Ruminants infected by Paramphistomidae flukes shed eggs in the feces, which pass through different stages in the environment until the infective stages (metacercariae) are reached. The activity of the soil fungus Mucor circinelloides on the development of eggs of the rumen fluke Calicophoron daubneyi was presently tested with 3 probes, i.e., in petri plates, feces, and an aqueous environment (tubes). The effect of the fungus was assessed by recording the numbers of undeveloped, nonviable, and embryonated eggs. Nonviable eggs were considered when vacuolization occurred, the inner structures were not clearly observed, the eggshell was broken, or the embryo inside was destroyed. By considering the ability of hyphae of M. circinelloides to develop in the presence of C. daubneyi eggs, attach to their surface, and penetrate and destroy the inner embryo, this ovicidal effect was classified as type 3. After a period of 50 days, the percentage of undeveloped eggs in the feces of infected cattle was 40%; furthermore, 27% of the eggs were nonviable, and 33% were embryonated (1 miracidium inside). The addition of 4 doses of M. circinelloides spores directly onto the feces resulted in 9–31% undeveloped eggs, 38–60% nonviable eggs, and 9–21% embryonated eggs, and no statistical significances were obtained among the different doses. Placing the eggs of C. daubneyi into an aqueous solution containing 10⁷ spores of M. circinelloides/ml for 29 days resulted in 43% undeveloped eggs, 40% nonviable eggs, and 17% embryonated eggs, whereas in the controls, the percentages were 48%, 12%, and 40%, respectively. These data demonstrate the usefulness of the spores of the fungus M. circinelloides in limiting the development of the eggs of the trematode C. daubneyi.

The expansion of parasite distributions outside of their native host and geographical ranges has occurred repeatedly over evolutionary time. Contemporary examples include emerging infectious diseases (EIDs), many of which pose threats to human, domestic animal, and wildlife populations. Theory predicts that parasites with complex life cycles will be rare as EIDs due to constraints imposed by host specialization at each life-cycle stage. In contrast to predictions of this theory, we report 2 new intermediate hosts in the 3-host life cycle of the liver fluke Dicrocoelium dendriticum in Cypress Hills Provincial Park, Alberta, Canada. Results of sequence analysis of the cytochrome oxidase 1 (cox1) mitochondrial gene identified the terrestrial snail Oreohelix subrudis and the ant Formica aserva as first and second intermediate hosts, respectively, in the region. Neither of these intermediate hosts, nor their suite of domestic and wild mammalian grazers used in the life cycle, occurs within the native range of D. dendriticum in Europe. Our results from host surveys show that the prevalence of D. dendriticum in samples of O. subrudis varied between 4% and 10%, whereas mean metacercariae intensity in F. aserva varied between 33 and 41 (n = 163, mean ± SD = 38 ± 35). These results are the first to describe the complete life cycle of emerging lancet fluke in western North America. The process of multi-level ecological fitting, in which the lancet fluke possesses pre-existing traits to utilize host resources, rather than host species, at each life-cycle stage provides a mechanism for the establishment of this complex life cycle in a novel habitat and in novel hosts.

Understanding temporal variation of host–pathogen dynamics can be important for predicting disease risks and anticipating how disease systems may change in response to natural or human disturbances. Seasonal changes in weather, especially those associated with changes in temperature or precipitation, are often a key component of temporal changes in infection risk and can have important impacts on disease systems. However, these patterns can be difficult to track due to interannual variation and the need for longer term, multi-year surveillance efforts. We assessed seasonal and annual changes in the trematode component community of first-intermediate host stream snail Elimia (= Oxytrema = Goniobasis) proxima across 5 streams in the southern Appalachian Mountains. Over 3 yr, we found no evidence of consistent seasonal peaks of trematode infection in E. proxima. There was some across-site consistency in infection prevalence over 4 yr, because high prevalence sites tended to maintain higher prevalence from year to year, relative to lower prevalence sites. In addition, we examined the relationship between prevalence of first-intermediate host infection, weather variables, and site-level factors, including snail density and water quality metrics. Trematode prevalence was negatively related to total precipitation, which may have been due to the movement of infectious parasite stages and hosts downstream during high flows. We found no strong relationships between trematode prevalence and snail density or any of the water quality metrics examined in this study, indicating that snail infection may be driven primarily by definitive host activity.

Piroplasmosis, a disease of domestic and wild animals, is caused by tick-borne protozoa in the genera of Theileria and Babesia. There is limited information available about the prevalence of piroplasmosis in ticks in China, and to assess the potential threat of piroplasmosis in China, we investigated the infections of ovine and bovine Babesia and Theileria species in ticks collected from cattle, yaks, sheep, horses, and camels in several regions of China where tick-borne diseases have been reported. In total, 652 ticks were collected from the animals in 6 provinces of China. Babesia spp. and Theileria spp. were detected with a PCR-RLB method and identified by sequencing. Overall, 157 ticks (24.1%) were infected with 5 Babesia and 4 Theileria species. Among tested tick samples, 134 (20.6%) were single infections with 1 of 7 piroplasm species, with Theileria annulata (118/652, 18.1%) being dominant. Only 23 (3.5%) tick samples were double or triple infected, Theileria luwenshuni and Theileria sinensis (18/652, 2.8%) were frequently observed in co-infections. Some piroplasm species were carried by ticks that were not previously reported to be vectors.

Understanding host–parasite interactions is essential for ecological research, wildlife conservation, and health management. While most studies focus on numerical traits of parasite groups, such as changes in parasite load, less focus is placed on the traits of individual parasites such as parasite size and shape (parasite morphology). Parasite morphology has significant effects on parasite fitness such as initial colonization of hosts, avoidance of host immune defenses, and the availability of resources for parasite replication. As such, understanding factors that affect parasite morphology is important in predicting the consequences of host–parasite interactions. Here, we studied how host diet affected the spore morphology of a protozoan parasite (Ophryocystis elektroscirrha), a specialist parasite of the monarch butterfly (Danaus plexippus). We found that different host plant species (milkweeds; Asclepias spp.) significantly affected parasite spore size. Previous studies have found that cardenolides, secondary chemicals in host plants of monarchs, can reduce parasite loads and increase the lifespan of infected butterflies. Adding to this benefit of high cardenolide milkweeds, we found that infected monarchs reared on milkweeds of higher cardenolide concentrations yielded smaller parasites, a potentially hidden characteristic of cardenolides that may have important implications for monarch–parasite interactions.

Serologic tests are widely accepted and applied as means to detect anti-Toxoplasma gondii immunoglobulin G antibodies. In this study, recombinant matrix antigen (rMAG1) was induced by isopropyl-β-d-thiogalactoside and purified by nickel–nitrilotriacetic acid purification system. We then developed and optimized an indirect enzyme-linked immunosorbent assay (ELISA) through checkerboard assays using serial dilutions of antigens and sera to assess the potential use of rMAG1 in serologic detection of T. gondii infection in dogs. Serum samples from 93 domestic dogs were analyzed by western blot and rMAG1-ELISA. The results were compared with those obtained from an ELISA with the soluble Toxoplasma lysate antigens (TLA). We found that although yielding an excellent agreement (96.7%) with western blot data (κ = 0.9659), rMAG1-ELISA produced higher sensitivity (93.9% vs. 87.8%) and specificity (98.3% vs. 96.7%) than TLA-ELISA. In addition, receiver operating characteristic analysis also revealed that rMAG1-ELISA is in more agreement with western blot (area under the curve [AUC] = 0.985) relative to TLA-ELISA (AUC = 0.955). These results indicated that the rMAG1-ELISA established in this study provides a promising and reliable tool for serologic detection of T. gondii infection in dogs.

This study investigated the presence of Hepatozoon spp. in jaguars (Panthera onca) and domestic animals in the Cerrado, Amazon, and Pantanal biomes of Brazil. Between February 2000 and January 2010, blood samples were collected from 30 jaguars, 129 domestic dogs (Canis lupus familiaris), and 22 domestic cats (Felis catus) for molecular tests. All of the jaguars from the Pantanal (n = 22) and Cerrado (n = 4) and 3 of 4 jaguars from the Amazon were positive for Hepatozoon spp. Domestic dogs (62.8%) and cats (31.8%) were also positive for the agent. Hepatozoon nucleotide sequences from jaguars and domestic cats grouped with other Hepatozoon felis, whereas Hepatozoon from domestic dogs showed high similarity to Hepatozoon canis. Different species of Amblyomma were identified as parasitizing the jaguars and may act as vectors for Hepatozoon spp. Jaguars from the 3 sites were healthy and did not seem to be threatened by the hemoparasite within its population or environments. Most likely, jaguars play an important role in the maintenance of Hepatozoon spp. in nature.

Pallisentis indica Mital and Lal, 1976 was originally described from Channa gachua Hamilton (Channidae) in Kali Nadi River, Aligarh, India. The parasite was later placed in the subgenus Brevitritospinus Amin, Heckmann, Ha, Luc, and Doanh, 2000. Our collection from the spotted snakehead Channa punctatus Bloch & Schneider in another locality of the same stream in Aligarh produced many specimens with variable traits, revealing new structures that have never before been described in the Acanthocephala, especially relating to the ducted trunk spines. The proboscis has 4 circles of 10 hooks each, with hooks in the anterior 2 circles being considerably larger than those in the posterior 2 circles. Y-shaped trunk spines are ducted in 2 regions separated by a spineless zone. The anterior collar spines are in complete rings of 9–17 circles of crowded spines and the larger posterior trunk spines are in 1 (posterior) to 41 (anterior) circles extending to level of cement glands in males posteriorly. Considerable variations from the original description and new structures are reported for the first time.

This study investigates the systematic position of some species of the genus Saccocoelioides Szidat, 1954, and the species Culuwiya cichlidorum Aguirre-Macedo and Scholz, 2005, from North and Middle America using new morphological data and partial sequences of 2 nuclear genes, the large subunit and the internal transcribed spacer 2 from ribosomal DNA. In total 74 specimens representing 4 species of Saccocoelioides (41 of Saccocoelioides sogandaresi, 3 of Saccocoelioides chauhani, 6 of Saccocoelioides lamothei, and 12 of Saccocoelioides olmecae) plus 12 specimens of Culuwiya cichlidorum were analyzed. The phylogenetic analyses inferred with maximum likelihood method and Bayesian inference showed that the 4 species of Saccocoelioides formed a clade divided into 4 subclades representing each species. In addition, 7 specimens sequenced from the type host and locality of Culuwiya cichlidorum were nested in 2 clades: the first clade with specimens of C. cichlidorum from Costa Rica, and the second clade with specimens of S. sogandaresi from Mexico, Honduras, Nicaragua, and Costa Rica. Our analyses suggest that C. cichlidorum should be reallocated into Saccocoelioides, as was originally designated Saccocoelioides cichlidorum n. comb., is restricted to Nicaragua and Costa Rica and associated with cichlid fishes. In contrast, the specimens identified previously as Culuwiya cichlidorum from the coast of Gulf of Mexico by Aguirre-Macedo and Scholz belong to S. sogandaresi, which has a wide distribution that extends from Galveston Bay (U.S.A.) in Gulf of Mexico to Atlantic and Pacific slopes associated with poeciliid and cichlid fishes. New morphological data derived from scanning electron microscopy photographs of the body surface show a characteristic pattern of spination that is useful to distinguish between S. cichlidorum n. comb. and S. sogandaresi.

Much progress has recently been made in revising the taxonomic assignments of genera originally classified in the polyphyletic “Tetraphyllidea.” Many of these genera, including Echeneibothrium, were accommodated in the order Rhinebothriidea. However, beyond this larger taxonomic action, little work has been conducted on this genus over the past 50 yr. Consequently, the criteria used for characterizing species of Echeneibothrium have lagged behind those typically used in more modern descriptions of elasmobranch-hosted cestode taxa. A series of collecting trips to Chile to obtain cestodes from the yellownose skate, Dipturus chilensis, provided a unique opportunity to apply modern morphological and molecular methods to investigate the 3 species of Echeneibothrium reported parasitizing this skate, specifically Echeneibothrium megalosoma, Echeneibothrium multiloculatum, and Echeneibothrium williamsi. In addition to redescribing all 3 species, using morphological data from light and scanning electron microscopy, maximum likelihood and bayesian inference phylogenetic analyses of the D1–D3 regions of the 28S rDNA gene were conducted to assess their relationships among other echeneibothriids for which comparable data are available. Sequencing of 59 specimens representing these 3 species of Echeneibothrium allowed us to assess the intra- and interspecific variation in the 28S rDNA gene. The redescriptions use standardized terminology for scolex morphology, proglottid anatomy, and microthrix forms and pattern; they also expand on the original descriptions to include data on scolex size, ovary size, vas deferens and vaginal configurations, testes arrangement, and genital pore position. Our morphological work led to a major reinterpretation of the scolex morphology with the recognition that all 3 species bear an apical bothridial sucker, rather than an apical loculus, prompting emendation of the diagnosis for the family Echeneibothriidae. The presence of a band of spinitriches at the apex of the apical modification of the scolex proper seems to represent an important feature for distinguishing the 2 portions of the myzorhynchus across species. Intraspecific variation ranged from 0 to 7 bp across species and interspecific variation ranged from a low of 39–46 bp between E. williamsi and E. multiloculatum to a high of 61–66 bp between E. multiloculatum and E. megalosoma. Phylogenetic analyses indicate that the 3 species of Echeneibothrium hosted by the yellownose skate are not each other's closest relatives, suggesting multiple colonization events of D. chilensis have occurred. Further phylogenetic investigation is also likely to confirm the status of the genus Pseudanthobothrium as a synonym of Echeneibothrium because its species generally group among members of Echeneibothrium.

A new coccidian species (Protozoa: Apicomplexa: Isospora) is described parasitizing white-necked thrushes Turdus albicollis Vieillot, 1818; rufous-bellied thrushes Turdus rufiventris Vieillot, 1818; pale-breasted thrushes Turdus leucomelas Vieillot, 1818; and yellow-legged thrushes Turdus flavipes Vieillot, 1818 from 3 different localities in Brazil. Isospora sabiai n. sp. has oocysts that are subspherical to ellipsoidal, 20.9 × 18.6 μm, with smooth, delicate, bilayered wall, ∼1.1 μm thick. Micropyle inconspicuous or imperceptible. Oocyst residuum absent, but small polar granules rounded or comma-shaped are present. Sporocysts are elongate ellipsoidal to reniform, 16.5 × 9.2 μm. The Stieda body is knob-like. Sub-Stieda body rounded to conical, sometimes homogeneous with the Stieda body. Sporocyst residuum is present, usually as a cluster of numerous granules. Sporozoites are vermiform with 2 refractile bodies. The oocysts and sporocysts of I. sabiai n. sp. are uniform in the proportionality of width on length, but exhibited different patterns of size associated with each host species; therefore, an ecological discussion is introduced aimed at associating these morphometrical patterns of the oocysts with the habits of the different species of thrushes. This is the seventh isosporoid coccidian reported from New World turdids.

Here we report a case of ulcerative caseous gastroesophagitis associated with Rameshwarotrema uterocrescens, Rao, 1975 (Digenea: Pronocephalidae), in a juvenile green turtle (Chelonia mydas) from southern Brazil. Similar pathologies have been reported only in adult green turtles from Costa Rica. This paper presents the second report of parasitic esophagitis due to R. uterocrescens and the first occurrence in juvenile green turtles along coastal Brazil.

We found hundreds of mites behind the eyes of a Double-crested Cormorant, Phalacrocorax auritus (Suliformes: Phalacrocoracidae). The mites were Neottialges evansi (Acari: Hypoderatidae), representing the first report of this parasite in P. auritus from western North America. Deutonymphs of N. evansi are endoparasites, typically reported infecting fat deposits over the pectoral muscles, axillary areas, and vent of cormorants. Here mites infected only orbital tissues, a new infection site for hypoderatid mites. We suggest a lack of reports of this infection site could be explained by limited scrutiny of orbits, and deutonymphs mites infecting orbits may be more common than expected.