Pterobdella amara is redescribed from specimens from the type locality in India, and from the type host in Queensland, Australia. A neotype is designated from the type locality. The presence of conspicuous finlike bodies along the lateral margins of P. amara was greatly exaggerated in the original description. The trachelosome and anterior portion of the urosome are wide and flat, but there are no finlike bodies present. The urosome tapers abruptly posterior to the flattened portion, becomes cylindrical, and remains of constant width to the caudal sucker. The oral sucker is small and the caudal sucker is terminal. The body is smooth and lacks pigmentation, except for 1 pair of eyes on the oral sucker. Important internal characters are 2 pairs of mycetomes, 5 pairs of testisacs, confluent gonopores, extensive accessory gland cells on the male atrium and ejaculatory ducts, a spacious coelom consisting of dorsal and ventral sinuses with expansive connections between each at urosome ganglia, and interganglionic expansions of the dorsal sinus. Rhopalobdella japonica from stingrays in Japan is synonymized with P. amara and becomes a subjective junior synonym. This leech is a parasite in the oral cavity of the stingrays Pastinachus sephen and Himantura uarnak in India and Australia, and Dasyatis akajei in Japan.

The Gyrodactylus spp. fauna on species of gobies, Pomatoschistus, Gobiusculus, and Knipowitschia (Gobiidae: Teleostei), from the western Mediterranean and Adriatic seas is strikingly similar to that found in the Baltic Sea and eastern Atlantic Ocean, both in morphology and in internal transcribed spacer (ITS) rRNA. The fauna consisted of Gyrodactylus branchialis, G. ostendicus, G. gondae, G. rugiensis, G. rugiensoides, and G. arcuatus. No new species have been found. A morphometric comparison between G. branchialis from the Mediterranean and Adriatic seas and its type locality in Ostend (Belgium) showed significant differences in ventral bar and marginal hook features. The morphometric variation was lower in G. rugiensis, whereas no significant differences were found in G. ostendicus. Gyrodactylus branchialis and G. ostendicus collected on P. microps were slightly different in the ITS rDNA (∼0,6%) compared with specimens on the closely related P. marmoratus, probably reflecting ongoing speciation. A hybrid zone was identified in the Vaccarès lagoon complex (France) where both host species are sympatric. There was no clear geographic or host-related pattern in the variation found in the ITS2 rDNA in G. arcuatus sampled from P. microps, G. flavescens, Pungitius pungitius, K. panizzae, and its original host Gasterosteus aculeatus (2 polymorphic sites). Of all studied species, only G. arcuatus, G. rugiensis, and G. rugiensoides showed minor intraspecific variation in the ITS rDNA. Hence, the physical separation by a shoreline of more than 10,000 km is hardly reflected in the parasite ITS rDNA.

The western fence lizard, Sceloporus occidentalis, is refractory to experimental infection with Borrelia burgdorferi sensu stricto, one of several Lyme disease spirochetes pathogenic for humans. Another member of the Lyme disease spirochete complex, Borrelia bissettii, is distributed widely throughout North America and a similar, if not identical, spirochete has been implicated as a human pathogen in southern Europe. To determine the susceptibility of S. occidentalis to B. bissettii, 6 naïve lizards were exposed to the feeding activities of Ixodes pacificus nymphs experimentally infected with this spirochete. None of the lizards developed spirochetemias detectable by polymerase chain reaction for up to 8 wk post-tick feeding, infected nymphs apparently lost their B. bissettii infections within 1–2 wk after engorgement, and xenodiagnostic I. pacificus larvae that co-fed alongside infected nymphs did not acquire and maintain spirochetes. In contrast, 3 of 4 naïve deer mice (Peromyscus maniculatus) exposed similarly to feeding by 1 or more B. bissettii-infected nymphs developed patent infections within 4 wk. These and previous findings suggest that the complement system of S. occidentalis typically destroys B. burgdorferi sensu lato spirochetes present in tissues of attached and feeding I. pacificus nymphs, thereby potentially reducing the probability of transmission of these bacteria to humans or other animals by the resultant adult ticks.

Diclidophora merlangi (Kuhn, in Nordmann, 1832), as species specific to whiting, Merlangius merlangus (Linnaeus, 1758), is reported and described for the first time on the gills of Atlantic cod Gadus morhua (Linnaeus, 1758). Of the about 1,200 cod examined in this article, only 2 specimens of D. merlangi occurred on 2 fish, suggesting that they represented accidental infections. The 2 specimens showed specific traits of D. merlangi, but their size was considerably smaller than that of D. merlangi on whiting. Principal-component analyses showed that the morphology of the specimens on cod was more similar to that of D. merlangi than those of other congeneric species from the North Atlantic, additionally supporting their assignment to D. merlangi. Quantitative data documenting the potential reproductive consequences of D. merlangi occurring on cod is also provided. The testes and germaria of the specimens on cod were noticeably smaller than those of D. merlangi on whiting, but the number of testes was similar and spermatozoa were observed in the sperm duct. By contrast, the aspect and smaller size of the oocytes suggested that D. merlangi on cod could not produce viable ova, although 1 specimen exhibited an egg with normal sized and shaped capsule.

The Gyrocotylidea, a small and enigmatic group of intestinal parasites of chimaeras, has been considered to be related either to the Monogenea, or, more frequently, to the most primitive monozoic tapeworms (Cestoda), i.e., the Amphilinidea and Caryophyllidea. The present study, based on transmission electron microscopical observations of a species of Gyrocotyle from the rabbit fish, Chimaera monstrosa, in the North Atlantic, demonstrates for the first time the presence of microtriches as surface structures of gyrocotylideans. Because microtriches are considered to be an autapomorphy of tapeworms (Cestoda), in which they differ from other Neodermata (Monogenea and Trematoda), the present data represent another source of evidence in support of a close relationship between the gyrocotylideans and the tapeworms sensu stricto (Eucestoda). Simple morphology, small size, and shape uniformity of the microtriches of Gyrocotyle sp. may indicate they represent an original (plesiomorphic) form that then evolved in more derived cestode groups into a variety of types present mainly on the scolex. The microtriches of Gyrocotyle sp. resemble those found in caryophyllidean, spathebothriidean, pseudophyllidean, and trypanorhynch cestodes, which are considered to represent the most basal groups of the Eucestoda.

Ultrastructural characters in spermiogenesis and spermatozoa are considered important tools to elucidate the phylogenetic relationships within the Platyhelminthes. In the Anoplocephalidae, ultrastructural data refer to the spermatozoon of 14 species, whereas data on spermiogenesis refer to only 7 species. The present study focused on the spermiogenesis and spermatozoon of the anoplocephalid cestode Mosgovoyia ctenoides, as revealed by transmission electron microscopy. Type IV spermiogenesis was detected, beginning with the formation of a differentiation zone containing 2 centrioles, with a centriolar adjunct and vestigial striated rootlets. Different forms of the latter character have been described in other anoplocephalids. This study supports spermiogenesis of type IV as the most frequent in the Anoplocephalidae and confirms the presence of a centriolar adjunct in yet another type IV spermiogenesis species. The spermatozoon of M. ctenoides possesses 1 axoneme of the 9 ‘1’ trepaxonematan type, 2 crestlike bodies, dense plates, and granules of electron-dense cytoplasmic material, nucleus, and twisted cortical microtubules. It was again confirmed that the presence of granular material and the absence of both a periaxonemal sheath and intracytoplasmic walls are constant characters in the spermatozoa of all the Anoplocephalinae.

Adults of alveolar Echinococcus species with different uterine structures were collected from Vulpes corsac in the Hulunbeier Pasture of Northeastern China in 2001. They were Echinococcus multilocularis Leuckart, 1863 (type No. 3, similar to E. m. multilocularis), with vaselike uterus; Echinococcus cf. sibiricensis Rausch et Schiller, 1954 (type No. 1), with pyriform uterus; and Echinococcus sp. (type No. 2) with spherical uterus at segment top. The metacestode development in rodents also differed among those 3 parasites. In the case of E. multilocularis (type No. 3), many germinal cells grew on the inner surface of early cysts, most of which metastasized into host tissue to form brood vesicles or from the germinal cell layer on the inner surface of the vesicle wall. Cells also had an appearance of proliferating by means of alveolar buds from alveolar tissue that developed outward to form new alveolar foci. In Echinococcus cf. sibiricensis (type No. 1), the formation of alveolar vesicles was due to the metastasizing of germinal tissue into host tissue; protoscoleces grew in the center of alveolar vesicles. In type No. 2 (Echinococcus sp.), the formation of the alveolar vesicle was by multiplication of germinal cell layers on the inner surface of alveolar cysts; protoscoleces grew from the germinal cell layer and mesh in the vesicles. On the basis of uterine structure and on differences in development of metacestodes in experimental rodents, we propose that the 3 types of Echinococcus represent 3 independent species: E. multilocularis, Echinococcus sibiricensis, and Echinococcus sp. (type No. 2—as yet under study).

We investigated the host selection mechanism of actinospore stages of 2 myxosporeans, Myxobolus arcticus and Thelohanellus hovorkai, infecting masu salmon (Oncorhynchus masou) and common carp (Cyprinus carpio), respectively. Discharge of the polar filaments and sporoplasm release by M. arcticus actinospores occurred within the first 5 min of exposure to skin mucus of masu salmon. The actinospores also reacted to the mucus of nonsusceptible fish, i.e., sockeye salmon (Oncorhynchus nerka) and goldfish (Carassius auratus), although the reactivity was comparatively lower. After exposure of masu, and sockeye and chum salmon (Oncorhynchus keta) to M. arcticus actinospores, the penetration of sporoplasms was observed in the fins and gills of masu and sockeye salmon to a similar extent and to a lesser extent in chum salmon. Thelohanellus hovorkai actinospores exhibited a slow response of sporoplasm release to common carp mucus as well as penetration into the gills of common carp. Neither chemoresponse to mucus of nonsusceptible fish (goldfish and sockeye salmon) nor sporoplasm invasion in goldfish was observed for T. hovorkai actinospores. These results indicate notable differences in the host selection at the time of entry between M. arcticus and T. hovorkai; the former responds quickly to fish mucus with low host specificity, whereas the latter was highly host specific in a dilatory reaction.

The mechanism by which lung-stage schistosomula expose proteins at the host–parasite interface to nutrient, but not antibody, uptake has been obscure. We have found that Schistosoma mansoni and Schistosoma haematobium larvae emerging from host lung at a pH of around 7.5, and fixed with diluted formaldehyde (HCHO), readily bind specific antibodies in indirect membrane immunofluorescence. Data on inhibitors and activators of parasite tegument-bound, magnesium-dependent, neutral sphingomyelinase (nSMase), and sphingomyelin biosynthesis inhibitors revealed that equilibrium in schistosomular sphingomyelin breakdown and biosynthesis prevents antibody binding, yet permits access of small HO-CH₂-OH polymers to interact with and cross-link proteins at the host–parasite interface, allowing for their serological visualization.

Neurocysticercosis is a parasitic infection of the human central nervous system caused by the cestode Taenia solium. The most common clinical manifestations of neurocysticercosis are seizures. Taenia crassiceps cysticercosis in mice has been used as an experimental model for T. solium cysticercosis. Granulomas surrounding murine cysticerci have striking immunopathological resemblance to human neurocysticercosis; early stage granulomas were able to induce seizures in a rodent model. To assess the role of proinflammatory cytokines in early stage granulomas, we isolated RNA from murine cysticercal granulomas and checked for cytokine expression by reverse transcriptase-polymerase chain reaction (RT-PCR) and/or ribonuclease (RNase) protection assays. Cytokine expression was compared with histological stages. Interleukin (IL)-1α, IL-1β, IL-1 receptor antagonist, and tumor necrosis factor (TNF-α) were the major cytokines detected in all granulomas. Signals for IL-12, IL-18, and IL-6 RNA were not consistently detected and, when detected, were barely demonstrable. Expression of migration inhibitory factor (MIF), IL-6, IL-1α, TNF-α, and IL-18 was not significantly different between early and late-stage granulomas. Expression of IL-1β, IL-1 receptor antagonist, and IL-12 p40 were higher in late, compared with early, stages. Thus, we demonstrated a broad range of cytokines in these granulomas. However, we did not document preferential expression of any proinflammatory cytokines in early stage granulomas. Thus, proinflammatory cytokines are not responsible for the seizures in the rodent model of neurocysticercosis.

A coelomic myxozoan infection was detected in freshwater polychaetes, Manayunkia speciosa from the Klamath River, Oregon/California, a site enzootic for the myxozoan parasites Ceratomyxa shasta and Parvicapsula minibicornis. The tetractinomyxon type actinospores had a near-spherical spore body 7.9 × 7.1 μm, with 3 spherical, protruding polar capsules, no valve cell processes, and a binucleate sporoplasm. Parvicapsula minibicornis-specific primers Parvi1f and Parvi2r amplified DNA from infected polychaetes in a polymerase chain reaction (PCR) assay. The small subunit 18S rRNA gene of the spores was sequenced (GenBank DQ231038) and was a 99.7% match with the sequence for P. minibicornis myxospore stage in GenBank (AF201375). Chinook salmon (Oncorhynchus tshawytscha) exposed to a dose of 1,000 actinospores per fish tested PCR positive for P. minibicornis at 14 wk postinfection and presporogonic stages were detected in the kidney tubules by histology at 20 wk. This life cycle is 1 of only about 30 known from more than 1,350 myxozoan species, and only the second known from a freshwater polychaete.

Development and growth of parasites depend on resources provided by the host and the parasite's ability to use them. Identifying specific costs incurred by the host provides insight for assessment of parasite energy budgets, which differ among taxa and ontogenetic stages. Data from this study were analyzed using an accelerated failure-time model with intensity as a covariate. Results indicated significantly reduced survival of amphipods, Hyalella azteca, infected with the acanthocephalan Corynosoma constrictum compared with uninfected controls. Male and female amphipod survivorship and infection intensity did not differ; however, amphipods with high-intensity infections (>16 larvae) died earlier compared with amphipods with low-intensity infections (<3 larvae). The majority of infected amphipods died between 12 and 24 days postexposure, a period of rapid larval development. It is hypothesized that host death may be due either to an increase in overall larval nutritional demands or to parasite-mediated depletion of a specific host substance. Results from this study suggest that developing C. constrictum satisfies energy requirements by depriving amphipod hosts of resources normally used for somatic growth and maintenance.

Quantitative studies of a crowding effect on cysticercoids of Hymenolepis diminuta in the intermediate host are few and limited in scope. In this study, we developed a technique to rapidly collect morphological information on large numbers of parasites, and verified the utility of geometric models for simple and accurate estimation of cysticercoid size for quantitative studies. These models were tested using measurements from 4,899 H. diminuta obtained from 666 Tribolium confusum exposed 1–4 wk previously. Length, width, and depth of the body and cercomer (when present) can be used in conjunction with these models to provide the most accurate estimation of parasite size. However, parasite body length alone can be used, with adjustment for effects of host diet and infection intensity, to predict the remaining measurements in incomplete specimens. Parasites that developed in higher intensity infections, or in hosts with reduced food intake, were narrower and had a proportionately shorter cercomer. Host age, sex, and mating status, and parasite age also had statistically significant, but small-magnitude, effects on parasite shape.

The effects of temperature change on phospholipid content in metacercariae of Posthodiplostomum minimum and their second intermediate hosts, Lepomis macrochirus, were examined to gauge similarities in the homeoviscous adaptation of host and parasite membranes to environmental thermal change. Heart, liver, and muscle tissues from individual L. macrochirus responded to environmental temperature declines with a decrease in the ratio of phosphatidylethanolamine (PE) to phosphatidylcholine (PC). Increases in membrane PE concentration increase membrane fluidity, maintaining fish membrane function as environmental temperature declines. However, the metacercariae of P. minimum exhibit changes in cholesterol levels, total lipid levels, and lipid composition (PE/PC) that contrast the normal changes for homeoviscous membrane adaptation exhibited by their fish intermediate hosts. The parasites seem to rely on their hosts for homeoviscous adaptation within normal developmental temperature ranges, pooling both cholesterol and PE as energetic stores for development and ontological transitions signaled by elevated temperatures.

A sample of 204 skinks (Squamata: Scincidae) from 10 genera representing 24 species were collected from 10 different localities in New Guinea and examined for blood parasites. Hemogregarines, trypanosomes, microfilarial worms, and 8 infections showing 2 distinct morphological types of malaria parasites (Plasmodium sp.) were observed. Molecular sequence data, in the form of mitochondrial cytochrome b sequences from the Plasmodium infections, showed 2 distinct clades of parasites, 1 in Sphenomorphus jobiense hosts and 1 in Emoia spp., which correspond to the 2 morphotypes. There was substantial genetic variation between the 2 clades, as well as within the clade of Emoia parasites. Nearly half of the skinks sampled had green blood pigmentation, resulting from the presence of biliverdin in the plasma; however, only 1 of these lizards was infected with Plasmodium sp. and only 2 had any blood parasites. These preliminary results suggest a high degree of phylogenetic diversity but a very low prevalence of Plasmodium spp. infections in the skinks of this globally important biodiversity hot spot.

Little is known of the blood parasites of coral reef fishes and nothing of how they are transmitted. We examined 497 fishes from 22 families, 47 genera, and 78 species captured at Lizard Island, Australia, between May 1997 and April 2003 for hematozoa and ectoparasites. We also investigated whether gnathiid isopods might serve as potential vectors of fish hemogregarines. Fifty-eight of 124 fishes caught in March 2002 had larval gnathiid isopods, up to 80 per host fish, and these were identified experimentally to be of 2 types, Gnathia sp. A and Gnathia sp. B. Caligid copepods were also recorded but no leeches. Hematozoa, found in 68 teleosts, were broadly hemogregarines of 4 types and an infection resembling Haemohormidium. Mixed infections (hemogregarine with Haemohormidium) were also observed, but no trypanosomes were detected in blood films. The hemogregarines were identified as Haemogregarina balistapi n. sp., Haemogregarina tetraodontis, possibly Haemogregarina bigemina, and an intraleukocytic hemogregarine of uncertain status. Laboratory-reared Gnathia sp. A larvae, fed experimentally on brushtail tangs, the latter heavily infected with the H. bigemina-like hemogregarine, contained hemogregarine gamonts and possibly young oocysts up to 3 days postfeeding, but no firm evidence that gnathiids transmit hemogregarines at Lizard Island was obtained.

Taenia solium, a cestode that causes neurocysticercosis and taeniasis in humans, has a complex life cycle. The adult tapeworm develops in the intestine of human beings and is also responsible for neurocysticercosis, which is caused by the metacestode or cysticercus that develops in the brain. Recently, we have cloned the coding region for T. solium calreticulin (TsCRT) as a functional Ca² -binding protein. Calreticulin is a ubiquitous protein involved in cellular Ca² homeostasis and protein folding. These important functions affect several aspects of cell physiology. To explore the expression of TsCRT during the T. solium life cycle, we used a specific polyclonal antibody raised against recombinant TsCRT to localize this protein by immunolabeling techniques. In sections of cysticerci obtained from swine muscle, as well as of adult tapeworms obtained after infection of hamsters with cysticerci, TsCRT was preferentially localized in tegumentary and muscle cytons of the suckers and rostellum. In mature proglottids obtained from infected humans, positive staining was observed in spermatogonia, ovogonia, uterine epithelium, and cells of the vas deferens. In the gravid uterus, the morula and early stage embryos were highly positive to TsCRT. However, expression diminished as embryonic development progressed and was absent in fully developed oncospheres that were surrounded by an embryophore. A similar down regulation was observed during spermatogenesis. Although early spermatocytes showed a high expression of TsCRT, mature spermatozoa present in the vas deferens were completely negative. These data indicate that calreticulin expression is spatially and temporally regulated during development of T. solium, especially during germ cell development and embryogenesis. In addition, these original images illustrate, for the first time, these processes at a histological level.

A Taenia solium 2-Cys peroxiredoxin (Ts2-CysPrx) clone was isolated from a T. solium adult cDNA library. The clone encodes a polypeptide comprising 197 amino acids with a predictive Mr = 21,836. It has the 2 classical cysteine domains from the typical 2-Cys peroxiredoxins, and its primary amino acid sequence shows higher identity with 2 Echinococcus 2-Cys peroxiredoxins. Northern and Southern blot hybridizations exhibit an mRNA with a size of ∼1.0 kb, encoded by 1 gene. Ts2-CysPrx was expressed in Escherichia coli and purified by anion-exchange chromatography. Biochemical analysis showed Ts2-CysPrx is a dimer composed by monomers of ∼22 kDa that presented activity with hydrogen peroxide (H₂O₂) and cumene hydroperoxide. It presented the catalytic mechanism for a typical 2-CysPrx because the homodimeric oxidized form is reduced to a monomeric form by thioredoxin (Trx) and by dithiothreitol (DTT) and was converted to a homodimeric oxidized form by H₂O₂. Western blot studies using antibodies against Ts2-CysPrx revealed that the protein is expressed during the entire T. solium life cycle, as in other Taenia species. Immunohistochemical studies indicated that Ts2-CysPrx is localized on the tegument and in tegumentary and muscle cells of cysticerci. We also show that T. crassiceps cysticerci can tolerate H₂O₂ levels of 2.5 mM for 2.5 hr.

Expressed sequence tag (EST) analysis of the diploid and triploid Paragonimus westermani genes was done to have a rapid and informative outlook of the gene-expression profiles of the parasites. Totals of 506 and 505 ESTs were generated from the diploid and triploid P. westermani cDNA libraries. Based on the BLASTx search results of the diploid P. westermani ESTs, 308 (60.9%) matched significantly with formerly identified genes and 198 (39.1%) showed no significant homology in the GenBank database. A similar homology pattern was shown from the triploid EST BLASTx search results with 346 (68.5%) sharing homology with previously identified genes and 159 (31.5%) showing no significant homology. The EST data from both libraries were analyzed and grouped into 9 categories. Comparison of the 2 EST pools revealed high similarities among the categories of the significantly matched genes. Single genes matched repeatedly were also observed in the 2 EST data. Some genes were found that are not yet characterized in P. westermani; these genes were matched by both the diploid and triploid ESTs. Further study of these genes may provide us with more understanding on the parasite's biology and their specific functions in the 2 strains.

Myxobolus metynnis n. sp. (Phylum Myxozoa) is described in the connective subcutaneous tissues of the orbicular region of the fish, Metynnis argenteus (Characidae), collected in the lower Amazon River, near the city of Peixe Boi, Pará State, Brazil. Polysporic, histozoic plasmodia were delimited by a double membrane with numerous microvilli on the peripheral cytoplasm. Several life-cycle stages, including mature spores, were observed. An envelope formed by numerous fine and anastomosed microfibrils was observed at the spore surface. The spore body presented an ellipsoidal shape and was about 13.1 μm long, 7.8 μm wide, and 3.9 μm thick. Elongated-pyriform polar capsules were of equal size, measuring 5.2 μm in length, 3.2 μm in width, and possessing a polar filament with 8–9 turns around the longitudinal axis. The binucleated sporoplasm contained a vacuole and numerous sporoplasmosomes. These were circular in cross-section, showing an adherent eccentric, dense structure, with a half-crescent section. Based on the morphological differences and host specificity, we propose that the parasite is a new species named Myxobolus metynnis n. sp.

A new ascarid of elasmobranchs, Terranova amoyensis sp. n., is described from the intestine of the red stringray, Dasyatis akajei (Müller and Henle), from Taiwan Strait. This is the second report from this genus with a gubernaculum in fish. The new species differs from its congeners mainly in the following combination of characters: the 3 lips are unequal in size and different in shape, i.e., the subventral lips are asymmetric bilaterally and larger than the dorsal lip; the latter lip is bilaterally symmetrical. The ventriculus is spherical, and the cecum is short relative to the esophagus. Spicules are unequal in size, 1.48 mm long for the right spicule and 1.34 mm for the left spicule, or 4.3 and 3.9% of body length, respectively. Nineteen pairs of caudal sessile papillae (excluding phasmids) are present, of which 13 pairs are precloacal; pairs 14 and 15 lie close together on either side of the cloaca, composing ad-cloacal papillae (the pair near the tail end are twins). The remaining 4 pairs of postcloacal papillae form a group near the tail tip (pair 18 also twins and near the phasmids). The gubernaculum is I-shaped. The excretory pore is located on top of a coniform prominence whose location is just behind or between the bases of the 2 subventral lips. The vulva is prominent at one-third of the anterior part of the body; the distance from the vulva opening to the anterior body end is 17.4 mm (13.61–21.41), 26.8% (25.14–28.93%) of the body length.

The Holarctic distribution of Babesia microti within small rodents implies an ancient association. A seminal report of piroplasms in Alaskan voles suggested to us the possibility that B. microti entered North America within Eurasian microtine rodents dispersing through Beringian corridors. To test this hypothesis, we analyzed samples from Alaskan rodents by polymerase chain reaction for evidence of infection with B. microti; one-third of the rodents were found to be infected. Sequence analysis of the 18S rDNA gene demonstrates that Alaskan B. microti comprises a clade that infects microtines in several sites across North America and is distinct from a clade that is zoonotic.

Guidus n. gen. (Cestoda, Tetraphyllidea) is proposed for 3 cestode species from skates (Bathyraja spp.: Rajiformes, Rajidae). Members of Guidus differ from those of all other phyllobothriid genera in possessing 4 sessile and conspicuously muscular, saclike bothridia; a bothridial aperture toward anterior end of scolex, and perpendicular to scolex axis; aperture surrounded by a continuous sphincter of circular muscles, and 1 marginal accessory sucker. A new species, Guidus argentinense n. sp., is described, the diagnosis of Marsupiobothrium antarcticum is emended, and it is transferred to the new genus along with Marsupiobothrium awii. These species can be easily distinguished from G. argentinense by the presence of lappets in the bothridial margin. In addition, the diagnosis of Marsupiobothrium is emended based on the redescription of the type species, Marsupiobothrium alopias.

Specimens of Echinobothrium diamanti n. sp. (Cestoda: Diphyllidea) were recovered from the spiral intestine of Iago omanensis and Mustelus mosis (Carcharhiniformes: Triakidae), in the Gulf of Aqaba, Red Sea. The new species can be distinguished from all other species in Echinobothrium by the presence of a conspicuous vaginal sphincter. Echinobothrium diamanti possesses a corona of spines between the apical armature and the bothria, as in Echinobothrium notoguidoi, Echinobothrium musteli, and Echinobothrium scoliodoni, also parasites of sharks. However, E. diamanti possesses more testes per proglottid than E. notoguidoi and E. scoliodoni, and it is larger and has more spines per column on the cephalic peduncle than E. musteli and E. notoguidoi, and it also has circum-medullary vitelline follicles rather than distributed in lateral columns. Echinobothrium diamanti is the first species of diphyllidean reported from the triakid genus Iago.

Aspidodera sogandaresi n. sp. (Heterakoidea: Aspidoderidae) from Dasypus novemcinctus Linnaeus, 1758 is herein described. This nematode occurs in armadillos from as far south as the canal zone of Panama, north through central Mexico, and into the southern United States. Previously identified as Aspidodera fasciata (Schneider, 1866), this new species has blunt projections on the lips and lateral expansions at the distal tips of the spicules, whereas A. fasciata has conspicuous digitiform projections on the lips, and a terminal round expansion at the tips of the spicules. Other species of the family present in North America include Aspidodera binansata Railliet and Henry, 1913; Aspidodera vazi Proença, 1937; and Lauroia trinidadensis Cameron, 1939.

A new species of ectoparasitic glossiphoniid leech was found feeding on frogs in the Nature Center Pond and elsewhere in Deschutes County, Oregon. The new species of Placobdella resembles the southern alligator leech, Placobdella multilineata Moore, 1953, notwithstanding their vast geographic separation in North America. The new species is readily distinguished by possessing subdivided annuli, by its papillation and pigmentation patterns as well as by the arrangement of ovarian tissues. There is strong evidence of nocturnality and of the potential for parasitizing humans.

Food-borne trematodiasis is an emerging public health problem with more than 10% of the world's population at risk of infection, yet there are only 2 drugs available for treatment and morbidity control. We assessed the effect of a promising broad-spectrum anthelmintic drug, i.e., tribendimidine, with an experimental focus on adult Echinostoma caproni. Female NMRI mice were infected with 30 E. caproni for 2 wk and then administered single oral doses of tribendimidine ranging between 25 and 500 mg/kg. Three days post-treatment, mice were necropsied, and adult worms were recovered from their intestines. Worm burden reductions were assessed against untreated control mice. In addition, scanning electron microscopic observations were done on adult E. caproni recovered from mice given a single dose of 150 mg/kg tribendimidine intragastrically 2, 4, and 8 hr post-treatment. Worm burden reductions of 100% were achieved at doses of 125 mg/kg and above. Severe damage of the tegument, including extensive peeling, formation of blebs, and structural loss of the definition of collar and tegumentary spines already occurred within 2 hr after drug administration. Our findings call for further investigations using tribendimidine in other trematode– animal models, because this compound shows promising trematocidal activity.

Antibodies to Toxoplasma gondii were assayed in sera of 63 cats and 80 pigs from 71 farms located at Rondônia State, Western Amazon, Brazil, by the modified agglutination test (MAT) and the indirect immunofluorescent antibody test (IFAT). Antibodies (MAT ≥ 1: 25) were found in 55 of 63 cats (87.3%) with titers of 1:25 in 2, 1:50 in 2, 1:100 in 7, 1:200 in 1, 1:400 in 2, 1:800 in 9, 1:1,600 in 6, and 1:3,200 or higher in 26 cats. By IFAT, antibodies were found in 55 cats (87.3%) with titers of 1:25 in 2, 1:50 in 1, 1:100 in 4, 1:200 in 4, 1: 400 in 1, 1:800 in 13, 1:1,600 in 12, and 1:3,200 or higher in 18 cats. In pig sera, by MAT, antibodies were found in 30 of 80 pigs (37.5%) with titers of 1:25 in 2, 1:50 in 3, 1:100 in 2, 1:200 in 8, 1:400 in 3, 1:800 in 5, 1:1,600 in 3, and 1:3,200 or higher in 4 pigs. By using the IFAT (titers ≥ 1:64), antibodies were found in 35 (43.7%) pigs. The ingestion of undercooked tissues of infected pigs can be a source of T. gondii infection for humans and cats. However, the high seroprevalence of T. gondii in cats from the Amazon seems most likely to be indicative of high contamination of the environment by oocysts.

The disease caused by Taenia solium is progressively being recognized as a growing global threat for public human health and pig husbandry that requires the development of effective control measures. A central participant in the taeniasis/cysticercosis transmission network is the human carrier of the adult tapeworm because of its great potential in spreading the infection. Herein, evidence is presented that a primary infection of golden hamsters with orally administered T. solium cysticerci improved the host's resistance against a secondary infection. Likewise, previous vaccination increased the hamster's resistance. Similar high levels of protection (>78%) were induced by systemic or oral vaccination with the S3Pvac anticysticercosis synthetic peptide vaccine or the highly immunogenic recombinant chimera based on the protective peptide KETc1 bound to Brucella spp. lumazine synthase (BLS-KETc1). Increased resistance after primo-infection and vaccination possibly results from changes in the immune conditions prevailing in the host's intestine. The contribution to protection from the KETc1 and BLS epitopes in a chimeric vaccine is under study. Preventive vaccination of definitive hosts of T. solium against the tapeworm, the most relevant step in the taeniasis/cysticercosis transmission, may greatly impact the dynamics of endemic disease and has not been studied or tried previously.

Avian lice occupy different habitats in the host plumage that the physical environment outside the host body may affect in several ways. Interactions between host plumage and water may be an important source of such effects. Here, we use a comparative approach to examine the effect of a host's diving behavior on the taxonomic richness of its lice. Louse genera richness was significantly lower in clades of diving birds than on their nondiving sister clades. Species richness of host and body mass did not differ significantly between these clades; thus, these factors did not bias our results. This study suggests that the hosts' diving behavior can effectively influence ectoparasite communities.

Without antibiotic treatment, the Lyme-disease–causing bacterium, Borrelia burgdorferi can be cultured from the peripheral blood of human patients nearly 6 wk post-tick bite. To determine if Lyme disease spirochetes can be transmitted from a spirochetemic donor mouse to a naive recipient during blood transfusion, blood taken from immunocompetent infected mice was transfused into either immunodeficient (SCID) mice, inbred immunocompetent animals (C3H/HeJ), or outbred mice. Nine of 19 (47.7%) immunodeficient mice, 7 of 15 (46.8%) inbred immunocompetent mice, and 6 of 10 (60.0%) outbred mice became infected with B. burgdorferi after transfusion. Our results indicate that it is possible to acquire B. burgdoferi infection via transfused blood in a mouse model of Lyme borreliosis.

Starting from January 2004 to December 2004, 665 blood serum samples from pigeons (Columba livia) were collected from 44 pigeonaries in 11 counties and 20 regions in Taiwan. These samples were examined by latex agglutination test (LAT) for antibodies to Toxoplasma gondii by using the LAT. Antibodies were found in 4.7% (31/ 665) of pigeons at a LAT titer of 1:32 or higher. The prevalence in Taiwan was highest in the northern areas (6.0%; 13/216) and lowest in the eastern areas (1.8%; 2/111).

The oriental eyeworm, Thelazia callipaeda (Spirurida, Thelaziidae), infects a range of definitive hosts, such as dogs, cats, foxes, rabbits, and humans. This parasite usually lives under the nictitating membrane of the eye, where the adult females release first-stage larvae into the lachrymal secretions; these larvae are subsequently ingested by the intermediate arthropod host within which they develop to the infective, third-stage larvae. The latter larvae are then deposited into the eyes of the definitive host. Recently, T. callipaeda has been reported to infect dogs, foxes, and/or cats in Europe (Italy, France, and Germany). Human thelaziosis (HT) is considered to be an underestimated parasitic disease, whose prevalence appears to have increased in poor socioeconomic settings in many Asian countries, including China. In humans, the disease can be subclinical or symptomatic, exhibiting epiphora, conjunctivitis, keratitis, excessive lachrymation, corneal opacity, and/or ulcers. Knowledge about HT is presently fragmentary and mainly limited to clinical case reports. This article provides a background on the parasite and its life cycle, reviews cases of human thelaziosis, summarizes key aspects regarding the diagnosis of thelaziosis, and proposes future research and methods of control of the disease in humans, particularly in Asia.