Hormones play a significant role in murine Taenia crassiceps cysticercosis, and they may also participate in the susceptibility to Taenia solium cysticercosis. In the present study, in vitro effects are reported for human chorionic gonadotropin (hCG) on the larval stages of T. crassiceps (WFU strain) and T. solium. Our results reveal the presence of receptors for hCG in different developmental phases of both cultured parasites. On day 30, both taeniid species had the highest percentage of receptors in the neck, strobila, and suckers, but these receptors decreased by day 60, delimiting the segments and the exterior of the developing proglottids in T. solium. At the same time, there was a large number of hCG receptors in the area of the presumptive cirrus organ and in calcareous corpuscles within the parenchyma. This is the first report detecting receptors for hCG on different larval stages of T. crassiceps and T. solium. A direct effect of hCG could be recognized by the cysticerci as a factor contributing to the growth and development of T. crassiceps and T. solium cysticerci, respectively.

The gill monogene communities of Pimephales promelas (fathead minnow) in 3 distinct sites on converging streams were investigated from 2004 to 2006 in 3 different seasons. Thirty collections of P. promelas were made in southeastern Nebraska along 3 converging tributaries: Elk Creek (40.88534°N, 96.83366°W), West Oak Creek (40.9082°N, 96.81432°W), and Oak Creek (40.91402°N, 96.770583°W), Lancaster County, Nebraska. In all, 103 P. promelas were collected from Elk Creek, 115 from West Oak Creek, and 78 from Oak Creek and examined for gill monogenes. Among the P. promelas collected, 93.5% were infected with up to 3 species of Dactylogyrus, including Dactylogyrus simplex Mizelle, 1937, Dactylogyrus bychowskyi Mizelle, 1937, and Dactylogyrus pectenatus Mayes, 1977. Mean intensities at Elk Creek, West Oak Creek, and Oak Creek were 17.6, 22.8, and 25.1, and prevalences 88, 95, and 97%, respectively. At these 3 sites: (1) P. promelas does not share Dactylogyrus species with Semotilus atromaculatus (Creek chub) or Notropis stramineus (Sand shiner); (2) fish size and sex are not predictive of Dactylogyrus infection; (3) Dactylogyrus spp. vary (not always predictably) in their seasonal occurrence; (4) populations of Dactylogyrus spp. respond to environmental differences among sites; and (5) the community structure of Dactylogyrus spp. (order of abundance) is independent of environment.

Previous molecular genetic analyses indicate that Opisthorchis viverrini is a complex of at least 2 cryptic species in Thailand and the Lao People's Democratic Republic (PDR). Opisthorchis viverrini sensu lato (s.l.) populations can be divided into 6 genetic groups, which correlate with 5 different river wetlands systems. The present study examines the infectivity, growth, fecundity, and body size of O. viverrini s.l. isolates from these systems. Worm recovery was lowest in the Songkhram River, which differed significantly from all other wetland systems. In addition, the Chi River and Nam Ngum River populations also differed significantly. A similar pattern was found for fecundity. These results support the genetic/molecular data indicating a subdivision of O. viverrini populations on the basis of watershed and that propose the existence of cryptic species in Thailand and the Lao PDR.

Parasite transmission is a dynamic process that can be affected by factors including host and parasite population dynamics. Raccoons (Procyon lotor) are the definitive host of Baylisascaris procyonis, an intestinal roundworm. Transmission of this parasite has been linked to raccoon behavior and human land-use patterns; however, we do not know the importance of host population structure. Therefore, the objective of this study was to determine the relationship between raccoon population attributes and prevalence of B. procyonis. We necropsied 307 trapped or road-killed raccoons collected during 2000–2006 from the Chicago area. In addition, we examined, via fecal samples (n  =  433), the patterns of B. procyonis prevalence as they relate to population dynamics among 3 subpopulations within the larger study. Baylisascaris procyonis was seen in 39% of 307 necropsied raccoons. There were differences in prevalence as a function of host age and sex. Baylisascaris procyonis was observed in 18% of 433 fecal samples obtained from live-trapped raccoons, and there were differences according to age, but not by sex. We found that the host populations consistently differed in density across study areas, but were similar regarding sex and age structure. Differences in host density were associated with differences in prevalence, suggesting that possible differences between populations, as well as ecological differences in sites and raccoon behavior, may have influenced parasite prevalence.

Schistosomiasis continues to be a significant public health threat in the world. In the area of parasitic diseases, it is widely considered second only to malaria as a global health problem, with an incalculable drain on the economic resources of countries where it is endemic. Schistosoma japonicum is widespread in eastern and southeastern Asia, where the amphibious snail, Oncomelania hupensis, is the intermediate host. In the present study, we found that infection of O. hupensis with the mature eggs of another trematode, Exorchis sp., inhibited development of S. japonicum mother sporocysts in O. hupensis. Exorchis sp. commonly infects the edible fish Parasilurus asotus in China, but it is harmless to humans. This discovery provides an opportunity for possible biological control of S. japonicum infection and transmission. Additionally, it has the potential to substantially reduce the impact of the global S. japonicum that is independent of antihelminthic use. The mechanisms used by Exorchis sp. to inhibit infection by S. japonicum in the snail require further investigation.

Three parasitic copepods new to the well-studied Mediterranean fauna are reported. Two of them, Mitrapus oblongus (Pillai, 1964) and Clavellisa ilishae Pillai, 1962, are of Indo-Pacific origin and are considered here to have co-invaded the Mediterranean through the Suez Canal on Erythrean (Red Sea) immigrant hosts. Both are reported here from native Mediterranean clupeid fish hosts; this is the first evidence of host switching of any metazoan parasites from Erythrean immigrants to native fish hosts. The third parasite, Nothobomolochus fradei Marques, 1965, was previously known from the Gulf of Guinea and the Arabian Gulf. Possible explanations of its presence on clupeid hosts in Egyptian waters off Alexandria are discussed. The parasite utilizes an Erythrean immigrant clupeid and a native Mediterranean species as hosts. This account provides evidence of parasite and host faunal mixing on an unexpected scale.

A review of the structure and functionality of monogenoidean head glands is provided. The unique features of the biochemical methods used by parasites to attach to, or detach from, fish hosts are highlighted. The potential use of monogenoidean cephalic secretions in the surgical field, and particularly in the production of bioadhesives, is suggested and critically supported by comparison with other available hemostatic agents.

Ticks can be transported over large distances and across geographical barriers by avian hosts. During the spring migrations of 2003 to 2005, 9,768 passerine birds from 4 bird observatories along the southern coastline of Norway were examined for ticks. Altogether, 713 birds carried a total of 517 larvae and 1,440 nymphs. The highest prevalence of tick infestation was observed in thrushes and dunnock (Prunella modularis). The degree of tick infestation varied during each season, between localities, and from year to year. Blackbirds (Turdus merula) caught in localities with many ticks had greater infestation than those from localities with few or no ticks, suggesting local tick recruitment. A similar study performed during 1965–1970 involving 2 of the bird observatories in the present study found ticks on 4.2% of birds, while we found infestation of 6.9% at the same localities (P < 0.001). With the exception of 10 nymphs and 1 larva, the predominant tick was Ixodes ricinus. Seven nymphs of Hyalomma rufipes and 1 larva of Dermacentor sp. were also found. No species of Dermacentor had previously been found in Norway.

Androlaelaps maurii, a new species of laelapine mite, is described on the basis of female specimens collected from the pelage of the akodontine rodent, Deltamys kempi, from La Plata River basin in Argentina. Androlaelaps maurii can be differentiated from closely related species by its smaller size, the differing distribution of setae in the dorsal shield, and an unarmed opithogaster. This mite appears to be host specific to D. kempi and occurs on this rodent throughout its distribution in Argentina and Uruguay.

A new species of rhynchobdellid leech, Placobdella ringueleti n. sp., is described based on the examination of 25 specimens. Leeches were collected from body appendages of freshwater turtles (Kinosternon leucostomum, Dermatemys mawii, and Staurotypus triporcatus) from Chiapas, Mexico. The new species resembles other members of the genus in the ocular morphology, bilobated ovaries, and presence of 1 pair of elongated mycetomes, but it is distinguished from them by the dorsal papillar pattern, by having a continuous longitudinal mid-dorsal stripe along the dorsal surface and papillae on the dorsal surface of the posterior sucker. Placobdella ringueleti represents the third species of the genus in Mexico. The type locality of the new species is part of the “El Ocote” Biosphere Reserve, Chiapas, Mexico.

One previously described species, Haliotrema striatohamus Zhukov, 1981, found off the coast of Cuba and Campeche (Gulf of Mexico), is redescribed and transferred to Haliotrematoides Kritsky, Yang and Sun, 2009, as Haliotrematoides striatohamus (Zhukov, 1981) n. comb. This transfer is based on the study of new specimens of this species found in the gill lamellae of grunts, i.e., Haemulon aurolineatum Cuvier, Haemulon plumierii (Lacepède), and Haemulon sciurus (Shaw) (Haemulidae), all from the southern coast of Quintana Roo, Mexico. In addition, another previously described species, Haliotrema brevispirocirrus Zhukov, 1981 from Haemulon striatum (Linnaeus) from Havana, Cuba, is also transferred to Haliotrematoides based on the comparative morphology of its original description. Data are provided for prevalence and mean intensity as well as for the morphologic and biometric variability of H. striatohamus from different hosts. The new replacement of H. striatohamus (Zhukov, 1981) n. comb. and H. brevispirocirrus (Zhukov, 1981) n. comb. infecting these taxa represents the first known species of Haliotrematoides on these fishes and new geographical records for these dactylogyrid monogenoids.

Anisakis simplex s.s. specimens from Gadus morhua, Gadus ogac, Reinhardtius hippoglossoides, Clupea harengus, Micromesistius poutassou, Pleurogrammus monopterygius, and Oncorhynchus nerka, caught in the north Atlantic and Pacific, were examined. Identity of the parasite species was confirmed using a molecular key. All specimens were used for amplifying a part of the non-coding sequence of the AT-rich region, flanked by the nad6-nad4L-trnW-trnE-rrnS-trnS2, and trnN-trnY-nad1 genes. This part of the mtDNA was chosen as a promising fragment, which could yield information regarding population differentiation. The number of samples and their geographical origin was sufficient to compare the 2 regions. The Bayesian analysis provided strong support for a population split into 2 groups, one representing A. simplex s.s. samples from the Pacific, and the other representing all the Atlantic samples. It is highly probable that observed subpopulations were constituted after the connection between the Atlantic and Pacific had been closed and movement between these 2 oceans was prevented.

In an evolutionary context, parasites tend to be morphologically conservative relative to their hosts. However, the rate of neutral molecular evolution across many parasite lineages is faster than in their hosts. Although this relationship is apparent at the macroevolutionary scale, insight into the processes underpinning it may be gained through investigations at the microevolutionary scale. Birds and their ectoparasitic lice have served as important natural experiments in co-evolution. Here, we compared mitochondrial and morphological divergence in 2 recently diverged avian host lineages and their parasites. Gálapagos hawks (Buteo galapagoensis) are phenotypically divergent from their closest mainland relatives, the Swainson's hawk (Buteo swainsoni). Both species are host to a feather louse species of Craspedorrhynchus (Insecta: Phthiraptera: Ischnocera, Philopteridae). We sequenced the 5′ end of the mitochondrial gene cytochrome oxidase c subunit I (COI) from a set of hawks and lice. Although this fragment allowed unambiguous identification of host and parasite lineages on the islands and the mainland, only a single variable site was present in the 2 hosts, but 2 major Craspedorrhynchus clades divergent by ∼10% were recovered that sorted perfectly with host species. We found significant population genetic structure within the Galápagos Craspedorrhynchus lineage. While the host species are highly differentiated phenotypically, the 2 Craspedorrhynchus louse lineages are phenotypically overlapping, although subtle but significant morphological differences exist.

We examined the effect of Plagiorchis elegans on egg production and survival on Bulinus truncatus and Helisoma trivolvis trivolvis. Both species are incompatible hosts for P. elegans. Helisoma t. trivolvis occurs sympatrically with P. elegans; B. truncatus does not. Overall, P. elegans had no effect on survivorship or egg production in H. t. trivolvis or on the survivorship of B. truncatus. Its effect on egg production in B. truncatus was transitory; egg production was reduced by 50% for 5 wk following exposure but returned to normal thereafter. Neither egg production nor survivorship was affected in adult H. t. trivolvis. Egg production ceased at 14 wk post-exposure (PE), but resumed when the snails were paired. Young H. t. trivolvis also produced eggs after exposure, but later than the adults and only after they had been paired with another snail. This suggests that a need for periodic cross-fertilization in H. t. trivolvis rather than the effect of the parasite is responsible for the cessation of egg production in this species. Survivorship in young H. t. trivolvis was significantly higher in exposed snails between wk 7 to 10 PE than in controls.

The Erythrean invasive swimming crab Charybdis longicollis established dense populations in the Levantine Basin of the Mediterranean Sea in the mid 20th century. The crabs were subsequently parasitized by the rhizocephalan Heterosaccus dollfusi, itself an Erythrean alien. In May 2008, the crab populations were sampled at the southern (Israel) and northern (Turkey) limits of its introduced range. The prevalence of infection was 3 times as high, and multiple externae-bearing hosts more than 4 times as many, in Israeli waters as in Turkey. It seems that off the Israeli coast, the water temperature permits the synchronous ontogenetic development of both host and parasite, ensuring the availability of plentiful young, recently-molted, prospective hosts for infection by the short-lived parasite cypris. It is possible that the lower water temperature off Antalya (Turkey) may affect the timing of ontogenetic development of one species or the other, or increase the mortality of infected hosts, resulting in drastically reduced parasite prevalence.

Infection by trematode parasites generally affects life history traits of their intermediate hosts. Reduction in life expectancy and reproductive capacity have previously been documented in Fasciola gigantica-infected Lymnaea ollula, but the influence of the endocrine system on this specific host–parasite interaction has not been previously examined. In the present study, we observed survival, growth pattern, and reproductive output of L. ollula following exposure to F. gigantica. Both the survival and the growth pattern of infected snails were similar to those of the non-infected control group. However, a significant difference was apparent in fecundity, as infected snails consistently showed lower levels of egg and embryo production throughout a 7-wk observation period. Semi-quantitative RT-PCR also revealed down-regulation of estrogen receptor expression in infected snails during the first 4 wk of infection. Nonetheless, the inhibition of estrogen signaling was transient, as they regained expression in the later phase of infection. It is, therefore, suggested that other hormones of the complex endocrine system may be involved in the reduced fecundity of L. ollula following F. gigantica infection.

The life cycle from release of myxospore sporoplasm to mature actinospore for the myxozoan parasite Ceratomyxa shasta in the freshwater polychaete host is described. Infection was initiated through exposure to lab-infected waters. Mature myxospores were present in the gut of segment 4 by 2 hr post-exposure (PE). Migration of early developmental stages occurred from the gut epithelium, through the nervous system, and into the epidermis. Once the parasite reached the epidermis, development typically occurred in segments 6–10. Life stages in the epidermis included a proliferative stage (schizogony), development of a pansporocyst (gametogony), sexual reproduction (gametogamy), and spore formation (sporogony). At water temperatures averaging 17.3 C, schizogony began by 3 hr PE, gametogony by 14 days PE, gametogamy by 35 days PE, and sporogony between 35 and 49 days PE. Development of mature actinospores took approximately 49 days PE. Up to 13,650 ± 7,807 actinospores could be released from a single polychaete over a 14-day period. Actinospores appeared to be released directly through the epidermis into the water column.

The digenetic trematode, Proctoeces lintoni, is a parasite of the rocky intertidal ecosystems of the Chilean Pacific coastline. Although this species is relatively well known, the first intermediate host has not yet been described. In the present study, we used experimental protocols and field studies to identify the host that harbors the sporocysts and cercariae stages of the parasite. The first intermediate host was shown to be the dominant mussel of the mid-littoral zone, Perumytilus purpuratus.

Metacercariae of Himasthla alincia (Echinostomatidae) were discovered in brackish water bivalves in the Republic of Korea; their growth and development were observed in experimental animals. Five species of clams (Mactra veneriformis, Solen grandis, Meretrix petechialis, Cyclina sinensis, and Tapes philippinarum) were found to harbor the metacercariae of H. alincia. Chicks, rats, and mice were orally fed the metacercariae, and worms were recovered from their intestines from day 1 to day 20 postinfection (PI). Only chicks appeared to be a fairly suitable host, although the worm recovery was low, i.e., 1.5% from 17 chicks, and the number decreased from 2.6% on day 1 PI to 1.3% on day 20 PI. Worm development in chicks was quick and remarkable during days 10–20 PI. Adult flukes were morphologically characterized by the presence of a head collar with 31 dorsally uninterrupted collar spines, including 4 end-group spines, and distribution of vitellaria only up to the most posterior margin of the cirrus sac. We verified that several species of brackish water clams are second intermediate hosts for H. alincia, and that its life cycle occurs in the Republic of Korea.

Schistosomiasis, also known as Bilharzia, is an infectious disease caused by several species of Schistosoma. Twenty million individuals suffer severe symptoms and 200,000 people die annually from the disease. The host responds to the presence of S. mansoni by producing reactive oxygen species that cause oxidative stress. We hypothesized that schistosomes produce antioxidants in response to oxidative stress. A known antioxidant protein is methionine sulfoxide reductase (Msr). Methionine residues can be oxidized to methionine sulfoxide in the presence of oxidizing agents, and the process is readily reversed by the action of the Msr system. Two S. mansoni MsrB genes (MsrB1 and MsrB2) were cloned and the recombinant proteins were expressed in bacteria and purified. The S. mansoni MsrB proteins contained the common conserved catalytic-and zinc-coordinating cysteines. Analysis of the proteins showed that both proteins promote the reduction of both free methionine sulfoxide (Met[O]) and dabsyl-Met(O) to free methionine (Met) and dabsyl-Met, respectively, while exhibiting differences in their specific activities toward these substrates. Using real-time polymerase-chain reaction (RT-PCR), both proteins were found to be expressed in all stages of the parasite's life cycle, with the highest level of expression of both proteins in the egg stage. This is the first description of MsrB proteins from a parasite.

With the recent completion of the Brugia malayi genome, proteomics offers a new resource for a deeper understanding of the biology of filarial parasites. We employed 2-dimensional (2D) gel electrophoresis followed by peptide mass fingerprinting on a matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometer to identify Brugia adult worm proteins and then determined which proteins were recognized by the host humoral immune response. We identified 18 unique proteins, several of which were determined to be antigenic by immunoblot. The proteins identified here may contribute to future studies to analyze the transmission and pathogenesis of lymphatic filariasis.

The present investigation reports the results from a 2-yr study conducted on the prevalence and associated lesions of the nematode Cheilospirura (Acuaria) hamulosa (Nematoda, Acuarioidea) in a sample size of 478 indigenous fowl collected from different localities of Kashmir Valley, India. The investigation revealed the annual prevalence for the nematode for the first and second yr of study to be 3.4% (8/233) and 3.7% (9/245), respectively, with an overall prevalence of 3.5% (17/478). Parasitized birds did not present with clinical signs. Despite the low parasite burdens, the lesions induced by C. hamulosa were severe. Histological examination of the infected gizzard revealed discrete and coalescing nodular and cystic lesions in the mucosa and musculature which contained sections of the parasite. Cellular reaction in the lesions was characterized by a large number of lymphocytes, monocytes, plasma cells, heterophils, and, in some of the sections, severe eosinophilic reaction. The mucosa and submucosa showed markedly thickened and diffuse mononuclear infiltration as well as reactive lymphoid nodules.

Amphibians of 24 species were surveyed for acanthocephalans in 4 nature reserves in 2 Chinese provinces during 2004–2006. Pseudoacanthocephalus bufonis (Echinorhynchida) occurred in both nature reserves in Guangxi Province. In the Jing Xi County Provincial Nature Reserve, P. bufonis infected 36 of 62 amphibians at a mean intensity of 9.9. Less than 250 km away, at Shiwandashan National Nature Reserve, 5 of 20 amphibians were infected at a mean intensity of 6.2. Pseudoacanthocephalus bufonis was not found in either of the reserves in Guizhou Province. In the Kuan Kuoshui Nature Reserve, 9 of 28 amphibians were parasitized at a mean intensity of 2.0 by a previously undescribed species of Pseudoacanthocephalus, and no acanthocephalan occurred in a small sample of 2 toads at Dashahe Nature Reserve. The new species, Pseudoacanthocephalus reesei n. sp., differs from all others in the genus by typically having 14 longitudinal rows of 4 hooks, each of which is much longer than corresponding hooks of any other species of the genus. The length of proboscis hooks increases from the apex to the base of the proboscis, further distinguishing the new species from all but Pseudoacanthocephalus nguyenthileae.

Myxobolus ridouti n. sp. and M. ridgwayi n. sp. are described, respectively, from Pimephales notatus (Rafinesque) and Semotilus atromaculatus (Mitchill) in Algonquin Park, Ontario, Canada. Both are intracellular in striated muscles of the body flank. Spores of M. ridouti n. sp. are subcircular (9.5–10.5 μm long by 9.4–10.9 μm wide); those of M. ridgwayi n. sp. are oval (10.0–12.1 μm long by 9.5–10.5 μm). Both species have spores with a small, distinct swelling (1 μm) on the spore valve near the posterior sutural ridge, similar to that described for Myxobolus insignis Eiras, Malta, Varella, and Pavanelli, 2005. It looks to be non-nuclear in origin, apparently part of the internal face of a spore valve, and could be taxonomically useful. Partial sequence data of the 18S rDNA from both species are unique among those species in the genus that have been sequenced. The sequences have the greatest overall identity with various species of Myxobolus from cyprinids in North America, Europe, and Asia, with a constructed molecular phylogeny having the 2 new species forming a separate clade.

In 1999, a single specimen of the Tolai hare, Lepus tolai Pallas, 1778, from the Gobi region of Mongolia was examined and had a new species of eimerian parasite in its intestinal contents. Eimeria gobiensis n. sp. is relatively large; it possesses 2 oocyst walls and a very well-developed oocyst residuum. Oocysts of the new species possess a thick wall with a double layer, a massive 3-layered micropyle, and are ellipsoidal, with average length and width of the oocyst of 38.6 × 24.2 µm, respectively. The range in measurements of these oocysts extends from 27.3 to 49.2 µm in length by 18.8 to 32.5 µm in width, with a length/width ratio  =  1.6; the oocyst residuumis is composed of a sub-spheroidal mass of small granules with an average size of 12.0 × 11.0 µm; sporocysts are ovoidal with an average length × width of 15.0 × 7.7 µm, respectively, and a range in length extending from 9.2 to 21.0 µm by 5.0 to 12.0 µm in width. In addition, each sporozoite has a large, medial, refractile body with an average size of 6.0 × 5.0 µm.

The original description of Henneguya pellis, a myxozoan parasitizing blue catfish Ictalurus furcatus, is supplemented with new data on histopathology, spore morphology, and 18S small subunit (SSU) ribosomal DNA (rDNA) sequence. Plasmodia presented as both internal and external, raised, cyst-like lesions on the body wall of the peritoneal cavity and on the skin. The cysts contained numerous elongate, lanceolate myxospores, flattened parallel to the suture line. The spore body was 14.8 ± 1.1 µm (range 13.0–17.1) long and 4.8 ± 0.8 µm (range 4.0–7.4) wide in frontal view. The caudal appendages were 77.7 ± 8.8 (range 57.4–96.4) in length. There were 2 pyriform polar capsules, unequal in length, with the longer capsule measuring 7.2 ± 0.6 µm (range 6.2–8.4) in length and the shorter capsule measuring 6.5 ± 0.5 µm (range 5.5–8.0). The polar capsules were not significantly different in width, measuring 1.7 ± 0.2 µm (range 1.4–1.9). There were 8 turns in the polar filament coil. The total length of the spore was 92.5 ± 9.2 µm (range 73.3–113.5). Spore morphology and site of development are similar to that of Henneguya sutherlandi from channel catfish; however, 18S rDNA sequence data support previous findings that identify H. pellis and H. sutherlandi as 2 distinct species.

The synlophe, or system of longitudinal cuticular ridges characteristic of some trichostrongyloid nematodes, is examined in detail for 6 of 8 species in Longistrongylus (Ostertagiinae) that occur in ungulates across sub-Saharan Africa. Among the species of Longistrongylus examined, 5 are characterized by a tapering pattern laterally in the cervical zone (anterior to the esophageal-intestinal junction), which is largely consistent among multiple male and female specimens; in contrast, for Longistrongylus meyeri the lateral pattern is parallel. The synlophe is bilaterally symmetrical, with ridges extending from the base of the cephalic expansion to near the caudal extremity in males and females. Ridges are acutely pointed, with perpendicular orientation and absence of gradient as viewed in transverse section. Species-specific patterns in conjunction with the numbers of ridges may serve to augment an array of diagnostic characters for species of Longistrongylus and contribute to increasingly accurate identification of female specimens. Among 5 of 6 species examined in the current study, the numbers of ridges in males was equal to or exceeded that observed in females, a pattern seen only in Africanastrongylus among the 15 genera of the Ostertagiinae. The differential numbers of ridges in males and females may represent another character among the suite of attributes that in part diagnose the genus Longistrongylus.

Two new species of Crossobothrium were found inhabiting Notorynchus cepedianus, the broadnose sevengill shark, collected from the coast of Buenos Aires Province, Argentina. Crossobothrium antonioi n. sp. is the smallest species in the genus and has at least 3 times as many testes per mature proglottid than any other congener. It can be further distinguished from other species of Crossobothrium by the possession of crenulated bothridial margins and a different microthrix pattern. Crossobothrium pequeae n. sp. is distinguished from all other species in the genus using the following combination of characters: worm size, number of testes per mature proglottid, bothridial margins, microthrix pattern, and the extension of ovary and testicular fields in cross section. Species in Crossobothrium, with the exception of C. laciniatum, seem to be restricted to hexanchid sharks, and a single species of shark can be parasitized by multiple species of Crossobothrium, as is the case with N. cepedianus, and probably Hexanchus griseus.

Whitegonimus ozoufae n. gen., n. sp. (Digenea: Zoogonidae) is reported from the stomach of Patagonotothen tessellata in the harbor of Ushuaia in the Beagle Channel (Tierra del Fuego, Argentina) at a depth of 7–9 m. The female genital system structure indicates the new taxon belongs in the subfamily Lepidophyllinae (Zoogonidae). None of the genera previously described is similar to the new genus. The most important taxonomic features are the spined tegument, lack of enlarged circumoral spines, gonads arranged in tandem, long caeca, vitelline follicles extending from the level of the ventral sucker to the posterior end of anterior testis, and a Y-shaped excretory vesicle. Only 3 genera, Overstreetia, Anarhichotrema, and Pseudopalaeorchis, have testes arranged in tandem, but they differ from the new genus in possessing enlarged circumoral spines, oral sucker size, esophagus length, length of caeca, vitellaria restricted to hindbody, the form of the ovary, and an I-shaped excretory vesicle.

Fibromermis roarki n. gen., n. sp. (Nematoda: Mermithidae) is described from the hemocoel of chironomid imagos of Ablabesmyia monilis (L.) eclosing from the headwaters of the Mississippi River at Gulsvig Landing in northern Minnesota in the summer of 2007. The new genus is described, distinguished from the most closely related tetrapapillate aquatic mermithid genus, and the new species described. Intensity and sex specificity of infection are recorded from 28 host adult chironomids of a single cohort. The new species represents the fourth tetrapapillate mermithid species described from the area and the third tetrapapillate genus.

The Hepatozoon species in the myocardium of Japanese martens (Martes melampus melampus) was characterized by histological and molecular methods. Histologically, granulomatous nodules with Hepatozoon sp. merozoites/gametocytes, or schizonts, or both were observed in the hearts of Japanese martens. The most frequently observed forms were merozoites/gametocytes within phagocytes; each host cell included a zoite, which was not microscopically identifiable as a merozoite or gametocyte. Schizonts were oval in shape and 36.9 ± 5.7 × 28.9 ± 3.4 µm in size; each schizont had approximately 20–60 nuclei. The size of the merozoites could not be measured because no mature schizonts were observed. In the analyses of the partial 18S rRNA gene sequence, it was strongly suggested that the Hepatozoon sp. in Japanese marten and the Hepatozoon sp. in pine marten (Martes martes) in Scotland were the same species.

Species of Hysterothylacium Ward & Magath, 1917 (Nematoda: Anisakidae) have previously been reported only from marine and freshwater fishes. Here, we describe a new species that infects red-spotted newts (Notophthalmus viridescens), a North American amphibian species with fully aquatic adults. Aside from the unique characteristic of infecting an amphibian host, the new species differs from congeners by the presence of lateral alae, the length of intestinal cecum (0.54–0.73 mm, 39.67–49.09% of esophageal length), the size of the spicules (0.33–0.39 mm, 2.75–3.25% of body length), and the absence of tail tip ornamentation. The absence of fish in the ponds from which these specimens were obtained suggests that newts are the normal definitive host for this species. We suggest that this species might have diverged from a Hysterothylacium parasite of the freshwater fishes which usually live in close proximity with newts.

Angiostrongylus lenzii n. sp. (Nematoda: Metastrongyloidea) is described and illustrated from the pulmonary artery of the wild rodent Akodon montensis Thomas, 1913, collected in the municipality of Teresopólis, Rio de Janeiro State, Brazil. It represents the 17th species of the genus and the 2nd in South America as parasites in rodents. This new species is the most similar morphologically to Angiostrongylus vasorum, Angiostrongylus gubernaculatus, Angiostrongylus schmidti, and Angiostrongylus morerai. It can be distinguished from them by the morphology of the caudal bursa, ventral rays 2 and 3 with conspicuous knobs, differences in width and length of lateral and dorsal rays, presence of rays 8, and length of spicules.

Some discrepancies between microscopy and PCR-based methods have been recently recorded in the diagnosis of Leucocytozoon spp. infection in naturally infected birds. To clarify this issue, blood samples from 109 yellow-whiskered greenbuls Andropadus latirostris were investigated using both the microscopic examination of blood films and a nested mitochondrial cytochrome b PCR. The overall prevalence of Leucocytozoon spp. infection was 4% after the standard microscopic examination and 17% using the PCR diagnostics. Samples from 9 randomly chosen birds that were microscopy negative, but PCR positive, were then examined microscopically by screening 2 entire blood films from each individual bird. Sporozoites of Leucocytozoon spp. were observed in 4 birds, and 1 gametocyte of the parasite was seen in each of 2 birds. We conclude that sensitive PCR-based diagnostics are able to detect extremely light parasitemias of circulating sporozoites and gametocytes of hemosporidian parasites. Because of the PCR detection of sporozoites of unknown fate in the peripheral circulation, conclusions regarding the distribution of hemosporidian lineages in wildlife should be made with caution. To be accepted as the lineages of successfully developing species of hemosporidians, such PCR-based information should be supported with the detection of blood stages of the parasites. The present study emphasizes the crucial need for a synthesis of information provided by the tools of traditional parasitology and molecular biology, particularly in field studies of blood parasites.

Khawia saurogobii n. sp. is described from the intestine of the cyprinid fishes Saurogobio dabryi and Saurogobio dumerili in China. The new species belongs to the Lytocestidae and is placed in Khawia because of its afossate scolex, vitelline follicles in the cortical parenchyma, uterus not looping anterior to the cirrus sac, gonopores separate but close together in distinct genital atrium, external seminal vesicle absent, and postovarian follicles present. The new species differs from other congeneric species by the shape of the body markedly tapering posteriorly from the end of the anterior third, the shape of the scolex that is very short and markedly wider than the neck, spatulate without incisions, but shallow superficial grooves, vitelline follicles and testes starting immediately posterior to the scolex, and an ovary with long, posterior arms bent medially, thus giving the shape of an inverted A.

Treatment of liver fibrosis associated with Schistosoma japonicum ova-induced granulomas remains a challenging proposition. There is a close relationship between high levels of interleukin-13 (IL-13) and the development of severe schistosome fibrosis. In contrast, IL-13 receptor (R) α2 has an effective role in attenuation of profibrosis. Several Chinese herbs have significant beneficial effects in liver disease. Accordingly, the purpose of the present study was to investigate the therapeutic effect of Paeoniflorin (PAE) on liver fibrosis. A mouse model for liver fibrosis was established, using infection with S. japonicum cercariae via the skin. Liver tissue was used to examine the effect of PAE on hydroxyproline, collagen I and III, and IL-13 and IL-13Rα2. The results showed that PAE has significant suppressive effect on the increase of both hepatic hydroxyproline and collagen I and III, which are the main components of extracellular matrix (ECM). Meanwhile, PAE not only inhibits IL-13 production, it also elevates IL-13Rα2 in PAE-pretreated groups compared with controls. These results suggested that PAE can improve liver fibrosis due to S. japonicum infection. The effect of PAE appears to depend on a decrease of IL-13 and an increase of IL-13Rα2.

Phosphorylation of parasite proteins plays a key role in the process of cell invasion by Trypanosoma cruzi, the etiologic agent of Chagas' disease. In this sense, characterization of parasite kinases and phosphatases could open new possibilities for the rational design of chemotherapeutic agents for the treatment of Chagas' disease. In this work, we analyzed phosphatase activities in T. cruzi homogenates from 2 strains belonging to different lineages and with different resistance to oxidative stress. Tulahuen 2 cells (Lineage I) showed higher phosphatase activities and specificity constants when compared to the Y strain (Lineage II). Tulahuen 2 had an optimum phosphatase activity at pH 4.0 and the Y strain at pH 7.0. In both cases, neutral–basic, but not acid, phosphatase activities were increased in the presence of Mg² . Although calcium had an inhibitory effect at a pH of 7.0 and 8.0 in the Y strain, this inhibition was restricted to pH 8.0 in the other strain. Different substrates and acid phosphotyrosine and alkaline phosphatase inhibitors exhibited distinct effects on the phosphatase activity of both strains. Our results provide a better understanding of T. cruzi phosphatases and reinforce the notion of heterogeneity among T. cruzi populations.

Valinomycin and salinomycin-Na, 2 ionophorous antibiotics, exhibited in vitro antibabesial activities against Babesia gibsoni that infected normal canine erythrocytes containing low potassium (LK) and high sodium concentrations, i.e., LK erythrocytes, which completely lack Na,K-ATPase activity. The level of parasitemia of B. gibsoni was significantly decreased when the parasites were incubated in culture medium containing either 10⁻¹ ng/ml valinomycin or 10² ng/ml salinomycin-Na for 24 hr. Four-hour incubation in the culture medium containing 5 µg/ml salinomycin-Na led to the destruction of most parasites. In contrast, when the parasites infected canine erythrocytes containing high potassium (HK) and low sodium concentrations, i.e., HK erythrocytes, the in vitro antibabesial activities of both ionophorous antibiotics seemed to be weakened, apparently due to the protection by the host cells. Therefore, differential influences of ionophorous antibiotics on LK and HK erythrocytes were observed. In LK erythrocytes, the intracellular concentrations of potassium, sodium, and adenosine triphosphate (ATP) were not modified, and hemolysis was not observed after incubation in the medium containing each ionophorous antibiotic. These results suggested that these ionophorous antibiotics did not affect cells without Na,K-ATPase, and directly affected B. gibsoni. In HK erythrocytes, the ionophorous antibiotics increased the intracellular sodium concentration, and decreased the intracellular potassium and ATP concentrations, causing obvious hemolysis. Additionally, the decrease of the intracellular ATP concentration and the hemolysis in HK erythrocytes caused by valinomycin disappeared when the activity of Na,K-ATPase was inhibited by ouabain. These results indicate that modification of the intracellular cation concentrations by the ionophorous antibiotics led to the activation of Na,K-ATPase and increased consumption of intracellular ATP, and that the depletion of intracellular ATP resulted in hemolysis in HK erythrocytes. Moreover, the antibabesial activity of valinomycin disappeared when B. gibsoni in LK erythrocytes were incubated in culture media containing high potassium concentrations. This showed that the intracellular cation concentration in the parasites was not modified in those media and would remain the same.

The majority of pathogens that cause high host mortalities are capable of infecting more than 1 host species. One characteristic of pathogens, which enables infection of multiple hosts, is the existence of free-living infectious stages, e.g., zoospores that are produced in vast numbers. Understanding the influence of environmental factors, particularly temperature, on the production and survival of these free-living stages is key to predicting future spread and emergence of disease. The rosette agent, Sphaerothecum destruens, is a significant multi-host intracellular fish parasite, with an obligate intracellular spore stage and a free-living (extracellular), potentially infectious, zoospore stage. It has caused high mortalities in endangered and commercially important fish species. Here we investigate the influence of temperature on S. destruens zoospore production and longevity. Our results indicate a wide temperature tolerance of the spore and zooflagellate stage with later onset and longer lifespan of zoospores at lower temperatures. This has important implications for the environmental persistence of S. destruens and provides additional information on the pathogen's life cycle with direct implications for S. destruens risk assessment.

In total, 70 spotted sandpipers, Actitis macularius, were examined for helminth parasites; 47 from Belize, 18 from Texas, and 5 from Montana. The compound communities consisted of 10 species of helminths for Belize, 5 for Texas, and 6 for Montana, for a total of 17 different species. The most prevalent and abundant helminths for Belize were 3 microphallid trematodes, Paramaritremopsis solielangi, Levinseniella carteretensis, and Microphallus kinsellai; for Texas, the cestodes Kowalewskiella cingulifera and Choanotaenia cayennensis; and for Montana, the cestodes Anomotaenia hypoleuci and K. cingulifera. The cestode K. cingulifera was the only species recorded from all 3 localities. The cestode A. hypoleuci was the only specialist. Characteristics for helminth compound communities from the 3 localities were similar in terms of low mean species richness, medium diversity, and in uneven parasite distribution. Infracommunities were species poor for all 3 localities. For the Belize sample, only 6 of the 47 hosts harbored as many as 3 helminth species, and only 1 harbored more, at 5 species. Only 1 host harbored as many as 3 species in the sample from Texas, and a single host harbored a high of 4 species for Montana. There were no significant differences for mean species richness or mean abundance among the 3 localities. There were no significant differences for species richness or mean abundance between the combined freshwater sample from Texas and Montana and the marine sample from Belize. There were no significant positive or negative associations between pairs of helminth species.

We used molecular techniques to characterize bacteria associated with the nematomorph Gordius robustus (Leidy). This worm is a parasite of the fall field cricket, Gryllus pennsylvanicus (Burmeister), which is infected with the symbiotic bacteria, Wolbachia. Because of this close association, our a priori expectation was that G. robustus may be similarly infected. However, results of denaturing gradient gel electrophoresis and sequencing of amplified 16S rDNA failed to detect any bacteria (symbiotic or non-symbiotic) in G. robustus. These unexpected findings suggest that G. robustus has no internal bacterial community and indicate that close association with a Wolbachia-infected host is insufficient for the transmission of bacteria from insect to nematomorph.

Pesticides can elevate trematode infections in amphibians. However, direct adverse effects of pesticides on embryos and free-living stages of trematodes have not been thoroughly explored, despite the potential for these effects to reduce amphibian trematode infections. We measured the effects of atrazine, glyphosate, carbaryl, and malathion on embryo and miracidium (free-living stage) survival of Echinostoma trivolvis, a common trematode of amphibians. We found no evidence of biologically relevant effects of these pesticides at ecologically relevant concentrations.

Patterns of infracommunity similarity were examined for 27 male and 6 female common snapping turtles, Chelydra serpentina serpentina, collected from Westhampton Lake on the campus of the University of Richmond in Richmond, Virginia, during the summer months of 1979 and 1980. Patterns of infracommunity similarity based on parasite abundance emphasized differences between years and between host sexes. Patterns of similarity based on parasite presence or absence emphasized differences among the months sampled. This suggests that there were consistent seasonal changes across both years in terms of which parasites were present, but that there were differences between years in terms of the abundances of those parasites.