Helminth Diversity Research Articles

Morphological and molecular data on helminths of Didelphis virginiana and Philander vossi (Mammalia: Didelphidae) from the Yucatán Peninsula, southeast Mexico

In the present study, helminths from six Didelphis virginiana and one Philander vossi are reported using morphological techniques (clearing, staining, and scanning electron microscopy). Additionally, the 28S rRNA sequences of individuals from nine helminth taxa are provided. Phylogenetic analyses were performed with the new 28S rRNA sequences to confirm the identification and the genealogical relationships of the parasites. Thirteen helminth taxa were identified, comprising the trematodes Brachylaima sp. and Platynosomum illiciens, the cestode Mathevotaenia sp., the nematodes Cruzia americana, Cruzia tentaculata, Viannaia arriaguensis, Viannaia sp., Travassostrongylus sp., Strongyloides sp., Turgida turgida, Trichuris minuta, and Trichuris sp., and the acanthocephalan Oligacanthorhynchus microcephalus. All opossums were infected with at least four helminth taxa. In total, 17 new 28S rRNA sequences from nine helminth taxa were provided. These data, combined with previous records in Mexico, increase the number of helminth taxa parasitizing D. virginiana and P. vossi to 41 and 29, respectively. However, these reports are incompletes and concentered in localities of some states. It is possible that new surveys in the Nearctic and even Neotropical regions will reveal a higher helminth diversity in these mammals in the country.

Host-associated helminth diversity and microbiome composition contribute to anti-pathogen defences in tropical frogs impacted by forest fragmentation.

Habitat fragmentation can negatively impact wildlife populations by simplification of ecological interactions, but little is known about how these impacts extend to host-associated symbiotic communities. The symbiotic communities of amphibians play important roles in anti-pathogen defences, particularly against the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). In this study, we analyse the role of macroparasitic helminth communities in concert with microbial communities in defending the host against Bd infection within the context of forest fragmentation. We found that skin microbial and helminth communities are disrupted at fragmented habitats, while gut microbiomes appear more resilient to environmental change. We also detected potential protective roles of helminth diversity and anti-pathogen microbial function in limiting Bd infection. Microbial network analysis revealed strong patterns of structure in both skin and gut communities, with helminths playing central roles in these networks. We reveal consistent roles of microbial and helminth diversity in driving host-pathogen interactions and the potential implications of fragmentation on host fitness.

Diversity of Helminths of Insectivorous Mammals (Mammalia: Eulipothyphla) from Large Forest Protected Areas of the Middle Volga Region (European Russia)

Insectivores (Eulypotiphla) are a substantial component of Russian forest ecosystems. The parasites of these animals also form an important part of natural biocenoses and act as one of the factors in the formation of biodiversity. The Mordovia Nature Reserve and National Park “Smolny” are large, forested areas located in the center of European Russia. We studied the helminth fauna of insectivores in these protected areas in 2018–2022. In total, using the method of complete helminthological necropsy, we examined 478 individuals of shrews, moles, and hedgehogs and recorded 34 species of parasitic worms, i.e., 8 trematode, 7 cestode, 1 acanthocephalan, and 18 nematode species. The most diverse helminth fauna was found in Sorex araneus (22 species). The composition of helminths in S. isodon (12), Neomys fodiens (9), Sorex minutus, and Erinaceus roumanicus (8 species each) turned out to be less diverse. The lowest species diversity of helminths was observed in Neomys milleri (3) and Talpae europaea (2 species). Taking into account the newly obtained data, we conducted a review of the helminth diversity in shrews, hedgehogs, and moles in the Middle Volga region. According to our literature data, the helminth fauna of insectivores in this region consists of 52 species, including 14 cestodes, 13 trematodes, 22 nematodes, and 3 acanthocephalans. Most of them belong to the Palearctic faunal complex (36 species). The helminth fauna of insectivores in the studied protected areas was compared with the helminth fauna of micromammals in other areas of the Middle Volga region. Our comparative analysis showed a high and average degree of similarity in the helminth fauna within individual species and genera of Eulipotyphla.

Tremátodos y acantocéfalos asociados a mojarra amarilla (Caquetaia kraussii) en un sistema de laguna costera, San Onofre, Colombia

In Colombia, ichthyozoonoses caused by helminths are little studied and remain neglected by the public health sector, representing an interaction to be explored regarding biodiversity and health. Caquetia kraussi is a native fish of Colombia and Venezuela that is economically important due to its high consumption by local communities. This research records the fauna of parasitic helminths associated with C. kraussi in a coastal lagoon system in the Colombian Caribbean. Thirty-two specimens of C. kraussi were captured and inspected in February and December 2020, resulting in the collection of 242 helminths at the metacercariae stage and adults. Parasites included metacercaria of the trematodes Clinostomum sp., Austrodiplostomum sp., two forms of Posthodiplostomum and adults of Oligogonotylus andinus, and adults of the acanthocephalan Neoechinorhynchus sp. These results indicate that C. kraussii acts as a definitive host for O. andinus and Neoechinorhynchus sp., and as an intermediate host for Clinostomum sp., Posthodiplostomum spp. and Austrodiplostomum sp. This research reports for the second time a population of O. andinus in Colombia and the occurrence of a morphoespecies of the genus Neoechinorhynchus that could constitute a new record for Colombia. In addition to contributing to the knowledge of the diversity of fish-associated helminths, the results of this research will make it possible to generate recommendations for the management and control of helminthiasis in artificial fish farming systems that are supplied by natural tributaries, and favor the establishment of hosts and parasites.

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.

Prevalence of Helminths Infection in Wild Rodents of Northwestern Iran.

Rodents act as reservoirs, intermediate hosts, or definitive hosts for various zoonotic helminths. Parasitic diseases are among the critical factors affecting the survival and composition of wild rodent populations. Wild rodents share their habitat with domestic free-grazing animals, mainly sheep, stray dogs, and cats, which allows the transmission of helminth infections, such as Toxocara and Trichinella, to these animals. This study investigated the helminth parasite fauna of wild rodents in East Azerbaijan province, north-western Iran, and discussed the possibility of parasite transmission among wild rodents. A total of 204 rodents of 17 different species (spp.) were collected in north-western Iran. Information about the genus, developmental stage, and rodent spp. was recorded for each animal. The gastrointestinal tract, liver, and diaphragm were examined for the presence of helminths. The recovered specimens were identified based on references. The prevalence rate of helminth infection among the captured rodents was 67.16%. Meriones persicus (M. persicus) showed the highest infection and diversity rates. This spp. harbored the zoonotic helminth Capillaria hepatica and some spp. belonging to the genera Toxocara, Syphacia, and Hymenolepis. M. persicus specimens from mountainous areas showed the highest infection rate. This study aimed at evaluating the potential role of wild rodent spp. as reservoirs of helminth infection in East Azerbaijan province, Iran. M. persicus was the most common spp. in our study and represented a higher proportion of the infected rodents in terms of helminth diversity and frequency. Harboring zoonotic helminths, M. persicus represents a health risk. Further studies are recommended to evaluate the prevalence of these parasites in the human community and inform people concerned about the risk of disease transmission to humans through rodents.

DEVELOPMENT AND APPLICATION OF A METHOD FOR GENETIC DETECTION OF ENTEROBIUS VERMICULARIS IN SAMPLES OF PATIENTS WITH ENTEROBIАSIS

Purpose. The routine diagnosis of enterobiasis consists of a microscopic examination of perianal imprints on a transparent scotch tape for the presence of parasitic eggs. However, this method has low sensitivity when the number of eggs is small. The development of highly sensitive and specific methods, such as PCR, will increase the possibilities of detecting the parasite and will enable its genetic characterization. Material/Methods. The study was conducted from May 2022 to September 2022 and comprised 24 patients infected with Enterobius vermicularis. DNA was extracted from parasite eggs/adult worms using PureLink Genomic DNA Mini Kit (INVITROGEN), according to the manufacturer's instructions. Nested polymerase chain reaction (PCR) for detection of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was applied with two sets of primers. Results. The developed and described method for genetic determination of Enterobius vermicularis in samples from infected individuals is suitable and applicable to improve the diagnosis of the disease, as well as for further phylogenetic research of the parasite, which is of great importance for its successful treatment and control. Conclusions. Regardless of existing morphological diagnostic methods, genotyping studies concerning Enterobius vermicularis need to be deepened. Molecular-biological analyses increase diagnostic sensitivity, provide valuable knowledge about the geographic distribution and diversity of helminths, and allow the monitoring of therapy.

Helminth diversity and seasonality of Angiostrongylus cantonensis in hedgehogs from Mallorca.

Sentinel surveillance plays a critical role in monitoring pathogen circulation, assessing potential threats for species conservation, and evaluating the risk of spillover to human populations. This study provides a comprehensive exploration of helminth parasites in the Mediterranean-distributed hedgehog species Atelerix algirus in Mallorca, Balearic Islands. Using an integrated approach that combines necropsies and morphological and molecular identifications using the COI gene, we identified 11 helminth taxa in 135hedgehogs, representing half of those that died at the local wildlife hospital in Mallorca between 2019 and 2022. We report an overall A. cantonensis prevalence of 11.5% and confirm the first case of a subclinical neuroangiostrongyliasis infection in a wildlife host. Infection prevalences over the year revealed that only two species, the nematode A. cantonensis and the cestode Mathevotaenia sp., had a seasonal pattern, with most A. cantonensis cases occurring in autumn and, to a lesser extent, Mathevotaenia sp. cases in winter. This pattern is probably due to the higher abundance and greater activity of snails and slugs (intermediate hosts) during these seasons, with important implications for public health and strategies for prevention of neuroangiostrongyliasis. Other key findings include a high prevalence (88.1%) of the lungworm Crenosoma striatum and detection of the acanthocephalan Moniliformis saudi for the first time in A. algirus. We anticipate that our study will facilitate surveillance efforts and clarify species identities in future studies. Given the lethal effects of A. cantonensis infection in hedgehogs, further studies are needed to evaluate the threat this parasite represents to European wildlife.

Epidemiology and diversity of gastrointestinal tract helminths of wild ruminants in sub-Saharan Africa: a review.

This review summarises studies on distribution, diversity, and prevalence of gastrointestinal helminth infections in wild ruminants in sub-Saharan Africa. The results showed that109 gastrointestinal tract (GIT) helminth species or species complexes were recorded in 10 sub-Saharan African countries. South Africa reported the highest number of species because most studies were carried out in this country. Eighty-eight nematode species or species complexes were recorded from 30 wild ruminant species across eight countries. The genus Trichostrongylus recorded the highest number of species and utilised the highest number of wild ruminant species, and along with Haemonchus spp., was the most widely distributed geographically. Fifteen trematode species or species complexes were reported from seven countries. The genus Paramphistomum recorded the highest number of species, and Calicophoron calicophoron was the most commonly occurring species in sub-Saharan African countries and infected the highest number of hosts. Six cestode species or species complexes from one family were documented from 14 wild hosts in seven countries. Moniezia spp. were the most commonly distributed in terms of host range and geographically. Impala were infected by the highest number of nematodes, whilst Nyala were infected by the highest number of trematode species. Greater kudu and Impala harbored the largest number of cestodes. The prevalence amongst the three GIT helminths taxa ranged between 1.4% and 100% for nematodes, 0.8% and 100% for trematodes, and 1.4% and 50% for cestodes. There is still limited information on the distribution and diversity of GIT helminths in wild ruminants in most sub-Saharan African countries.

Diversity of helminths parasitizing Phalacrocorax brasilianus (Gmelin, 1789) in the Brazilian Amazon.

This study was carried out in northern Brazil to determine the prevalence of helminth parasites that infect Phalacrocorax brasilianus (Gmelin, 1789). Between July 2020 and July 2023, adult and larvae parasites were collected from the respiratory and gastrointestinal tract of 30 birds that died in fishing nets and in fishing corral in the municipality of Soure on Marajó Island. The identified parasites included the nematodes Contracaecum sp., Contracaecum australe, Contracaecum rudolphii sensu lato, Contracaecum microcephalum, Contracaecum multipapillatum, Syncuaria squamata, Desportesius invaginatus, Tetrameres sp., Aplectana sp., Cyathostoma sp., Eucoleus contortus, Baruscapillaria spiculata, Baruscapillaria appendiculata; the trematodes Drepanocephalus spathans, Austrodiplostomum mordax, Austrodiplostomum compactum, Hysteromorpha triloba; the cestodes Paradilepis caballeroi; and the acanthocephalans Andracantha sp., Southwellina hispida and Southwellina macracanthus. The whole prevalence was 96.66% (29/30) and the most frequent helminths were nematodes (96.66%; 29/30), followed by acanthocephalans (66.66%; 20/30). These data increase the knowledge about helminths in cormorants widely distributed to Marajó Island.

Islands, saurians and parasites

A review and discussion of the results obtained after more than 40 years of research on parasites of insular saurian reptiles in some areas of the Mediterranean and the Atlantic has been carried out. Twenty-seven species and subspecies belonging to seven different genera of lizards were analysed, revealing the existence of diverse helminth communities, related to different biotic and abiotic characteristics of the hosts and habitats. The biogeographical and evolutionary particularities of the endemic parasites found are detailed and commented, as well as the peculiarities of the helminth fauna of the hosts in relation to their type of feeding or their age and size. The capacity and opportunity of saurian hosts in the dispersal of parasite species and the importance of parasites as bioindicators are also analysed.

Helminth fauna of saffron cod <i>Eleginus gracilis</i> in the coastal waters of the Magadan Region (northern coast of the Okhotsk Sea)

Results of parasitological investigation of saffron cod Eleginus gracilis Tilesius, 1810 are presented. The fish samples were collected in 6 distanced marine areas at the coast of Magadan Region, generally corresponded with local stocks or herds of this species. In total, 29 helminth species are identified, including 8 cestodes, 11 trematodes, 5 nematodes, and 5 acanthocephalans. The highest species diversity of helminths is detected for the saffron cod from the Odyan Bay (24 species) and the lowest – for the saffron cod from the Amakhton Bay (16 species). Occurrence and intensity of infestation is the highest for trematodes Hemiurus levinseni, Podocotyle reflexa, and Brachyphallus crenatus, nematodes Ascarophis pacifica, and acanthocephalans Echinorhynchus gadi and Corynosoma strumosum. The number of detected worm species is close to the total number of these parasites recorded for saffron cod in the Far-Eastern Seas and adjacent Pacific – 33 species (excluding monogeneans). Cestodes Diplocotyle olrikii, trematodes Bucephaloides iskaensis, and acanthocephalans Bolbosoma caenoforme are registered for the first time for saffron cod in the Okhotsk Sea. There is found for the first time in the studied area that saffron cod is a definitive host for trematodes Steganoderma formosum and a paratenic host for acanthocephalans Andracantha mergi. Eight species dangerous from medical and (or) veterinary point are detected: Nybelinia surmenicola, Diphyllobothrium sp., Pyramicocephalus phocarum, Anisakis simplex, Pseudoterranova decipiens, Bolbosoma caenoforme, Corynosoma semerme, and C. strumosum. The data on helminth infestation are not useful for differentiation of the saffron cod sub-populations in the northern Okhotsk Sea because of almost permanent partial mixing of these groups.

Overview of Helminths in Land Vertebrates from the Mordovia Nature Reserve, European Russia

In this study, we summarized our own and literature data on the helminth fauna in amphibians, reptiles, birds, and mammals inhabiting the Mordovia Nature Reserve (European Russia). The history of research on parasitic worms in vertebrates has more than 70 years here. Nowadays, 242 species of helminths have been identified in vertebrates in this protected area: 54 cestodes, 87 trematodes, 98 nematodes, and 3 acanthocephalans. Of these, 169 helminth species have an indirect life cycle, while 73 develop directly. 217 revealed parasite species use vertebrates as definitive hosts and 21 as intermediate and/or parathenic hosts. Three species of trematodes, Gorgoderina vitelliloba, Haplometra cylindracea, and Opisthioglyphe ranae combine the larval and mature lifestyle stages in amphibians. The most diverse helminth fauna is in rodents (41 species), birds (38), artiodactyls (37), and insectivores (35). Less rich in amphibians (32), bats (32), reptiles (26), and carnivores (19). Only six parasite species are found in hares. Most of the helminth species recorded in the vertebrates of the Mordovia Nature Reserve belong to the Palearctic faunistic complex – 107 species. Fifty-eight species are cosmopolitan. The range of 39 species covers the Holarctic. The distribution of 37 species of helminths is limited to Europe. Seventy-three of 242 species found in the nature reserve’s vertebrates have medical and veterinary importance as potential pathogens of dangerous zoonoses.

A Report of Neglected Zoonotic Helminth Infections among House Rats in Selected Areas of Metro Manila and Region IV-A CALABARZON, Philippines

Soil-transmitted helminthiasis remains to be a major global health issue predominantly in tropical and sub-tropical regions including the Philippines. People living in poor areas without adequate sanitation are at high risk of contracting these diseases. Rodents and other mammalian species living near humans can serve as potential reservoir hosts and accelerate the spread of these parasitic infections. However, there are only few data and studies on environmental contamination, animal reservoirs, and the zoonotic potential of these parasites. The aim of this study was to determine the faunal diversity of helminths among house rats in selected areas of Metro Manila and CALABARZON, Philippines. This information will serve as baseline data for the development of long-term and effective approaches to prevent and control the zoonotic transmission in the country. A total of 60 house rats were caught and grossly examined. The overall prevalence of soil-transmitted helminth infections was 96.67% (58/60). Of the cases, 51.67% (31/60) were reported in Metro Manila while 45.00% (27/60) were reported in CALABARZON. Capillaria hepatica was the most dominant endoparasite with the highest prevalence and intensity of infection. The four identified helminths namely Capillaria hepatica, Taenia taeniaeformis, Hymenolepis diminuta, and Raillietina spp. transmitted by these Rattus species namely Rattus norvegicus and Rattus tanezumi pose a health risk to the public as they are important reservoirs of zoonotic parasites that are capable of transmitting infection to humans. Therefore, it is necessary to regularly monitor and control rodent populations to reduce the spread of parasites in urban and rural areas.

Diversity and Composition of Gastrointestinal Helminths and Gram-Negative Bacteria of the West African Rainbow Lizard (Agama picticauda) in a Human-Modified Landscape: Implications for Conservation and Zoonosis

Emerging infectious diseases are negatively impacting herpetofaunal populations globally, posing a major conservation threat. Anthropogenic perturbations of natural habitats may influence wildlife disease dynamics and spillover events. Although viral and fungal diseases of vertebrates have received considerable studies, there is scant information on the enteric bacteria and helminths of herpetofauna. Here, we assessed the gastrointestinal helminths and Gram-negative bacteria of the West African rainbow lizard (Agama picticauda) in a human-dominated landscape in Accra, Ghana. We used the flotation method and standard cultural, morphological, and biochemical methods, for helminths and bacteria, respectively. Four helminth species, Ascaris spp., Enterobius spp., Pharyngodon spp., and Oxyurid spp., were identified, with overall high (71.9%) prevalence. Ascaris spp. (χ2 = 33.33, p < 0.001 ) and Pharyngodon spp. (χ2 = 14.5, p < 0.001 ) were more prevalent in suburban lizards during the wet season than dry season. The prevalence of Ascaris spp. and Enterobius spp. was significantly higher (χ2 = 12.34, p < 0.001 ) in urban than suburban lizards, while Oxyurid spp. was more prevalent (χ2 = 4.75, p = 0.03 ) in the suburban lizards during the wet season. The gut bacteria identified (prevalence) were Escherichia spp. (86.5%), Enterobacter spp. (75.7%), Proteus spp. (67.6%), Shigella spp. (40.5%), Klebsiella spp. (21.6%), and Salmonella spp. (16.2%). The prevalence of Escherichia spp. and Proteus spp. was significantly higher (χ2 = 5.77–7.34, p = 0.01 – 0.02 ) in suburban lizards than urban lizards during the wet season. Some Ascaris spp., Enterobius spp., Escherichia spp., Enterobacter spp., Shigella spp., and Salmonella spp. are found in humans. Our data can serve as baseline information for long-term monitoring studies of reptile-parasites-environment interactions in the Accra plains of Ghana. Further studies using molecular techniques are needed to ascertain the zoonotic helminths and bacteria of A. picticauda.

External and gastrointestinal parasites of the black-faced ibis Theristicus melanopis (Pelecaniformes: Threskiornithidae) in the Los Ríos region, southern Chile.

The black-faced ibis, Theristicus melanopis, is considered a useful bird species for agricultural activity because it preys upon various invertebrate and vertebrate pests. Although it is a common species in Chile, limited information is available regarding its parasites. The main objective of this study was to recover the diversity of ectoparasites and gastrointestinal helminths in black-faced ibises living in the communes of Valdivia and Panguipulli, Los Ríos region. A total of 74 specimens were received for examination from the Centro de Rehabilitación de Fauna Silvestre at the Universidad Austral de Chile (CEREFAS-UACh), Valdivia, in 2011-2015. Black-faced ibises were externally inspected for ectoparasites by direct examining of the plumage, and necropsies were performed to examine digestive and respiratory organs in search of endoparasites. For each taxon, prevalence, mean intensity, mean abundance, and range of parasites per bird were estimated. Five species of ectoparasites and six species of helminths were identified. A total of 298 lice (Insecta: Phthiraptera) belonging to four species were collected: Ardeicola melanopis (13.51%), Colpocephalum trispinum (20.27%), Ibidoecus fissisignatus (4.05%), and Plegadiphilus mamillatus (9.46%). In addition, one feather mite species, Diodochaetus melanopis (Acari: Pterolichoidea) (17.56%), was isolated. In 48 black-faced ibis (64.86%), a total of 1229 gastrointestinal helminths were found: two nematodes, Porrocaecum heteropterum (55.41%) and Baruscapillaria obsignata (24.32%); one tapeworm Eugonodaeum nasuta (20.27%); two digeneans, Echinoparyphium recurvatum (1.35%) and Strigea bulbosa (6.76%); and the acanthocephalan Sphaerirostris sp. (1.35%). The findings of the following parasites present new host-parasite associations: P. mamillatus, D. melanopis, B. obsignata, E. recurvatum, S. bulbosa, and Sphaerirostris sp. Additionally, the louse P. mamillatus, feather mite D. melanopis, platyhelminths E. nasuta, E. recurvatum and S. bulbosa, and the acanthocephalan Sphaerirostris sp. are new records for the fauna of Chile.

Diversity and prevalence of gastrointestinal helminths of free-roaming dogs on coastal beaches in Ecuador: Potential for zoonotic transmission.

Free-roaming dogs are highly exposed to a range of zoonotic parasites, including helminths, which can be transmitted to humans, particularly in rural tropical settings of developing countries. To evidence the diversity and prevalence of gastrointestinal helminths in the stools of free-roaming dogs on the public Pacific coastal beaches of Ecuador, a cross-sectional study was conducted from August 2021 to August 2022. The sampling beaches are located along the tropical Pacific coastal region. Stools were collected from the ground in containers with 10% formalin and processed using the Ritchie method; eggs were identified under a microscope. A total of 573 stools were examined from 20 beaches; the overall prevalence was 157 (27.4%) for one or more helminths. Ten parasites were identified, nine of which are potentially zoonotic. Ancylostoma spp. was the most prevalent (19.4%), followed by Toxocara spp. (7.2%). Trichuris spp., Dipylidium caninum, Diphyllobothrium spp., Capillaria spp., Dicrocoelium spp., Heterobilharzia americana, Hymenolepis spp. and Spirocerca spp. were also observed. Five of them are reported for the first-time infecting dogs in Ecuador. Hence, we evidenced that Ecuadorian beaches are highly contaminated with the dogs' zoonotic gastrointestinal helminths, posing a great risk to public health. Differences in the presence and prevalence were found in samples of tropical humid and dry climate zones. Therefore, based on our findings, we encourage the implementation of broad antiparasitic treatment and prevention strategies to reduce the zoonotic risk.

First helminthological data on the Iberian adder, Vipera seoanei

The helminth fauna present in the gut contents of Iberian adders, Vipera seoanei (Squamata: Viperidae), were characterised and analysed in respect to biological and eco-geographic factors that may affect the occurrence and diversity of helminths in this species. A total of 317 samples of preserved stomachs and intestines, covering the distributional range of V. seoanei, were examined. Similar to other Vipera species from the Iberian Peninsula, the helminth fauna was also impoverished in V. seoanei, but unlike other Vipera species from Central and East Europe, helminths were mostly found in adult vipers, and occurred in vipers located at the periphery of the species range, characterised by low elevation, high temperature and precipitation levels, and abundant pastures.

Helminths of freshwater turtles in Northeastern Brazil: parasite–host–environment relationships

ABSTRACT The parasitic fauna of reptiles is considered understudied compared to that of other vertebrates and is even less well known than the parasitic fauna of chelonians. Yet parasites are considered one of the main controllers of host populations because they can strongly impact population structure and species diversity. The objective of the present study was to identify the helminth fauna infecting freshwater turtles Phrynops geoffroanus and Mesoclemmys tuberculata, to evaluate the effects of host features (body mass and sex) and seasonality (dry and rainy seasons) on the abundance of parasites, and to compare infection rates in each host species between different biomes (Caatinga and Atlantic Forest) in an area of Northeastern Brazil. We found seven species of helminths that belong to Nematoda (Physaloptera sp., Serpinema amazonicus, Serpinema monospiculatus and Spiroxys figueiredoi), Cestoda (unidentified specimen), Digenea (Echinostomatidae) and Monogenea (Polystomoides brasiliensis). For both freshwater turtle species, we did not find a significant difference in the abundance of helminths related to the maximum carapace length, body mass or host sex; however, males had higher prevalence than females, while females presented greater abundance when infected. We observed significant differences in the infection levels between biomes and between seasons (dry and rainy), where the Atlantic Forest specimens showed higher infection rates compared to the Caatinga and the highest rates occurred in the dry season. The main parasitological parameters observed in P. geoffroanus and M. tuberculata showed that the studied biomes directly influenced the levels of parasitic infection. Variations in habitat characteristics can directly influence patterns of helminth diversity and abundance, and interactions between these characteristics can generate differences in parasitism rates of the same host species in different environments.

RANGE EXPANSION OF GREEN TREEFROGS (HYLA CINEREA) IN SOUTHERN ILLINOIS: NO EVIDENCE OF PARASITE RELEASE.

For several decades, green treefrogs (Hyla cinerea) have been undergoing rapid range expansion northward and eastward in Illinois, Indiana, and Kentucky. While range expansion of green treefrogs in these states may be linked to climate change, a recent study suggested this expansion could be facilitated by parasites, given that expanded range populations of green treefrogs from Kentucky and Indiana exhibited significant decreases in helminth species diversity compared to those examined from historical locations of Kentucky. Because rapid range expansion may lead to hosts escaping their parasites (= parasite release), a reprieve from parasitic infection could allocate additional resources to growth and reproduction and thus facilitate the expansion. The present study compares patterns of helminth diversity for green treefrogs from historical and 2 types (early and late expansion) of expanded range locations of southern Illinois to test whether these range-expansion populations are also experiencing a reduction in parasitism due to parasite release. The results of this study did not find significant differences in helminth diversity when helminth communities of green treefrogs from their historical and expanded ranges were compared. These results appear to downplay the putative role of parasite release in the northward range expansion of H. cinerea in Illinois. Studies are underway to determine whether local factors, including abiotic conditions and amphibian host diversity, play a more prominent role in influencing helminth diversity of green treefrogs.