This study investigated associations between Trypanosoma lewisi and Xenopsylla cheopis, a common cyclical vector of T. lewisi; Polyplax spinulosa, a reported mechanical vector; and Laelaps echidnina and Laelaps lamborni, 2 rodent mites of Rattus norvegicus in Durban, South Africa. In total, 379 R. norvegicus individuals were live-trapped at 48 sites in 4 locality types around Durban during a 1-yr period. Rats were euthanized, cardiac blood was taken to check for hemoparasites, and ectoparasites were removed for identification. Parasite species richness was higher in pups (2.11) and juveniles (1.02) than adults (0.87). Most rats in the study harbored 1 or 2 of the 5 parasites surveyed. Rats with trypanosomes and fleas were more prevalent in the city center and harbor, where juveniles were most affected. Rats with lice were more prevalent in informal settlements and urban/peri-urban areas, where pups had the highest infestations. There was a significant positive association between rats with fleas and trypanosomes and a negative association between rats with lice and trypanosomes. Location and rat age were significant predictors of T. lewisi, X. cheopis, and P. spinulosa. Mites showed no strong association with trypanosomes. Ectoparasite associations are possibly habitat and life-cycle related. We conclude that Durban's city center, which offers rats harborage, an unsanitary environment, and availability of food, is a high-transmission area for fleas and trypanosomes, and consequently a potential public health risk.

Piroplasmosis is one of the most important diseases of livestock, constraining optimal production and leading to economic loss. This study was carried out to detect Theileria annulata by using 2 different molecular techniques: recombinase polymerase amplification (RPA) and conventional polymerase chain reaction (PCR). Blood samples were collected from 274 ticks infesting asymptomatic cattle from several counties in the Chakwal, Faisalabad, and Jhang districts of Punjab Province in Pakistan by using FTA cards. After extraction of genomic DNA, each sample was subjected to RPA optimized to amplify a 281-bp fragment of the Enolase gene for T. annulata. The specificity of the test was confirmed using positive DNA samples of related piroplasm species, whereas the analytical sensitivity was calculated using different serial dilutions of a long fragment of the same gene. The RPA results were positive for 48 (17.51%) of 274 samples. All 274 samples were screened using conventional PCR, and 21 (7.66%) samples were positive for T. annulata. All the samples that were RPA positive but PCR negative were sequenced, which confirmed the results of RPA. The highest positive rate was found in Chakwal district, followed by Faisalabad and Jhang districts. This study demonstrates the application of highly sensitive and specific rapid diagnostic methods for T. annulata to a regional screening program. This is the first report of tick-borne disease from Pakistan by using RPA.

The trematode Posthodiplostomum minimum MacCallum, 1921 (white grub) is a common parasite of centrarchid fishes, frequently reaching high prevalence and intensity in local populations. However, significant variation in infection has been observed across Lepomis Rafinesque, 1819 sunfish species, which are common and abundant hosts for this parasite. Previous observations suggest both extrinsic factors (e.g., habitat-specific characteristics and environmental parameters) and intrinsic factors (e.g., host size, behavior, and susceptibility) as important predictors of infection in this parasite–host system. In the present study, we evaluated the prevalence and intensity of P. minimum in 6 sympatric species of Lepomis sunfish (total of 563 individuals) across 9 lakes in eastern Ohio, U.S.A., that range in surface area from 5.6 to 1,448.7 hectares, and assessed the importance of both extrinsic and intrinsic factors as predictors of infection. We found that collection site (extrinsic factor) and host body mass and species identity (intrinsic factors) were the strongest predictors of infection intensity. Specifically, infection intensity was negatively associated with lake surface area and positively associated host body mass. Lepomis macrochirus (bluegill sunfish) and hybrid sunfish displayed the highest infection intensities, whereas Lepomis cyanellus (green sunfish) and Lepomis gulosus (warmouth sunfish) were significantly less burdened. We were unable to conclude if the observed variation among host species was due to host ecology or susceptibility. These general findings were supported by classification and regression tree (CART) analysis, which optimally partitioned variation in individual host infection intensities by using lake size and host body mass (but not host species identity). Although infection intensity was negatively associated with lake surface area (even among host individuals of the same size and species), the causal mechanisms involved remain unresolved and should be the impetus of future work on this parasite–host system.

Leeches (Annelida: Hirudinea) possess powerful salivary anticoagulants and, accordingly, are frequently employed in modern, authoritative medicine. Members of the almost exclusively marine family Piscicolidae account for 20% of leech species diversity, and they feed on host groups (e.g., sharks) not encountered by their freshwater and terrestrial counterparts. Moreover, some species of Ozobranchidae feed on endangered marine turtles and have been implicated as potential vectors for the tumor-associated turtle herpesvirus. In spite of their ecological importance and unique host associations, there is a distinct paucity of data regarding the salivary transcriptomes of either of these families. Using next-generation sequencing, we profiled transcribed, putative anticoagulants and other salivary bioactive compounds that have previously been linked to blood feeding from 7 piscicolid species (3 elasmobranch feeders; 4 non-cartilaginous fish feeders) and 1 ozobranchid species (2 samples). In total, 149 putative anticoagulants and bioactive loci were discovered in varying constellations throughout the different samples. The putative anticoagulants showed a broad spectrum of described antagonistic pathways, such as inhibition of factor Xa and platelet aggregation, which likely have similar bioactive roles in marine fish and turtles. A transcript with homology to ohanin, originally isolated from king cobras, was found in Cystobranchus vividus but is otherwise unknown from leeches. Estimation of selection pressures for the putative anticoagulants recovered evidence for both positive and purifying selection along several isolated branches in the gene trees, and positive selection was also estimated for a few select codons in a variety of marine species. Similarly, phylogenetic analyses of the amino acid sequences for several anticoagulants indicated divergent evolution.

Two cryptic species of haploporid digeneans belonging in Saccocoelioides are described from Costa Rica: one from a poeciliid fish, Poecilia gillii, and the other from a characid fish, Astyanax aeneus. Traditional morphological features are examined and found to be largely inefficient for differentiating among the new species and 20 New World congeners. Comparison of ribosomal DNA sequences among the 2 new species, 2 North American, 4 Middle American, and 3 South American species of Saccocoelioides, including the type-species Saccocoelioides nanii from Argentina and Saccocoelioides sogandaresi from Texas, is effective in differentiating among these species. A Bayesian inference analysis is conducted using a concatenated alignment of the same 2 ribosomal gene regions from 35 species belonging in the Haploporoidea and rooted by the atractotrematid Isorchis anomalus. The analysis provides stronger support for a close relationship between species in Saccocoelioides and Intromugil; thus, Intromugil is transferred from the Waretrematinae to the Chalcinotrematinae. Additionally, interrelationships among 11 species of Saccocoelioides are resolved and reveal a distinct genetic rift suggesting the presence of 2 distinct lineages within the genus, 1 containing the type-species and the other containing a group of species that more closely resemble other genera in the subfamily. Taxonomy of Saccocoelioides is discussed, and observations made during the present study justify taking several taxonomic actions: new combinations are proposed for Saccocoelioides tilapiae n. comb., formerly in the now-defunct Culuwiya, and Saccocoelioides ruedasueltensis n. comb., formerly in Chalcinotrema; Saccocoelioides guaporense nomen novem is proposed for Lecithobotrioides elongatus; Saccocoelioides papernai is considered a junior subjective synonym of Saccocoelioides overstreeti; Saccocoelioides godoyi is considered a junior subjective synonym of Saccocoelioides szidati; Saccocoelioides magnorchis and Saccocoelioides saccodontis are considered species inquirendae; and Saccocoelioides adelae is considered a nomen nudum. Four new hosts are reported for Saccocoelioides cichlidorum: Amphilophus lyonsi, Amatitlania nigrofasciatus, Amatitlania septemfasciatus, and Hypsophrys nicaraguensis. Molecular data call into question some existing species identifications in Saccocoelioides and reveal that molecular tools combined with traditional taxonomy are required for accurately identifying species in the genus. Twenty-two species of Saccocoelioides are formally accepted, but it is noted that as new molecular data become available, some of these species may be transferred to other genera in the subfamily.

Increasing rates of Rocky Mountain spotted fever (RMSF) in the southwestern United States and northern Mexico underscore the importance of studying the ecology of the brown dog tick, Rhipicephalus sanguineus, the vector in that region. This species is reported to comprise distinct tropical and temperate lineages that may differ in vectorial capacity for RMSF and are hypothesized to be limited in their geographical range by climatic conditions. In this study, lineage was determined for ticks from 9 locations in California, Arizona, and Mexico by DNA sequencing of 12S, 16S, and D-loop ribosomal RNA. As expected, sites in northern California and eastern Arizona had temperate-lineage ticks, and phylogenetic analysis revealed considerable genetic variability among these temperate-lineage ticks. However, tropical-lineage ticks extended north from Oaxaca, Mexico were well established along the entire border from San Diego, California to western Arizona, and were found as far north as Lytle Creek near Los Angeles, California (a site where both lineages were detected). Far less genetic variability in the tropical lineage despite the large geographical distances is supportive of a hypothesis of rapid northward expansion. Discovery of the tropical lineage north of the identified climatic limitations suggests that more work is needed to characterize this tick's ecology, vectorial capacity, expansion, possible evolution, and response to climate change.

Free pre-tetrathyridia of Mesocestoides sp. are described, for the first time, from samples obtained from the coelomic cavity of a ground skink, Scincella lateralis, from Oklahoma. Closer examination of these early-stage tapeworms revealed they were transitional metamorphosis stages between a post-hexacanth procercoid form to the full metacestode of Mesocestoides. A series of transitional stages was found that span the full period of sucker and apical organ development. However, we did not see any fully developed tetrathyridia, i.e., having classic Mesocestoides morphology but with the apical sucker absent following developmental atrophy. This is the first time that metamorphic pre-tetrathyridial stages of a Mesocestoides sp. have been reported in vivo from a natural infection. These observations corroborate earlier reports of such stages of Mesocestoides vogae developed in vitro, though the previously reported isolate of M. vogae is asexually proliferative, and the species from the present study showed no sign of asexual proliferation. The fact that these immediately post-hexacanth stages can occur in a single lizard intermediate host may suggest that Mesocestoides spp. might develop through a simple 2-host life cycle rather than an obligate 3-host cycle that has been speculated to occur by most previous authors. DNA sequence comparisons and phylogenetic analyses based on mitochondrial 12S, cox1, and nad1 genes have demonstrated that our specimens from S. lateralis represent a species clearly distinct from all previously sequenced Mesocestoides and closely related to 2 forms from domestic dogs and Channel Island fox in California previously published as Mesocestoides sp. C.

Two new species of myxosporeans are described from the gallbladders of estuarine stonefish, Synanceia horrida, and reef stonefish, Synanceia verrucosa, from localities off Cairns, in tropical north Queensland and in Moreton Bay in southern Queensland, Australia. Sphaeromyxa horrida n. sp. can be distinguished from congeners in the morphologically distinct “balbianii” species group within Sphaeromyxa on the basis of morphometric differences in length and width of mature spores, length and width of polar capsules, and unique small-subunit (SSU) ribosomal (rDNA) sequence composition relative to other taxa. Replicate SSU rDNA sequences generated from Sph. horrida n. sp. collected from Sy. horrida and Sy. verrucosa in tropical north Queensland and from Sy. horrida in Moreton Bay were identical, suggesting that this species is widely distributed along the east coast of Australia. Myxidium lapipiscis n. sp. can be distinguished from the majority of described Myxidium species on the basis of its relatively small mature spore size (6.1−7.9 μm long × 3.1−3.9 μm wide), and its unique SSU rDNA sequence. Specimens putatively identified as M. lapipiscis n. sp. were found in Sy. horrida from both tropical north Queensland and Moreton Bay, suggesting that this taxon is also widely distributed along the east coast of Australia. However, no molecular data were available for the specimens from tropical north Queensland for comparative genetic analyses. Bayesian inference and maximum likelihood analysis of the SSU rDNA sequences for these 2 new species revealed that Sph. horrida n. sp. formed a strongly supported clade with Sphaeromyxa zaharoni Diamant, Whipps, and Kent, 2004, which was described from the scorpaeniform, Pterois miles, from the Red Sea. This is the first report of myxozoans infecting stonefish (Synanceiidae).

Raphidascarididae are among the most abundant and widespread parasitic nematodes in the marine environment. The life-cycle of most raphidascaridid species is poorly known and information about their distribution and host range is lacking in many geographical areas, as is the taxonomy of several species. A study of larval and adult stages of Hysterothylacium fabri (Rudolphi, 1819) Deardorff and Overstreet, 1980 (Nematoda: Raphidascarididae) infecting the striped goatfish Mullus surmuletus Linnaeus, 1758 (Mullidae) and the Mediterranean stargazer Uranoscopus scaber Linnaeus, 1759 (Uranoscopidae) from the Ionian Sea (central Mediterranean) has been carried out by combining light and scanning electron microscopy observations and molecular analyses through polymerase chain reaction-restriction fragment length polymorphism and sequencing of the ITS rDNA gene. Results indicate that U. scaber and M. surmuletus represent suitable definitive and intermediate/paratenic hosts of H. fabri, respectively, in the Mediterranean and highlight the importance of combining genetic and morphological data to study the taxonomy and epidemiology of parasites widely distributed in different fish species and aquatic ecosystems.

The objectives of the present study were to isolate Beauveria bassiana strains from cattle farm soils, analyze the phylogenetic relationships among the fungal strains isolated from these soils, and determine the acaricidal effect of B. bassiana isolates on engorged Rhipicephalus microplus tick strains resistant or susceptible to chemical acaricides. Six strains of B. bassiana were obtained and isolated from cattle farm soils in the Mexican tropics using the Galleria bait method, and their acaricidal effect was assessed against 2 populations of R. microplus (“Media Joya” chemical acaricide-resistant strain or “CLAR” chemical acaricide-susceptible strain) using the adult immersion test. The BbV03 strain produced 86.7% and 60% mortality in resistant and susceptible ticks on day 20, respectively, whereas the BbV04 strain produced 66.7% and 53.5% mortality in resistant and susceptible ticks on day 20, respectively. The BbV03 and BbV04 strains reduced egg laying on both R. microplus populations. There was no statistical difference in the acaricidal effect of B. bassiana strains among chemical acaricide-susceptible or -resistant R. microplus populations (P > 0.05). The BbV03 strain was the most virulent against R. microplus with an LC₅₀ of 2 × 10⁷ and LC₉₉ of 7 × 10⁸ conidia/ml. We found that the 6 B. bassiana isolated clustered in the same clade with other previously reported B. bassiana strains (from GenBank) but were separated into 3 different sub-clades. This study shows that some B. bassiana strains are a promising coadjuvant alternative for biological tick control, including tick populations that are resistant to chemical acaricides. Beauveria bassiana is present in the pastures of tropic cattle farms, and there are genetic variations between B. bassiana strains living in this ecosystem that might play an important role in the natural control of R. microplus in cattle farm paddocks.

The cell microarray chip is a polystyrene plate with 20,944 microchambers, and it is used to detect red blood cells (RBCs) infected with the causative agent of malaria, Plasmodium. Plasmodium-infected red blood cells (iRBCs) stained with a nuclear staining dye (SYTO 21) form a monolayer on the bottom of the microchambers, and about 130 RBCs are accommodated in each such microchamber of the chip. The iRBCs in the RBC monolayer (containing 2.7 million RBCs) can be identified using a fluorescence detector, and the infection rate can be calculated by counting the number of fluorescent-positive RBCs. This diagnostic device is highly sensitive and hence advantageous for early diagnosis of malaria infections in endemic areas. However, a standard positive control for Plasmodium-infected RBCs is required to ensure that the reagents and detectors of these cell microarray chips are working efficiently in remote endemic areas. Here, we introduce “pseudo-iRBC beads,” which consist of a mixture of DEA beads mimicking RBCs and DEA beads coated with nucleic acids mimicking nuclei of the parasite. These beads can be stained with SYTO 21, applied onto the cell microarray chip to form a monolayer, and detected using the fluorescence detector in the same way as iRBCs. Therefore, the introduction of pseudo-iRBC beads as a positive control ensures unbiased malaria diagnoses with the cell microarray chip device in remote endemic areas.

Gizzard helminths were examined in 100 (50 adult, 50 juvenile) female northern pintails (Anas acuta). Sixty-three individual helminths, representing 5 species (Amidostomum acutum, Echinuria uncinata, Epomidiostomum uncinatum, Streptocara crassicauda, and Gastrotaenia cygni) were found. Twenty-seven northern pintails were infected with 1–3 helminth species and averaged 1.4 species. Overall, A. acutum and G. cygni were the most prevalent and abundant species (20%, n = 31 and 10%, n = 25, respectively), followed by S. crassicauda (5%, n = 5), E. uncinata (1%, n = 1), and E. uncinatum (1%, n = 1). Intensity of infection for A. acutum, E. uncinata, E. uncinatum, S. crassicauda, and G. cygni was 1.6 ± 0.3 [SE], 1.0 ± 0, 1.0 ± 0, 1.0 ± 0, and 2.5 ± 0.6, respectively. Our findings represent new information about gizzard helminth infections in northern pintails wintering along the Texas coast.

The phylogenetic position of Clinostomum heluans Braun, 1899 within the genus Clinostomum Leidy, 1856 is reported in this study based on sequences of the barcoding region of the mitochondrial cytochrome c oxidase subunit 1 gene (COX1). Additionally, molecular data are used to link the adult and the metacercariae of the species. The metacercariae of C. heluans were found encysted infecting the cichlid fish Australoheros sp. in Minas Gerais, Brazil, whereas the adults were obtained from the mouth cavity of the Great White Egret, Ardea alba, in Campeche, Mexico. The COX1 sequences obtained for the Mexican clinostomes and the Brazilian metacercaria were almost identical (0.2% molecular divergence), indicating conspecificity. Similar molecular divergence (0.2–0.4%) was found between sequences of C. heluans reported here and Clinostomum sp. 6 previously obtained from a metacercaria recovered from the cichlid Cichlasoma boliviense in Santa Cruz, Bolivia. Both maximum likelihood and Bayesian inference analyses unequivocally showed the conspecificity between C. heluans and Clinostomum sp. 6, which form a monophyletic clade with high nodal support and very low genetic divergence. Moreover, tree topology reveals that C. heluans occupies a basal position with respect to New World species of Clinostomum, although a denser taxon sampling of species within the genus is further required. The metacercaria of C. heluans seems to be specific to cichlid fish because both samples from South America were recovered from species of this fish family, although not closely related.

Among approximately 14 human-pathogenic microsporidian species, Enterocytozoon bieneusi is the most common. It can inhabit the small intestines, causing chronic diarrhea and wasting syndrome. Prevalence and genotype data for E. bieneusi in humans is available for only a few provinces of China. In the current study, 93 fecal specimens were collected from diarrheic children in Chongqing. Polymerase chain reaction amplification and sequencing of the internal transcribed spacer (ITS) region of the E. bieneusi rDNA sequence identified 11 (11.83%) positive specimens. Among them, 8 (8.60%) are from patients of ages ranging from 2 mo to 6 yr old and 3 (3.23%) from patients 7 to 11 yr old. In total, 6 genotypes (4 novel genotypes and 2 known genotypes) were identified in this study. Phylogenetic analysis showed that all the genotypes identified in the present study belong to group 1, which previously has been described as a zoonotic group. This could mean these infections were acquired zoonotically, and it may be prudent to warn those people having close contact with animals of this potential risk.

We report the importation into Connecticut, U.S.A., of an exotic tick, Hyalomma truncatum (Koch) (Acari: Ixodidae), on a human with recent travel history to Africa. The tick was identified using key morphological characters and through DNA sequencing. This case report highlights continuing risk associated with the importation of exotic tick vectors of medical and veterinary significance on international travelers returning to the United States from abroad.

Domestic cats are a final host for some hepatic trematodes, and cat meat is used for human consumption in several parts of northern Vietnam. Since there is no tradition for commercial cat rearing in the area, cats are purchased alive from other areas as well, i.e., southern Vietnam and neighboring countries, and brought to slaughterhouses. This uncontrolled trade in live cats could pose a risk for spread of various parasites, including hepatic trematodes. Hence, in this study, we investigated the infections by hepatic trematodes in cats from the slaughterhouses. Cat livers were sampled from 12 slaughterhouses. Clonorchis sinensis and Platynosomum fastosum were found in 14 of 78 necropsied cats of local origin, while more than half of the non-local cats (170 of 318) were infected by C. sinensis, P. fastosum, or Opisthorchis viverrini. The non-local cats had higher prevalence (odds ratio = 6.61, P < 0.01, 95% CI: 2.34–19.41) and intensity of infection (count ratio = 6.47, P < 0.01, 95% CI: 1.77–23.59) by C. sinensis than local cats. Prevalence of P. fastosum infection did not differ significantly between the 2 groups of cats. Opisthorchis viverrini was found at low prevalence (2.5%) in non-local cats. The presence of O. viverrini in cats sampled in northern Vietnam and the high prevalence and intensity of infection in cats of non-local origin suggest that cats are transported over great distances, and this poses a risk of spreading these trematodes.

The dairy industry in Pakistan is booming, and investors are anxious to fund dairy farms that are using high-milk-producing (exotic) cattle breeds such as Holstein Friesians that are not native to the country. Unfortunately, the benefits of increased milk production do not provide resistance to pathogens present in regions where the exotic breeds are introduced. Therefore, the current study was conducted to evaluate the economic impact of Theileria annulata on a commercial Holstein Friesian dairy farm in the District of Ranjanpur, in the Province of Punjab, Pakistan. The economic impact of T. annulata infection was calculated for cattle with subclinical and clinical theileriosis. Losses were estimated based on milk production, morbidity, mortality, and tick control costs (organophosphate sprays). Animals were classified into groups after screening for mastitis, teat abnormality, abnormal parturition, intestinal parasites, and hemoparasites (T. annulata, Babesia spp., and Anaplasma spp.). Microscopy was done for hemoparasites and intestinal parasites. PCR was used to confirm microscopic identification of T. annulata. Animals were classified into 3 groups: group A (normal), group B (subclinical theileriosis), and group C (acute theileriosis). Hemoparasites were observed microscopically in 28.7% of cows. Theileria annulata was found in 8%, and the herd incidence (new cases) of T. annulata was 2.8%. Milk production, animal rectal temperature, and body condition scores between group A and groups B and C were significantly different (P < 0.05). But the enlargement of sub-scapular lymph node and interval of body condition score of the 3 groups were not significant (P > 0.05). The total expenditure incurred due to theileriosis was US $74.98 per animal and 13.83% of total farm costs. Hence theileriosis caused significant economic loss of US $18,743.76 (0.02 million) on this Holstein Friesian dairy.

We document chigger mite (Acari: Trombiculidae) ectoparasitic infestation (prevalence and intensity) on a population of Catharus ustulatus (Turdidae) wintering at a site (PAD A) in southeastern Peru undergoing development for natural gas exploration. We compare prevalence (i.e., the proportion of individuals infested by chigger mites) and intensity (i.e., the average number of larvae and larvae clusters in infested individuals) at forest edge (<100 m) and interior (>100 m) from PAD A because variations in biotic (e.g., vegetation cover) and abiotic (e.g., relative humidity and temperature) factors are expected to influence chigger mite abundance. Chigger mite prevalence was 100%; all C. ustulatus captured were infested regardless of distance. The range of variation in larvae (2–72 larvae/individual) and cluster intensity (1–4 clusters/individual) did not differ between edge and interior (P > 0.05), despite differences in herbaceous vegetation cover (U_M-W = 180, n = 30, 31; P < 0.01). Ectoparasitic prevalence and intensity in long-distance migratory birds might add risks to an already hazardous journey; because ectoparasitic variation and other selective pressures experienced by individuals at each locality not only may be a cause of within-site mortality, but, by affecting the physical condition of birds, may be carried over to subsequent sites and affect reproductive success and survival. Documenting ectoparasitism at any phase of the life cycle of migrants could improve understanding of population declines of migratory birds.

Adult female guinea worms (Dracunculus spp.) usually are reported to occur singly in the extremities of their hosts, from which they deliver their larvae into the water through fistulae in the host's skin. We visually examined for the presence of worms in the fascia of the limbs of skinned carcasses of 184 river otters (Lontra canadensis) harvested in Arkansas and report observations of cysts on wrists and ankles found on 12 otters. Cysts averaged 15.6 × 24.6 mm in diameter, were round to oval, and contained masses of up to 19 adult female Dracunculus sp. (mean 6.7). We speculate that high levels of infection in consumed paratenic hosts might have caused high infection rates, leading to large cyst formation in otters, as larvigerous Dracunculus sp. females accumulated in extremities. No males were discovered during the study, so identification of a sample of worms was based on molecular techniques.

The Magellanic Penguin (Spheniscus magellanicus) is native to Argentina, Chile, and the Falkland/Malvinas Islands, and is a regular winter migrant in Uruguayan and Brazilian coastal waters. The species is known to be susceptible to a variety of gastrointestinal nematodes, cestodes, trematodes, and acanthocephalans, as well as renal trematodes and pulmonary nematodes. Schistosomes (Platyhelminthes, Trematoda, Schistosomatidae) and microfilariae (Nematoda, Secernentea, Onchocercidae) were histologically identified in Magellanic Penguins (Spheniscus magellanicus) that died while under care at rehabilitation centers in southern Brazil. Phylogenetic analysis of the COI gene, ITS-1 region, 5.8S rRNA gene, ITS-2 region, and 28S rRNA gene sequences of the schistosome revealed that it is closely related to, but distinct from, a schistosome reported from the African Penguin (Spheniscus demersus). The schistosomes from Magellanic and African Penguins were grouped with Gigantobilharzia huronensis, Gigantobilharzia melanoidis, and Dendritobilharzia pulvurenta; however, the lack of a clearly monophyletic origin precludes determining their genus. The incidental discovery of novel parasites during a study that did not specifically aim to investigate the occurrence of helminths underscores the value of histopathological examination as an exploratory diagnostic approach.

Parasites often use external cues to identify and move toward environments where they are likely to encounter suitable hosts. The trematode parasite Euhaplorchis californiensis produces cercariae that emerge from California horn snails (Cerithideopsis californica [= Cerithidea californica]) to infect California killifish (Fundulus parvipinnis) as second intermediate hosts. Based upon work on a congeneric Euhaplorchis species from Florida, and based on the ecology of its killifish host, we hypothesized that E. californiensis cercariae in southern California estuaries are positively phototactic and negatively geotactic, using both sunlight and gravity to guide their movement to the upper water column. To distinguish positive phototaxis from negative geotaxis, we first quantified E. californiensis movement in response to light along a horizontal plane and determined they were positively phototactic. In a second experiment, we quantified E. californiensis movement along a vertical plane in response to an overhead light, a light from below, or no light. We found that E. californiensis exhibit negative geotaxis in the absence of light, but will swim in the direction of gravity to move toward a light source from below. Thus, E. californiensis are both positively phototactic and negatively geotactic, but cercariae prioritize phototactic cues. These results suggest that E. californiensis cercariae aggregate in the open water, indicating that the pelagic zone represents an area of high infection risk for California killifish hosts.

This paper reports the first occurrence of Plesiochorus cymbiformis (Digenea: Gorgoderidae) in a loggerhead turtle (Caretta caretta [Testudines, Cheloniidae]) in Brazil and describes the histological findings of related injuries to the urinary bladder.

In southern regions of Western Siberia, Ixodes persulcatus ticks co-exist with Ixodes pavlovskyi. Both tick species have similar morphology, and natural hybridization of I. persulcatus and I. pavlovskyi ticks has been observed. To investigate the role of I. pavlovskyi ticks and I. persulcatus/I. pavlovskyi hybrids as vectors, correct identification of tick species is necessary. The nuclear crt gene might be useful in distinguishing I. persulcatus from I. pavlovskyi ticks. Genetic variability in this gene has been studied and substantial differences between crt gene sequences of I. persulcatus and I. pavlovskyi ticks has been demonstrated. In this study, maximum-likelihood analysis showed that sequences of I. persulcatus and I. pavlovskyi ticks were identical or highly homologous among themselves. These results were confirmed by a Bayesian phylogeny. We conclude that crt gene sequences of I. persulcatus and I. pavlovskyi cannot be used for distinguishing these tick species and that the conflicting results of prior studies reflect samples from incorrectly identified ticks rather than real genetic differences between I. persulcatus and I. pavlovskyi.