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Results 241 to 270 of 1075:

A drop in the bucket of the megadiverse chewing louse genus Myrsidea (Phthiraptera, Amblycera, Menoponidae): ten new species from Amazonian Brazil

Michel P. Valim, Jason D. Weckstein

Folia Parasitologica 60[5] 377-400 (2013) | DOI: 10.14411/fp.2013.040

Abstract: Ten new species of Myrsidea Waterston, 1915 parasitic on members of the avian families Formicariidae, Thraupidae, Tyrannidae, Troglodytidae and Icteridae are described herein. They and their type hosts are M. isacantha sp. n. ex Chamaeza nobilis Gould, M. circumsternata sp. n. ex Formicarius colma Boddaert (Formicariidae); M. cacioppoi sp. n. ex Lanio fulvus (Boddaert), Mbrasiliensis sp. n. ex Tangara chilensis (Vigors), M. saviti sp. n. ex Tangara schrankii (Spix) (Thraupidae), M. rodriguesae sp. n. ex Cnipodectes subbrunneus (Sclater), M. cnemotriccola sp. n. ex Cnemotriccus fuscatus (Wied-Neuwied), M. lathrotriccola sp. n. ex Lathrotriccus euleri (Cabanis) (Tyrannidae), M. faccioae sp. n. ex Cyphorhinus arada transfluvialis (Todd) (Troglodytidae), and M. lampropsaricola sp. n. ex Lampropsar tanagrinus (Spix) (Icteridae). Among these are two new Myrsidea species described from the avian family Formicariidae, which previously had only a single described Myrsidea species, and a new host record for M. cinnamomei Dalgleish et Price, 2005 ex Attila citriniventris Sclater. Analysis of mitochondrial cytochrome oxidase I sequences for these and other neotropical Myrsidea species provides an assessment of their phylogenetic relationships and indicates that all of these newly described species are genetically distinct. We also put these descriptions into context by estimating the potential number of unnamed Myrsidea species in Brazil, given the known diversity of potential hosts and typical levels of host specificity for Myrsidea species. Our estimate indicates that Brazilian Myrsidea species diversity is likely more than an order of magnitude greater than the number of described Myrsidea species known from Brazil, highlighting the need for future work on this megadiverse ectoparasite genus.

Does the prevalence of latent toxoplasmosis and frequency of Rhesus-negative subjects correlate with the nationwide rate of traffic accidents?

Jaroslav Flegr, Madhukar Dama

Folia Parasitologica 61[6] 485-494 (2014) | DOI: 10.14411/fp.2014.061

Latent toxoplasmosis is probably the most common protistan parasitic disease with many indirect negative impacts on human health. One of the important impacts is impaired psychomotor function leading to reduced driving efficiency in Toxoplasma-seropositive subjects. Numerous case-control studies have established a positive relation between the seroprevalence of Toxoplasma gondii (Nicolle et Manceaux, 1908) and probability of traffic accidents in study populations. The prevalence of toxoplasmosis varies between populations according to local geographical conditions, hygienic practices and kitchen habits. Similarly, we see a striking variation in the incidence of traffic accidents across countries. Hence, we compiled the largest ever data set on the seroprevalence of toxoplasmosis and tried to understand its role in traffic accident-related deaths and disabilities across 87 countries. Simple nonparametric analysis showed a positive and strong relation of T. gondii seroprevalence and traffic accident related disabilities. Further, we conducted multivariate analysis to control for confounding factors. After controlling for wealth, geographical latitude, health of population, length of roads and number of vehicles, the correlation disappeared. When the frequency of RhD negativity and its interaction with toxoplasmosis were included into the model, the effects of toxoplasmosis seemingly returned. However, the analysed data suffered from the problem of multicollinearity. When a proper method of analysis, ridge regression, was applied, the effects of toxoplasmosis prevalence and RhD negativity frequency disappeared again. The existence of a strong correlation between the prevalence of toxoplasmosis and health of population in particular countries, which was the probable cause of multicollinearity and possible reason for the negative result of the present study, suggests that 'asymptomatic' latent toxoplasmosis could have a large impact on public health.

Parasite richness in fish larvae from the nearshore waters of central and northern Chile

Gabriela Muñoz, Mauricio F. Landaeta, Pamela Palacios-Fuentes, Zambra López, María Teresa González

Folia Parasitologica 62[1] 29 (2015) | DOI: 10.14411/fp.2015.029

In the present study, we determine the presence of parasites in fish larvae collected from nearshore waters along the northern and central coast of Chile. The parasites were identified to the lowest possible taxonomic level based on morphological and molecular analyses. The fish sample was composed of 5 574 fish larvae. Of these, 3% harboured only larval ectoparasitic copepods whereas no endoparasites were found in the 1 141 fish evaluated for this group of parasites. The parasitic copepods collected were initially classified as 'morphotypes' according to differences in morphological characteristics. They were then analysed using molecular techniques based on the 28S and COI genes. Seven morphotypes of parasitic copepods (mostly at chalimus stages) were recognised: two of the morphotypes belonged to Pennellidae Burmeister, 1835, three to Caligidae Burmeister, 1835 and two were not identified. Only five morphotypes of copepods were analysed using molecular sequences, which confirmed the existence of six species: two pennellids of the genus Trifur Wilson, 1917 and two caligids of the genus Caligus Müller, 1785, plus two additional species that were morphologically different from these taxa. The pennellids were present in several fish species, being generally more prevalent than the caligids, in both the central and northern localities of Chile. Multispecies infections in larval fish were infrequent (< 1%). We conclude that fish larvae were rich in parasites, considering that these hosts exhibited small body sizes and were very young. We suggest that fish larvae could play a role, as intermediate hosts, in the life cycle of the parasitic copepods found.

The good, the bad and the ugly: Emys trinacris, Placobdella costata and Haemogregarina stepanowi in Sicily (Testudines, Annelida and Apicomplexa)

Vincenzo Arizza, Francesco Sacco, Debora Russo, Rita Scardino, Marco Arculeo, Melita Vamberger, Federico Marrone

Folia Parasitologica 63:029 (2016) | DOI: 10.14411/fp.2016.029

Endemic Sicilian pond turtles Emys trinacris Fritz, Fattizzo, Guicking, Tripepi, Pennisi, Lenk, Joger et Wink were examined for the presence of haemogregarine parasites. The presence of haemogregarines, occurring mainly in the microgametocyte stage (13.2 ± 0.12 μm in length and 6.4 ± 0.52 μm in width), was observed in approximately 9% of the sampled E. trinacris. Based on the observed morphology and on the sequencing of nuclear 18S rDNA, we identified the parasite as Haemogregarina stepanowi Danilewsky, 1885. Morphometric study of uninfected and infected red blood cells has shown that H. stepanowi induces different changes in erythrocyte shape depending on the infective stage. The differential count of leukocytes in specimens infected with H. stepanowi showed no significant difference compared with healthy specimens. However, considering the health problems which might be induced by H. stepanowi in the closely related European pond turtle Emys orbicularis (Linneaus), monitoring of the health status of the infected Sicilian populations of E. trinacris is desirable. The restricted distribution of populations of Emys infected with haemogregarines in Sicily is quite puzzling and the possible human-mediated introduction of the parasite in Sicily is briefly discussed.

Myxobolus pseudowulii sp. n. (Myxozoa: Myxosporea), a new skin parasite of yellow catfish Tachysurus fulvidraco (Richardson) and redescription of Myxobolus voremkhai (Akhmerov, 1960)

Bo Zhang, Yanhua Zhai, Yang Liu, Zemao Gu

Folia Parasitologica 64:030 (2017) | DOI: 10.14411/fp.2017.030

Two species of Myxobolus Bütschli, 1882 were found in yellow catfish Tachysurus fulvidraco (Richardson). A species of Myxobolus infecting the gills was morphologically identified as Myxobolus voremkhai (Akhmerov, 1960) and it was characterised here with additional morphological and molecular data. The other species of Myxobolus infecting the host's skin did not conform to any known myxosporean species. It is characterised by the presence of round, black or milky white plasmodia with black spots. Myxospores are pyriform in frontal view and lemon-shaped in lateral view, measuring 12.9-16.2 μm (14.6 ± 0.7 μm) in length, 8.1-10.8 μm (9.4 ± 0.5 μm) in width, and 6.1-8.1 μm (7.0 ± 0.4 μm) in thickness. Two ampullaceous polar capsules are slightly unequal in size, larger polar capsule 7.2-9.5 μm (7.9 ± 0.4 μm) long by 3.0-3.9 μm (3.5 ± 0.2 μm) wide, smaller capsule 6.9-8.0 μm (7.4 ± 0.3 μm) long by 2.9-3.9 μm (3.4 ± 0.2 μm) wide. Polar filaments are coiled with seven to nine turns. Histologically, the plasmodia develop in the stratum spongiosum of skin dermis, resulting in epithelial cell shedding and immunological cell infiltration. Given the morphological and molecular differences between this species and other species of Myxobolus, we proposed the name of Myxobolus pseudowulii sp. n. for this parasite from the skin of yellow catfish. Interestingly, some spores of the new species possess Henneguya-like caudal appendages. Phylogenetically, M. pseudowulii sp. n. and M. voremkhai infecting yellow catfish group together in one clade with other parasites of Siluriformes, indicating that parasites clustering according to the fish host order may be an important factor affecting the evolution of species within the Myxobolus clade.

Haemogregarine (Apicomplexa: Adeleorina) infection in Vanderhaege's toad-headed turtle, Mesoclemmys vanderhaegei (Chelidae), from a Brazilian Neotropical savanna region

Vinícius C. Goes, Elizângela S. Brito, Rafael M. Valadão, Camila O. Gutierrez, Amanda M. Picelli, Lúcio A. Viana

Folia Parasitologica 65:012 (2018) | DOI: 10.14411/fp.2018.012

Knowledge of blood parasites in Brazilian chelonians is limited, since they have been recorded in only six species. Mesoclemmys vanderhaegei (Bour) is a freshwater turtle with a wide geographic distribution in Brazil, but there is little information about its natural history. This paper reports on a study of the prevalence and infection intensity of a haemogregarine in two subpopulations of M. vanderhaegei. The study was conducted in two areas of Cerrado in the Upper Paraguay River basin in the state of Mato Grosso, Brazil, between November 2010 and August 2013. Ninety-five (53%) of the 179 turtles captured were positive for haemogregarine parasites. The parasitic forms observed were two morphotypes of intraerythrocytic gametocytes. The prevalence differed between size classes, increasing significantly according to the animals' body size. There was no significant difference between prevalence and sex, or between sampling periods. The mean parasite intensity was 9 parasites/2,000 erythrocytes (0.45%) and the parasite population presented an aggregated distribution, with an aggregation index of 19 and discrepancy of 0.772. This is the first record of a hemoparasite in the freshwater turtle M. vanderhaegei.

Spathebothriidea: survey of species, scolex and egg morphology, and interrelationships of a non-segmented, relictual tapeworm group (Platyhelminthes: Cestoda)*

Roman Kuchta, Rebecca Pearson, Tomáš Scholz, Oleg Ditrich, Peter D. Olson

Folia Parasitologica 61[4] 331-346 (2014) | DOI: 10.14411/fp.2014.040

Tapeworms of the order Spathebothriidea Wardle et McLeod, 1952 (Cestoda) are reviewed. Molecular data made it possible to assess, for the first time, the phylogenetic relationships of all genera and to confirm the validity of Bothrimonus Duvernoy, 1842, Diplocotyle Krabbe, 1874 and Didymobothrium Nybelin, 1922. A survey of all species considered to be valid is provided together with new data on egg and scolex morphology and surface ultrastructure (i.e. microtriches). The peculiar morphology of the members of this group, which is today represented by five effectively monotypic genera whose host associations and geographical distribution show little commonality, indicate that it is a relictual group that was once diverse and widespread. The order potentially represents the earliest branch of true tapeworms (i.e. Eucestoda) among extant forms.

New genus of opecoelid trematode from Pristipomoides aquilonaris (Perciformes: Lutjanidae) and its phylogenetic affinity within the family Opecoelidae

Michael J. Andres, Eric E. Pulis, Robin M. Overstreet

Folia Parasitologica 61[3] 223-230 (2014) | DOI: 10.14411/fp.2014.033

Bentholebouria colubrosa gen. n. et sp. n. (Digenea: Opecoelidae) is described in the wenchman, Pristipomoides aquilonaris (Goode et Bean), from the eastern Gulf of Mexico, and new combinations are proposed: Bentholebouria blatta (Bray et Justine, 2009) comb. n., Bentholebouria longisaccula (Yamaguti, 1970) comb. n., Bentholebouria rooseveltiae (Yamaguti, 1970) comb. n., and Bentholebouria ulaula (Yamaguti, 1970) comb. n. The new genus is morphologically similar to Neolebouria Gibson, 1976, but with a longer cirrus sac, entire testes, a rounded posterior margin with a cleft, and an apparent restriction to the deepwater snappers. Morphologically, the new species is closest to B. blatta from Pristipomoides argyrogrammicus (Valenciennes) off New Caledonia but can be differentiated by the nature of the internal seminal vesicle (2-6 turns or loops rather than constrictions), a longer internal seminal vesicle (occupying about 65% rather than 50% of the cirrus sac), a cirrus sac that extends further into the hindbody (averaging 136% rather than 103% of the distance from the posterior margin of the ventral sucker to the ovary), and a narrower body (27% rather than 35% mean width as % of body length). A Bayesian inference analysis of partial sequence of the 28S rDNA from Neolebouria lanceolata (Price, 1934), Cainocreadium lintoni (Siddiqi et Cable, 1960), Hamacreadium mutabile Linton, 1910, Opecoeloides fimbriatus (Linton, 1910), Podocotyloides brevis Andres et Overstreet, 2013, the new species, and previously published comparable sequences from 10 opecoelid species revealed two clades. One clade includes deep-sea (≥ 200 m) and freshwater fish opecoelids + Opecoeloides Bremser in Rudolphi, 1819, and a second clade included those opecoelids from shallow-water marine, perciform fishes.

Eutetrarhynchid trypanorhynchs (Cestoda) from elasmobranchs off Argentina, including the description of Dollfusiella taminii sp. n. and Parachristianella damiani sp. n., and amended description of Dollfusiella vooremi (São Clemente et Gomes, 1989)

Adriana Menoret, Verónica A. Ivanov

Folia Parasitologica 61[5] 411-431 (2014) | DOI: 10.14411/fp.2014.056

During a parasitological survey of teleosts and elasmobranchs in the Argentine Sea, 3 species of eutetrarhynchids were collected from the batoids Myliobatis goodei Garman and Psammobatis bergi Marini, and the shark Mustelus schmitti Springer. The specimens collected from Mu. schmitti were identified as Dollfusiela vooremi (São Clemente et Gomes, 1989), whereas the specimens from My. goodei and Ps. bergi resulted in new species of Dollfusiella Campbell et Beveridge, 1994 and Parachristianella Dollfus, 1946, respectively. Dollfusiella taminii sp. n. from Ps. bergi is characterised by a distinct basal armature with basal swelling and a heteroacanthous homeomorphous metabasal armature with 7-9 falcate hooks per principal row. Parachristianella damiani sp. n. from My. goodei lacks a distinct basal armature, having 2-3 initial rows of uncinate hooks, a heteroacanthous heteromorphous metabasal armature with the first principal row of small hooks, followed by rows with 10-14 large hooks. This is the first record of Parachristianella in the southwestern Atlantic. The amended description of D. vooremi includes the detailed description of the tentacular armature, including SEM micrographs of all tentacular surfaces. This species is characterised by a basal armature consisting of rows of uncinate and falcate hooks, a basal swelling and a metabasal armature with billhooks on the antibothrial surface and uncinate hooks on the bothrial surface. The scolex peduncle of D. vooremi is covered with enlarged spinitriches. This species is restricted to carcharhiniform sharks, since the report of D. vooremi in Sympterygia bonapartii Müller et Henle off Bahía Blanca (Argentina) is dubious.

Zoonotic Enterocytozoon bieneusi in raw wastewater in Zhengzhou, China

Jianbin Ye, Ji Yan, Jia Xu, Ke Ma, Xuepeng Yang

Folia Parasitologica 64:002 (2017) | DOI: 10.14411/fp.2017.002

Contamination of Enterocytozoon bieneusi Desportes, Charpentier, Galian, Bernard, Cochand-Priollet, Laverne, Ravisse, et Modigliani, 1985 in water sources may cause outbreaks of microsporidiosis. To examine the occurrence of E. bieneusi, 108 raw wastewater samples were collected from three wastewater treated plants in Zhengzhou, China. In total, 46 samples were PCR positive for E. bieneusi. A total of 15 ITS genotypes was identified, including ten known genotypes (D, BEB6, I, J, PigEbIX, PigEBITS5, EbpA, Peru6, Peru8, Type IV) and five novel genotypes (HNWW1, HNWW2, HNWW3, HNWW4, HNWW5). Nine genotypes belonged to a known zoonotic group (group 1) and the other genotypes belonged to potential zoonotic group (group 2). Most of the genotypes had been identified in wildlife or domestic animals in former reports in Zhengzhou. The occurrence of E. bieneusi in wastewater was probably related to the rainfall day before sampling. Of 36 sampling days, 20 days had rainfall on the previous day and 16 days had none. As many as 43 of 60 samples were found to be E. bieneusi-positive in the 20 days which had rainfall on the previous day. Only three of 48 samples were found to be E. bieneusi-positive in the 16 days without rainfall the day before. The significant difference of the occurrence of E. bieneusi was observed between wet days and dry days by t-test (43/60 vs 3/48, p < 0.01). This indicates that the occurrence of E. bieneusi in wastewater in Zhengzhou mainly originated from animals and was probably related to rainfall the day before sample collection. Given the zoonotic genotypes detected in wastewater, animal faeces should be treated appropriately before being drained into the water source.

Cryptosporidium testudinis sp. n., Cryptosporidium ducismarci Traversa, 2010 and Cryptosporidium tortoise genotype III (Apicomplexa: Cryptosporidiidae) in tortoises

Jana Ježková, Michaela Horčičková, Lenka Hlásková, Bohumil Sak, Dana Květoňová, Jan Novák, Lada Hofmannová, John McEvoy, Martin Kváč

Folia Parasitologica 63:035 (2016) | DOI: 10.14411/fp.2016.035

Understanding of the diversity of species of Cryptosporidium Tyzzer, 1910 in tortoises remains incomplete due to the limited number of studies on these hosts. The aim of the present study was to characterise the genetic diversity and biology of cryptosporidia in tortoises of the family Testudinidae Batsch. Faecal samples were individually collected immediately after defecation and were screened for presence of cryptosporidia by microscopy using aniline-carbol-methyl violet staining, and by PCR amplification and sequence analysis targeting the small subunit rRNA (SSU), Cryptosporidium oocyst wall protein (COWP) and actin genes. Out of 387 faecal samples from 16 tortoise species belonging to 11 genera, 10 and 46 were positive for cryptosporidia by microscopy and PCR, respectively. All samples positive by microscopy were also PCR positive. Sequence analysis of amplified genes revealed the presence of the Cryptosporidium tortoise genotype I (n = 22), C. ducismarci Traversa, 2010 (n = 23) and tortoise genotype III (n = 1). Phylogenetic analyses of SSU, COWP and actin gene sequences revealed that Cryptosporidium tortoise genotype I and C. ducismarci are genetically distinct from previously described species of Cryptosporidium. Oocysts of Cryptosporidium tortoise genotype I, measuring 5.8-6.9 µm × 5.3-6.5 µm, are morphologically distinguishable from C. ducismarci, measuring 4.4-5.4 µm × 4.3-5.3 µm. Oocysts of Cryptosporidium tortoise genotype I and C. ducismarci obtained from naturally infected Russian tortoises (Testudo horsfieldii Gray) were infectious for the same tortoise but not for Reeve's turtles (Mauremys reevesii [Gray]), common garter snake (Thamnophis sirtalis [Linnaeus]), zebra finches (Taeniopygia guttata [Vieillot]) and SCID mice (Mus musculus Linnaeus). The prepatent period was 11 and 6 days post infection (DPI) for Cryptosporidium tortoise genotype I and C. ducismarci, respectively; the patent period was longer than 200 days for both cryptosporidia. Naturally or experimentally infected tortoises showed no clinical signs of disease. Our morphological, genetic, and biological data support the establishment of Cryptosporidium tortoise genotype I as a new species, Cryptosporidium testudinis sp. n., and confirm the validity of C. ducismarci as a separate species of the genus Cryptosporidium.

Two new species of Tetragonocephalum (Cestoda: Lecanicephalidea) from Pastinachus sephen (Myliobatiformes: Dasyatidae) from the Gulf of Oman

Atabak Roohi Aminjan, Masoumeh Malek

Folia Parasitologica 64:014 (2017) | DOI: 10.14411/fp.2017.014

In the present study two new species of Tetragonocephalum Shipley et Hornell, 1905, T. mackenziei sp. n. and T. kazemii sp. n., are described from the spiral intestine of the cowtail stingray, Pastinachus sephen (Forsskål), from the northern coast of the Gulf of Oman. Tetragonocephalum mackenziei is distinguished from the 16 other valid species of Tetragonocephalum by a unique combination of characteristics, i.e. sperm-filled seminal receptacle in immature proglottids, body length (7.7-17.5 mm), body width (213-288 µm), number of proglottids (34-49), number of testes (10-14), size of scolex (228-315 µm × 213-288 µm) and size of acetabula (56-73 µm × 61-75 µm). Tetragonocephalum kazemii is morphologically distinguishable from its valid congeners and T. mackenziei based on a combination of characteristics, including body length (28.8-36.6 mm), number of proglottids (50-65), number of testes (30-42), size of scolex (388-564 µm × 326-448 µm), size of acetabula (62-86 µm × 57-90 µm) and testes (25-39 × 21-32). This brings the total number of validly described species of Tetragonocephalum to 18 and expands our knowledge of this diverse genus to now include the Gulf of Oman, as well as Arafura Sea, northern Indian Ocean and western Pacific Ocean.

Mice serve as paratenic hosts for the transmission of Caryospora duszynskii (Apicomplexa: Eimeriidae) between snakes of the genus Elaphe

David Modrý, Jan R. Šlapeta, Břetislav Koudela

Folia Parasitologica 52[3] 205-208 (2005) | DOI: 10.14411/fp.2005.027

Caryospora duszynskii Upton, Current et Barnard, 1984 was successfully transmitted to snakes of the genus Elaphe by feeding them previously infected mice. Fifty thousand oocysts were orally administered to two mouse strains, BALB/c and Crl:CD-1(ICR)BR, which were subsequently fed to captive-born coccidia-free Elaphe guttata (L.) in two respective independent experiments. Both E. guttata expelled C. duszynskii oocysts in their faeces, beginning on day 18 and 26 post infection (p.i.) and shed oocysts continuously through the end of the experiment, day 230 and 135 p.i., respectively. There were no parasitic stages or lesions in mice, as revealed by histological examination. Experiments proved that rodents serve as paratenic hosts for C. duszynskii. In summary we discuss the life-cycle strategies of Caryospora spp. in reptiles and present three general modes of their development.

Seroprevalence and risk factors of infections with Neospora caninum and Toxoplasma gondii in hunting dogs from Campania region, southern Italy

Tereza Machačová, Eva Bártová, Kamil Sedlák, Radka Slezáková, Marie Budíková, Diego Piantedosi, Vincenzo Veneziano

Folia Parasitologica 63:012 (2016) | DOI: 10.14411/fp.2016.012

Hunting dogs have probably a higher level of exposure to Neospora caninum Dubey, Carpenter, Speer, Topper et Uggla, 1988 and Toxoplasma gondii Nicolle et Manceaux, 1908 than other canine populations for their different lifestyle. The aim of our survey was to determine the seroprevalence of N. caninum and T. gondii in hunting dogs from southern Italy and assess risk factors related to these protozoan infections. Blood samples were collected from 398 hunting dogs (19 different breeds, aged from 5 month to 14 years). The sera were screened by indirect fluorescence antibody test; a titre ≥ 50 was considered positive. Antibodies to N. caninum and T. gondii were detected in 59 (15%) dogs with titres from 50 to 3 200 and in 94 (24%) dogs with titres from 50 to 1 600, respectively, with co-infection in 25 (6%) dogs. Statistical difference (p ≤ 0.05) was found only for infection with T. gondii between two age groups: ≥ 2-4 years (16%) and ≥ 4-7 years (33%); other observed characteristics were without statistical significance. Our results suggest that the hunting dogs could play an important role in the transmission cycle of N. caninum between wild animals and livestock. This is the first detection of antibodies to T. gondii in hunting dogs in Italy.

Conflict between morphology and molecular data: a case of the genus Caryophyllaeus (Cestoda: Caryophyllidea), monozoic tapeworms of cyprinid fishes

Eva Bazsalovicsová, Ivica Králová-Hromadová, Jan Brabec, Vladimíra Hanzelová, Mikuláš Oros, Tomáš Scholz

Folia Parasitologica 61[4] 347-354 (2014) | DOI: 10.14411/fp.2014.035

Molecular analysis of an extensive specimen collection of morphologically distinct tapeworms of the genus Caryophyllaeus Gmelin, 1790 (Cestoda: Caryophyllidea), parasites of cyprinid fishes in the Palaearctic Region, brought evidence of host-related plasticity in critical morphological characters widely used for species circumscription and classification of these tapeworms. The results obtained here do not support the traditionally used morphological concept of species-defining characters of the order Caryophyllidea Carus, 1863, especially due to high morphological plasticity of the scolex and the anterior end of the body. Several morphotypes within both Caryophyllaeus laticeps (Pallas, 1781) and Caryophyllaeus brachycollis Janiszewska, 1953 generally corresponding to different hosts and geographical regions, were recognised likely suggesting host- and geography-related intraspecific morphological variability. Genetic data confirmed euryxenous host specificity of both species, most profoundly C. laticeps, but did not support the existence of cryptic species. In fact, some of the fish hosts may harbour both of the congeneric species including several of their respective morphotypes. The pattern of morphological and genetic divergence observed in both cestode species studied indicates a scenario of possible host range extensions and subsequent parasite diversification. If molecular sequence variability and host-related morphological polymorphism are confirmed in other groups of monozoic cestodes, it may complicate species identification and straightforward classification of these parasites.

Life cycle and settlement of an Australian isolate of Ichthyophthirius multifiliis Fouquet, 1876 from rainbow trout

James M. Forwood, James O. Harris, Matt Landos, Marty R. Deveney

Folia Parasitologica 62[1] 13 (2015) | DOI: 10.14411/fp.2015.013

Ichthyophthirius multifiliis Fouquet, 1876, a ciliate parasite, is a cosmopolitan and problematic parasite of cultured freshwater fish. Each geographical isolate of I. multifiliis has variations in life cycle timing under different abiotic water conditions, such as temperature and salinity. We assessed the effects of salinity and temperature on the development and the preferred settlement site of a temperate Australian isolate of I. multifiliis. The time until theront release was significantly different between each temperature; development time was longest at 5 °C with a mean time of 189 h and decreased to a mean time of 11.7 h at 30 °C. At 5 °C our isolate produced a mean of 267 theronts per tomont, which increased to a mean of 493 theronts at 25 °C and reduced to a mean of 288 theronts at 30 °C. Theront length showed an inverse relationship to temperature; mean length was 62 μm at 5 °C and 41 μm at 30 °C. Our isolate reproduced faster at all temperatures and a greater sensitivity to salinity than all reported profiles for temperate isolates. Parasite abundance was highest on the dorsal region of the fish. An accurate understanding of temperature-life cycle information and optimal region to sample for surveillance will aid in the development of specific management plans for the Australian isolate of I. multifiliis, facilitating the strategic timing of treatments.

Molecular phylogenetic confirmation of Gnathostoma spinigerum Owen, 1836 (Nematoda: Gnathostomatidae) in Laos and Thailand

Jurairat Jongthawin, Pewpan M. Intapan, Oranuch Sanpool, Penchom Janwan, Lakkhana Sadaow, Tongjit Thanchomnang, Sakhone Laymanivong, Wanchai Maleewong

Folia Parasitologica 63:002 (2016) | DOI: 10.14411/fp.2016.002

We report the molecular-phylogenetic identification of larvae of the nematode genus Gnathostoma Owen, 1836 collected from a snake, Ptyas koros Schlegel, in Laos and adult worms from the stomach of a dog in Thailand. DNA was extracted and amplified targeting the partial cox1 gene and the ITS-2 region of ribosomal DNA. Phylogenetic analyses indicated that all five advanced third-stage larvae and seven adult worms were Gnathostoma spinigerum Owen, 1836. This is also the first molecular evidence of infection with G. spinigerum in a snake from Laos.

Redescription and molecular diagnosis of Hepatozoon theileri (Laveran, 1905) (Apicomplexa: Adeleorina: Hepatozoidae), infecting Amietia quecketti (Anura: Pyxicephalidae)

Edward C. Netherlands, Courtney A. Cook, Nico J. Smit, Louis H. du Preez

Folia Parasitologica 61[4] 293-300 (2014) | DOI: 10.14411/fp.2014.046

Blood smears prepared from the peripheral blood of 20 wild caught Amietia quecketti (Boulenger) from the North-West University Botanical Gardens, North West Province, South Africa, were examined for the presence of haemogregarines. A haemogregarine species comparative in morphology, host and geographical locality to that of Haemogregarina theileri Laveran, 1905 was detected. The original description of H. theileri was based solely on frog peripheral blood gamont stages. Later, further parasite stages, including trophozoites and merogonic liver stages, were recorded in a related Amietia sp. from equatorial Africa. This species was originally classified as a member of the genus Haemogregarina Danilewsky, 1885, but due to the close life cycle and morphological resemblance to those of Hepatozoon species, H. theileri was later transferred from Haemogregarina to Hepatozoon Miller, 1908. In the present study, meront and merozoite stages not described before, along with previously observed trophozoite, immature and mature gamont stages, are described from the peripheral blood of hosts. In addition, comparative phylogenetic analysis of the partial 18S rDNA sequence of Hepatozoon theileri to those of other haemogregarine species, including those of species of Hepatozoon and a Haemogregarina, support the taxonomic transfer of H. theileri to Hepatozoon, nesting H. theileri within a clade comprising species parasitising other amphibians. This is the first molecular and phylogenetic analysis of an African anuran species of Hepatozoon.

A comparative study of Ligophorus uruguayense and L. saladensis (Monogenea: Ancyrocephalidae) from Mugil liza (Teleostei: Mugilidae) in southern Brazil

Natalia C. Marchiori, Antoine Pariselle, Joaber Pereira Jr., Jean-François Agnèse, Jean-Dominique Durand, Maarten P.M. Vanhove

Folia Parasitologica 62[1] 24 (2015) | DOI: 10.14411/fp.2015.024

Representatives of Ligophorus Euzet et Suriano, 1977 were found on the gills of Mugil liza Valenciennes caught in southern Brazil. They were identified as Ligophorus uruguayense Failla Siquier et Ostrowski de Núñez, 2009 and Ligophorus saladensis Marcotegui et Martorelli, 2009, even though specific identification proved to be difficult due to inconsistencies in some diagnostic features reported for these two species. Therefore, a combined morphological and molecular approach was used to critically review the validity of these species, by means of phase contrast and confocal fluorescence microscopical examination of sclerotised hard parts, and assessing the genetic divergence between L. saladensis, L. uruguayense and their congeners using rDNA sequences. The main morphological differences between the two species relate to the shape of the accessory piece of the penis and the median process of the ventral bar. The accessory piece in L. uruguayense is shorter than in L. saladensis, has a cylindrical, convex upper lobe and straight lower lobe (vs with the distal tip of the lower lobe turning away from the upper lobe in the latter species). The ventral bar has a V-shaped anterior median part in L. uruguayense (vs U-shaped in L. saladensis). The two species are suggested to be part of a species complex together with L. mediterraneus Sarabeev, Balbuena et Euzet, 2005. We recommend to generalise such comparative assessment of species of Ligophorus for a reliable picture of the diversity and diversification mechanisms within the genus, and to make full use of its potential as an additional marker for mullet taxonomy and systematics.

A study on African animal trypanosomosis in four areas of Senegal

Sophie Ravel, Oleg Mediannikov, Géraldine Bossard, Marc Desquesnes, Gérard Cuny, Bernard Davoust

Folia Parasitologica 62[1] (2015) | DOI: 10.14411/fp.2015.044

In Senegal, several areas provide great potential for agriculture and animal production, but African animal trypanosomosis (AAT) is one of the major constraints to the development of more effective livestock production systems. A study was conducted to assess the current situation of AAT in this country. Surveys were carried out between June 2011 and September 2012 in four different areas: Dakar, Sine Saloum, Kedougou region and Basse Casamance in several animal species: dogs (152), donkeys (23), horses (63), sheep (43), goats (52) and cattle (104), distributed in the four sites. Molecular tools (PCR) indicated 3.4% positive animals including dogs, donkeys, a goat and cattle. The savannah type of Trypanosoma congolense Broden, 1904 (53% of positive cases) and the forest type of T. congolense (subgenus Nannomonas Hoare, 1964) were predominant. Trypanosoma vivax Ziemann, 1905 (subgenus Duttonella Chalmers, 1918) was only present in one animal and no trypanosome of the subgenus Trypanozoon Lühe, 1906 was found. Half of the positive cases were detected in Sine Saloum, where T. congolense savannah-type was predominant, and the other half in Basse Casamance, where T. congolense forest-type was predominant; no cases were found in Dakar or in the Kedougou region. A high risk of infection in dogs with T. congolense savannah-type was shown in Sine Saloum, requiring prevention and control of dogs in this area. The involvement of tsetse flies in the transmission of T. congolense in Sine Saloum and Basse Casamance is discussed.

Induction of prominent Th1 response in C57Bl/6 mice immunized with an E. coli-expressed multi T-cell epitope EgA31 antigen against Echinococcus granulosus

Majid Esmaelizad, Gholamreza Ahmadian, Khosrow Aghaiypour, Mehdi Shamsara, Habibellah Paykari, Majid Tebianian

Folia Parasitologica 60[1] 28-34 (2013) | DOI: 10.14411/fp.2013.004

First step in developing an epitope-based vaccine is to predict peptide binding to the major histocompatibility complex (MHC) molecules. We performed computational analysis of unique available EgA31 sequence to locate appropriate antigenic propensity positions. T-cell epitopes with best binding affinity values of < 50% inhibitory concentration were selected using different available servers (Propred and IEDB). Peptides with 100% population coverage were selected. A DNA fragment corresponding to the furin linker enriched in Golgi apparatus was inserted sequentially between each epitope sequences in a synthetic DNA in order to cleave the chimeric protein into four separated peptides. Subsequently, the synthetic DNA was cloned into the pGEX4T-1 and pEGFP-N1 vectors and GST-ChEgA31 was expressed in E. coli strain BL21-DE3. The recombinant protein was detected by western blotting using an HRP-conjugated polyclonal anti-GST antibody. Fusion protein purified by affinity chromatography was used to raise antisera in rabbits. Results in agar gel immunodiffusion assay indicated induction of specific antibodies against multiepitope antigen in the tested rabbits. Cytokine assay was carried out in C57Bl/6 mice and the levels of cytokines were analyzed by sandwich ELISA. Interestingly, production of specific IFN-γ was prominently higher in mice immunized with GST-ChEgA31 and pEGFP-ChEgA31 (650-1 300 pg/ml) compared to control groups. No difference was observed in the level of IL-10 and IL-4 in immunized and GST control group. Challenge study with 500 live protoscolices of Echinococcus granulosus on immunized mice demonstrated protectivity level (50-60%). Based on our results, it appeared that the chimeric protein in the study was able to stimulate T-helper cell-1 (Th1) development and high level of cell mediated immunity in mice.

The molecular phylogeny of the digenean family Opecoelidae Ozaki, 1925 and the value of morphological characters, with the erection of a new subfamily

Rodney A. Bray, Thomas H. Cribb, D. Timothy J. Littlewood, Andrea Waeschenbach

Folia Parasitologica 63:013 (2016) | DOI: 10.14411/fp.2016.013

Large and small rDNA sequences of 41 species of the family Opecoelidae are utilised to produce phylogenetic inference trees, using brachycladioids and lepocreadioids as outgroups. Sequences were newly generated for 13 species. The resulting Bayesian trees show a monophyletic Opecoelidae. The earliest divergent group is the Stenakrinae, based on two species which are not of the type-genus. The next well-supported clade to diverge is constituted of three species of Helicometra Odhner, 1902. Based on this tree and the characters of the egg and uterus, a new subfamily, the Helicometrinae, is erected and defined to include the genera Helicometra, Helicometrina Linton, 1910 and Neohelicometra Siddiqi et Cable, 1960. The subfamily Opecoelinae is found to be monophyletic, but the Plagioporinae is paraphyletic. The single representative of the Opecoelininae (not of the type genus) is nested within a group of deep-sea 'plagioporines'. The two representatives of the Opistholebetidae are embedded within a group of shallow-water 'plagioporine' species. The Opistholebetidae is reduced to subfamily status pro tem as its morphological and biological characteristics are distinctive. This implies that as opecoelid systematics develops with more molecular evidence, several further subfamilies will be recognised. Many of the morphological characters were found to be homoplasious, but the characters defining the Helicometrinae and Opecoelinae, such as filamented eggs, reduced cirrus-sac and uterine seminal receptacle, are closely correlated with the inferred phylogeny.

A novel stage-specific glycosomal nucleoside diphosphate kinase from Trypanosoma cruzi

María de los Milagros Cámara, León Bouvier, Chantal Reigada, Fabio A. Digirolamo, Melisa Sayé, Claudio A. Pereira

Folia Parasitologica 64:006 (2017) | DOI: 10.14411/fp.2017.006

Nucleoside diphosphate kinases (NDPK) are key enzymes involved in the intracellular nucleotide maintenance in all living organisms, especially in trypanosomatids which are unable to synthesise purines de novo. Four putative NDPK isoforms were identified in the Trypanosoma cruzi Chagas, 1909 genome but only two of them were characterised so far. In this work, we studied a novel isoform from T. cruzi called TcNDPK3. This enzyme presents an atypical N-terminal extension similar to the DM10 domains. In T. cruzi, DM10 sequences targeted other NDPK isoform (TcNDPK2) to the cytoskeleton, but TcNDPK3 was localised in glycosomes despite lacking a typical peroxisomal targeting signal. In addition, TcNDPK3 was found only in the bloodstream trypomastigotes where glycolytic enzymes are very abundant. However, TcNDPK3 mRNA was also detected at lower levels in amastigotes suggesting regulation at protein and mRNA level. Finally, 33 TcNDPK3 gene orthologs were identified in the available kinetoplastid genomes. The characterisation of new glycosomal enzymes provides novel targets for drug development to use in therapies of trypanosomatid associated diseases.

Three new gonad-infecting species of Philometra (Nematoda: Philometridae) parasitic in Lutjanus spp. (Lutjanidae) in the northern Gulf of Mexico off Florida, USA

František Moravec, Micah Bakenhaster, Emma J. Fajer-Ávila

Folia Parasitologica 61[4] 355-369 (2014) | DOI: 10.14411/fp.2014.041

Based on light and scanning electron microscopical studies, three new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from marine fishes of the genus Lutjanus Bloch (Perciformes: Lutjanidae) in the northern Gulf of Mexico: P. longispicula sp. n. from the ovary of the northern red snapper L. campechanus (Poey) (type host) and silk snapper L. vivanus (Cuvier); P. latispicula sp. n. from the ovary and rarely testes of the grey snapper L. griseus (Linnaeus); and P. synagridis sp. n. (only males available) from the ovary of the lane snapper Lutjanus synagris (Linnaeus). These species are mainly characterised by the lengths of spicules (378-690 µm, 135-144 µm and 186-219 µm, respectively) and spicule shapes, structure of the distal portion of the gubernaculum and the structure of the male caudal end. These are the first valid, nominal species of gonad-infecting philometrids reported from fishes of the family Lutjanidae in the western Atlantic region.

Pentastome assemblages of the Nile crocodile, Crocodylus niloticus Laurenti (Reptilia: Crocodylidae), in the Kruger National Park, South Africa

Kerstin Junker, Frikkie Calitz, Danny Govender, Boris R. Krasnov, Joop Boomker

Folia Parasitologica 63:040 (2016) | DOI: 10.14411/fp.2016.040

Thirty-two specimens of the Nile crocodile, Crocodylus niloticus Laurenti (Reptilia: Crocodylidae), from the Kruger National Park, South Africa, and its vicinity were examined for pentastomid parasites during 1995 to 1999 and 2010 to 2011. Pentastomid parasites occurred throughout the year and were widespread in the study area with an overall prevalence of 97% and an overall mean abundance of 23.4 (0-81). Pentastome assemblages comprised six species in three sebekid genera: Alofia nilotici Riley et Huchzermeyer, 1995, A. simpsoni Riley, 1994, Leiperia cincinnalis Sambon, 1922, Sebekia cesarisi Giglioli in Sambon, 1922, S. minor (Wedl, 1861) and S. okavangoensis Riley et Huchzermeyer, 1995. The possible influence of host age, gender and geographic location (river system) on pentastome prevalence, abundance and species richness was investigated. Generally, neither host age, gender nor locality did affect infracommunities, likely because all hosts examined were adult or subadult and displayed comparable foraging behaviour, resulting in similar exposure pathways to fish intermediate hosts. Additionally, the longevity of pentastomids would contribute to accumulative infections as hosts mature. Structuring of pentastome assemblages was observed in as far as S. minor was the dominant species based on overall prevalence and abundance, followed by the equally common species S. cesarisi and L. cincinnalis. With an overall prevalence ranging from 34% to 41% and relatively low abundances, A. nilotici, A. simpsoni and S. okavangoensis form the rarer component of pentastome communities.

A new feather mite of the genus Dolichodectes (Astigmata: Proctophyllodidae) from Hippolais polyglotta (Passeriformes: Acrocephalidae) in Spain

Sergey V. Mironov, Jorge Doña, Roger Jovani

Folia Parasitologica 62[1] (2015) | DOI: 10.14411/fp.2015.032

A new feather mite species, Dolichodectes hispanicus sp. n. (Astigmata: Proctophyllodidae), is described from the Melodious Warbler Hippolais polyglotta (Vieillot) (Passeriformes: Acrocephalidae) in Spain. The new species is closest to the type species of the genus, D. edwardsi (Trouessart, 1885) from the Grear Reed-Warbler Acrocephalus arundinaceus (Linnaeus) (Acrocephalidae). Adults of D. hispanicus differ from those of D. edwardsi by dimensional characteristics, in particular, by having shorter aedeagus that does not extend to the anal suckers in males and shorter hysteronotal shield in females. Tritonymphs of D. hispanicus are much more distinctive and differ from those of D. edwardsi by having the prodorsal shield covering all the prodorsum, the hysteronotal shield occupying about three quarters of the hysterosoma, and idiosomal setae h3 being filiform. The morphological description of the new species is augmented by sequence data from the mitochondrial cytochrome c oxidase subunit I gene fragment (COI).

Carcinopodacarus polymorphus gen. n. et sp. n. from Guira guira (Cuculiformes: Cuculidae) in Brazil: a first example of male polymorphism in the family Dermationidae (Acariformes: Analgoidea)

Fabio Akashi Hernandes, Luiz Gustavo A. Pedroso, Andre V. Bochkov

Folia Parasitologica 62[1] 9 (2015) | DOI: 10.14411/fp.2015.009

Carcinopodacarus polymorphus gen. n. et sp. n. (Acariformes: Dermationidae: Dermationinae) is described from the guira cuckoo Guira guira (Gmelin) (Cuculiformes: Cuculidae) in Brazil. The new genus differs from the closest genus, Psittophagoides Fain, 1964, by the following features: in both sexes, the anterior spines of trochanters I and II are absent (vs present in Psittophagoides), setae d2 are distinctly developed (vs only alveoli), and genual setae mGI are absent (vs present); in males, the hysteronotal shield is split transversally at the level of trochanters III (vs hysteronotal shield entire); in females, the platelets situated posterior to the propodonotal shield are absent (vs present), the metapodosomal sclerites are present (vs absent), and the adanal shields are fused anteriorly to each other (vs separated from each other). In this species, andropolymorphism is detected for the first time for the family. It involves various characters but the most impressive feature is the structure of legs III. In hetero- and mesomorphic males, these legs are strongly hypertrophied and have a distinct ventral spur on femora III; in homeomorphic males, legs III are not modified and subequal to legs IV.

No association between current depression and latent toxoplasmosis in adults

Shawn D. Gale, Andrew N. Berrett, Bruce Brown, Lance D. Erickson, Dawson W. Hedges

Folia Parasitologica 63:032 (2016) | DOI: 10.14411/fp.2016.032

Changes in behaviour and cognition have been associated with latent infection from the apicomplexan protozoan Toxoplasma gondii (Nicolle et Manceaux, 1908) in both animal and human studies. Further, neuropsychiatric disorders such as schizophrenia have also been associated with latent toxoplasmosis. Previously, we found no association between T. gondii immunoglobulin G antibody (IgG) seropositivity and depression in human adults between the ages of 20 and 39 years (n = 1 846) in a sample representative of the United States collected by the Centers for Disease Control as part of a National Health and Nutrition Examination Survey (NHANES) from three datasets collected between 1999-2004. In the present study, we used NHANES data collected between 2009 and 2012 that included subjects aged 20 to 80 years (n = 5 487) and used the Patient Health Questionnaire 9 (PHQ-9) to assess depression with the overall aim of testing the stability of the results of the prior study. In the current study, the seroprevalence of T. gondii was 13%. The percentage of subjects reporting clinical levels of depression assessed with the PHQ-9 was 8%. As before, we found no association between T. gondii IgG seroprevalence and depression (OR = 1.01, 95% CI = 0.81-1.25; p = 0.944) while controlling for sex, educational attainment, race-ethnicity, age, poverty-to-income ratio and cigarette smoking. We also found no positive associations between anti-T. gondii antibody titre and depression (OR = 1.00, 95% CI = 0.96-1.06; p = 0.868). Moreover, we found no association between T. gondii seroprevalence or antibody titre and suicidal ideation (seroprevalence: OR = 1.22, 95% CI = .85-1.75; p = 0.277, titre: OR = 1.05, 95% CI = 0.98-1.14; p = 0.177). Defining depression to also include subjects currently taking antidepressant medication even with non-elevated questionnaires did not find evidence of a positive association between latent toxoplasmosis and depression. In the present study, neither T. gondii seroprevalence nor anti-T. gondii antibody titre was positively associated with depression or suicidal ideation among subjects aged 20 to 80 years.

A synthesis of our current knowledge of philometrid nematodes, a group of increasingly important fish parasites

František Moravec, Isaure de Buron

Folia Parasitologica 60[2] 81-101 (2013) | DOI: 10.14411/fp.2013.010

Abstract: Members of the Philometridae represent the most important group of dracunculoid nematodes parasitizing fishes. In his monograph treating the Dracunculoidea, Moravec (2006) reported a total of 11 genera and 105 species of philometrids parasitizing freshwater, brackish-water and marine fishes. However, during the last six years (2007-2012), an additional 42 new species of Philometridae have been described, representing a 40% increase of the number of nominal species. Most of these species (30) belong to Philometra Costa, 1845, mainly represented by parasites of marine fishes, a few others (8) to Philometroides Yamaguti, 1935, and a single one to each of the following genera: Caranginema Moravec, Montoya-Mendoza et Salgado-Maldonado, 2008, Dentiphilometra Moravec et Wang, 2002, Dentirumai Quiazon et Moravec, 2013* and Spirophilometra Parukhin, 1971. Moreover, three new genera, Afrophilometra Moravec, Charo-Karisa et Jirků, 2009, Caranginema and Dentirumai, were erected. Representatives of seven genera, Afrophilometra, Buckleyella Rasheed, 1963, Caranginema, Dentiphilometra, Dentirumai, Paraphilometroides Moravec et Shaharom-Harrison, 1989 and Rumai Travassos, 1960, were studied using scanning electron microscopy (SEM) for the first time. Thirteen known but poorly described philometrid species were redescribed and, in some species of Caranginema and Philometra, previously unknown conspecific males were discovered and described. The male surface ultrastructure studied by SEM provided new taxonomically important features for species distinction. Gene sequencing was used in several recent studies and advanced our understanding of phylogenetic interrelationships among representatives of seven genera (Afrophilometra, Alinema Rasheed, 1963, Caranginema, Nilonema Khalil, 1960, Philometra, Philometroides and Rumai) and of the extent of the biodiversity of philometrids. New data were obtained on the biology and pathogenicity of several species of Nilonema, Philometra, Philometroides and Rumai. The need to carry out surveys in order to find males and to use SEM and gene sequencing to identify philometrids is emphasized. Appropriate quantitative methods to determine the impact of philometrids in ovarian tissue on host fecundity are recommended. Further detailed studies on philometrids would be significant not only from the theoretical viewpoint, but also because of their practical implications. A list of philometrid nematode species by continents is provided.

The natural history of Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 (Acanthocephala) in a high Arctic lake

Raija-Liisa Aura, Daniel P. Benesh, Risto Palomäki, E. Tellervo Valtonen

Folia Parasitologica 62[1] (2015) | DOI: 10.14411/fp.2015.051

The acanthocephalan Echinorhynchus bothniensis Zdzitowiecki and Valtonen, 1987 differs from most other species in the genus Echinorhynchus Zoega in Müller, 1776 by infecting mysids (order Mysida) instead of amphipods (order Amphipoda) as intermediate hosts. Here we report on the occurrence of E. bothniensis in mysids (Mysis segerstralei Audzijonytė et Väinölä) and in its fish definitive hosts in a high Arctic lake. Out of 15 907 sampled mysids, 4.8% were infected with a mean intensity of 1.05 worms (range 1-5), although there was notable variation between samples taken in different years and sites. Larger mysids appear more likely to be infected. Of five fish species sampled, charr,Salvelinus alpinus (Linnaeus), and a benthic-feeding whitefish morph, Coregonus lavaretus (Linnaeus), were the most heavily infected (mean abundances of 80 and 15, respectively). The adult parasite population in fish exhibited a female-biased sex ratio (1.78 : 1). Although E. bothniensis is rather unique in infecting mysids, many aspects of its natural history mirror that of other acanthocephalan species.

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