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The purpose of the research is to study the parasite fauna of the common frog (Rana temporaria Linnaeus, 1758) inhabiting the vicinity of the Visim Nature Biosphere Reserve.Materials and methods. The species composition, dominance structure and endoparasite infection of 32 individuals of R. temporaria caught along the banks of the upper reaches of the Sulem Riverwere assessed according to the following indicators: the prevalence and intensity of infection and abundance index.Results and discussion. The species composition of parasites in a common frog from the vicinity of the Visim Nature Biosphere Reserve is presented for the first time. Five species of macroparasites have been identified, classified as Nematoda: Oswaldocruzia filiformis (Goeze, 1782), Neoraillietnema praeputiale (Skrjabin, 1916), Cosmocerca ornata (Dujardin, 1845), Rhabdias bufonis (Schrank, 1788) and as Platyhelminthes: Haplometra cylindracea (Zeder, 1800). One species of endosymbiotic protozoa of Chromista, Opalina ranarum was recorded (Purkinje et Valentin, 1835). The prevalence of the infection of common frogs by helminths reaches 100%, the abundance index is 11.06, and protozoa is 93.8% and 62.16, respectively. Nematodes O. filiformis (the prevalence of infection 96.9%, and abundance index 7.97) and R. bufonis (the prevalence of infection 46.9%, abundance index 2.28) predominate. It was shown that nematode N. praeputiale was not found in the parasitocenosis of immature amphibians, and trematode H. cylindracea was not found in adult animals. The proportion of O. filiformis and C. ornata increases with age in common frogs. It was found that the animals of the July population are infected with nematode R. bufonis largely. Regardless of the age of R. temporaria, the probability of colonization by O. ranarum in spring will be higher.

One of the candidates for the role of a model species in the study of the biology and evolution of helminthes is the nematode R. bufonis. For this status, insufficient information has been accumulated on the nematode infection of the hosts in biotopes of different landscapes, on the long-term, seasonal and gender-age dynamics of the helminth abundance, on the peculiarities of the development cycle in natural conditions and under anthropogenic pollution. In this work, data are presented on the infection of the moor frog from 14 biotopes of the steppe zone of the Republic of Kazakhstan. Data were obtained from the autopsy of 2637 specimens of R. arvalis. Almost half of the hosts were caught at the experimental site (0.5–0.7–500 m) in the floodplain of the Irtysh River, where helminthological monitoring of R. arvalis was conducted for 14 years. It was established that the distribution of the number of R. bufonis in the populations of the moor frog belongs to the over scattered distribution. According to the level of host infection extensiveness, the abundance index, and the ratio of the actual and theoretical number of nematodes, three groups of biotopic samples were distinguished: those with high, medium, and low values of infection parameters. The infestation of the amphibian R. bufonis was determined by the presence and size of zones in the biotopes with a moistened and oxygen-enriched substrate. Part L4 of R. bufonis on the way to the lungs of the moor frogs get stuck in small vessels, enter the body cavity and accumulate. Helminthes in the body cavity grow in length, but their genitals do not develop. The nematode infestation of frogs depends on the time of sampling, the age, and to a lesser extent, the sex of the caught individuals. The highest values of the extent of invasion of the host’s lungs and body cavity and the number of helminthes in the natural conditions of the Irtysh River floodplain and in anthropogenic biotopes was observed in May and September, the lowest – in July. The minimum abundance of R. bufonis and the extent of lung invasion of R. arvalis is typical for younger age groups (body length 13.0-30.0 mm), the maximum – for older groups (body length > 36.1 mm). The host body cavity is more infected in young individuals (body length 20.1–30.0 mm). Large R. arvalis (body length > 36.1 mm) are less infected. Homing, or the proportion of R. bufonis, which successfully populate the lungs of the youngest frogs (body length ≤ 20.0 mm) is 42.3, and the largest amphibians (body length ≥ 44.1 mm) is 87.7 % In the Irtysh River floodplain and in the anthropogenic biotopes of the city of Pavlodar, the nematode twice implements a development cycle during one season. The first, spring-summer, is carried out in May – July of each current season. Post-invasive larvae of the spring generation that have penetrated the body cavity of R. arvalis remain there for 2.5–3 months. The spring generation of parasitic female nematodes lasts longer in the lungs, at that some of the individuals merge with the seasonal flow of autumn helminth generation. The development of the latter occurs in two stages. During the first one, all free-living stages of the nematode develop. It ends infecting of the host’s lungs and body cavity. Further development is interrupted by the winter dormancy of the frog and its parasites. The last part of the autumn cycle of nematode development in warm autumn (August – September) occurs within one month. The second stage of the life cycle of R. bufonis: the release of eggs by females into the lungs of frogs ends at the beginning of the next season. The second cycle of helminth development, including winter dormancy, lasts 11–13 months. R. bufonis is a species with opportunistic populations. Long-term waves of nematode abundance and infection of the lungs and body cavity of R. arvalis occur in the floodplain of the river Irtysh synchronously, with a period of 3–4 years.

Summary Fourty seven specimens of Pelophylax ridibundus were collected in the vicinity of Shiraz, Fars Province, Iran in 1972. Fourteen helminth species were found, eight digeneans (Diplodiscus subclavatus, Halipegus alhaussaini, Haematoloechus similis, Codonocephalus urniger, and four species of metacercariae) and 6 nematodes (Cosmocerca ornata, Rhabdias bufonis, Abbreviata sp., Eustrongylides sp., Onchocercidae gen. sp. and one species of larval nematodes). Of these, only six are adults, while 8 are in their larval stage. The most prevalent helminths were the metacercariae of Codonocephalus urniger (61.7%) and the larvae Abbreviata sp. (55.32%). The adults with the highest prevalence are the digenean Halipegus alhaussaini, and the nematode Cosmocerca ornata (34% in both cases).

This is the first review of the helminth fauna of the moor frog Rana arvalis Nilsson, 1842 from the Volga river basin (Russia). The article summarizes the authors’ and literature data on the helminthic fauna of this species. The method of complete helminthological dissection was used. Thirthy-eight helminth species were recorded from three classes: Cestoda (1), Trematoda (28), and Chromadorea (9). Nine helminth species are new to the moor frog in Russia: trematodes Gorgodera varsoviensis Sinitzin, 1905, Strigea falconis Szidat, 1928, larvae, Neodiplostomum spathoides Dubois, 1937, larvae, Tylodelphys excavata (Rudolphi, 1803), larvae, Pharyngostomum cordatum (Diesing, 1850), larvae, Astiotrema monticelli Stossich, 1904, larvae and Encyclometra colubrimurorum (Rudolphi, 1819), larvae, nematodes Strongyloides spiralis Grabda-Kazubska, 1978 and Icosiella neglecta (Diesing, 1851). The cestode Spirometra erinacei (Rudolphi, 1918), larvae were observed of this amphibian species in the Volga basin for the first time. The nematodes Rhabdias bufonis, Oswaldocruzia filiformis, Cosmocerca ornata and the trematode Haplometra cylindracea form the core of the helminth fauna of the moor frog. Information on species of helminths includes systematic position, localization, areas of detection, type and scheme of life cycle, geographical distribution, and degree of specificity to host amphibians.

Sixty-nine subdesert toads, Amietophrynus (Bufo) xeros, were collected in Shendi, Sudan, from August to November 2014, and examined for the first time for the presence of internal helminth parasites. Sixty-seven (97.1%) of the toads were found infected with one or more helminth species including, four Nematoda: Aplectanamacintoshii, Rhabdiasbufonis, Strongyloidesprokopici, and Oswaldocruzia sp.; one Trematoda: Mesocoelium sp.; one Cestoda: Lanfrediella sp. A higher prevalence and intensity of infection was found in male toads compared with females, and old toads were found to harbor a higher prevalence and intensity of infection when compared to younger ones. However, neither of these differences was statistically significant. In addition, there were no significant correlations found between the gender of the toads examined and either the prevalence or intensity of infection of any of the helminth species. Likewise, the prevalence and intensity of infection of the helminth species were not significantly correlated with the snout-vent length of the toads.

The composition of helminths and infestation indices of two frog species of living in Western Siberia (Rana arvalis (n = 1082) and Rana amurensis (n = 33)) have been studied. Nine helminth species, including four nematodes and five trematodes, have been found. The following species were dominant and infected both frog species: nematodes Rhabdias bufonis, Oswaldocruzia filiformis, and Cosmocerca ornata and trematodes Haplometra cylindracea. The moor frog also hosted Dolichosaccus rastellus, Opisthioglyphe ranae, Pharingostomum cordatum (larvae), Parastrigea robusta (larvae), and Neyraplectana schneideri. The moor frog was characterized by higher species richness and diversity of helminths than the Siberian tree frog. The overall rates of helminth infestation have been the same in the moor frog and the Siberian tree frog. The invasion extensity was 85–100%; the index of abundance was 5.2–27.5. Differences in infestation rates of certain species by helminths were due to the biological peculiarities of the frog species.

The lung-dwelling nematode Rhabdias engelbrechti sp. n. was found in five of eight examined banded rubber frogs in Limpopo Province, South Africa. The species is differentiated from species of Rhabdias Stiles et Hassall, 1905 occurring in the Afrotropical Realm based on the presence of a globular cuticular inflation at the anterior end, the buccal capsule walls being distinctly divided into anterior and posterior parts, the buccal capsule size (6-9 μm × 16-18 μm), and the body length (3.8-6.1 mm). Rhabdias engelbrechti is the tenth species of the genus found in Afrotropical anurans. Our molecular phylogenetic analysis based on the complete sequences of the ITS region and partial sequences of large subunit (28S) gene of the nuclear ribosomal RNA demonstrates that the new species is more closely related to the Eurasian species Rhabdias bufonis (Schrank, 1788) than to two other species from sub-Saharan Africa represented in the tree. In addition, partial sequences of the mitochondrial protein coding cox1 and ribosomal 12S genes of the new species have shown significant differences from all previously published sequences of these genes from African species of Rhabdias.

Parasite load effect on the spermatozoa motility of the moor frog ( Rana arvalis Nilsson, 1842) native urinal sperm has been evaluated for the first time. Seven species of parasites were identified: Nematoda — Oswaldocruzia filiformis (Goeze, 1782), Neoraillietnema praeputiale (Skrjabin, 1916), Cosmocerca ornata (Dujardin, 1845), Rhabdias bufonis (Schrank, 1788); Trematoda — Dolichosaccus rastellus (Olsson, 1876), Haplometra cylindracea (Zeder, 1800); Opalinatea — Opalina ranarum (Dujardin, 1841). We found no impact of population specificity on sperm motility. The strong negative correlation between motile spermatozoa proportion and O. ranarum abundance was observed. For the purpose of selecting the optimal model of dependence pattern (linear-, logarithmic-, sigmoid- or threshold function), the Consistent Akaike Information Criterion (CAIC) was used. When the O. ranarum abundance was above the estimated threshold — 7.3 (95% CI 0.9 – 13.6) trophonts per probe, the expected probability to observe motile spermatozoa in the urinal sperm of moor frog decreased by 3.6 (95% CI for Risk Ratio: 1.9 – 6.8) times.

In this research, two bufonid toad species (Bufo bufo and Bufo (Pseudepidalea) viridis) were collected in Denizli province (Inner-west Anatolia Region — the eastern part of Aegean Region) Turkey between 2006 and 2009 and examined first time for helminths. Of 6 Bufo bufo, 5 (97.87 %) were infected with one or more helminths, of 47 Bufo viridis 46 (87.91 %) were infected with one or more helminths. The helminth fauna of Bufo bufo included 5 species of which were 4 species of nematodes (Rhabdias bufonis, Oswadocruzia filiformis, Cosmocerca ornata, and Oxysomatium brevicaudatum), and 1 species of acanthocephalan (Acanthocephalus ranae). The helminth fauna of Bufo (Pseudepidalea) viridis comprised 7 species with 1 species of monogenean (Polystoma viridis), 1 species of cestoda (Nematotaenia dispar), and 5 species of nematodes (R. bufonis, O. filiformis, C. ornata, C. commutata, and O. brevicaudatum). R. bufonis, O. filiformis, C. ornata, and O. brevicaudatum were observed in both bufonid toads.

The population of the common toad, Bufo bufo, on Jersey (Channel Islands, UK) has undergone a marked decline over recent years. Hypothesized causes for this decline include land use change, pollution, climate change and predation. We examined the carcasses of 97 wild adult common toads for gastrointestinal and pulmonary helminths. In addition, 31 adult toad carcasses were examined for the presence of ranavirus infection, and 212 wild common toads were examined for the presence of infection with the fungus Batrachochytrium dendrobatidis. Three nematode species Rhabdias bufonis, Aplectana macintoshii and Oswaldocruzia filiformis, and one species of cestode, Nematotaenia dispar, were identified. None of the animals examined tested positive for either B. dendrobatidis or ranavirus infection. Although this study should be considered a preliminary health screening, results lead us to suggest the decline of the common toad on Jersey is more likely to be driven by environmental factors rather than by pathogens.

Information on the parasites of common African toads ( Bufo regularis ) is still limited, judging by the global efforts to conserve amphibians. This informed the decision to provide baseline data of the gastrointestinal parasites of B. regularis of Umuahia South Local Area (LGA) of Abia State, Nigeria. Using standard methods, 321 B. regularis comprised of males, n =145, 45.17% and females n =176, 54.83% were collected from five communities (Old Umuahia, Amakama, Okwu, Ubakala and Agbama) in Umuahia South LGA, between June and November 2014. They were later examined for gastrointestinal parasites using standard procedures. Data analysis revealed that male B. regularis had more (n = 61, 19.03%) gastrointestinal parasites than the females (n = 58, 18.69%). Different species of gastrointestinal parasites belonging to class Cestoda ( Osphiotaenia nigriocollis, Lanfrediella sp and Proteocephalid Cestode larva ); Trematoda ( Messoceolium monody and Echinostoma revolutum ), Nematoda ( Amplicaecum africanum, Rhabdias bufonis, Ascaridoid, Oswaldocruzia pipiens and Camallanus sp ) and Protozoa ( Nyctotheroides bambuiensis, Lankesterellla bufonis and Protoopolina sp ) were identified with prevalence 20.25%, 4.36%, 7.48% and 4.98%, respectively. Prevalence of parasites varied significantly (p

Examination of a small collection of the green toad from Baghdad area, central Iraq revealed presence of two cestodes Proteocephalus sp. and Nematotaenia dispar and four nematodes Oswaldocruzia filiformis, Cosmocerca commutat, Cosmocercoides variabilis and Rhabdias bufonis.

A total of 33 agile frogs (Rana dalmatina) were collected from 7 localities in Edirne, Bursa and Adapazarı Provinces (Northwest of Turkey), between 1987–2007 and examined for the first time for helminths. R. dalmatina harbored one species of Monogenea (Polystoma sp.), 3 species of Digenea (Diplodiscus subclavatus, Pleurogenoides medians, and Pleurogenes claviger), 4 species of Nematoda (Rhabdias bufonis, Oswaldocruzia filiformis, Cosmocerca ornata, and Oxysomatium brevicaudatum) and one species of Acanthocephala (Acanthocephalus ranae). All helminths represent new host records for Rana dalmatina in Turkey.

Fifty-four Caucasian parsley frogs, Pelodytes caucasicus, from Turkey were examined for helminths in 2005. Found were 1 species of Digenea, Gorgodera cygnoides; 5 species of Nematoda, Agfa tauricus, Aplectana brumpti, Cosmocerca ornata, Oswaldocruzia filiformis, and Rhabdias bufonis; and 1 species of Acanthocephala, Pseudoacanthocephala caucasicus. Pelodytes caucasicus represents a new host record for each of the parasite species; Agfa tauricus and Pseudoacanthocephala caucasicus are reported from Turkey for the first time.

One hundred forty-three banded frogs Rana camerani were collected from 2 localities in Turkey between 2000 and 2004 and examined for helminths. One species of Monogenea (Polystoma sp.), 5 species of Digenea (Gorgodera cynoides, Gorgoderina vitelliloba, Haplometra cylindricae, Opisthioglyphe rastellus, Pleurogenoides medians), 1 species of Cestoda (Nematotaenia dispar), 3 species of Nematoda (Cosmocerca ornata, Oswaldocruzia filiformis, Rhabdias bufonis), and 1 species of Acanthocephala (Acanthocephalus ranae) were found. Rana camerani represents a new host record for each of the collected parasite species.

Fifty-four Rana holtzi and 84 Rana macrocnemis from Turkey were examined for helminths. Rana holtzi harbored 3 species of Digenea (Gorgoderina vitelliloba, Haplometra cylindracea, Opisthioglyphe rastellus) and 1 species of Nematoda (Cosmocerca ornata). Rana holtzi is a new host record for these helminths. Rana macrocnemis harbored 1 species of Monogenea (Polystoma macrocnemis), 5 species of Digenea (Opisthioglyphe rastellus, Gorgoderina vitelliloba, Haplometra cylindracea, Pleurogenes claviger, Pleurogenoides medians), 3 species of Nematoda (Rhabdias bufonis, Cosmocerca ornata, Oswaldocruzia filiformis), and 1 species of Acanthocephala (Acanthocephalus ranae). Rana macrocnemis represents a new host record for H. cylindracea, O. rastellus, and P. medians.

Marsh frogs (Rana ridibunda) were collected in Antalya province, southwestern Turkey, during 2001 and 2002 and examined for helminths. Of 258 frogs, 235 (91.1%) were infected with 1 or more helminths. The helminth fauna of R. ridibunda comprised 16 species: 10 species of trematodes (Codonocephalus urnigerus [metacercariae], Diplodiscus subclavatus, Gorgodera cygnoides, Gorgoderina vitelliloba, Pleurogenoides medians, Prosotocus confusus, Brachycoelium salamandrae, Haematoloechus breviansa, Encyclometra colubrimurorum [metacercariae], and Opisthioglyphe ranae), 5 species of nematodes (Rhabdias bufonis, Cosmocerca commutata, Neoxysomatium sp., Eustrongylides sp., and Abbreviata sp. [larvae]), and the acanthocephalan Acanthocephalus ranae. Encyclometra colubrimurorum (metacercariae), B. salamandrae, Neoxysomatium sp, Eustrongylides sp., and larval Abbreviata sp. represent new host records for R. ridibunda in Turkey.

In this paper we considered information on the helminth fauna of the European common brown frog (Rana temporaria Linnaeus, 1758) from 10 regions of the Volga basin. This study includes consolidated data of different authors over the last 30 years, supplemented by the results of our own research. There are reliably known finds of 29 species of helminths: Monogenea — 1, Trematoda — 21, Nematoda — 7. Trematodes Gorgodera asiatica Pigulevsky, 1945, Paralepoderma cloacicola (Luhe, 1909), mtc. and nematodes Icosiella neglecta (Diesing, 1851) were observed for the first time in a given host on the territory of Russia and the Volga Basin. Six species of worms make the basis of helminth fauna: nematodes Rhabdias bufonis, Oswaldocruzia filiformis, Neoxysomatium brevicaudatum and Cosmocerca ornata, trematode Haplometra cylindracea and monogenea Polystoma integerrimum. These six species are the most common and widespread parasites of the brown frog. For each species of helminths there is the following information included: taxonomic position, localization, area of detection, biology, definitive hosts, geographic distribution, the degree of host-specificity.

In the developing field of biological gerontology, rapid advances have recently been made in the genetics of ageing in the nematode Caenorhabditis elegans. The aim of this work is to develop an understanding of the general mechanisms determining the ageing process. Within the last decade the prospect of actually achieving this somewhat hubristic aim has begun to look startlingly real. In this context, knowledge of every aspect of the biology of ageing in nematodes is of added interest. Here the patterns of ageing observed among parasitic and free-living nematodes are surveyed and compared. Like insects, nematode species exhibit enormous differences in the rate of ageing, with maximum life spans varying over more than a 1000-fold range, from three days in free-living Rhabdias bufonis adults, to at least 15 years in the filarial parasite Loa loa. The possible evolutionary and mechanistic causes of such differences in ageing are discussed.

The common toad, Bufo bufo, from Trabzon Province, Turkey, was found to harbor 5 species of Nematoda: Aplectana acuminata, Aplectana macintoshii, Cosmocerca ornata, Oswaldocruzia filiformis, and Rhabdias bufonis, and 1 species of Acanthocephala, Acanthocephalus ranae. With the exception of Rhabdias bufonis, all represent new host records for Bufo bufo in Turkey.

The morphology of infective third-stage larvae of Rhabdias bufonis, R. rubrovenosa, R. sphaerocephala, R. fuscovenosa, R. elaphe, Entomelas entomelas and E. dujardini is described. The sheath structure in the studied larvae appeared to be similar to that described in other species of the family Rhabdiasidae, its chequered aspect being caused by a combination of outer longitudinal striations and inner longitudinal as well as transverse ridges. The larvae were similar in general morphology but differed in the presence/absence of anterior apical protuberances (pseudolabia), the shape and ornamentation of the tail tip, and the structure of lateral alae in the caudal region of the body. No relationship between the morphological characters of the larvae of the studied species and their taxonomic position or specificity of adult parasites to a particular host group was observed. Regardless, the larvae of each species can be identified by a combination of morphological peculiarities in the anterior and caudal regions of the body.

In this research, a total of 298 Eurasian marsh frogs, Pelophylax ridibundus (Pallas, 1771) were collected from different localities in Denizli province (Inner-west Anatolia Region, the eastern part of Aegean Region) Turkey between 2006 and 2009 and examined for helminths. Of 262 (87.91 %) Pelophylax ridibundus samples were infected with one or more helminths. Pelophylax ridibundus harbored eight species of digeneans (Diplodiscus subclavatus, Gorgoderina vitelliloba, Gorgodera cygnoides, Pleurogenoides medians, Prosotocus confusus, Skrjabinoeces breviansa, Encyclometra colubrimurorum and Ophistoglyhe ranae), one species of cestode (Nematotaenia dispar), two species of acanthocephalans (Acanthocephalus ranae and Pomphorhynchus laevis), and six species of nematodes (Rhabdias bufonis, Oswaldocruzia filiformis, Cosmocerca ornata, Oxysomatium brevicaudatum, Eustrongylides sp. and Abbreviata sp.). P. ridibundus represents a host record for Nematotaenia dispar in Turkey.

Summary The nematode Rhabdias bufonis is an anuran lung parasite with a heterogonic life cycle, characterized by alternation of gonochoristic (free-living) and hermaphroditic (parasitic at late larval and adult stages) generations. Adult parasites containing unhatched embryos were isolated from infected amphibians, but all other stages were cultured under controlled laboratory conditions with bacteria on agar plates. Development was studied with particular reference to a comparison of the two generations. No deviation from the strict heterogonic life cycle could be induced by alterations in the conditions of culture. The early embryonic lineages in the two generations are similar but not identical. Early development in both generations takes approximately twice as long as that in Caenorhabditis elegans, and the sequence of divisions is more variable. Nuclei counted in late embryos were similar in number (mean numbers: free-living generation 502; parasitic generation 570). Their number increases only moder...

In this investigation, seventeen Turkish worm lizards, Blanus strauchi, and eighteen slow worms, Anguis fragilis, collected from Turkey, were examined for helminths. Blanus strauchi harbored 2 species of Nematoda: Pharyngodon spinicauda and Aplectana sp. (larvae); Anguis fragilis harbored 5 species of Nematoda:, Rhabdias bufonis, Entomelas entomelas, Oswaldocruzia filiformis, Cosmocerca ornata and Oxysomatium brevicaudatum. Blanus strauchi represents a new host record for Pharyngodon spinicauda and Aplectana sp. Anguis fragilis, represents a new host record for Cosmocerca ornata. Turkey is a new locality record for Pharyngodon spinicauda.

SUMMARYDensity-dependence in worm establishment, numbers, biomass and larval production were examined in primary infections of 0, 10, 40, 80 and 160 larvae of the lung nematode, Rhabdias bufonis in the common toad, Bufo bufo. The infection procedure established 4 non-overlapping levels of infection which persisted until 6 weeks post-infection (p.i.), after which there was an overall decline up to 12 weeks p.i. Worm numbers had no direct effect on adult worm survival but temporal changes in worm weight were density-dependent. Adult worm establishment in the lungs declined significantly as the numbers of worms in the lungs increased. At the lowest exposure dose, 86% of the larvae administered reached maturity in the lungs while at the highest, only 37% did so. Also, the numbers of immature larvae outside the lungs increased as adult worm numbers increased. Both features provide evidence for a threshold limit to the numbers of worms maturing in the lungs. Worm numbers also affected larval output per host and per capita fecundity. A significant positive relationship between per capita fecundity and per capita worm weight suggested that density-dependence acted primarily to constrain the growth of individual worms. Finally, the constraints imposed on worm growth and fecundity were apparently relaxed when worm density decreased, providing evidence for density-dependent flexibility in per capita fecundity. Density-dependence in worm establishment and per capita fecundity are mechanisms which may potentially regulate this host–parasite interaction in the field. Both mechanisms may be functionally related to physical space limitations in the lungs, within which worms must compete for finite nutrients.

SUMMARYIn hybridogenetic systems, hybrid individuals are fully heterozygous because one of the parental genomes is discarded from the germinal line before meiosis. Such systems offer the opportunity to investigate the influence of heterozygosity on susceptibility to parasites. We studied the intensity of lung parasites (the roundwormRhabdias bufomisand the flukeHaplometra cylindracea) in 3 populations of water frogs of theRana lessonae-esculentacomplex in eastern France. In these mixed populations, hybrid frogs (R. esculenta) outnumbered parental ones (R. lessonae). Despite variation in parasite intensity and demographic variability among populations, the relationship between host age and intensity of parasitism suggests a higher susceptibility in parentals than in hybrids. Mortality is probably enhanced by lung parasites in parental frogs. On the other hand, while parental frogs harboured higher numbers ofH. cylindraceathan hybrid frogs, the latter had higher numbers ofR. bufonis. Despite such discrepancies, these results support the hybrid resistance hypothesis, although other factors, such as differences in body size, age-related immunity, differential exposure risks and hemiclonal selection, could also contribute to the observed patterns of infection.

Fifty-four Rana holtzi and 84 Rana macrocnemis from Turkey were examined for helminths. Rana holtzi harbored 3 species of Digenea (Gorgoderina vitelliloba, Haplometra cylindracea, Opisthioglyphe rastellus) and I species of Nematoda (Cosmocerca ornata). Rana holtzi is a new host record for these helminths. Rana macrocnemis harbored 1 species of Monogenea (Polystoma macrocnemis), 5 species of Digenea (Opisthioglyphe rastellus, Gorgoderina vitelliloba, Haplometra cillindracea, Pleurogenes claviger, Pleurogenoides medians), 3 species of Nematoda (Rhabdias bufonis, Cosmocerca ornata, Oswaldocruzia filiformis), and 1 species of Acanthocephala (Acanthocephalus ranae). Rana macrocnemis represents a new host record for H. cylindracea, O. rastellus, and P. medians.

One hundred forty-three banded frogs Rana camerani were collected from 2 localities in Turkey between 2000 and 2004 and examined for helminths. One species of Monogenea (Polystoma sp.), 5 species of Digenea (Gorgodera cynoides, Gorgoderina vitelliloba, Haplometra cylindricae, Opisthioglyphe rastellus, Pleurogenoides medians), 1 species of Cestoda (Nematotaenia dispar), 3 species of Nematoda (Cosmocerca ornata, Oswaldocruzia filiformis, Rhabdias bufonis), and 1 species of Acanthocephala (Acanthocephalus ranae) were found. Rana camerani represents a new host record for each of the collected parasite species.

TRABZON YÖRESİ SİĞİLLİ KURBAĞA(BUFO BUFO (LNNAEUS, 1758)) (ANURA ; BUFONIDAE) `LARININHELMİNT FAUNASIÖZET:Trabzon ilinden toplanmış olan 42 siğilli kurbağa helminthleri incelenmiştirNemathelmintlerden Rhabdias bufonis (Schrank, 1788) ait 407 birey, Cosmocercaornata (Dujardin, 1845) ait 879 birey, Aplectana macintoshii (Stewart, 1914) ait 136birey , Aplectana acuminata (Schrank, 1788) ait 88 birey, Oswaldocruzia filiformis(Goeze, 1782) ait 362 birey ve Acanthocephalus bufonis (Shipley, 1903) 756 bireyinyapısal özellikleri gözden geçirilmiştir.Rhabdias bufonis dışındaki parazitler Türkiye'de siğilli kurbağada ilk kezyakalanmıştır. için yeni kayıttır. Ayrıca bu türlerden Aplectana macintoshii veAcanthocephalus bufonis'in Türkiye için yeni kayıt olduğu tespit edilmiştir..ANAHTAR KELİMELER: Siğilli kurbağa, Nematod, Akanthosephal, Rhabdiasbufonis, Cosmocerca ornata, Aplectana macintoshii, Aplectana acuminata,Oswaldocruzia filiformis ve Acanthocephalus bufonis. HELMINTH PARASITES OF THE COMMAN TOAD, BUFO BUFO(LINNAEUS;1758)(ANURA: BUFONIDAE) FROM TRABZONABSTRACTThe helminth fauna of 42 common toads, Bufo bufo, in the Trabzon province ofnorth-eastern Turkey comprised 6 species: Rhabdias bufonis (Schrank, 1788) ,Cosmocerca ornata (Dujardin, 1845) Diesing, 1861, Aplectana macintoshii (Stewart,1914) Travassos, 1931, Aplectana acuminata (Schrank, 1788) Railliet & Henry, 1916,Oswaldocruzia filiformis Goeze, 1782 and Acanthocephalus bufonis (Shipley, 1903).All parasites except Rhabdias bufonis represent new host records for Bufo bufo inTurkey.Aplectana macintoshii and Acanthocephalus bufonis is the first report fromTurkey.KEY WORDS: Bufo bufo, Platyhelminthes, Nemathelminthes, Acanthocephala,Rhabdias bufonis, Cosmocerca ornata, Aplectana macintoshii, Aplectana acuminata,Oswaldocruzia filiformis and Acanthocephalus bufonis Turkey. 47

SUMMARYThis review considers three case studies based on macroparasites of anurans: (a) natural infections in the permanently-aquaticXenopus laeviswhich represent the worm burdens acquired, and the implications for pathology, when hosts are exposed to continuous, year-round, transmission; (b) the desert toad,Scaphiopus couchii, which experiences invasion very briefly each year and provides a simplified system involving only a single significant infection (Pseudodiplorchis americanus); (c) the mesicBufo bufowhich has been the subject of experimental laboratory studies designed to measure the effects ofRhabdias bufonisinfection on host growth, physical performance and survival. Experimental manipulation of bothScaphiopusandBufoprovide quantitative data on disease effects of macroparasites, including precise measurements of parasite-induced host mortality. Field data forXenopusandScaphiopusshow that, despite high initial worm burdens from efficient transmission, infection levels at parasite maturity are modulated below those leading to significant disease. Experimental data forScaphiopusandBufohave documented the time-course and magnitude of this decline in intensities, and there is circumstantial evidence forScaphiopusthat this regulation is host-mediated. Immunological studies onXenopusshow that disease effects of the pathogenicPseudocapillaroides xenopodisare exacerbated in thymectomised hosts and reversed by implantation of thymuses from MHC-compatible donors. Thus, whilst factorial experiments can demonstrate the potential of helminths to cause significant disease and mortality in anuran host-macroparasite interactions, powerful post-invasion regulation of worm burdens appears to exert a strong control of parasite-induced disease in natural host populations.

We tested the effects of body size and nematode infection on the stamina and burst performance of juvenile toads, Bufo bufo. Tadpoles were reared in ponds at high (120 individuals/1000 l) and low (60 individuals/1000 l) densities, resulting in a 29.0% difference in mass at metamorphosis. Ten days after metamorphosis, metamorphs were exposed to 0, 10 or 80 infective larvae of the lung nematode, Rhabdias bufonis, resulting in mean a posteriori worm burdens of 0, 3.4 and 7.5 worms per host, respectively

Rhabdias bufonis which can be found plentifully in every toad intestine throughout the year, were employed in these experiments consisting in vitro and in vivo examinations. Experiment in vitro : Each group of five worms were put in drug solutions. The charges in their movement in the solution 'were recorded until the moving stopped, estimating the toxicities of the drugs to the worms. Experiment in vivo : The drugs were given toads per os. From the following day observations on the numbers of worms excreted from the toads were continued for six days. On the last day of the observations, these toads were dissected to see the pathological changes caused by diugs in the alimentary canal and other organs concerned. Twenty nine drugs were tested by this method. Some of them were effective in vitro experiment and others were effective in vivo experiment, while most popular anthelmintics were proved to be effective in both expeiments.

1. Frogs were collected from a single area in the West Riding of Yorkshire and examined for adult helminth parasites. The following species were found:Polystoma integerrimum, Gorgoderina vitelliloba, Haplometra cylindracea, Dolichosaccus rastellus, Rhabdias bufonis, Cosmocerca ornata, Oswaldocruzia filiformis, Aplectana acuminataandAcanthocephalus ranae.2. The seasonal incidence and intensity of infection was studied by monthly examinations of 2413 frogs over a period of 4 years. The highest incidence of parasitization by helminths occurred in the autumn. In general, when the incidence was high, the intensity of infection was also high.3. The incidence of infection was generally higher in male than in female frogs. This effect of the host's sex was much more marked immediately before the breeding season than at any other time of the year.4. Possible reasons for these variations in levels of infection are discussed.

SummaryAn investigation of the carbohydrate energy metabolism ofRhabdias bufonis, the lung-dwelling nematode parasite of the African toad,Bufo regularis, indicates that the nematode stores very little glycogen (0·137 ± 0·003% on a fresh weight basis) but does utilize oxygenin vitro. The intracellular distribution and high levels of activity observed for the enzymes phosphoenolpyruvate carboxykinase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, malic enzyme and fumarate reductase suggest two alternative pathways of carbohydrate energy metabolism.

LARGE numbers of frogs (Rana temporaria) have been examined for helminth, parasites during the period 1956–60. On analysing the results of these investigations, it was found that the level of parasitization in male frogs during and immediately before the breeding season was considerably higher than that in females. This difference between the levels of parasitization in the two sexes was particularly marked in the case of the trematodes, Polystoma integerrimum and Gorgoderina vitelliloba, the nematode, Rhabdias bufonis, and the acanthocephalan, Acanthocephalus ranae. After the breeding season, the difference became less marked. This is evident from Table 1, which is based on the results obtained by examining approximately 500 frogs from a single locality, over a period of four years. Similar, although less conclusive, results have been obtained by Markov1 and Mazurmovich2.

In this study, 236 marsh frogs Rana ridibunda collected from Lake Hazar (Elazig, Turkey) at 15 d intervals between March 2001 and February 2002 were examined for endohelminths; of these, 148 (62.71%) frogs were found to be infected with helminths. In total, 9 helminth species (3 trematodes, 5 nematodes and 1 acanthocephalan) were identified. We observed Gorgoderina vitelliloba (prevalence 2.97%) in the urinary bladder, Haematoloechus variegatus (4.66%) and Rhabdias bufonis (8.90%) in the lung, Pleurogenoides medians (1.69%), Oswaldocruzia filiformis (3.81 %) and Acanthocephalus ranae (26.27 %) in the small intestine, Neoxysomatium brevicaudatum (16.95%) and Cosmocercoides sp. (3.39%) in the large intestine, and Eustrongylides excisus (14.41 %) in the body cavity and on the stomach. No helminth was found in the spleen, kidney, gall bladder, liver, heart or muscle. Of the 9 helminth species identified, Acanthocephalus ranae (26.27 %) had the highest prevalence and abundance and Oswaldocruzia filiformis (8.33 + 4.09) had the highest mean intensity.

The somatic, diploid, and haploid chromosome numbers were determined in the hermaph- rodite (24, 12, eggs 6, spermatozoa 5 or 6). Oocytes in the ovary synapsis zone contain 6 tetrads. The tetrads seem to disappear in the growth zone and reappear in the oocyte just prior to fertilization. After sperm penetration, the tetrads move to the periphery and form 2 polocytes by rapid meiotic divisions. Spermatogenesis occurs in the testis zone. Primary spermatocytes show 5 large tetrads and 2 small heterochromosomal dyads which lag on the spindle during division. Each resultant secondary spermato- cyte has 1 small and 5 large dyads. In the equational division, one of the lagging heterochromosomes (X) is lost in a small cytophore as cytokinesis occurs. Two spermatids are produced, one with 5 chromosomes and the other with 6 chromosomes. Fertilization occurs in the seminal receptacle and results in either free- living males (2N = 11) or females (2N = 12). Prior to 1929, the common nematode found in the lungs of frogs of the genus Rana in the United States had been identified as Rhabdias bufonis Schrank 1788. Walton (1929) clearly showed that these worms had been identified improperly and named the new species Rhabdias ranae. Gregory (1966) showed that R. ranae had the same life cycle as R. bufonis with free- living and parasitic generations. The parasitic form is a protandrous hermaphrodite and the free-living forms are males and females. Gametogenesis and fertilization in the life cycle of R. bufonis were determined in 1911 by two researchers. Schleip (1911), working exclusively with the parasitic phase, found that that diploid chromosome number was 12. This hermaphrodite produced eggs with six chromo- somes and sperm with either five or six chro- mosomes. Fertilization resulted in two types of larvae, one with a diploid number of 12 chromosomes and the other with 11 chromo