We herein describe a new species of Cathariotrematinae Bullard, 2021 (Monogenoidea: Monocotylidae Taschenberg, 1879) and propose a new genus to accommodate it. Nasigulper itsgotatao n. gen., n. sp. infects the olfactory lamellae (nose) of the deepwater gulper shark, Centrophorus granulosus (Bloch and Schneider, 1801) (Squaliformes: Centrophoridae) from the north-central Gulf of Mexico outer continental shelf. The new species was assigned to Cathariotrematinae by having a 3-part attachment organ (TAO) and by lacking open loculi that symmetrically encircle a cluster of >2 loculi in the center of the haptor. The proposal of a new genus is warranted because the new species is the only known monocotylid that has a TAO comprising 3 closed loculi with 2 relatively small hamuli flanking the posteriormost loculus. The most morphologically similar cathariotrematine genus is represented by a single species (Squalotrema llewellyni Kearn and Greene, 1983) that infects the spiny dogfish, Squalus acanthias (Squaliformes: Squalidae) in the North Sea. Nasigulper itsgotatao differs from Squalotrema llewellyni by having a TAO comprising 3 closed loculi, relatively small hamuli flanking the posteriormost loculus, and a relatively short, sinous ovovitelline duct and by lacking depressions associated with the central loculus. Squalotrema llewellyni has a TAO comprising 3 supraloculi, hamuli that are equal to the length of the posteriormost loculus, a central loculus having a central depression flanked by 2 pear-shaped depressions anterolaterally, and an extensive ovovitelline duct that is sinuous sinistral to the proximal ovary. A phylogenetic analysis of all acceptable monocotylid 28S sequences recovered the new species sister to isolates of Cathariotrema selachii (MacCallum, 1916) Johnston and Tiegs, 1922 from the Gulf of Mexico (no sequence of a species of Squalotrema exists). The new genus and species are the sixth and eighth, respectively, added to Cathariotrematinae.

Morphologic development of unidentified Sarcocystis sp. schizonts associated with encephalitis in a 9-wk-old gray fox (Urocyon cinereoargenteus) from Texas is described. Sarcocystis schizonts were confined to lesions. They were sparsely distributed and their staining affinity for hematoxylin and eosin varied with developmental stages; immature schizonts were deeply stained compared with mature schizonts. Most parasites were extravascular and the host cell was not identified for those that were intracellular. The parasite divided by endopolygeny, in which the nucleus became lobulated but lobes remained connected. Schizonts were up to 30 lm long and contained up to 32 merozoites/nucleus. The merozoites were slender and unlike any known species of Sarcocystis. The schizonts were distinct from Sarcocystis neurona schizonts, which cause encephalitis in many species of animals.

Swimmer's itch is caused by the accidental penetration of human skin by various species of avian schistosomes that naturally cycle in bird and snail hosts. Little is known about the ontogeny of avian schistosomes in their vertebrate hosts, especially in wild birds. Taking advantage of the abundance of common merganser (Mergus merganser) broods on northern Lower Peninsula lakes in Michigan, we obtained fecal samples from 97 common mergansers, focusing on ducklings (n = 75) of 13 different ages but also including birds that were 1 yr and older. Miracidia hatching from fecal samples were quantified per gram of feces to determine the timeline and reproductive output of naturally acquired schistosome infections. All ducklings 18 days or younger were negative. Beginning at 21 days old, some ducklings were passing a small number of eggs, with the percentage of ducklings passing eggs increasing with age. The number of eggs passed by ducklings remained low until approximately 7 wk of age. At 52 days and older, all ducklings were passing eggs and the number of miracidia produced was frequently many times higher, strongly consistent with published mitigation studies that duckling relocation severely reduces snail infections and case reports of swimmer's itch. Surprisingly, second-year common mergansers also passed high numbers of schistosome eggs but may contribute less to successful transmission to snails based on the published success of mitigation by duckling relocation. All brooding hens sampled were positive but passed low numbers of eggs. This is the first study of the development patterns of any avian schistosome in wild young-of-the-year birds, and the patterns are compared with the few known laboratory studies on worm development.

Host specificity is essential to understanding the ecology and evolution of parasites, and it is often complicated to estimate because of the presence of morphologically similar but genetically distinct species. Morphological identification of larval trematodes is often challenging because of the lack of diagnostic characteristics that only appear in the sexually mature adult stage. The difficulty in accurate species identification may obscure their compatibility with the host species. We investigate the parasites infecting 2 Asian mud snail species, Batillaria multiformis and Batillaria attramentaria, at 1 site where the 2 host snails co-occur to identify the level of their host specificity. We found that the morphospecies Cercaria batillariae was the most common trematode species in B. attramentaria and B. multiformis. We conducted polymerase chain reaction (PCR) –based restriction fragment-length polymorphism (RFLP) analyses of 77 C. batillariae infections in B. attramentaria and 150 in B. multiformis. We further sequenced the representative RFLP patterns to evaluate their phylogenetic relationship. We observed 6 genetically distinct species infecting 2 host species. Of those, 2 parasite species exclusively infected B. attramentaria, and 1 was found only in B. multiformis. Although 3 parasite species infected both hosts, 2 of them showed highly biased infections to either host species. Our study suggests that trematodes in the Batillaria snails can be host specific and highlighted the usefulness of molecular genetics for assessing host specificity.

Toxoplasma gondii is a coccidian parasite capable of infecting humans and other warm-blooded animals, with approximately 30% of the world's population chronically infected. Workers who handle animals occupationally, such as veterinarians in small-animal practices, are at a higher risk of infection. Common risk factors among these workers include contact with cats and other animals in a clinical setting. For this reason, this study aimed to determine the seroprevalence of anti-T. gondii immunoglobulin (Ig)G and IgM antibodies among small-animal veterinary personnel in Veracruz, Mexico. Blood samples were collected from 133 healthy individuals and examined using an enzyme-linked immunosorbent assay. A detailed survey on work activities was conducted. The findings showed a 2.2% positive rate for specific anti-T. gondii IgG antibodies and a 0% rate for anti-T. gondii IgM antibodies, which underscores the need for further preventive educational programs to reduce exposure to T. gondii infection in this population.

Many human infections are transmitted through contact with household pets. The purpose of this cross-sectional study was to determine the occurrence of ticks and fleas on pets (dogs and cats) in local veterinary clinics in Statesboro, Georgia. We screened ectoparasites for Rickettsia and Bartonella and assessed owner knowledge and practices related to tick- and flea-borne diseases. Ectoparasites were collected and identified using standard taxonomic keys, and their genomic DNA was extracted. Three TaqMan assays were used to test ectoparasites for flea-borne Rickettsia DNA. Nested PCR targeting riboflavin synthase encoding gene (ribC) was used to detect Bartonella species DNA. Restriction fragment length polymorphism analysis and sequencing were used to identify the microorganisms detected. Upon providing written consent, owners completed a self-administered questionnaire to provide information concerning their knowledge and practices about vector-borne diseases. Data from 27 pets were collected from 2 veterinary clinics during September to December 2014. A total of 58 ectoparasites including fleas (n = 51) and ticks (n = 7) were collected from 19 cats and dogs. The cat flea, Ctenocephalides felis (n = 44), was the predominant flea species followed by Pulex sp. (n = 7). All ticks were Ixodes scapularis. Using PCR, RFLP, and sequencing, it was determined that the majority of cat fleas contained DNA of known human pathogens, including Rickettsia asembonensis (72.5%), Rickettsia felis (5.9%), Bartonella henselae (2%), and Bartonella quintana (7.8%). DNA of B. quintana was also detected in 2 Pulex sp. fleas and 2 ticks. Two animals had ectoparasites co-infected with Rickettsia and Bartonella. Most owners (95.7%) knew that fleas can transmit animal disease agents, but they were less aware that fleas can spread diseases to humans, and only 12.5% of owners knew about cat scratch disease. Our data indicate that there is a risk of flea- and tick-borne zoonotic infections in households owning cats and dogs. Educational materials, vector-control preventive measures, and appropriate personal attitudes and practices are needed to ensure public health safety and wholesome interactions with pets.

The family Camallanidae Railliet and Henry, 1915 comprises parasitic nematodes found in the digestive tracts of fishes, amphibians, and reptiles. In this family, the taxonomic status of several genera is still under debate. Zeylanema Yeh, 1960, is a genus of uncertain status that was segregated from Camallanus Railliet and Henry, 1915. Some researchers have argued that Zeylanema is either a subgenus or junior synonym of Camallanus based on morphological characteristics. No genetic information for Zeylanema has been reported to date, and therefore the molecular phylogenetic relationships of the genus have not been investigated. In this study, nucleotide sequences for 18S and 28S ribosomal DNA and mitochondrial cytochrome c oxidase subunit I of Zeylanema worms were analyzed, and these data were combined with detailed morphological observations. Molecular phylogenetic trees based on 18S and 28S sequences were constructed. The sequences for the Zeylanema worms were included in a single Camallanus clade. This result supported the previous opinion that Zeylanema is a subgenus or junior synonym of Camallanus. These results should prompt further studies to evaluate the taxonomic status and relationships of other genera within the Camallanidae.

We describe Baccigeroides currani n. sp. (Digenea: Gymnophalloidea) infecting the intestinal mucosa of the Gulf menhaden, Brevoortia patronus Goode, 1878 (Clupeiformes: Alosidae) from the Gulf of Mexico. The new species differs from its congeners by the combination of having an oral sucker that is more narrow than (vs. equal to or larger than) the ventral sucker, ceca that extend posteriad to the middle of the post-testicular space (vs. to the level of the testes), a cirrus sac that extends posteriad to the middle of or beyond the posterior margin of the ventral sucker (vs. wholly confined to the forebody or slightly overlapping the anterior margin of the ventral sucker), a bipartite (vs. unipartite) seminal vesicle, and a post-testicular (vs. pre-testicular) ovary. We emend Baccigeroides Dutta, 1995 to include features of the new species and its congeners: ceca that extend posteriad to the middle of the post-testicular space, a cirrus sac that extends posteriad to the middle of or beyond the posterior margin of the ventral sucker, a bipartite seminal vesicle, a median genital pore, a post-testicular ovary, a dorsal Laurer's canal pore opening near the posterior body end, and an excretory system with arms merging anteriorly at the level of the pharynx. The ITS2 and 28S sequences of the new species were most similar to those of Bacciger bacciger (Rudolphi, 1819) Nicoll, 1914 (type species) and Pseudobacciger cheneyae Sun, Bray, Yong, Cutmore, and Cribb, 2014. Phylogenetic analyses of the 28S and ITS2 sequences each recovered species of Bacciger Nicoll, 1914, Baccigeroides, and Pseudobacciger Nahhas and Cable, 1964 as closely related taxa and sister to the gymnophalloids of Tandanicolidae Johnston, 1927. Bacciger was polyphyletic (B. currani, Cercaria rangiae Wardle, 1983, and P. cheneyae nested in the clade of Bacciger spp.) and requires revision. We reject the synonymy of Baccigeroides opisthonemae (Nahhas and Cable, 1964) n. comb. and Baccigeroides ovatus (Price, 1934) Cutmore, Bray, and Cribb, 2018 because they are morphologically distinct; however, both species require redescription based on the types and new specimens collected from the type host and type locality. The present study comprises the first phylogenetic analysis that includes a sequence of Baccigeroides and the first report of species of Baccigeroides infecting an alosid from the northern Gulf of Mexico.

Fischoederius elongatus (Poirier, 1883) is a common rumen fluke found in Asia and Africa. Nucleotide sequence data for F. elongatus have been reported but are limited to certain ribosomal and mitochondrial DNA regions. High diversity in the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 (COI) haplotypes has been reported in some Asian countries. Some researchers have advocated the possibility of cryptic species within F. elongatus based on the high genetic diversity within the species as well as the genetic distance within and between sister species. However, the number of examined parasites, hosts, and geographic regions was limited in these studies, and the intraspecific variation of the species remains unclear. Therefore, additional studies are required to provide more insight into the genetic variation of F. elongatus. This study characterized F. elongatus in the rumen of Cambodian cattle and documented its genetic information and intraspecific variation. The flukes were morphologically identified, and the molecular structure of the 28S and COI regions was analyzed. The partial sequences of 28S from the 45 specimens yielded 2 genotypes, and the 28S sequences of F. elongatus seem to be highly conserved in Cambodia. In contrast, partial sequences of COI from 44 specimens exhibited 29 distinct haplotypes, and the similarity among the haplotypes was 92.9–99.7%, indicating high diversity of the COI sequence in the Cambodian F. elongatus population. In both 28S and COI phylogenetic trees, the present sequences formed a single clade with Gastrothylacidae species; however, the 4 genera within the family did not form genus-specific clades. These results suggest that complete species identification of Gastrothylacidae is difficult to perform based solely on the 28S and COI sequences. The molecular population genetics of F. elongatus in Cambodia were found to be highly diverse in COI sequences, and a star-like haplogroup was also detected. In addition, some haplotypes were identical to those from neighboring countries, such as India and Thailand, and no distinct country-specific haplogroups were found. Therefore, ancient domestication, artificial migration, and the contemporary import of host cattle may have involved genetic populations in these countries. Highly diverse COI haplotypes were found with few or no differences in morphology, and the diverse haplotypes found in the current and previous studies were unlikely to originate from cryptic species.

Sucking lice are obligate parasites of eutherian mammals and are generally considered to be host-specific parasites. Molecular investigations have found that some current louse taxonomy is incorrect and does not reflect the relationships among families and species. Western chipmunks (23 species of Tamias) and the eastern chipmunk (Tamias striatus) are infested by 2 different species of Hoplopleura sucking lice, Hoplopleura arboricola and Hoplopleura erratica. Hoplopleura arboricola has been found on 19 of 23 western chipmunk species, and H. erratica has only been recorded as a parasite of T. striatus. We investigated the relationships between these chipmunk lice and louse systematic status by supplementing published sequence data with additional sequences and morphological examinations. We estimated phylogenetic relationships using 1,107 coding loci in a maximum-likelihood framework and a species tree approach. In addition to the phylogeny, we calculated raw pairwise distances of the cytochrome oxidase subunit 1 gene (COI) between clades. Both phylogenetic approaches recovered 2 well-supported clades of H. arboricola, 1 of which included H. erratica, suggesting that the 2 louse species are not distinct. Further, examination of louse specimens found no morphological traits that distinguish lice from any of the lineages, including differentiating H. erratica from H. arboricola. The average pairwise distance of COI sequences between the 2 major H. arboricola clades exceeded that of the distances between H. erratica and either of the H. arboricola clades. Based on the genetic similarities and phylogenetic relationships of the lice, it appears that an ancestral louse was associated with western chipmunks and then transferred to the eastern chipmunk. Using the phylogenetic and morphological evidence presented here, Hoplopleura arboricola Kellogg and Ferris, 1915 is relegated to a junior subjective synonym of Hoplopleura erratica (Osborn, 1896). A holotype from the type series is designated for H. erratica. These results suggest a history of chipmunk host species interactions that enabled ectoparasites to disperse between chipmunk species and illustrate the importance of phylogenomic analyses to study species interactions and the history of interspecific associations.

In a parasitological survey of the least killifish, Heterandria formosa (Girard), from Ward Creek in Louisiana, we encountered a myxozoan parasite in the gallbladders of this host bearing myxospores consistent with a Myxidium species. Prevalence was 72.2% in 18 hosts examined, with infection characterized by the presence of sheetlike to discoid plasmodia, approximately 1–2 mm across, floating freely in the gallbladder. Myxospores were observed in the plasmodia and found floating freely in the bile and were elliptoid and fusiform in valvular and sutural views respectively. The myxospore poles were slightly pointed away from the midline of the sutural plane of the myxospore. The myxospore valve surface had 9–12 striations. Mean myxospore dimensions (range, µm) were 13.7 (13.0–14.2) long, 6.5 (5.4–7.2) wide, and 6.4 (6.1–6.7) thick. Two equal-sized polar capsules were broadly ovoid to spherical, oriented to opposite extremes of the myxospore, and contained a tubule with 4–6 coils. Mean polar capsule dimensions (and range) were 4.3 (3.6–4.9) long and 3.6 (3.2–4.4) wide. Morphologically, the myxospores of this species were distinct from those of most other Myxidium species, and for the few species where dimensions overlapped, the average dimensions were different, and host and locality were also distinct. As such, we described this as Myxidium fonti n. sp. in honor of William F. Font. Phylogenetically, M. fonti is sister to Myxidium phyllium from another poeciliid host, and these species fall into a larger biliary tract lineage of myxosporeans. The relationships support previous work that suggests that tissue specificity, with some exceptions, is important in the phylogeny of myxosporeans.

Dirofilaria ursi is a filarial nematode of American black bears (Ursus americanus) transmitted by black flies (Simuliidae). Overt clinical disease associated with D. ursi infection of bears has not been reported; however, adult or larval (i.e., microfilarial) stages of the parasite can be found incidentally in the subcutis, connective tissues of the abdomen and thorax, or on blood films. Over the last 60 yr, D. ursi has been reported in black bears throughout the northern United States and Canada. However, very few surveys have been conducted since 2000, particularly in the northeastern United States where black bear populations have expanded significantly over recent decades. During 2018–2020, blood films collected from 129 black bears from Pennsylvania during all seasons were examined for microfilariae. Microfilariae that were morphologically consistent with D. ursi were identified in 33 (25.6%) of the 129 sampled black bears. The average number of microfilariae per positive blood film was 27.4 (range: 1–282). Age, sex, and season did not have a significant effect on detection of Dirofilaria infection in black bears. Molecular identification of Dirofilaria species via polymerase chain reaction (PCR) and sequencing of the 18S rRNA gene region was conducted for 11 whole blood samples whose blood films contained microfilariae (average of 17.3 microfilariae/film; range: 1–55). Ten of the 11 whole blood samples were PCR positive for Dirofilaria, and the sequences were highly similar to sequences of Dirofilaria repens available in GenBank. The results of this study are consistent with those of previous D. ursi surveys in North American black bears and indicate that Dirofilaria infection is common in black bears in Pennsylvania but does not appear to be associated with overt disease.

Parasites can alter their hosts in a myriad of ways, including their physiology, movement, and behavior. In this study, we investigated how trematode parasites impact the movement and behavior of their first intermediate host, the keystone grazer Pleurocera proxima, in both the lab and the field. Trematode parasites frequently castrate their snail first intermediate hosts and can increase metabolic needs. Therefore, we predicted that infected snails would have increased feeding rates, prefer eating food over spending time with conspecifics, and move significantly less than uninfected snails. To test this, we conducted a series of experiments. First, we conducted a field experiment to quantify feeding rates of infected and uninfected P. proxima snails. We found that infected snails consumed 14% more than did uninfected snails. Next, we conducted a laboratory preference experiment to quantify the amount of time spent with either food or a conspecific. We found that snails, regardless of infection status, spent more time with conspecifics than with food. We then investigated how infection influenced movement in both a social context and an isolated context under laboratory conditions. We found that infected snails moved less than did uninfected snails in a social context but more than did uninfected snails in an isolated context. We also investigated whether these differences in preference and movement would translate into altered dispersal in the field. We found no effect of infection status on the distance or direction traveled in the field. This work demonstrates that parasites can influence host movement and behavior in substantial ways and, importantly, that these effects can be dependent on social context. Future work on parasite-mediated behavior should be conducted to investigate these effects under different biotic (as we have done) and abiotic contexts to establish a robust understanding of the role parasites play in shaping our ecosystems.

It has been known for over 25 yr that feces from rats infected with the tapeworm Hymenolepis diminuta are more attractive to tenebrionid beetle intermediate hosts than feces from uninfected rats. Although it has been demonstrated that a volatile chemical (or chemicals) in infected rat feces attracts the intermediate host Tribolium confusum, the volatile chemical(s) have never been identified. This study aimed to identify and compare the volatiles in the feces of rats before and after infection with H. diminuta. Four 8-wk-old female Sprague Dawley rats were infected with H. diminuta. Fecal samples pre- and postinfection were collected, and volatiles were trapped by vacuum on a polymer adsorbent and identified with gas chromatography–mass spectrometry analysis. Limonene was detected in preinfection but not postinfection feces. Five carboxylic acids were isolated only from postinfection feces. Butanoic acid was found in the greatest relative amount, but also 3-methylbutanoic acid, 2-methylbutanoic acid, pentanoic acid, and hexanoic acid were found. This is the first report identifying the volatiles found in the feces of rats infected with H. diminuta.

The avian uropygial gland secretes preen oil, a complex blend of lipids that birds spread on their feathers during preening. Although preen oil is known to help birds maintain feather condition, there has been increasing evidence suggesting preen oil also affects other organisms that reside on bird feathers, such as bacteria, mites, and lice. In a series of experiments, we investigated the effects of Rock Dove (Columba livia) preen oil on the behavior and survival of feather-feeding wing lice (Columbicola columbae). These lice spend the majority of their lives hidden between flight feather barbs to avoid bird preening. However, because lice cannot feed on flight feathers, they regularly migrate to bird body regions to consume thinner insulative feather barbs. We found that lice strongly preferred to spend time on body feather regions treated with preen oil compared with untreated feather regions, but this preference disappeared when lice encountered preen oil on either flight feathers or on filter paper arenas. As lice are only known to feed on body feathers, our data suggest that preen oil may be consumed by lice or that lice prefer to feed in preen oil–rich regions to increase the chances of encountering and perhaps consuming bacteria or mites that feed on preen oil. Contact with preen oil also influenced louse locomotion, with lice reducing the turn rate (though not velocity) while walking on arenas treated with preen oil, which is also consistent with a preference for preen oil. However, in vitro survival analyses showed that lice kept on preen oil–treated body feathers experienced a moderate but significant reduction in survival compared with lice on untreated body feathers. In contrast, lice on treated and untreated flight feathers showed similar rates of survival. Overall, our behavioral data and survival analyses suggest that louse interactions with preen oil are more complex than previously thought. Further research is needed to determine how these in vitro impacts of preen oil on louse behavior and survival influence bird–louse interactions in more natural settings.

The objective of the study was to identify the prevalence of anti-Toxoplasma gondii antibodies and estimate their possible association with some risk factors in intensive management and small-scale dairy farms from Aguascalientes, Mexico. Blood samples were collected from 240 clinically healthy cows from intensive management and small-scale dairies distributed in 5 municipalities from Aguascalientes State, Mexico. Serum samples were processed by indirect immunofluorescence taking the 1:64 dilution as the cutoff point. The association between seroprevalence and possible risk factors was estimated. The general seroprevalence was 43% (103/240). In the group of intensive management dairies, seroprevalence was 40% (48/120), and in the group of small-scale dairies seroprevalence was 46% (55/120); these values were not significantly different. In all municipalities and dairies, seropositive animals were identified. Among the municipalities, the seroprevalence was 29–65%, and among dairies seroprevalence was 20–80%. Coexistence with other animals (odds ratio = 1.8) and not having a rodent control program (odds ratio = 2.1) were identified as risk factors. The identified seroprevalence is considered important regardless of the management system and suggests a high exposure to the parasite.