In salt marsh ecosystems, daggerblade grass shrimp, Palaemon (Palaemonetes) pugio, play a crucial role in food webs and serve as the definitive host for the bopyrid isopod Probopyrus pandalicola. These ectoparasites infest the branchial chambers of grass shrimp, which can lead to decreased energy availability and sterilization of infected hosts. Although bopyrid isopod infestation of daggerblade grass shrimp has been frequently reported in literature from coastal marshes of the southeastern United States, the prevalence of this parasite has not been recently documented in daggerblade grass shrimp from marshes of the northeastern United States. The goal of this project was to quantify the prevalence of Pr. pandalicola infestations in Pa. pugio across Cape Cod, Massachusetts. We evaluated bopyrid isopod prevalence from shrimp collected from 5 different salt marsh habitats along Cape Cod in August 2021. Bopyrid isopod infestations were found in shrimp at 4 of 5 salt marshes, with prevalence ranging from 0.04 to 14.1%. Seasonal resampling of one of the salt marshes revealed the highest average infestation prevalence in spring (<17.1%) and an isolated high of 30.3% prevalence in a single salt panne. A series of linear and multivariate models showed that panne area, shrimp abundance, and distance to shoreline were related to Pr. pandalicola shrimp infestations in salt pannes in summer. This study describes the prevalence of the bopyrid isopod infesting daggerblade grass shrimp in salt marshes in New England, with implications for how parasitized shrimp influence salt marsh food webs in which they are found.

A total of 366 individuals of Lutjanus argentiventris (Peters, 1869) were collected over a 5-yr period (October 2018 to June 2022) from Acapulco Bay, Mexico. Parasite communities in Lutjanus argentiventris were quantified and analyzed to determine the main factors that generate changes in species richness and/or species composition over time. The digeneans and copepods were the best-represented parasite groups. The parasite communities were characterized by a high numerical dominance of ectoparasites, mainly isopod larvae. Species richness at the component community level (9–23 species) was similar to the reported richness in other Lutjanus spp. The parasite communities of Lutjanus argentiventris exhibited high variability in species composition, suggesting that each parasite species may respond differently to environmental changes. However, the species richness and diversity were fairly stable over time; therefore, a clear pattern of interannual variation was not observed. Variations in the community structure probably were due to factors such as host traits (e.g., feeding behavior and body size), and possible interannual differences in environmental factors amplified by the occurrence of the anomalous event of La Niña.

Histomoniasis, caused by the protozoan, Histomonas meleagridis, is an economically important disease of turkeys, and it also affects several other species of domesticated and wild Galliformes, including chickens. Under natural conditions, the parasite is transmitted through eggs of a nematode, Heterakis gallinarum, that shares its hosts with Hi. meleagridis. The protozoan infects tissues of both male and female He. gallinarum and eventually is carried within the worm egg. Histomonas meleagridis more readily infects and develops in chickens, and the proximity of chicken farms is a major risk factor for outbreaks in turkeys. Chemoprophylaxis had controlled Hi. meleagridis in turkeys very successfully, but histomoniasis has recently reemerged in turkeys because anti-histomonal drugs are no longer permitted by the United States Food and Drug Administration because of the concerns for residual toxins in poultry meat. Horizontal transmission of the protozoan in the absence of worm eggs remains a mystery because the flagellate trophozoite excreted in the feces of turkeys is not viable for any length of time. A proposed resistant stage of the protozoan has not yet been conclusively demonstrated. Here we review the discovery of the protozoan and the current status of the disease and its control.

Herein, we provide a supplemental description of Caballerotrema annulatum (Diesing, 1850) Ostrowski de Núñez and Sattmann, 2002 (Digenea: Caballerotrematidae Tkach, Kudlai, and Kostadinova, 2016) based on specimens collected from the intestine of an electric eel, Electrophorus cf. varii (Gymnotiformes: Gymnotidae) captured in the Amazon River (Colombia). This caballerotrematid can be differentiated from its congeners by the following combination of morphological features: body surface spines forming contiguous transverse rows, concentric (wrapping dorso-ventrally around body), distributing into posterior body half (vs. restricted to anterior body half in Caballerotrema brasiliense Prudhoe, 1960; indeterminate for Caballerotrema aruanense Thatcher, 1980 and Caballerotrema piscicola [Stunkard, 1960] Kostadinova and Gibson, 2001); head collar lacking projections (vs. having them in C. brasiliense, C. aruanense, and C. piscicola), narrow (head collar more narrow than maximum body width vs. the head collar being obviously wider than the body in C. brasiliense, C. aruanense, and C. piscicola); corner spines clustered (vs. corner spines distributing as 2 separated pairs in C. brasiliense, C. aruanense, and C. piscicola); pharynx approximately at level of the corner spines (vs. pharynx far anterior to corner spines in C. brasiliense, C. aruanense, and C. piscicola); and testes ovoid and nonoverlapping (C. aruanense; vs. sinuous and overlapping in C. brasiliense and C. piscicola). Based on our results, we revise the diagnosis of Caballerotrema Prudhoe, 1960 to include features associated with the shape and distribution of body surface spines, orientation and position of head collar spines, cirrus sac, seminal vesicle, oviduct, Laurer's canal, oötype, vitellarium, and transverse vitelline ducts. We performed Bayesian inference analyses using the partial large subunit ribosomal (28S) DNA gene. Our 28S sequence of C. annulatum was recovered sister to that of Caballerotrema sp. (which is the only other caballerotrematid sequence available in GenBank) from an arapaima, Arapaima gigas (Schinz, 1822) (Osteoglossiformes: Arapaimidae) in the Peruvian Amazon. Our sequence of C. annulatum comprises the only caballerotrematid sequenced tethered to a morphological description and a voucher specimen in a lending museum. The present study is a new host record and new locality record for C. annulatum. The phylogeny comprises the most resolved and taxon-rich evolutionary hypothesis for Echinostomatoidea published to date.

Some helminth test methods for sanitation samples include a phase extraction step to reduce lipid content and final pellet size before microscopy. Hydrophilic and lipophilic solutions are used to create 2 phases, with a plug of organic material or debris in between, whilst eggs are supposedly compacted at the bottom of the test tube. We tested 10% formalin, acetoacetic buffer, and acid alcohol as the hydrophilic solutions, and ethyl acetate and diethyl ether as the lipophilic solvents for egg recoverability from water, primary sludge, and fatty sludge. Normally, the supernatant and debris plug are discarded and the sedimented pellet of eggs is microscopically examined. We, however, also collected the entire supernatant plus debris plug to determine where eggs were possibly lost. We found that eggs were lost when samples were extracted with 10% formalin + ethyl acetate, 10% formalin + diethyl ether, acetoacetic buffer + ethyl acetate, and acetoacetic buffer + diethyl ether combinations (<50% egg recovery). Acid alcohol + ethyl acetate resulted in 93.2, 89.8, and 57.3% egg recovery in the pellet of water, primary sludge, and fatty sludge, respectively; however, the size of the final pellet was not reduced, defeating the purpose of the extraction step. We thus recommend that this step be excluded.

Enteric parasites can have wide-ranging effects throughout an ecosystem, often driving coevolutionary and ecological processes. Parasites have long been overlooked in conservation efforts because of the negative impact inflicted on their hosts; however, parasites make up a significant component of Earth's biodiversity and host conservation efforts need to be parasite inclusive. The Vancouver Island marmot (VIM), Marmota vancouverensis, is an endangered alpine rodent endemic to Vancouver Island, British Columbia, Canada. Captive-bred VIMs are released to augment the wild population, but their susceptibility to parasites is unknown. The objectives of this study were to describe the diversity, prevalence, severity, and temporal variation of VIM enteric parasites. Noninvasive fecal samples were collected from wild and captive marmots and analyzed using a modified McMaster fecal egg floatation technique to indicate parasite prevalence and relative mean abundance. We identified oocysts and ova from 3 parasite taxa including a protozoan coccidium not previously described in the VIM (prevalence 68%), an ascarid nematode Baylisascaris laevis (prevalence 82%), and an anoplocephalid cestode Diandrya vancouverensis (prevalence 8%). Depending on the species, comparisons revealed variation in parasite infection by sex, by colony, and between wild and captive VIMs, but not among age classes or by female reproductive status. Finally, captive VIMs displayed significant monthly variation in parasite prevalence and mean egg abundance, suggesting a seasonal influence on parasite egg shedding. This information is critically important for future research investigating the influences of these trends on the health, ecology, and conservation of VIMs and their parasites.

The tadpole-dwelling pinworm, Gyrinicola batrachiensis (Walton, 1929) Adamson, 1981 was recognized as the sole representative of the genus across Canada and the United States. However, evaluation of the morphology of these parasites across their range revealed considerable morphological variability that suggested diagnosable morphotypes. These morphotypes were associated with different species of anurans, several of which occurred in sympatry. Herein we use an extensive geographic sampling across the United States to obtain the morphotypes, screen their genetic diversity, and analyze this information using an integrative approach. We reconstructed their phylogeny using nuclear ribosomal partial genes 18S and 28S, ITS1, 5.8S, and ITS2, as well as 5 mitochondrial genes generated with Next-Generation sequencing technology. This phylogeny reveals 3 well-resolved lineages, which upon the use of a statistical approach (bPTP [Bayesian implementation of the Poisson tree processes]) supports the delimitation of 4 distinct groups equivalent to species. These putative species groups were tested using morphological characteristics paired with a MANOVA and canonical variate analysis. Results suggest that at least 4 species of Gyrinicola are present within North America, resulting in the resurrection of G. armatus (Walton, 1933) and the description of 2 new species.

Two new species of lung-dwelling nematodes are described from North American frogs: Rhabdias aurorae n. sp. from Rana aurora and Rhabdias conni n. sp. from Rana clamitans and Rana catesbeiana from Arkansas; the latter species was also found in Oklahoma and Georgia. Rhabdias aurorae n. sp. differs from other Nearctic congeners in the combination of the following characteristics: buccal capsule 22–25 µm wide, elongated tail covered with inflated cuticle, esophagus with prominent dilatation in anterior part and 6 small circumoral lips. Rhabdias conni n. sp. is morphologically closest to Rhabdias ranae Walton, 1929 and Rhabdias joaquinensis Ingles, 1936; it differs from them in the shape of lateral pseudolabia, the dimensions of the body, and the egg size. Both new species were found to be significantly different from the Nearctic congeners in the nucleotide sequences of nuclear ribosomal DNA (18S-ITS-28S region), 12S, and CO1 mitochondrial genes. The 2 new species differ from other currently sequenced Nearctic congeners by 1.1–2.7% of nucleotide positions in the nuclear rDNA region, 1.3–3.4% in the 12S gene, and 3.4–9.4% in CO1 gene. Molecular phylogenetic analysis based on nuclear ribosomal DNA sequences placed both new species into the clade consisting of Nearctic and Neotropical Rhabdias spp. The position of Rh. aurorae n. sp. within the clade is uncertain because of a polytomy, but Rh. conni n. sp. is nested within the “Rh. joaquinensis complex” related to Rh. ranae and Rhabdias tarichae Kuzmin, Tkach, and Snyder, 2003. The phylogenetic analysis based on nuclear ribosomal DNA sequences has revealed 3 evolutionary host-switching events from anuran to caudatan hosts among Rhabdias spp. that occurred in the Nearctic and Palearctic. The molecular phylogeny also suggests that Rhabdias may have originally evolved in what is now Africa.

Haliotrema pteroisi Paperna, 1972 (Monogenoidea: Dactylogyridae) was found parasitizing the gill lamellae of devil firefish, Pterois miles (Bennet) (Perciformes: Scorpaenidae), in the Red Sea off Safaga (26°44′N, 33°56′E), Egypt. The parasite species was described based on morphological features of available specimens and transferred to Platycephalotrema Kritsky and Nitta, 2019 (Dactylogyridae) as Platycephalotrema pteroisi (Paperna, 1972) n. comb. The occurrence of Pl. pteroisi off Safaga, Egypt, represented a range extension for the helminth of about 160 km to the southwest of the southern end of the Gulf of Aqaba. The transfer of the species to Platycephalotrema based on an evaluation of morphological features was supported by an analysis of molecular sequences of the 28S rDNA gene of Pl. pteroisi and 49 other dactylogyrid species. Maximum-likelihood, Bayesian inference, and maximum parsimony analyses of this dactylogyrid sequence data revealed H. pteroisi to nest with significant support within the clade of Platycephalotrema spp. During the literature review of dactylogyrid species infecting scorpionfishes, it was determined that Ancyrocephalus sp. of Dyer et al. from luna lion fish Pterois lunulata Temminck and Schlegel collected off Okinawa-jima, Japan represented an undescribed species of Platycephalotrema.

Naegleria fowleri is a protozoan that causes primary amebic meningoencephalitis (PAM). The infection occurs when the trophozoites enter the nasal cavity, adhere to the nasal mucosa, invade the epithelium, and migrate until they reach the olfactory bulb. Like other pathogens, there is evidence that the adhesion of N. fowleri to host cells is an important factor in the process of cytopathogenicity and disease progression. However, the factors involved in the adhesion of the pathogen to the cells of the nasal epithelium have not been characterized. The objective of this study was to identify a protein on the surface of N. fowleri, which could act as adhesin to the mouse nasal epithelium in the PAM model. The interaction between proteins of extracts of N. fowleri and cells of the nasal epithelium of BALB/c mice was analyzed using overlay and Western blot assays. A 72-kDa band of N. fowleri interacted directly with epithelial cell proteins, this polypeptide band was purified and analyzed by mass spectrometry. Analysis revealed that polypeptide bands of 72 kDa contained peptides that matched the membrane protein, actin 1 and 2, and Hsp70. Moreover, the N. fowleri extracts resolved in 2D-SDS-PAGE showed that 72-kDa spot interacted with proteins of mouse epithelial cells, which include characteristics of the theoretical data of molecular weight and pH obtained in the analysis by mass spectrometry. Immunofluorescence tests showed that this protein is located on the surface of trophozoites and plays an important role in the adhesion of amoeba either in vitro or in vivo assays, suggesting that this protein contributes during the N. fowleri invasion and migration to the brain, causing primary amoebic meningoencephalitis.

With the intensity and frequency of wildfires increasing rapidly, the need to study the ecological effects of these wildfires is also growing. An understudied aspect of fire ecology is the effect fires have on parasite–host interactions, including ectoparasites that might be pathogen vectors. Although some studies have examined the impacts of fire on ticks, studies on other ectoparasites, including pathogen vectors, are rare. To help address this knowledge gap, we examined the abiotic and biotic factors that predict the likelihood and extent of parasitism of deer mice (Peromyscus maniculatus) by fleas within a landscape of unburned and recovering burned (>9 yr postfire) mixed conifer forests. We sampled 227 individual deer mice across 27 sites within the Jemez Mountains of northern New Mexico in 2022 and quantified measures of parasitism by fleas (primarily Aetheca wagneri). These sites were distributed in both unburned areas (n = 15) and recovering burned areas (n = 12), with the latter derived from 2 large fires, the Las Conchas fire (2011) and the Thompson Ridge fire (2013). Using these data, we tested for differences in prevalence, mean abundance, and mean intensity of fleas on deer mice, focusing on the predictive importance of host sex and fire history. We also created generalized linear mixed-effects models to investigate the best host and environmental predictors of parasitism by fleas. Approximately a decade postfire, we found minimal evidence to suggest that fire history influenced either the presence or intensity of fleas on deer mice. Rather, at the current forest-regeneration stage, the extent of parasitism by fleas was best predicted by measures of host sex, body condition, and the trapline's ability to accumulate water, as measured through topography. As host body condition increased, the probability of males being parasitized increased, whereas the opposite pattern was seen for females. Male mice also had significantly greater flea loads. Among potential abiotic predictors, the topographic wetness index or compound topographic index (a proxy for soil moisture) was positively related to flea intensity, suggesting larger flea populations in burrows with higher relative humidity. In summary, although fire may potentially have short-term impacts on the likelihood and extent of host parasitism by fleas, in this recovering study system, host characteristics and topographic wetness index are the primary predictors of parasitism by fleas.

The atractid nematode Cyrtosomum penneri is an autoinfective parasite of several lizard species. Intraspecific transmission between hosts appears to occur exclusively through sexual copulation, yet it is unclear how worms are transferred between different host species. Our research aims to test the possibility of oral transmission of C. penneri using experimental infections. The lizards Anolis sagrei, Leiocephalus carinatus, Hemidactylus mabouia, and Agama picticauda were experimentally exposed to C. penneri in 1 of these groups: (1) oral infection using a feces and saline slurry to approximate host coprophagy, (2) oral infection with a large meal to approximate host predation, and (3) venereal infection using a pipette to confirm sexual transmission. Experimental infections to test venereal transmission were successful in A. sagrei, A. picticauda, and H. mabouia, but were unable to establish infections in L. carinatus. In the predation exposures, A. picticauda, A. sagrei, and H. mabouia hosted infections, whereas L. carinatus were uninfected. Finally, coprophagy experimental infections did not result in infections for any species of host. Our study corroborates venereal transmission of C. penneri in multiple species of lizards and establishes predation as an alternative route of infection. Predation as an oral route of transmission may provide C. penneri an opportunity for interspecific transmission that would otherwise be unlikely during host copulation.

The ischnoceran louse, Lipeurus tropicalis, which normally infests Gallus gallus domesticus, was subjected to in vitro study (35 ± 1 C, 75–82% relative humidity, on a feather diet). The life table was computed, and its intrinsic rate of natural increase (r) was calculated using the data from in vitro experiments. The value of the intrinsic rate of natural growth (r) is 0.032. Given this rate, a population of L. tropicalis should double after 21.66 days, indicating that it is a moderately paced breeder.

Myxospores discovered floating free in the bile of marine fishes from the south-central coast of Vietnam were identified using morphological and molecular methods, leading to the description of 2 new species. Ceratomyxa chauvanminhi n. sp. was detected in 16% (8/50) of cultured barramundi Lates calcarifer (Bloch) specimens, and Ceratomyxa sekoi n. sp. was found in 20% (5/25) of wild largehead hairtail Trichiurus lepturus Linnaeus specimens. The spores of C. chauvanminhi n. sp. are very shallowly ovoid, slightly crescent shaped, and 11.5 ± 0.5 (10.7–12.4) µm thick, 5.8 ± 0.2 (5.4–6.1) µm long, and 5.5 ± 0.2 (5.2–5.7) µm wide. Their posterior angles are slightly concave at 158.7° ± 4.2° (151.3°–164.8°), and they possess 2 equal spherical polar capsules 2.5 ± 0.2 (2.1–2.9) µm in diameter. The spores of C. sekoi n. sp. are 5.6 ± 0.2 (5.0–6.1) µm long, 75.5 ± 4.8 (68.9–90.0) µm thick, and 5.5 ± 0.1 (5.4–5.6) µm wide, with 2 equal, slightly anterior spherical polar capsules 2.1 ± 0.2 (1.7–2.4) µm in diameter. Although C. sekoi n. sp. spores resemble those of species of Myxodavisia Zhao, Zhou, Kent, and Whipps, 2008, characterized by long tapering valves, genetic analyses distinctly place this new species within the Ceratomyxa Thélohan, 1892 lineage. This study contributes to the understanding myxosporean diversity in Vietnamese waters and highlights the difficulty associated with distinguishing between the genera Ceratomyxa and Myxodavisia.

Muscles of 25 bobcats (Lynx rufus) from remote areas of Mississippi in 2017 were tested for parasites. Testing for Sarcocystis infections included microscopic examination of fresh unstained muscle squashes, pepsin digestion of hearts and tongues, and histological sections of paraffin-embedded tissues. Sarcocystis spp. infections were detected in the muscles of 21 (84%) by a combination of methods. Sarcocysts were detected in the unstained tongue squashes of 2 bobcats. Sarcocystis sp. bradyzoites were detected in the pepsin digests of 3 of 19 hearts, and 12 of 19 tongues. In paraffin-embedded histological sections, sarcocysts were detected in 7 of 25 hearts, 17 of 25 tongues, and 5 of 23 limb muscles. Based on the character of the cyst wall, at least 3 morphologic types of sarcocysts were detected: those with small spikes on the cyst wall, corresponding to Sarcocystis felis, those with long villar protrusions, corresponding to Sarcocystis neurona, and those lacking visible cyst wall protrusions, representing an unidentified type of sarcocyst. Myositis associated with sarcocysts was seen in the tongues of 3, and in the limb muscles of 1 bobcat. Multilocus genotyping of the DNA extracted from paraffin-embedded sections from 2 bobcats, employing 18S, 28S, COI, ITS-1, and 5.8S and rpoB genes, diagnosed Sarcocystis caninum, S. felis, Sarcocystis lutrae, and S. neurona. An encapsulated species of Trichinella was identified in the tongue of 1; it represents the first documented occurrences in bobcats from Mississippi. Taken together, these observations suggest intensive exposure of these wild carnivores to Trichinella tissue cysts, implies predation or scavenging on these tissues promotes parasite transmission, and raises caution concerning zoonotic risk when such meat is rendered for human consumption.

During March 2023, 7 green sunfish (Lepomis cyanellus) and 2 bluegill (Lepomis macrochirus) were collected from the Black River (White River drainage) in Lawrence County, Arkansas. In addition, during March 2023 and again in May–June 2023, 13 L. cyanellus and 6 L. macrochirus were taken from Butcherknife and Big Fork creeks (Ouachita River drainage), Polk County, Arkansas, 9 L. cyanellus were collected from the Caddo River, Montgomery County, Arkansas, and 5 green sunfish were taken from Clear Creek at Savoy, Washington County, Arkansas. All fish had their gill, gallbladder, fins, integument, musculature, and other major organs examined for myxozoans. The gill of 1 of 34 (3%) L. cyanellus was infected with a new myxozoan, Myxobolus fergusoni n. sp. Qualitative and quantitative morphological data were obtained from fresh myxospores, and molecular data consisted of a 1,933–base-pair sequence of the partial small subunit (SSU) ribosomal RNA (rRNA) gene. Phylogenetic analysis grouped M. fergusoni n. sp. with other centrarchid-infecting myxobolids from North America and placed this cluster in a larger clade comprising myxozoans that infect North American and European esocids, a North American aphredoderid, European percids, and a gasterosteid from Japan. Myxobolus fergusoni n. sp. infects the gill arches of L. cyanellus, similar to Myxobolus cartilaginis (Hoffman, Putz, and Dunbar, 1965), which was described from head cartilage, gill arches, and large fin rays of L. cyanellus. Another is Myxobolus mesentericus Kudo, 1920, which was described from the viscera of green sunfish. A large polysporic plasmodium filled with myxospores was present in a basifilamental location associated with multiple gill filaments at their junction with the gill arch. The intact plasmodium replaced connective tissue within the arch but elicited only mild proliferation of overlying epithelium and a minimal host inflammatory response. This is the third time a myxozoan has been described from L. cyanellus, as well as being the first time it has been described from an Arkansas specimen.