Chlorocresol has antibacterial and antifungal properties, yet its effectiveness in eradicating Acanthamoeba spp. remains unexplored. Acanthamoeba species trophozoites are usually sensitive to biocides, whereas cysts tend to be more resistant. This study aimed to evaluate the cysticidal activity of chlorocresol against Acanthamoeba polyphaga. Chlorocresol concentrations of 0.02, 0.04, and 0.08% were prepared and A. polyphaga cysts were incubated at room temperature (28–37 C) for 1, 24, 48, and 72 hr at each concentration. Cyst viability was evaluated using trypan blue staining and the percentage of nonviable cysts was calculated. For qualification assays, treated cysts were cultured on nonnutrient agar medium coated with Escherichia coli, incubated at 30 C, observed under a stereomicroscope for 30 days, and inoculated into peptone–yeast extract–glucose medium at 30 C for 72 hr. The results revealed that the A. polyphaga cysts were susceptible to 0.02, 0.04, and 0.08% chlorocresol. Chlorocresol made a significant difference in viability (P < 0.001) compared with the nontreated control for the same incubation time. This is the first study to examine the efficacy of chlorocresol against A. polyphaga cysts and it was highly effective. Chlorocresol could thus serve as an alternative chemical disinfectant for the eradication of A. polyphaga cysts as well as a prophylactic against transmission of other pathogenic microorganisms for which Acanthamoeba species can act as a carrier.

This paper provides a summary of new and revised records of pentastomes published since 1985 and also presents a checklist of all pentastome records from Australian reptiles and amphibians. The need to identify pentastome species, through both morphological and molecular characterization, is highlighted to enable a determination of the true diversity of pentastome species and their distribution within amphibians and reptiles in Australia.

Herein we describe a single nucleotide polymorphism-specific polymerase chain reaction (PCR) assay to rapidly detect and differentiate variants belonging to the European and North American lineages of Echinococcus multilocularis in clinical samples. This is an extremely relevant and applicable test in North America because the range of E. multilocularis continues to expand across the continent and because of a rise in prevalence in wildlife, domestic animals, and humans. The endemic North American (NA) and introduced European (EU) variants are believed to have different pathogenic potentials, with the EU variants being more infective and pathogenic than the NA variants. The rise of the EU variants of E. multilocularis increases the risk of spillover from wildlife to humans because of its increased potential for infectivity. Current PCR-based diagnostics can detect E. multilocularis deoxyribonucleic acid (DNA), but DNA sequencing is required to identify the specific variant. Our assay provides a straightforward conventional PCR method to differentiate the NA and EU variants, and we suggest this same approach could be used for the diagnosis of other parasites or variants that are genetically very similar. As surveillance continues for E. multilocularis across North America, identifying the different genetic variants from different geographic regions will become essential to understanding the current epidemiological shift that the parasite is experiencing, as well as informing public health decisions in affected areas.

Avian haemosporidians are a diverse group of protozoan parasites that infect a wide range of host species. Waterfowl are an ecologically and economically important group of hosts that have been underrepresented in studies of haemosporidians. Diving ducks have unique life history traits, and morphological, behavioral, and dietary differences separate them from more common dabbling ducks. Greater scaup (Aythya marila) and lesser scaup (Aythya affinis) are closely related diving ducks with declining population trends in North America. To better understand the diversity of haemosporidians within diving ducks and factors related to host infections in scaup, we surveyed 82 hunter-donated waterfowl from 8 species of divers, sea ducks, and dabblers from Green Bay, Wisconsin from 2019 to 2021. We used molecular detection methods and phylogenetic and statistical analyses to describe the diversity, host associations, and prevalence of haemosporidians. We detected 14 unique genetic lineages of haemosporidians, including 4 novel lineages. We identified at least 1 lineage of haemosporidian in each of the 8 host species of divers, sea ducks, and dabblers examined. Lesser scaup had more diverse haemosporidian communities than did greater scaup, but lineages showed no clustering among these hosts when incorporated in phylogenetic analyses with lineages from other Nearctic waterfowl. Female lesser scaup had the highest infection prevalence, but there was no effect of host age or year of sampling. Our findings underscore the importance of species and sex differences that could lead to a higher risk of infections. Our results also fill an important geographical sampling gap for haemosporidians along a key migratory route. Increased monitoring of haemosporidians in waterfowl could contribute to insights into parasite evolution and ecology and the conservation and management of host populations.

Hassalstrongylus Durette-Desset, 1971 (Nematoda: Heligmonellidae), includes 19 species that are distributed from the southwestern United States to central-western Argentina. Hassalstrongylus aduncus is a parasitic nematode of rodents from the subfamilies Arvicolinae, Murinae, and Sigmodontinae, and has been recorded from southern Virginia and Oklahoma to Costa Rica. This species was described by Chandler in 1932; the morphology of the synlophe was not included. Subsequently, in 1972, Durette-Desset described only the synlophe of the middle region of the body in both sexes. Despite its wide geographical distribution, to date, there has been no redescription that includes information complementary to the morphology of the synlophe, such as a study of the body surface or a molecular phylogenetic analysis. We reevaluated the morphology of some specimens that were presumably similar to H. aduncus parasite of Sigmodon sp. from Jalisco, Mexico, and it was determined that these corresponded to an undescribed species of the genus. Herein, we present a redescription of H. aduncus parasite of Sigmodon toltecus from Hidalgo, Mexico, with morphological traits such as the excretory pore, deirids, and ovijector, and provide a description of the synlophe in the anterior and posterior regions of both sexes and include scanning electron microscopy images. Hassalstrongylus geolayarum n. sp. is differentiated from H. aduncus by the number of ridges in the middle region of the body (23 vs. 21), as well as proportions between some traits of males and females such as total length/spicule length, total length/gubernaculum length, total length/length of the esophagus and total length/distance of the vulva and the size of the eggs (42 vs. 58 µm). Phylogenetic analysis is based on partial sequences of the nuclear ribosomal internal transcribed spacer region (ITS1 + 5.8S + ITS2) of the rDNA, using the maximum-parsimony, maximum-likelihood, and Bayesian inference methods revealed the close relationship of H. aduncus + H. geolayarum n. sp. within the Heligmosomoidea and confirmed the placement of the Hassalstrongylus monophyletic clade well-supported within Heligmonellidae. The new species presented a genetic divergence of 3.4–3.8% relative to H. aduncus. This is the first species of the genus described in Mexico. Presumably, there are more species not yet described throughout the geographic range of H. aduncus. A taxonomic review and molecular phylogenetic analysis are required in which more species and genes are analyzed in Heligmosomoidea to confirm the status of the nonmonophyletic groups recovered here.

Sarcocystis infections were found for the first time in the muscles of 3 of 3 gray wolves (Canis lupus) from Minnesota. Two kinds (thin-walled and thick-walled) of sarcocysts were detected, based on the appearance of the sarcocyst wall. In wolf 1, sarcocysts were thin-walled (<0.5 µm), and without any visible protrusions. Ultrastructurally, the sarcocyst wall was type 1a and identical to Sarcocystis svanai of the domestic dog (Canis familiaris). The second kind of sarcocyst, with a relatively thicker (>1 µm) sarcocyst wall, was detected in wolves 2 and 3. Ultrastructurally, the sarcocyst wall had undulating, pleomorphic villar protrusion of type 9c; these sarcocysts were identical to Sarcocystis caninum from the domestic dog. Molecularly, the 2 Sarcocystis species were characterized using 18S, 28S, COI, ITS-1, and rpoB genetic markers. All these markers showed 100% identity to either of the 2 species previously described from the domestic dog. The thick-walled sarococyst corresponded to Sarcocystis caninum, whereas the thin-walled sarcocyst corresponded to Sarcocystis svanai.

The structure of the envelopes (capsule and cyst) surrounding metacercariae of Stephanostomum baccatum (Nicoll, 1907) in the second intermediate host, the yellowfin sole Limanda aspera (Pallas 1814), is examined with the methods of light and transmission electron microscopy. The cyst, presumably formed by secretions of the metacercarial tegument, consists of 2 layers: the outer, very thin layer of an electron-dense, finely granular substance and the inner layer composed of loose material of a moderate electron density that includes dense bodies varying in size, shape, and localization. The capsule, formed by the host's cells, is also organized into 2 distinct layers. The inner layer of the capsule is loose, consisting of evenly spaced debris of degenerated cells and lipid droplets with inclusions of intact macrophages between them. The outer layer of the capsule consists of parallel rows of cells arranged around the parasite, with fibroblasts and macrophages being dominant types and granulocytes and lymphocytes found in smaller numbers. Aggregations of collagen fibers are located in narrow spaces between the cells. The number of lipid droplets in the outer layer is significantly smaller than in the inner layer. The capsules formed around the examined trematodes have several structural features that distinguish them from those of S. baccatum and Stephanostomum sp. metacercariae recovered from other fishes of the family Pleuronectidae. The major morphological features of such capsules are the lack of epithelioid or giant multinucleated cells and the presence of numerous lipid droplets. Investigating the structural details of the envelopes surrounding metacercariae in trematodes, as well as other helminths, contributes to our scientific understanding of parasite biology, which can, in turn, have broader implications for understanding host-parasite interactions and evolutionary biology.

Nematodes collected from the intestine of sompat grunt Pomadasys jubelini Cuvier, 1830 from Hann Bay in Dakar, Senegal represent a new species described herein as Dichelyne (Neocucullanellus) dakarensis n. sp., and investigated with the use of light and scanning electron microscopy. The new species differs from its congeners based on several characteristics, especially because the subgenus Neocucullanellus is the only 1 that has 2 ceca. In addition, the new species diagnosis is based on the number and arrangement of the caudal papillae as well as the size of the veil of spicules. Morphological data were supported by molecular analysis. Results obtained using SSU rDNA and COI distinguished the present specimens from other cucullanids. Molecular data indicated the close relatedness between the new species and Dichelyne cotylophora Ward and Magath, 1917.

Trichinella murrelli Pozio and La Rosa, 2000, is the primary sylvatic trichinellid encountered in temperate North America. During a survey for Sarcocystis in wild canids, a single worm matching the morphology of encapsulated Trichinella was observed in a muscle tissue squash from a gray fox male originating from Pennsylvania. The worm was photographed and then separated from the host tissue by artificial digestion, and genomic DNA was extracted from the worm. This DNA was subjected to species-specific multiplex PCR and short-read genomic sequencing. The banding pattern of the multiplex PCR indicated that the worm was T. murrelli, and the sequence of the mitochondrial Cytochrome c oxidase 1 gene and the ribosomal 18S ribosomal RNA, Internal Transcribed Spacer 1, 5.8S ribosomal RNA, Internal Transcribed Spacer 2, and 28S ribosomal RNA confirmed the diagnosis. This is the first report of T. murrelli in gray foxes that includes assays for assigning parasite species. This report confirms suspected data from surveys conducted over 30 yr ago and establishes a new host record for T. murrelli.

Dicyemids (Phylum Dicyemida) are endosymbionts present in the kidneys of benthic cephalopods. They usually consist of 10 to 40 cells and are characterized by 2 distinct body types: vermiform individuals and infusoriform larvae. Vermiform individuals remain attached to the internal surface of the host's renal appendages, while infusoriform larvae leave the renal sac to search for a new host. To investigate how dicyemids respond to various host and environmental cues, we evaluated phototaxis, chemotaxis, thigmotaxis, and rheotaxis responses of vermiform individuals and infusoriform larvae of 2 dicyemid species in a laboratory setting. Vermiform individuals did not exhibit phototaxis and chemotaxis to the major components of the host: urine, tissue fluids, or extracts of the host gills. However, they showed positive thigmotaxis and positive rheotaxis to slow water flow, probably contributing to enabling attachment to the renal appendages and remaining in the renal sac, respectively. The infusoriform larvae exhibited negative chemotaxis to host blood and negative thigmotaxis, but there was no evidence of phototaxis and rheotaxis. Negative thigmotaxis may facilitate the release of infusoriform embryos from the renal appendages. Negative chemotaxis to the host blood suggests that the infusoriform larvae do not enter through the vascular system to gain access to the renal sac, so the process by which infusoriform larvae enter the cephalopod host is yet to be determined.

Seventy of 190 (37%) mammals, representing 14 rodent and 2 lagomorph species examined in the Desert National Wildlife Refuge in southern Nevada, were parasitized by sucking lice (Phthiraptera: Anoplura). Twelve species of sucking lice (5 species of Hoplopleruridae, 7 species of Polyplacidae) were recorded. Nine of these louse species (Hoplopleura difficilis, Hoplopleura ferrisi, Hoplopleura onychomydis, Hoplopleura reithrodontomyis, Fahrenholzia reducta, Haemodipsus setoni, Neohaematopinus citellinus, Neohaematopinus neotomae, and Polyplax auricularis) are reported from Nevada for the first time, and Po. auricularis is recorded from Peromyscus eremicus (cactus deermouse) for the first time. Infestation prevalences, mean intensities, sex ratios, host associations, and host specificity are presented and discussed for each louse-host interaction.

Spiral valves from specimens of the giant electric ray Narcine entemedor Jordan & Starks, 1895 were examined in search of tapeworms at 2 localities of the Mexican tropical Pacific Ocean. Acanthobothrium oceguerai n. sp. is described herein based on material from Ventanilla, Oaxaca and from Acapulco Bay, Guerrero. The new species is a category 6 species, distinguished by being apolytic, retaining proglottids on the strobila until they are gravid, having strobila of 166–322 proglottids, having a small scolex and very long bothridia relative to the scolex, and having abaxial prongs that are short and thin in comparison to the axial prongs, which are longer and more robust. Acanthobothrium oceguerai n. sp. can be differentiated from other members of category 6 by the hooks, which are shorter, more robust, and smaller than those of the other members of this category. The phylogenetic analysis based on the 28S rRNA locus placed Acanthobothrium oceguerai n. sp. as sister to an unidentified species of larval Acanthobothrium from Philadelphia, Pennsylvania. In addition, sequences of the mitochondrial cytochrome oxidase subunit I gene and nuclear 18S rDNA were generated to provide support for future taxon sampling. Acanthobothrium oceguerai n. sp. is the fifth species of cestode reported from N. entemedor in the tropical eastern Pacific.

Parasitic infection with Toxoplasma gondii is prevalent in human and animal populations worldwide. Goat production for food and fiber has increased in popularity, and consumer demand for meat and dairy products has led to higher rates of human consumption in the United States. This trend has increased the importance of assessing the public health significance of these dietary commodities. The occurrence of T. gondii and its relevance to commercial goat production for the human food market in Mississippi has not been previously addressed. This study estimated the seroprevalence of T. gondii in breeding-age goats raised for human consumption from 4 counties in southwestern Mississippi. One hundred and forty-four goat serum samples were collected between August 2007 and April 2008 from Hinds (n = 55), Adams (n = 36), Yazoo (n = 36), and Copiah (n = 17) counties. The overall seroprevalence was 12.5% (18/144) and raises concern and justification for preventative measures including periodic surveillance of goat herds and production facilities to ensure a safe food commodity and food hygiene education for consumers.