The lecanicephalidean cestodes parasitizing the spiral intestine of the endangered giant freshwater whipray, Urogymnus polylepis (Bleeker), are investigated for the first time. Eight host specimens were collected between 2002 and 2008 at 2 collecting sites off the eastern coast of Borneo: 6 from the Kinabatangan River (Malaysia) and 2 from a fish market in Tarakan (Indonesia). Two of these individuals were found to be infected with a total of 3 new species of TetragonocephalumShipley and Hornell, 1905. Tetragonocephalum georgei n. sp. and Tetragonocephalum opimum n. sp. were recovered from a host specimen from the Kinabatangan River, and Tetragonocephalum levicorpum n. sp. was found parasitizing a host specimen purchased at a fish market in Tarakan. Specimens of each of the new species were prepared for light microscopy; specimens of 2 of the new species were prepared for scanning electron microscopy, and histological sections were prepared for 1 of the new species. The 3 new species are distinct from the 9 valid species of Tetragonocephalum and the 1 species inquirendum based on, for example, total length, number of proglottids and testes, and size of the scolex and acetabula. Tetragonocephalum georgei n. sp. and T. levicorpum n. sp. are unusual among their congeners in that they are euapolytic (i.e., gravid proglottids were not observed) rather than apolytic. They differ from one another in scolex and acetabula size. Tetragonocephalum opimum n. sp. is unusual among its congeners in its possession of vitelline follicles arranged in 2, rather than 3, regions in the proglottid. These new species increase the total number of valid species of Tetragonocephalum to 12 and the total number of known cestodes from U. polylepis to 13 species across 6 genera in 4 orders. This is the first account of lecanicephalideans reported from freshwater. The taxonomic status of each of the 32 nominal taxa historically associated with Tetragonocephalum is re-assessed. Type host identities of all valid species are revised and discussed in light of recent taxonomic efforts in the Dasyatidae Jordan and Gilbert.

Horses in Iceland have been isolated for more than 1,000 yr but still harbor a similar range of gastrointestinal parasites as do horses across the world. The long isolation of the horses and their parasites presumably means that no resistance genes have been introduced into the Parascaris spp. population. It is therefore of particular interest to investigate the efficacy of ivermectin on Parascaris spp. infecting Icelandic foals. Potential treatment failure of ivermectin in Iceland will add substantial new information on how resistance can arise independently. This study aimed to determine the efficacy of subcutaneous injection of ivermectin for the treatment of Parascaris spp. infection in foals and to identify the Parascaris species present in the west and north of Iceland. A fecal egg count reduction (FECR) test (FECRT) was performed on 50 foals from 8 farms, including an untreated control group of 6 foals, from September to November 2019. The foals were between 3 and 5 mo of age at the start of the study and had not previously been treated with anthelmintic drugs. Each foal was treated subcutaneously with off-label use of Ivomec^® injection 10 mg/ml or Noromectin^® 1% at a dose of 0.2 mg/kg. The FECR for each farm was calculated in 2 ways, by the eggCounts package in R and by the Presidente formula (FECRT). Both calculation methods resulted in efficacy levels between 0% and 80.78%, indicating ivermectin resistance on all farms. We also confirmed, by karyotyping, that the species of equine ascarid present in the west and north of Iceland is Parascaris univalens. This study provides evidence for treatment failure of ivermectin against P. univalens infection in foals. Since Icelandic horses have been isolated on the island for more than 1,000 yr, this implies that resistance alleles have developed independently in the Icelandic Parascaris population. The actual clinical impact of ivermectin resistance is unknown but another drug of choice should be considered to treat Parascaris infection in foals in Iceland.

Gastrointestinal nematode infection of small ruminants causes losses in livestock production. Plant compounds show promises as alternatives to commercial anthelmintics that have been exerting selective pressures that lead to the development of drug-resistant parasites. Soybean (Glycine max) is an economical value crop, with a higher protein content compared to other legumes. The objective of this study was to evaluate whether the protease inhibitors exuded from the G. max mature seeds have anthelmintic activity against Haemonchus contortus. To obtain the soybean exudates (SEX), mature seeds were immersed in 100 mM sodium acetate buffer, pH 5.0, at 10 C, for 24 hr. Then the naturally released substances present in SEX were collected and exhaustively dialyzed (cutoff 12 kDa) against distilled water. The dialyzed seed exudates (SEX_D) were heated at 100 C for 10 min and centrifuged (12,000 g, at 4 C for 15 min). The supernatant obtained was recovered and designated as the heat-treated exudate fraction (SEX_DH). The protein content, protease inhibitor activity, and the effect of each fraction on H. contortus egg hatch rate were evaluated. The inhibition extent of SEX, SEX_D, and SEX_DH on H. contortus egg proteases was 31.1, 42.9, and 63.8%, respectively. Moreover, SEX, SEX_D, and SEX_DH inhibited the egg hatching with EC₅₀ of 0.175, 0.175, and 0.241 mg ml^–1, respectively. Among the commercial protease inhibitors tested, only EDTA and E-64 inhibited the H. contortus hatch rate (79.0 and 28.9%, respectively). We present evidence demonstrating that soybean exudate proteins can effectively inhibit H. contortus egg hatching. This bioactivity is displayed by thermostable proteins and provides evidence that protease inhibitors are a potential candidate for anthelmintic use.

This study was carried out to identify the ectoparasites that infest owned dogs in the state of Tabasco, Mexico. In total, 1,302 dogs were sampled in the 5 ecological regions of Tabasco. The dog owners were surveyed to identify the factors associated with infestations. Ectoparasites were identified using taxonomic keys. Eleven species of ectoparasites were observed. General prevalence was 26.65%. Rhipicephalus sanguineus and Ctenocephalides felis were the most prevalent and abundant ectoparasites. The most important factors associated with ectoparasite infestations in the studied dogs were living outdoors, being a non-purebred, having short hair, being dark-haired, and having a body condition,3. Ectoparasite studies such as the one presented herein generate important information to create control programs focused on decreasing infestations in companion animals and thus the likelihood of zoonotic transmission of pathogens.

Few studies have examined community structure among myxozoan species in fish. Herein myxozoan communities are described from 2 cyprinid species, the spottail shiner (Notropis hudsonius) and the common shiner (Luxilus cornutus), from mesotrophic and eutrophic localities in rivers in southwestern Quebec, Canada. Four myxozoan species were found, and total prevalence ranged from 60 to 86.7% in spottail shiners at 4 localities along the Richelieu River. Component species richness ranged from 2 to 4 and mean infracommunity richness from 0.87 to 1.47. Prevalence, component species richness, and infracommunity species richness in the spottail shiner were comparable to those from other localities in the Great Lakes and St. Lawrence River that were exposed to municipal effluents. Nine myxozoan species were found in common shiners from the Bras d'Henri micro-watershed. Component species richness varied from 6 to 8 at 4 localities, with total prevalence being 100% at all localities except 1, where it was 80%. Mean infracommunity richness ranged from 1.73 to 2.27. Prevalence, component species richness, and infracommunity species richness in the common shiner from the Bras d'Henri micro-watershed were among the highest observed for myxozoan communities from any host species to date. It is concluded that moderate levels of eutrophication are sufficient to generate species-rich communities of myxozoan parasites in fishes.

To date, all free-living adult hairworms have been reported from aquatic habitats. However, in Oklahoma, a recently described gordiid, Gordius terrestris, is consistently encountered in terrestrial habitats. We found this gordiid species has a unique egg morphology, unlike that of any other hairworm species, with an outer shell separated by distinct space from a thick inner membrane surrounding the developing larva. Because of this unique egg morphology and the occurrence of free-living hairworms in terrestrial habitats, it was hypothesized that G. terrestris represents the first report of a hairworm species with a terrestrial life cycle. In this study, we observed thousands of free-living adult worms in terrestrial habitats such as wet lawns and underneath wet sod during the winter. We found evidence of worms mating in these terrestrial habitats, followed by female worms burrowing and ovipositing in the soil. In the laboratory, significantly more females burrowed in the soil than males, providing a plausible explanation for the extreme male-biased sex ratio observed for free-living worms found on wet lawns. Finally, we collected terrestrial earthworms infected with the cyst stage of this gordiid species in the field and confirmed those observations by infecting earthworms with G. terrestris larvae in the laboratory. Taken together, these observations strongly support the hypothesis that G. terrestris has a terrestrial life cycle.

CardicolaShort, 1953 is the most speciose aporocotylid genus (35 species) and includes marine and estuarine species of fish blood flukes that infect “higher ray-finned fishes” (Euteleostei). Several clades within Cardicola are recovered in phylogenetic analyses of the large subunit ribosomal DNA (28S), but morphological synapomorphies for those nucleotide-based clades remain elusive. The type species, Cardicola cardiocola (Manter, 1947) Short, 1953, has not been recollected in 73 yr and the original description was incomplete; making a genus revision challenging because of the ambiguous systematic position of its type species. Herein, we redescribe C. cardiocola by using the holotype (USNM 1337732) and new specimens collected from the type host, jolthead porgy, Calamus bajonado (Sparidae), from nearby the type locality. It differs from its congeners by the combination of having a body that is 5 times longer than wide, an anterior sucker with concentric rows of spines, 2–6 tegumental body spines per row, an esophageal gland that is 22–43% of the esophageal length, a testis that is 3–5 times longer than wide and that fills the intercecal space, a vitelline duct connecting to the anterior aspect of the oötype, an ascending uterus that lacks any coil, a descending uterus yielding a single coil, an obvious cirrus sac separated by constriction from the seminal vesicle, a tegumental protrusion surrounding the terminal end of cirrus sac, and a male genital pore that is posterior to the remainder of the genitalia. We also describe a new congener infecting the heart of yellowedge grouper, Hyporthodus flavolimbatus (Serranidae), from the Gulf of Mexico. It differs from its congeners by the combination of having an anterior sucker that does not extend beyond the anterior body margin, 2–5 tegumental body spines per row, posterior ceca that are 9 times length of the anterior ceca and that lack any coil, a testis that is 3 times longer than wide and that does not fill the intercecal space, an ovary that is >60% of the body width, a vitelline duct that connects to the anterior aspect of the oötype, a uterus that is >10% of the body width and that extends posterior to all genitalia, and a rounded posterior body margin. It is the first species of Cardicola to be described from a grouper (Serranidae). The 28S and internal transcribed spacer 2 phylogenetic analyses recovered the new species as a distinct lineage within the clade of Cardicola spp.

Herein, we describe several newly-collected specimens of Neopolystoma cf. orbiculare from the urinary bladder of 2 alligator snapping turtles, Macrochelys temminckii (Troost in Harland, 1835) (Cryptodira: Chelydridae Gray, 1831) from Comet Lake (30°35′46.94″N, 88°36′3.12″W), Pascagoula River, Mississippi. Our specimens differed from all previous descriptions of N. orbiculare and its junior subjective synonyms by the combination of having intestinal ceca adorned with triangular pockets and that terminate dorsal to the haptor, distinctive hooklets each having a handle and guard of approximately equal length and having a much longer and curved blade, 16 genital coronet spines that each possess 1–2 flanges per spine, pre-testicular vaginal pores, and vaginal ducts that are anterior to the junction of the oviduct and genito-intestinal canal. Some of our specimens were enantiomorphic (4 and 3 had a dextral and sinistral ovary, respectively). Nucleotide sequences (large subunit ribosomal DNA [28S], small subunit ribosomal DNA [18S], and cytochrome oxidase subunit 1 mitochondrial gene [COI]) for our specimens were most similar to GenBank sequences ascribed to N. orbiculare. Single-gene and concatenated phylogenetic analyses confirmed that NeopolystomaPrice, 1939 is polyphyletic and that our isolates share a recent common ancestor with those ascribed to N. orbiculare. This is the first record of a polystomatid from Mississippi, from the Pascagoula River, and from the alligator snapping turtle (and only the second species of Neopolystoma reported from any snapping turtle).

Freshwater gastropods of the genera Lymnaea Lamarck, 1799, Physa Draparnaud, 1801, Gyraulus Charpentier, 1837, Radix Montfort, 1810, and Stagnicola Jeffreys, 1830 are considered suitable intermediate hosts for avian schistosomes. A large trematode biodiversity survey performed across 3 yr on 6 lakes in Alberta confirmed 3 already-reported snail hosts for 7 North American avian schistosomes; however, the cytochrome c oxidase subunit 1 (COI) nucleotide sequence from 1 cercarial sample (from a single specimen of Planorbella trivolvis) was distinct from all other COI schistosome sequences. As part of a simultaneous, comparable study of P. trivolvis by us in Michigan, we collected another cercarial type from 6 lakes that was 99% similar (COI) to the aforementioned cercarial type. Phylogenetic analyses of the COI and 28S rDNA genes recovered the former cercaria in a clade of avian schistosomes. In Michigan, the feces of a Canada goose (Branta canadensis Linnaeus, 1758) had a miracidium with an identical COI nucleotide sequence. Preliminary swimmer's itch and cercarial emergence studies were performed to determine if the cercariae could cause swimmer's itch and to study the emergence pattern as compared with species of Trichobilharzia Skrjabin and Zakharow, 1920.

Falcaustra vietnamensis n. sp. is described from the small intestine of Physignathus cocincinus from north-central Vietnam. The new species is characterized by the large male worms (20.2–28.8 mm in length and 557–724 µm in width) relative to known members of the genus, 2 sharply pointed alate spicules of equal length (1,128–1,256 µm in length), gubernaculum including 2 separate pieces, 1 ventral with a pointed distal end and 1 dorsal with a blunt distal end (164–192 µm and 155–172 µm in length, respectively), and 12 pairs of caudal papillae. Female worms are larger than male worms (24.2–34.1 mm in length and 532–735 µm in width), with the vulva situated in the posterior half of body, and elliptical eggs, 60–70 µm long by 42–47 µm wide. Falcaustra vietnamensis n. sp. represents the 38th species assigned to the genus and the third species recorded from a lizard host in the Oriental biogeographical region. Partial sequences of the 18S ribosomal RNA gene (rDNA), internal transcribed spacer regions (ITS), and cytochrome c oxidase subunit 1 (COI) are provided for the new species. The molecular phylogenetic position of the genus Falcaustra is briefly discussed.

Eight species of ectoparasites were collected during 225 gray mouse lemur, Microcebus murinus (J. F. Miller), captures, in Ankarafantsika National Park, Madagascar, in 2010–2011. The ixodid tick, Haemaphysalis lemuris Hoogstraal, was the most common ectoparasite and was mostly represented by nymphs. Other ectoparasites recorded include the polyplacid sucking louse, Lemurpediculus madagascariensis Durden, Kessler, Radespiel, Zimmermann, Hasiniaina, and Zohdy; the ixodid tick, Haemaphysalis simplex Neumann; an undescribed laelapid mite in the genus Aetholaelaps; another laelapid belonging to the genus Androlaelaps; the chigger mite Schoutedenichia microcebi Stekolnikov; an undescribed species of atopomelid mite in the genus Listrophoroides; and an undescribed species of psoroptid mite in the genus Cheirogalalges. Except for the 2 species of ticks and 1 species of chigger, these ectoparasites may be host-specific to M. murinus. Total tick (H. lemuris and H. simplex) infestation was significantly greater in August than October, whereas louse (L. madagascariensis) infestation was significantly greater in October. There was no significant difference in tick infestations between male and female lemurs, but male lemurs had significantly more lice than female lemurs. Reproductive status was not a significant predictor of tick infestation in males and females.

The immune response of animals, including insects, is overcome by some parasites. For example, dauer larvae (DL) of the obligate entomopathogenic nematodes (EPNs) Heterorhabditis and Steinernema can invade insects, evade their defenses, and cause death. Although DL were long assumed to be the only infective stage of nematodes, recent reports suggest that L2-L3 larvae of facultative EPNs are also capable of killing insects. There are no studies, to our knowledge, about the role of nonimmunological barriers (the exoskeleton and its openings) in avoiding infection by DL and L2-L3 larvae, or whether these larval stages evade the host immune system in the same way. The objective of this study was to examine these questions by infecting Galleria mellonella with the facultative parasitic nematode Rhabditis regina. DL or L2-L3 larvae were either deposited on or near the moths or injected into their hemocoel. Once nematodes reached the hemocoel, the following host immune response parameters were quantified: prophenoloxidase, phenoloxidase, lytic activity, and the number of granular hemocytes. DL showed a greater ability to penetrate the exoskeleton than L2-L3 larvae. Once inside, however, both went unnoticed by the immune system and killed the insect. A higher number of granular hemocytes was activated by L2-L3 larvae than DL. We show for the first time that L2-L3 larvae can penetrate and evade the insect immune system. Further research is needed to compare facultative and specialized EPNs to determine which is more likely, with both DL and L2-L3 larvae, to evade insect defense barriers and produce death. The results will contribute to understanding the evolution of virulence in entomopathogenic nematodes.

The chigger, Euschoengastia pipistrelli Brennan, is a trombiculid mite that infests a variety of vespertilionid bats in North America. It has been reported from at least 9 species of bats from 18 U.S. states. However, nothing is available on the actual in situ infestation and ultrastructure of this chigger. Here we document some stereoscopic photographs of the infestation as well as a scanning electron micrograph of the mite from a common bat species. We also provide a summation of host and state records for this chigger.

The summer tanager, Piranga rubra (L., 1758) is a medium-sized songbird formerly belonging to the tanager family Thraupidae but now has been placed within the family Cardinalidae. Nothing is known about the coccidian parasites of this stunningly colorful bird. Feces from 2 P. rubra found dead in McCurtain County, Oklahoma were collected and examined for coccidia; 1 was found to be passing a new species of Isospora. Oocysts of Isospora mccurtainensis n. sp. are subspheroidal to ovoidal with a smooth bilayered wall, measure (length 3 width [L 3 W]) 21.7 3 19.5 µm, and have a L/W ratio of 1.1; a micropyle and oocyst residuum were absent but a bilobed and refractile polar granule is present. Sporocysts are ellipsoidal and measure 13.9 3 8.6 µm, L/W 1.6; a knoblike Stieda body is present as well as a distinct sub-Stieda body. The sporocyst residuum is composed of a granular compact cluster with a dense, irregular mass of granules lying between and dispersed among the sporozoites. This is the first coccidian reported from P. rubra and, most important, only the first known from the Cardinalidae in the mainland of the United States.

The Northern bobwhite quail (Colinus virginianus) is a popular game bird that has been experiencing a well-documented decline throughout Texas since the 1960s. While much of this decline has been attributed to habitat loss and fragmentation, recent studies have identified other factors that may also contribute to decreasing quail populations. Parasites, in particular, have become increasingly recognized as possible stressors of quail, and some species, particularly the eyeworm (Oxyspirura petrowi) and cecal worm (Aulonocephalus pennula) are highly prevalent in Texas quails. Eyeworm infection has also been documented in some passerines, suggesting helminth infection may be shared between bird species. However, the lack of comprehensive helminth surveys has rendered the extent of shared infection between quail and passerines in the ecoregion unclear. Thus, helminth surveys were conducted on bobwhite, scaled quail (Callipepla squamata), Northern mockingbirds (Mimus polyglottos), curve-billed thrashers (Toxistoma curvirostre), and Northern cardinals (Cardinalis cardinalis) to contribute data to existing parasitological gaps for birds in the Rolling Plains ecoregion of Texas. Birds were trapped across 3 counties in the Texas Rolling Plains from March to October 2019. Necropsies were conducted on 54 individuals (36 quail and 18 passerines), and extracted helminths were microscopically identified. Nematode, cestode, and acanthocephalan helminths representing at least 10 helminth species were found. Specifically, A. pennula and O. petrowi had the highest prevalence, and O. petrowi was documented in all of the study species. This research adds to the body of knowledge regarding parasitic infections in quail and passerines of the Rolling Plains ecoregion and highlights the potential consequences of shared infection of eyeworms among these bird species.

Quail populations in the United States have been declining for several decades, and the role that parasites may be playing in this decline is not well understood. The goal of this study was to document novel parasites that inhabited the scaled quail, Callipepla squamata, of the Trans-Pecos ecoregion of Texas. To do this, quail were collected by hunter-harvest, night-netting, and funnel-trapping and were necropsied in the laboratory to determine the parasites they hosted. After analyzing 386 birds, we identified Dispharynx sp. in one of the samples. This specimen is the first to be officially documented in scaled quail.