We report the morphological characteristics of oocysts of Eimeria lancasterensis Joseph, 1969, collected from 6 of 6 (100%) eastern gray squirrels, Sciurus carolinensis, collected in Arkansas (n = 3) and Oklahoma (n = 3), and Eimeria ontarioensis Lee and Dorney, 1971, recovered from an individual of S. carolinensis from Arkansas. Oocysts of E. lancasterensis were ovoidal to ellipsoidal, measuring (L × W) 24.0 × 14.6 (18–29 × 12–16) mm; shape index (L/W) was 1.6 (1.3–1.8). A micropyle and an oocyst residuum were absent, but up to 2 polar granules were present. Oocysts of E. ontarioensis were piriform and measured 40.6 × 26.0 (37–44 × 23–28); L/W was 1.6 (1.5–1.7). These oocysts possessed a distinct micropyle and rarely a polar granule but lacked an oocyst residuum. The DNA was isolated from both eimerians, and the 18S rDNA genetic markers were PCR-amplified, cloned, sequenced, and analyzed. To our knowledge, this study represents the first time 18S DNA sequence data have been generated from E. lancasterensis and E. ontarioensis found in North American sciurid hosts, as well as new geographic distribution records for these coccidians. In addition, we also include a tabular summary of these 2 species of Eimeria from Sciurus spp. worldwide, with information on their hosts, distribution, and taxonomically important morphological characteristics, including key measurements of oocysts and sporocysts.

Schistosomiasis is a globally burdensome parasitic disease caused by flatworms (blood flukes) in the genus Schistosoma. The current standard treatment for schistosomiasis is the drug praziquantel, but there is an urgent need to advance novel interventions such as vaccines. Several glycolytic enzymes have been evaluated as vaccine targets for schistosomiasis, and data from these studies are reviewed here. Although these parasites are canonically considered to be intracellular, proteomic analysis has revealed that many schistosome glycolytic enzymes are additionally found at the host-interactive surface. We have recently found that the intravascular stage of Schistosoma mansoni (Sm) expresses the glycolytic enzyme phosphoglycerate mutase (PGM) on the tegumental surface. Live parasites display PGM activity, and suppression of PGM gene expression by RNA interference diminishes surface enzyme activity. Recombinant SmPGM (rSmPGM) can cleave its glycolytic substrate, 3-phosphoglycerate and can both bind to plasminogen and promote its conversion to an active form (plasmin) in vitro, suggesting a moonlighting role for this enzyme in regulating thrombosis in vivo. We found that antibodies in sera from chronically infected mice recognize rSmPGM. We also tested the protective efficacy of rSmPGM as a vaccine in the murine model. Although immunization generates high titers of anti-SmPGM antibodies (against both recombinant and native SmPGM), no significant differences in worm numbers were found between vaccinated and control animals.

The acaricidal effect of 14 strains of Metarhizium anisopliae sensu lato isolated from soil of livestock farms in the Mexican tropics was evaluated against larvae and engorged females, and during the laying and hatching of eggs of Rhipicephalus microplus (Ixodida: Ixodidae). For each fungal strain, the larvae mortality percentage was evaluated through a larval immersion test, while the reproductive efficiency indices in engorged females were measured using adult immersion tests at a dose of 1 × 10⁸ conidia/ml. All strains of M. anisopliae (s.l.) proved to be highly effective against R. microplus larvae (66–100%) and engorged females (100%). The strains also showed a good effect in inhibiting egg laying (16.45–56.38%) and a moderate effect in decreasing egg hatching (5.24–32.68%). Two strains demonstrated to be effective against all development phases of R. microplus in an integrated manner.

An inventory of parasites infecting the jaguar (Panthera onca) across its distribution range is relevant for the conservation of this threatened big cat. In this study, we report the occurrence of helminths in a jaguar from Mexico using morphological techniques (cleared and stained mounts and scanning electron microscopy) and partial sequences of the 28S ribosomal RNA (28S rRNA) gene and the cytochrome c oxidase 1 mitochondrial (COI) gene. We also provide an updated list of helminth species reported in jaguars in the Americas. Three helminth taxa are identified in the jaguar examined from Mexico: Toxocara cati, Physaloptera sp., and Taenia sp. The new 28S rRNA sequences of To. cati, Physaloptera sp., and Taenia sp. and the COI sequence of Taenia sp. corroborate the identity of the helminths isolated from this host. One hundred and twenty-nine records of helminths parasitizing jaguars from 49 studies up to May 2023 were identified in the Americas. In most of these studies (73.6%), helminths were identified using coproparasitological techniques. Sixteen helminths (7 nematodes, 5 cestodes, 3 acanthocephalans, and 1 trematode) were identified at the species level in free-ranging and captive jaguars. The study demonstrates the value of an integrative taxonomy approach to increase the accuracy of parasite identification in wildlife, especially when helminth specimens are scarce or poorly fixed.

We propose Dulcitransversotrema n. gen. for the freshwater transversotrematids Dulcitransversotrema patialense (Soparkar, 1924) n. comb. and Dulcitransversotrema chauhani (Agrawal and Singh, 1960) n. comb. Dulcitransversotrema is unique by the combination of lacking an oral sucker and an extensively coiled uterus as well as having testes that are not deeply lobed and that abut or nearly abut the inner posterolateral margins of the digestive tract (vs. deeply lobed testes that abut the cyclocoel region of the digestive tract only or that do not abut the ceca), a pre-oral genital pore (vs. post-oral genital pore), an ovary that is anterior to and abuts or nearly abuts the sinistral testis (vs. an ovary that is separated from the sinistral testis by some distance or having an ovary that is median and immediately pre-testicular), non-embryonated eggs (vs. embryonated eggs), typically having none or sparse vitelline follicles between the testes and ceca (vs. having a wholly inter-cecal vitellarium comprising a pair of highly compacted clusters of vitelline follicles anterolateral to the testes or having numerous vitelline follicles between the testes and ceca), an oblong, median, and primarily inter-testicular vitelline reservoir (vs. an extensively elongate, pre-testicular vitelline reservoir that arches anteriorly around the sinistral testis), and a subterminal excretory pore opening on the dorsal body surface between the level of the cyclocoel and posterior body end (vs. a terminal excretory pore). We describe the redia and cercaria of Dulcitransversotrema cf. patialense from the red-rimmed melania snail, Melanoides tuberculata (Müller, 1774) (Cerithioidea: Thiaridae), and their corresponding adult from beneath the scales of the zebrafish, Danio rerio (Hamilton, 1822) (Cypriniformes: Danionidae). All hosts were sampled from a spring-fed earthen pond at a private aquaculture facility near Ruskin, Florida. No transversotrematid life cycle was known from North America previously. The large subunit ribosomal DNA and ribosomal internal transcribed spacer 2 sequences of D. cf. patialense from Florida were most similar to those from D. patialense infecting red-rimmed melania from Mayagüez, Puerto Rico and differed by 134 and 69 nucleotides, respectively. Both phylogenetic analyses recovered Dulcitransversotrema as monophyletic and sister to a clade comprising Transversotrema spp. plus Crusziella formosa Cribb, Bray, and Barker, 1992.

Birds have a diverse community of “permanent” arthropods that complete their entire life cycle on the body of the host. Because some of these arthropods are parasites that reduce host fitness, birds control them by grooming, which consists of preening with the beak and scratching with the feet. Although preening is the primary component of grooming, scratching is essential for controlling arthropods on the head and neck, which cannot be preened. Several unrelated groups of birds have evolved comb-like pectinate claws on the middle toenail of each foot. We tested the role of these claws in the control of arthropods by experimentally removing teeth from the claws of captive western cattle egrets (Bubulcus ibis) infested with chewing lice (Insecta: Phthiraptera), feather mites (Acari: Sarcoptiformes), and nasal mites (Acari: Mesostigmata). After a period of 4 mo, we compared the abundance of arthropods on experimental birds to that of control birds with intact teeth. We used video to quantify the grooming rates of the captive birds, which groomed twice as much as wild birds. Experimental and control birds did not differ significantly in grooming time. Both groups virtually eradicated the chewing lice, but not feather mites or nasal mites. We found no support for the hypothesis that pectinate claws increase the efficiency of arthropod control by grooming. Experiments with wild birds are needed to test the hypothesis further under conditions in which birds devote less time to grooming.

Freshwater snails are commonly studied within the context of their role as intermediate hosts for digenetic trematodes. However, there are fundamental data deficiencies related to our understanding of directly transmitted parasites, such as coccidia, for freshwater snails. Because variation in coccidia pathogenicity and transmission among snail species likely has major impacts on snail community structure, we aimed to investigate the spatial distribution and prevalence of coccidia in several freshwater snail species throughout the Ozark and Ouachita Mountains ecoregions in Arkansas. We opportunistically collected 220 freshwater snails from 24 Ozark sites in summer 2022 and scanned fecal slides for the presence of coccidia. In summer 2023, we surveyed an additional 146 snails from 19 Ouachita sites. To test for apparent interactions among coccidia and trematodes, we scanned feces from a subset of snails (Physa and Planorbella in the Ozarks) that did not have concurrent trematode infections and from those that did. We observed oocysts that morphologically conformed to Pfeifferinella ellipsoides in 2 of the 9 snail taxa from 7 of the 43 sites. Planorbella trivolvis was infected at 2 of 6 sites in the Ozarks and 0 of 5 sites in the Ouachitas. Physa species were infected at 6 of 14 sites in the Ozarks and 0 of 12 sites in the Ouachitas. In the Ozarks, Pl. trivolvis had an overall prevalence of 0.13 (6 of 47), whereas individuals in the genus Physa had an overall prevalence of 0.08 (8 of 97). Our chi-square and Fisher exact tests revealed no significant evidence for trematode–coccidia competition or synergism within the two snail species. There were no other species infected, and we did not observe any coccidia in the snails from the Ouachitas. Our survey of 366 snails among 9 taxa and 43 sites represents the largest survey for freshwater snail coccidia to date and indicates that both Pl. trivolvis and Physa spp. may be primary hosts and/or reservoir hosts for Pf. ellipsoides in freshwater snail communities. The highly aggregated distribution of Pf. ellipsoides in northwestern Arkansas requires further investigation. Our results led to proposal of several hypotheses for additional research, including questions regarding the variation of coccidia host specificity and virulence.

Eight ticks were found in Comacchio (FE), Italy parasitizing a young black iguana (Ctenosaura similis) that had been accidentally transported in a commercial plant container from Costa Rica. Specimens were identified morphologically as Amblyomma scutatum and then confirmed by the barcoding of the mitochondrial cytochrome c oxidase subunit 1 gene. Amblyomma scutatum is a common tick known to infest reptiles in Central America, Mexico, and Venezuela, but not in Europe. In Italy, the possibility for this tick to become endemic is unlikely because of the absence of its principal hosts. Nevertheless, this finding confirms the high risk of introducing exotic species that is linked with global commerce and therefore the need for veterinary control of shipments.

Dicyemids (phylum Dicyemida) are the most common and most characteristic endosymbionts in the renal sacs of benthic cephalopod molluscs: octopuses and cuttlefishes. Typically, 2 or 3 dicyemid species are found in a single specimen of the host, and most dicyemids have high host specificity. Host-specific parasites are restricted to a limited range of host species by ecological barriers that impede dispersal and successful establishment; therefore, phylogenies of interacting groups are often congruent due to repeated co-speciation. Most frequently, however, host and parasite phylogenies are not congruent, which can be explained by processes such as host switching and other macro-evolutionary events. Here, the history of dicyemids and their host cephalopod associations were studied by comparing their phylogenies. Dicyemid species were collected from 8 decapodiform species and 12 octopodiform species in Japanese waters. Using whole mitochondrial cytochrome c oxidase subunit 1 (COI) sequences, a phylogeny of 37 dicyemid species, including 4 genera representing the family Dicyemidae, was reconstructed. Phylogenetic trees derived from analyses of COI genes consistently suggested that dicyemid species should be separated into 3 major clades and that the most common genera, Dicyema and Dicyemennea, are not monophyletic. Thus, morphological classification does not reflect the phylogenetic relationships of these 2 genera. Divergence (speciation) of dicyemid species seems to have occurred within a single host species. Possible host-switching events may have occurred between the Octopodiformes and Decapodiformes or within the Octopodiformes or the Decapodiformes. Therefore, the mechanism of dicyemid speciation may be a mixture of host switching and intra-host speciation. This is the first study in which the process of dicyemid diversification involving cephalopod hosts has been evaluated with a large number of dicyemid species and genera.

During a 2021 parasitological survey of birds in the Nyae Nyae-Khaudum Dispersal Area (Kavango-Zambezi Transfrontier Conservation Area, Namibia), we collected 9 specimens of Dendritobilharzia pulverulenta (Braun, 1901) Skrjabin, 1924 infecting the blood (heart lumen) of a white-backed duck, Thalassornis leuconotus (Eyton, 1838) (Anseriformes: Anatidae), and a fulvous whistling duck, Dendrocygna bicolor (Vieillot, 1816) (Anatidae). These flukes were fixed for morphology and preserved for DNA extraction. We assigned our specimens to Dendritobilharzia Skrjabin and Zakharow, 1920 because they were strongly dorso-ventrally flattened in both sexes and had an intestinal cyclocoel with a zig-zag common cecum with lateral dendritic ramifications, numerous testes posterior to the cyclocoel and flanking the dendritic ramifications, and a tightly compacted convoluted ovary as well as lacking an oral sucker, ventral sucker, and gynaecophoric canal. Further, our specimens were morphologically identical to previously published descriptions of D. pulverulenta. Sequences of the 28S from our specimens were nearly identical to those identified as D. pulverulenta from North America (New Mexico), and our 28S phylogenetic analysis recovered D. pulverulenta within a polytomy of other Gigantobilharziinae spp. The CO1 phylogenetic analysis recovered a monophyletic Dendritobilharzia and, with low taxon sampling, a monophyletic Gigantobilharzia. This is the first record of a species of Dendritobilharzia infecting these ducks as well as the first record of an adult Dendritobilharzia from sub-Saharan Africa. The original description of adult D. pulverulenta (type locality: northern Sudan) was based on 2 males only, and hence the present study is the first description of female D. pulverulenta from Africa (the continent of the type locality). We reassign 2 Gigantobilharziinae spp. based on morphology and nucleotide evidence: Gigantobilharzia ensenadense (Lorenti, Brant, Gilardoni, Diaz, and Cremonte, 2022) Dutton and Bullard, n. comb., and Gigantobilharzia patagonense (Lorenti, Brant, Gilardoni, Diaz, and Cremonte, 2022) Dutton and Bullard, n. comb. We also comment on several avian schistosome sequences whose identities need confirmation or that likely have been misidentified.

Allegheny woodrats (Neotoma magister) are karst-specializing rodents that are rare or in conservation need in many states within their current range. Parasitism and habitat fragmentation have been suggested as primary reasons for declining populations. The presence, prevalence, and impact of ectoparasites, including fleas, ticks, and bots, is not fully understood rangewide. We collected Allegheny woodrat ectoparasites across 8 states in their range, identifying parasites via morphological and genetic means. Across contributions from 8 states, we discovered 2 woodrat-specific fleas parasitizing Allegheny woodrats: Orchopeas pennsylvanicus (all contributing states, n = 228) and Epitedia cavernicola (Indiana only, n = 9). The former was a new state record in New Jersey and Ohio. Woodrat specialists Ixodes woodi were morphologically identified as the dominant tick species (n = 38), and our contributions to genetic databases may ease confusion in future efforts. Three generalist species of ticks representing 8 individuals were identified as Dermacentor variabilis, Amblyomma americanum, and Ixodes scapularis. Only 2 bot fly species were recognized in Allegheny woodrats: 1 squirrel bot (Cuterebra emasculator) and 10 individuals of Cuterebra sp. not genetically conspecific to any known eastern U.S. rodent bot. The host specificity for fleas is not surprising, given that previous small-scale surveys and ticks primarily appear to be a mix of genus-specific (Ixodes woodi) and generalist species. There remains uncertainty with bots via morphological and genetic analyses. Our survey presents a wide-ranging baseline survey for Allegheny woodrats across their range, emphasizing the diversity (or specificity) of parasite groups for this species. An understanding of Allegheny woodrats and the health impact of ectoparasites is imperative because they face myriad challenges rangewide, especially considering the bot-driven demise of 1 woodrat in our study. Ectoparasites can have a marked impact on already-declining woodrat populations across their range and should not be overlooked in future surveys.