully protective immunity to reinfection. As such, how an individual complies to these repeated rounds of MDA can have a significant impact on parasite transmission. The importance of this factor is poorly understood at present. Few epidemiological studies have examined longitudinal trends in compliance in the many communities in areas of endemic helminth infection that are undergoing MDA. Reducing systematic non-compliance will obviously increase the number of individuals treated, but it may also alter the dynamics of parasite transmission.MethodsHere we develop an individual-based stochastic model of helminth transmission and MDA treatment to investigate how different patterns of compliance influence the impact of MDA for two groups of helminths, the soil transmitted nematode infections and the schistosome parasites. We study the effect of several alternative treatment and compliance patterns on the dynamics of transmission.ResultsWe find that the impact of different compliance patterns, ranging from random treatment at each round of chemotherapy to systematic non-compliance by a proportion of the population, is very dependent on both transmission intensity in a defined setting and the type of infection that the treatment is targeted at. Systematic non-compliance has a greater impact on the potential for elimination of Schistosoma mansoni transmission by intensive MDA, than it does on Ascaris lumbricoides.ConclusionsWe discuss the implications of our findings for the prioritisation of resources in MDA programmes and for monitoring and evaluation programme design. The key message generated by the analyses is that great care must be taken to record individual longitudinal patterns of compliance at each round of MDA as opposed to just recording overall coverage.

An updated look at the uneven distribution of cryptic diversity among parasitic helminths.

Cryptic parasite diversity is a major issue for taxonomy and systematics, and for attempts to control diseases of humans, domestic animals and wildlife. Here, we re-examine an earlier report that, after correcting for sampling effort, more cryptic species of trematodes are found per published study than for other helminth taxa. We performed a meta-analysis of 110 studies that used DNA sequences to search for cryptic species in parasitic helminth taxa. After correcting for study effort and accounting for the biogeographical region of origins, we found that more cryptic species tend to be uncovered among trematodes, and fewer among cestodes and animal-parasitic nematodes, than in other helminth groups. However, this pattern was only apparent when we included only studies using nuclear markers in the analysis; it was not seen in a separate analysis based only on mitochondrial markers. We propose that the greater occurrence of cryptic diversity among trematodes may be due to some of their unique features, such as their mode of reproduction or frequent lack of hard morphological structures, or to the way in which trematode species are described. Whatever the reason, the high frequency of cryptic species among trematodes has huge implications for estimates of parasite diversity and for future taxonomic research.

RNA Interference and Nonspecific Controls in Parasitic Helminths

Despite of the remarkable success of RNA interference (RNAi) application in the free-living nematode Caenorhabditis elegans, the exploitation of this powerful technique to helminths parasites with complex life-cycle has been a challenge for parasitologists. It has proved to be effective only for certain parasite species and specific target genes. To date, RNAi is the only methodology available for reverse genetics in trematodes and combined to rescue studies (such heterologous complementation) have been the only alternative to genetic manipulation in nematodes and helminths parasites, thus this subject is of great interest to the scientific community involved in the field. The RNAi technique is widely used to assess gene function in helminths parasites, in order to elucidate their role in parasite development, mechanisms of drug resistance, and validate therapeutic targets for disease control. After fifteen years of the first report of RNAi in parasitic helminths, many advances have been achieved, but pitfalls remain as challenges in gene expression manipulation in these organisms. In addition to the methodological particularities of the RNAi technique for each group of helminths, there are still other reasons behind the slow progress of RNAi in those parasites, such; the lack of homology between genes related to parasitism and genes of model organisms and the complex life cycle of these organisms, which results in difficulties for in vitro cultivation. At this point, a wide assortment of approaches for doubled stranded RNA “delivery” has been proposed. Thus, deeper studies on fundamental aspects of the RNAi methodology in parasitic helminths, such as off-target and the use of controls, can be useful in determining the reason of variations between and within species, facilitating the experimental design and the use of RNAi in the study and eradication of helminths parasites.

A Preliminary Survey of Gastrointestinal Helminths of Murids (Rodentia: Muridae) at Five Selected Localities in Western Sarawak

Field survey of gastrointestinal helminths on rodents from family Muridae were conducted at five localities inWestern Sarawak from June 2013 until April 2014. A total of 31 host individuals comprising six species ofmurids were examined for gastrointestinal helminths using opportunistic necropsy. The hosts examined wereLeopoldamys sabanus, Maxomys rajah, M. surifer, M. whiteheadi, Niviventer cremoriventer and Sundamysmuelleri. Of these host species, 186 individuals consisting of two taxonomic groups of helminths wererecovered, namely Nematoda and Cestoda. This study contributes to the growing literature on the infestation ofendoparasites in rodents especially in Sarawak.

Taxonomic Quality of Species Descriptions Varies over Time and with the Number of Authors, but Unevenly among Parasitic Taxa.

Although concerns are being raised about a potential shortage of taxonomists and systematists, recent analyses suggest instead that the number of researchers involved in taxonomic descriptions is higher than ever and that the average number of new species described annually per taxonomist has declined in recent decades. Here, using nine metrics of taxonomic quality, such as the number of morphological traits measured, the number of separate line drawings included, and whether or not gene sequences are provided, we explore variation in taxonomic quality as a function of the number of authors and other potential determinants across 2366 descriptions of parasitic helminths published in 1337 articles between 1980 and 2014. Taxonomic quality has generally increased over time, but unequally among different groups of helminths. For example, the number of scanning electron micrographs per description has risen significantly over time in cestodes and nematodes, but decreased for digeneans. For most metrics used, the greater the number of authors per species description, the higher its quality, suggesting not more taxonomists but more collaborations between taxonomists and experts from other fields to produce more comprehensive species characterizations. Re-descriptions of species were of higher quality than their original descriptions, and the improved quality correlated with the number of years elapsed between them. However, the extent of this improvement varied among helminth species with different host taxa. Overall, our findings provide a note of caution for anyone using trends in the number of species described per author to extrapolate the total number of extant species. They also reveal cultural differences among taxonomists working on different groups of parasites that can serve to identify areas for potential improvement. [Biodiversity; Cestoda; Digenea; integrative taxonomy; Nematoda.].

Novel PCRs for differential diagnosis of cestodes

Cestodes or tapeworms belong to a diverse group of helminths. The adult Taenia saginata and Taenia solium tapeworm can infest the human gut and the larval stage of Echinococcus spp. and T. solium can infect tissues of the human body, causing serious disease. Molecular diagnostics can be performed on proglottids, eggs and on cyst fluids taken by biopsy. Detection of cestodes when a helminthic infection is suspected is of vital importance and species determination is required for appropriate patient care. For routine diagnostics a single test that is able to detect and type a range of cestodes is preferable. We sought to improve our diagnostic procedure that used to rely on PCR and subsequent sequencing of the Cox1 and Nad1 genes. We have compared these PCRs with novel PCRs on the 12S rRNA and Nad5 gene and established the sensitivity and specificity. A single PCR on the 12S gene proved to be very suitable for detection and specification of Taenia sp. and Echinococcus sp. Both targets harbour enough polymorphic sites to determine the various Echinococcus species. The 12S PCR was most sensitive of all tested.

Comparison of community-wide, integrated mass drug administration strategies for schistosomiasis and soil-transmitted helminthiasis: a cost-effectiveness modelling study.

More than 1·5 billion people are affected by schistosomiasis or soil-transmitted helminthiasis. WHO's recommendations for mass drug administration (MDA) against these parasitic infections emphasise treatment of school-aged children, using separate treatment guidelines for these two helminthiases groups. We aimed to evaluate the cost-effectiveness of expanding integrated MDA to the entire community in four settings in Côte d'Ivoire. We extended previously published, dynamic, age-structured models of helminthiases transmission to simulate costs and disability averted with integrated MDA (of praziquantel and albendazole) for schistosomiasis and soil-transmitted helminthiasis. We calibrated the model to data for prevalence and intensity of species-specific helminth infection from surveys undertaken in four communities in Côte d'Ivoire between March, 1997, and September, 2010. We simulated a 15-year treatment programme with 75% coverage in only school-aged children; school-aged children and preschool-aged children; adults; and the entire community. Treatment costs were estimated at US$0·74 for school-aged children and $1·74 for preschool-aged children and adults. The incremental cost-effectiveness ratio (ICER) was calculated in 2014 US dollars per disability-adjusted life-year (DALY) averted. Expanded community-wide treatment was highly cost effective compared with treatment of only school-aged children (ICER $167 per DALY averted) and WHO guidelines (ICER $127 per DALY averted), and remained highly cost effective even if treatment costs for preschool-aged children and adults were ten times greater than those for school-aged children. Community-wide treatment remained highly cost effective even when elimination of helminth infections was not achieved. These findings were robust across the four diverse communities in Côte d'Ivoire, only one of which would have received annual MDA for both schistosomiasis and soil-transmitted helminthiasis under the latest WHO guidelines. Treatment every 6 months was also highly cost effective in three out of four communities. Integrated, community-wide MDA programmes for schistosomiasis and soil-transmitted helminthiasis can be highly cost effective, even in communities with low disease burden in any helminth group. These results support an urgent need to re-evaluate current global guidelines for helminthiases control programmes to include community-wide treatment, increased treatment frequency, and consideration for lowered prevalence thresholds for integrated treatment. Stanford University Medical Scholars Programme, Mount Sinai Hospital-University Health Network AMO Innovation Fund.

Особенности пространственной структуры популяций мермитид (nematoda, mermithida – полостных паразитов беспозвоночных)

The spatial structure of the mermithidae popu-lation is determined by a number of features of their general ecological organization. Mermi-thidae represent a special fourth group of poly-biotropic helminths which development occurs predominantly in the external environment with a very short time step of parasitic larvae. However, the basis of their local (focal) disse-mination is limited locomotor capabilities. Mermithidae are characterized by complex spatial population structure, which are species complexes of sub-populations.

Helminth parasites in the endangered Ethiopian wolf, Canis simensis.

Ethiopian wolves, Canis simensis, are an endangered carnivore endemic to the Ethiopian highlands. Although previous studies have focused on aspects of Ethiopian wolf biology, including diet, territoriality, reproduction and infectious diseases such as rabies, little is known of their helminth parasites. In the current study, faecal samples were collected from 94 wild Ethiopian wolves in the Bale Mountains of southern Ethiopia, between August 2008 and February 2010, and were screened for the presence of helminth eggs using a semi-quantitative volumetric dilution method with microscopy. We found that 66 of the 94 faecal samples (70.2%) contained eggs from at least one group of helminths, including Capillaria, Toxocara, Trichuris, ancylostomatids, Hymenolepis and taeniids. Eggs of Capillaria sp. were found most commonly, followed by Trichuris sp., ancylostomatid species and Toxocara species. Three samples contained Hymenolepis sp. eggs, which were likely artefacts from ingested prey species. Four samples contained taeniid eggs, one of which was copro-polymerase chain reaction (copro-PCR) and sequence positive for Echinococcus granulosus, suggesting a spillover from a domestic parasite cycle into this wildlife species. Associations between presence/absence of Capillaria, Toxocara and Trichuris eggs were found; and egg burdens of Toxocara and ancylostomatids were found to be associated with geographical location and sampling season.

Gryporhynchidae (Cestoda: Cyclophyllidea) in Mexico: species list, hosts, distribution and new records.

As a result of this study, 8 new host (Botaurus lentiginosus for Glossocercus caribaensis and Valipora mutabilis; Egretta caerulea for Valipora minuta; Egretta thula for Glossocercus cyprinodontis; Egretta tricolor and Nycticorax nycticorax for Glossocercus caribaensis; Pelecanus occidentalis and Platalea ajaja for Paradilepis caballeroi) and 31 new locality records for gryporhynchid cestode species in Mexico are presented. With these data, the total number of species of this group of helminths in Mexico becomes 25 (19 named species and 6 unidentified taxa), which have been registered as parasites of fishes (47 host species) and (or) birds (20 host species). This information comes from 102 localities, pertaining to 20 of 32 Mexican states. Five of the 25 taxa have been exclusivelly collected in fishes, 7 in fish-eating birds, and 13 in both groups of hosts. The most frequent metacestodes found in Mexican fishes are the merocercoids of Cyclustera ralli, Valipora mutabilis, Parvitaenia cochlearii and Valipora campylancristrota; in adult stage, Glossocercus caribaensis was the species with the largest host spectrum, while Paradilepis caballeroi has the widest distribution range. The work includes parasite/host lists, as well as habitat, distribution, references and information on specimens' deposition.

Richness and diversity of helminth species in eels from a hypersaline coastal lagoon, Mar Menor, south-east Spain

The composition and diversity of parasite communities and intestinal components, as well as infra-community structure, were assessed in eels Anguilla anguilla, from Mar Menor, a permanent Mediterranean hypersaline coastal lagoon. Data were used to determine whether this helminth community differs in composition and structure from that of eels in lagoons with lower salinity regimes and higher freshwater inputs. A total prevalence of 93% was detected. Specifically, parasites were identified as Deropristis inflata, Bucephalus anguillae, Contracaecum sp., Anguillicoloides crassus and two plerocercoid larvae belonging to theorder Proteocephalidae, the marine species representing 91% of the isolated helminths. In the total community, digenetic trematodes were the dominant group of helminths, and D. inflata, an eel specialist, dominated both the component community and the infra-community. Richness and diversity were low but similar to those reported in other saline lagoons, and maximum species per eel did not exceed four. At the infra-community level, higher abundance than in other brackish or marine Mediterranean environments was detected. The findings provide further evidence of the similarity in composition and structure of helminth communities in eels from various Mediterranean coastal lagoons. Moreover, salinity-dependent specificities are well supported and reflect the life history of individual eels.

Helminth Communities of Green and Brown Frogs from Poland (Lower Silesia Region)

Green Frogs (genus Pelophylax) and Brown Frogs (genus Rana) differ because of behavioral reasons. Green Frogs in the adult stage are associated strongly with aquatic environment, and the Brown Frogs, apart from reproduction, spend most of their lives in the terrestrial environment. The aim of this study was to investigate the helminth fauna of these frogs from Lower Silesia (Poland) and update data on occurrence of parasites in these hosts. During faunistic investigations, 116 frogs were subjected to parasitological studies. Adult stages of all helminth groups were present in the examined frogs. The highest species richness of helminths was observed in Rana arvalis, whereas the lowest species richness occurred in Pelophylax lessonae. In the examined material, we were able to identify Nematotaenia dispar in R. arvalis. Additionally, we recorded Icosiella neglecta and Hedruris androphora in Green Frogs. The parasite communities of Green Frogs were dominated by digeneans, but terrestrial amphibians (Brown Frogs), by nematode species (i.e., Cosmocerca ornata, Oswaldocruzia filiformis, and Rhabdias bufonis).

Biodiversidad de Nematoda parásitos de vertebrados en México

The richness of nematode parasites of wild vertebrates of Mexico known so far consists of 402 nominal species, which account for 4.8% of the world’s total. This group of helminths has been recorded in 720 localities in all states of Mexico, even though their representation is heterogeneous as states such as Aguascalientes have only 2 species, while others such as Chiapas have 86. The largest number of hosts studied corresponds to the Actinopterygii, with 167 species; however, the greatest richness of nematode species is found in mammals with 166 species. To complete the inventory of nematodes parasitic on wild vertebrates of Mexico is still a long and complex task. If the average rate of nematode species recorded by host reviewed (0.97) continues, and considering that there are 4 983 vertebrate species distributed in the country that have not been studied yet from the standpoint of nematology, we could estimate that at least 5 137 species of nematodes remain to be described in the country.