Several trematode species infect the eyes of fish as second intermediate hosts. In most cases the definitive host is a piscivorous bird. Studies of a few species have shown an increase in transmission due to decreased visual acuity of the fish host. However, this may vary depending on trematode microhabitat choice within the eye. Some trematode species are found in the lens, some are found in the vitreous humor, and others have been reported from the retina. Here we report 3 genera of eyeflukes in 3 locations of the eye in the intermediate fish host, Gambusia affinis. Clinostomum metacercariae were found attached to the outer sclera within the eye orbit, and Diplostomum metacercariae were found in the lens. Posthodiplostomum metacercariae were confirmed by histology to reside between the choroid and pigmented retina. Posthodiplostomum metacercariae were found in both eyes of all 20 fish examined and in high intensities (up to 27 metacercariae per eye). High trematode intensities between the choroid and pigmented retina found in this study may disrupt vision in this fish host. Our study is the first to document the microhabitat of all 3 trematode metacercariae within the eye of G. affinis.

This study surveyed gregarine parasites that infect the amphipod, Gammarus fasciatus, to investigate temporal dynamics in infracommunity structure. We sampled a population of hosts for 2 yr from the north branch of the Raritan River in New Jersey. These hosts were infected with 2 direct life cycle gregarine parasites, Rotundula gammari and Heliospora longissima. Infections were separated temporally, with the prevalence of R. gammari peaking within the amphipod population in the fall (prevalence = 78% year 1 and 97% year 2) and H. longissima peaking in early spring (prevalence = 41% year 1 and 52% year 2). Increases in host population density did not significantly correlate with the abundance of these 2 parasites. However, H. longissima abundance was positively correlated with host body weight while R. gammari showed no significant relationship. The mean body mass of amphipods infected with H. longissima was 20.7 ± 1. 2 mg, and with R. gammari 8.1 ± 0.2 mg, which suggests a sized-based infection pattern. Mixed species infections were infrequent with an overall prevalence of 4.6%. When both gregarine species co-infected the same host, the R. gammari but not the H. longissima infrapopulation size was significantly lower when compared to single-species infections, suggesting asymmetric interactions. We conclude that the observed temporal patterns of infection by the 2 parasites are driven by a seasonal change in host demographics and size-dependent infections. We argue that specificity for host developmental stages may have arisen as a mechanism to avoid overlap between these gregarine species.

The trematodes belonging to the genus Platynosomum are biliary parasites of birds and mammals (domestic and wildlife) in tropical and subtropical areas of the globe. Despite several reports on platynosomosis in captive nonhuman primates, mainly in South America, the taxonomy of species of Platynosomum that infect these hosts remains confused, and it is not clear whether the species found in cats is the same that infects nonhuman primates. Because a detailed morphological study of Platynosomum from nonhuman primates is lacking, in this study we analyzed specimens of Platynosomum recovered from the biliary system of Callithrix penicillata kept in captivity in an animal facility. The helminths were submitted to morphological and morphometric analyses in a light microscope and measurements of 16 morphological traits were taken. A kernel density estimation (KDE) was used to estimate density distributions of the measurements obtained as well as the occurrence of overlap with the ranges of the measurements known to 2 other species of Platynosomum previously described from South American marmosets, Platynosomum amazonensis and Platynosomum marmoseti. A principal component analysis (PCA) was also performed in order to evaluate the position of each of the 3 species in the multivariate gradient of morphometric measurements. The occurrence of a growth gradient was also evaluated by analysis of correlation between the measurements. Besides a great morphological variability, all specimens obtained from marmosets in this study were identified as Platynosomum illiciens (Braun, 1901). In addition, the published ranges of the measurements of P. amazonensis and P. marmoseti were completely contained within the ranges found in this study as revealed by KDE. The PCA did not show the formation of groups, and the 3 species were distributed along a growth continuum, also corroborated by correlation analysis. Therefore, P. amazonensis and P. marmoseti are here synonymized with P. illiciens. The involvement of wildlife hosts to the epidemiology of feline platynosomosis and implications for its control are briefly discussed.

Rhizocephalan barnacles in the genus Briarosaccus parasitize and castrate king crab hosts, thereby preventing host reproduction and potentially altering host abundance. To better understand how environmental factors in Alaska may influence Briarosaccus prevalence, we studied the effects of temperature and salinity on the larvae of Briarosaccus regalis (previously Briarosaccus callosus). Nauplius larvae were reared at 7 temperatures (2 to 16 C) and 8 salinities (19 to 40) to determine larval survival and development rates. Maximum survival occurred from 4 to 12 C and at salinities between 25 and 34. In the Gulf of Alaska and Bering Sea, ocean temperatures and salinities are often within these ranges; thus current conditions appear favorable for high B. regalis larval survival. In addition, temperature was negatively correlated with larval development time; thus warmer waters can reduce the time larvae are exposed to the dangers of the planktonic environment. Since only female B. regalis larvae can infect crabs, we investigated the sex ratios of B. regalis broods at different temperatures and how size and morphological traits can be used to sex cyprid larvae. Larval rearing temperature did not affect brood sex ratio (F_0.947, P = 0.369), but sex ratio varied among broods (F_221.9; P < 0.001). Male larvae (424.5 ± 24.3 μm [mean ± 1 SD]) were significantly larger than female larvae (387.6 ± 22.7 μm [mean ± 1 SD]; F_1,221.4; P < 0.001), consistent with other rhizocephalan cyprids, but sizes overlapped between the sexes such that morphological traits were also necessary for determining sex. Overall, this study provides new information on the larval biology, larval morphology, and environmental tolerances of B. regalis, an important king crab parasite.

For parasites with complex life cycles, the ecological traits determining host competence and seasonal changes in infection in natural habitats are often unclear, making it difficult to predict infection dynamics, including disease outbreaks. Hairworms (phylum Nematomorpha) require both aquatic and terrestrial hosts to complete their life cycle. Although hairworm host competencies have been tested in laboratory experiments, knowledge of the paratenic hosts (aquatic insect larvae) in their natural habitats is limited. This study clarified the species of aquatic insect larvae that are primarily infected by hairworms as paratenic hosts over a year in a mountain stream in central Honshu, Japan. The monthly prevalence and mean abundance of hairworm cysts were high in Ephemera japonica larvae (Ephemeridae: Ephemeroptera) throughout the study period (20.0–88.9 and 0.2–36.8%, respectively). These high prevalence and abundance values may be attributable to their filter-feeding behavior as well as their depositional habitat use. The hairworms also infected leptophlebiids (Ephemeroptera; scrapers), the perlid Calineulia sp., the chloroperlid Haploperla japonica (Plecoptera; predators), and chironomids (Diptera; filter-feeders or predators). The abundance of the cysts tended to be high in aquatic insects inhabiting pools rather than riffles, and the seasonality reflects the reproductive season of the hairworms as well as the phenology of their paratenic hosts. Filter-feeding ephemeropterans inhabiting pools were the major paratenic host of the hairworms in our study site, although their universality and effectiveness as the transporter to definitive hosts remain unclear.

Lyme disease is a serious health problem, with many patients requiring in-depth clinical assessment and extended treatment. In the present study, we provide the first records of the western blacklegged tick, Ixodes pacificus, and Ixodes spinipalpis parasitizing eastern cottontails, Sylvilagus floridanus. We also documented a triple co-infestation of 3 tick species (Ixodes angustus, I. pacificus, I. spinipalpis) feeding on an eastern cottontail. Notably, we discovered a unique member of the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) in Canada. Ixodes spinipalpis ticks, which were collected from an eastern cottontail on Vancouver Island, British Columbia (BC), were positive for B. burgdorferi s.l. With the use of polymerase chain reaction amplification on the tick extracts and DNA sequencing on the borrelial amplicons, we detected Borrelia genomospecies 2, a novel subgroup of the B. burgdorferi s.l. complex. Based on 416 nucleotides of the flagellin B (flaB) gene, our amplicons are identical to the Borrelia genomospecies 2 type strain CA28. Borrelia genomospecies 2 is closely related genetically to other B. burgdorferi s.l. genospecies, namely Borrelia americana, Borrelia andersonii, and B. burgdorferi sensu stricto (s.s.) that cause Lyme disease. Like some other borrelial strains, Borrelia genomospecies 2 can be missed by current Lyme disease serology. Health-care providers must be aware that Borrelia genomospecies 2 is present in I. pacificus and I. spinipalpis ticks in far-western North America, and patients with clinical symptoms of Lyme disease need to be assessed for potential infection with this pathogen.

Fertilization through hypodermic implantation of spermatophores has been recorded in at least 4 groups of leeches: Glossiphoniidae, Piscicolidae, Ozobranchidae, and Erpobdelliformes. In Piscicola respirans (Piscicolidae), vector tissue responsible for sperm transfer from a specialized region of the body to the ovaries has led to the non-random attachment of spermatophores on the body surface of the recipient leech. It has been suggested that in glossiphoniid leeches, spermatophores are implanted in any part of the body surface of the recipient leech without a clear pattern or preference for region. In order to determine if the donor leech implants its spermatophores in a specific area of the conspecific recipient's body, we surveyed 81 specimens of Haementeria officinalis (Clitellata: Glossiphoniidae) from a wild population in Guanajuato, Mexico, and recorded the distribution of the spermatophores over the recipient's body surface. We describe for the first time a spermatophore of H. officinalis using scanning electron and light microscopy. Spermatophores were found attached dorsally between somites XVII and XXI 59.57% of the time, and the rest were found in other parts of the body, including on the ventral surface. The non-specific attachment for spermatophores does not support the presence of specialized tissue responsible for sperm transfer and instead attributes the placement of implantation to mechanical characteristics of the copulation process.

The objectives of the present cross-sectional study were to isolate and genotype Toxoplasma gondii in free-range chickens from Grenada, West Indies. Using the modified agglutination test, antibodies to T. gondii were found in 39 (26.9%) of 145 free-range chickens with titers of 25 in 7 chickens, 50 in 6 chickens, 100 in 2 chickens, and 200 or higher in 24 chickens. The hearts of the 39 seropositive chickens were bioassayed in mice; viable T. gondii was isolated from 20 and further propagated in cell culture. Genotyping of T. gondii DNA extracted from cell-cultured tachyzoites using the 10 PCR-restriction fragment length polymorphism (RFLP) markers SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed 4 genotypes, including ToxoDB PCR-RFLP no. 2 (Type III), no. 7, no. 13, and no. 259 (new). These results indicated that T. gondii population genetics in free-range chickens seems to be moderately diverse with ToxoDB no. 2 (Type III) as the most frequent (15/20 = 75%) compared to other genotypes in Grenada.

Endogenous stages of the life cycle of Eimeria melanomytis, infecting the peripheral epithelial cells of villi of the small intestine of experimentally infected young dusky rice rats, Melanomys caliginosus, were studied. Giemsa-stained mucosal scrapings and histological sections were examined for all the stages. Eimeria melanomytis has 3 generations of meronts (M), different in size, shape, and number of merozoites (m); and in size, shape, and location of the nuclei within the cytoplasm of the meronts. The 3 meront types, M₁–M₃, respectively, had 11–14 (m₁), 7–10 (m₂), and 20–30 (m₃) merozoites. Macrogametocytes and microgametocytes, as well as macrogametes and microgametes, complete the sexual cycle forming the unsporulated oocysts. This parasite's endogenous development produced severe intestinal lesions in experimentally infected dusky rice rats.

Avian haemosporidian parasites provide a model system for understanding ecological and evolutionary host–parasite interactions. The diversity and distribution of these parasites remains incomplete, and, here, we provide the first range-wide assessment of avian haemosporidians in a continentally distributed host, the Northern Cardinal (Cardinalis cardinalis). Based on molecular techniques, we show geographical differences in prevalence and lineage diversity between host subspecies and identify several novel lineages. We use phylogenetic reconstruction to show where these lineages fit into the expanding evolutionary tree of avian haemosporidian lineages. All except 1 subspecies of Northern Cardinal are highly parasitized by a wide diversity of Plasmodium and Parahaemoproteus. Compared to published studies that used microscopy to determine prevalence in this host, we find a much higher number of infected individuals (67.4% vs. 45% or less). Consistent with previous studies, Parahaemoproteus from the Northern Cardinal was found to be highly host specific and geographically structured, whereas Plasmodium was less host specific and geographically unstructured.

Livestock production is a major sector of the Ugandan economy. Ugandan ruminant livestock (principally cattle and goats) are susceptible to hemoparasites that can cause serious clinical disease and production losses. Kibale National Park, in western Uganda, is a protected forest ecosystem surrounded by small-scale farms where cattle and goats are raised. We conducted a cross-sectional study of cattle and goats in this area and diagnosed hemoparasite infections by microscopy. We collected data on animal characteristics and management practices to assess risk factors associated with infection. We studied 186 cattle and 317 goats from 20 villages, including 16 villages directly adjacent to Kibale and 4 villages ≥3 km from the park boundary. Hemoparasites detected in cattle and goats were of the genera Theileria, Anaplasma, and Trypanosoma with a prevalence of 15.1%, 1.6%, and 4.3% respectively in cattle, and 10%, 6.0%, and 0.0%, respectively in goats. Trypanosomes infected approximately 8% of cattle in villages bordering Kibale but were never detected in cattle in “control” villages ≥3 km from the park. Trypanosomes were approximately 7 times more likely to infect animals in households that did not provide veterinary care to their animals than in households that provided routine veterinary care. Within cattle, Theileria infections were approximately 7 times more likely to occur in cross-bred cattle than in indigenous pure breeds. Anaplasma infections were approximately 3.5 times more likely to occur in cattle than in goats (no goats were diagnosed with Trypanosoma infection). These data suggest that proximity to the park, provision of veterinary care, and breed are significant risk factors for hemoparasites in this population of ruminants, and that, in general, cattle are more susceptible than goats.

In the blood fluke family Schistosomatidae, marine snails are well known as intermediate hosts. Eight families of marine snails have thus far been reported to host schistosomes across the world, most of which have been implicated in human cercarial dermatitis (HCD) outbreaks. As part of our larger effort to define the species diversity and biology of schistosomes in Argentina, in particular their role in causing HCD, we searched in the marine pulmonate snail (Siphonaria lessoni) for a schistosome species described previously from S. lessoni from southern Argentina. Additionally, gulls (Larus dominicanus) collected from a different project locality (inland) were examined, because they are known to spend time in the intertidal regions. Schistosome sporocysts were found in S. lessoni, and a small worm fragment was retrieved from a gull. Molecular phylogenies for 28S, ITS1-5.8S-ITS2, and cox1 genes revealed that the specimens from the gull and S. lessoni grouped closely together, suggesting they are conspecifics. Also, ITS1-5.8S-ITS2 sequences suggested one of the schistosomes from S. lessoni and a schistosome from a South African penguin were also conspecifics. Further study is needed to verify if these specimens comprise a distinct marine clade within the larger avian schistosome clade that is comprised mostly of species using freshwater snail hosts. Thus far, it appears this group of marine schistosomes may be more likely found in the southern hemisphere. It is unclear if the observed distribution pattern of schistosomes in Siphonaria is a result of sampling bias and/or indicative of a specific bird–snail–schistosome association. It is clear they are sharply differentiated from the basal marine clade of avian schistosomes that includes Austrobilharzia.

Cichlidocestus n. gen. is proposed to accommodate 2 new species of proteocephalidean cestodes, Cichlidocestus gillesi n. sp. from Cichlasoma amazonarum in Peru (type species) and Cichlidocestus janikae n. sp. from Hypsophrys nicaraguensis (all Perciformes: Cichlidae) in Costa Rica. The new genus is unique among all but 1 proteocephalidean genera in the position of the ovary that occupies the middle and posterior thirds of the median region of proglottids (vs. the ovary in the posterior third of proglottids near their posterior margin in all but 1 remaining taxa). In addition, Cichlidocestus is typified by the presence of a voluminous, spherical, internal seminal vesicle, several pairs of ventral excretory canals in the medulla, a pyramidal, quadrilobed scolex with an apical muscular sucker, and the posterior extent of the testes that may reach almost to the posterior margin of proglottids. The new genus shares the position of the ovary and its extension with Sciadocephalus (also a parasite of cichlids in the Neotropics as the new taxon); in all remaining proteocephalideans the ovary occupies the posterior third only. Sciadocephalus differs from Cichlidocestus by a different morphology of the scolex, which possesses an umbrella-like metascolex that is markedly wider than the strobila, the number of ventral osmoregulatory canals, and development of the uterus, which forms capsule-like formations filled with eggs in Sciadocephalus megalodiscus (vs. simple lateral diverticula in Cichlidocestus spp.). Both new species of Cichlidocestus can be easily distinguished from one another by the anterior extent of the poral vitelline follicles (anterior to the cirrus-sac, i.e., preporal, in C. gillesi vs. posterior, i.e., only postporal in C. janikae), size of the eggs (diameter of the external layer of the embryophore of C. gillesi 30–33 μm vs. 44–46 μm in C. janikae), and the number of uterine lateral diverticula (16–21 on 1 side in C. gillesi vs. only 8–12 in C. janikae) and the testes (37–46 in C. gillesi vs. 63–74 in C. janikae). Based on a phylogenetic analysis of the 28S rRNA gene (lsrDNA) sequences, C. gillesi forms a lineage sister to S. megalodiscus, thus supporting the morphological similarity of both genera that occur in fishes of the same family in the same zoogeographical region.

Two new species of Microsporidia were recognized in skeletal muscle of freshwater fishes from Finland. Myosporidium spraguei n. sp. from pike-perch Sander lucioperca occurred as mature spores within sporophorous vesicles (SPVs) within a xenoma. The ovoid spores were 3.8 μm long and 2.4 μm wide, based on transmission electron micrographs (TEM). The exospore and endospore were equally thick, the nucleus was monokaryotic and the polar filament was isofilar with 12 coils in a single rank, entirely adjacent to the prominent posterior vacuole. Small subunit (SSU) rDNA sequence confirmed the presence of M. spraguei n. sp. in burbot Lota lota. The second species, Microsporidium luciopercae n. sp., also from pike-perch, occurred within SPVs that occupied only a fraction of the volume of the otherwise intact myocyte; no xenoma was produced. Myocyte degeneration and necrosis occurred as mature spores dispersed into direct contact with the sarcoplasm. The ovoid spores were 4.6 μm long and 2.8 μm wide (based on TEM); they were monokaryotic and the polar filament was isofilar with 25 coils in a single rank in the posterior of the spore. The exospore was relatively thin with an irregular profile. Neither infection elicited an inflammatory response, although degenerate spores were observed within host cells, suggesting phagocytosis. Phylogenetic analysis of SSU sequences placed both organisms on distinct clades within the Marinosporidia.

Between September and November 1991, 54 adult skinks from 15 species were collected by hand or blowpipe from several localities on Rarotonga, Cook Islands, Ovalau Island, Fiji, and Papua New Guinea (PNG), and their feces were examined for coccidians. Species included 5 seaside skinks (Emoia atrocostata), 1 Pacific blue-tailed skink (Emoia caeroleocauda), 2 Fiji slender treeskinks (Emoia concolor), 15 white-bellied copper-striped skinks (Emoia cyanura), 1 Bulolo River forest skink (Emoia guttata), 6 dark-bellied copper-striped skinks (Emoia impar), 5 Papua five-striped skinks (Emoia jakati), 2 Papua slender treeskinks (Emoia kordoana), 3 Papua robust treeskinks (Emoia longicauda), 1 brown-backed forest skink (Emoia loveridgei), 3 Papua black-sided skinks (Emoia pallidiceps), 2 Papua white-spotted skinks (Emoia physicae), 2 Papua yellow-head skinks (Emoia popei), 1 Papua brown forest skink (Emoia submetallica), and 5 Fiji barred treeskinks (Emoia trossula) Species of Eimeria (Ei.) were detected from these Emoia (Em.) spp. and are described here as new. Oocysts of Eimeria iovai n. sp. from Em. pallidiceps from PNG were ellipsoidal with a bilayered wall (L × W) 26.5 × 18.1 μm, with a length/width ratio (L/W) of 1.1. Both micropyle and oocyst residuum were absent, but a fragmented polar granule was present. This eimerian also was found in Em. atrocostata from PNG. Oocysts of Eimeria kirkpatricki n. sp. from Em. atrocostata from PNG were ellipsoidal with a bilayered wall, 18.6 × 13.5 μm, L/W 1.4. A micropyle and oocyst residuum were absent, but a fragmented polar granule was present. This eimerian was also shared by Em. cyanura from the Cook Islands and Fiji, Em. impar from the Cook Islands, Em. loveridgei from PNG, Em. pallidiceps from PNG, Em. popei from PNG, and Em. submetallica from PNG. Oocysts of Eimeria stevejayuptoni n. sp. from Em. longicauda were subspheroidal to ellipsoidal with a bilayered wall, 18.7 × 16.6 μm, L/W 1.1. A micropyle and oocyst residuum were absent, but a fragmented polar granule was present. Oocysts of Eimeria emoia n. sp. from Em. longicauda from PNG were cylindroidal with a bilayered wall, 29.2 × 15.7 μm, L/W 1.9. A micropyle and oocyst residuum were absent, but a polar granule was present. These are the first eimerians reported from Emoia spp. and they add to our growing knowledge of the coccidian fauna of scincid lizards of the South Pacific.

Toxoplasma gondii is an obligate intracellular protozoan parasite and is able to infect birds and mammals including humans. In order to find effective antigen-adjuvant combinations that can boost the immunogenicity and protection of antigen vaccines against toxoplasmosis, we examined the protective efficacy in mice immunized with recombinant protein HSP70 when co-administered with ginseng stem-and-leaf saponins (GSLS) isolated from Panax ginseng. All immunized mice produced significantly high levels of specific antibodies against rTgHSP70, and splenocytes from mice presented strong proliferative immune responses. Vaccinated mice displayed a significantly increased percentage of CD4 and CD8 T cells, indicating a strong immune response was triggered. The cellular and humoral immune responses were enhanced, which could be reflected of the increased mRNA levels of IFN-γ and IL-4, respectively. Immunization with rTgHSP70 and GSLS prolonged survival time of the treated mice compared to the controls, which died within 6 days after challenge with the virulent T. gondii RH strain. Our data demonstrate that by addition with GSLS, rTgHSP70 induced a strong immune response and provided partial protection against T. gondii; therefore GSLS could be used as a promising vaccine adjuvant against acute toxoplasmosis.

Perkinsus marinus is a protozoan parasite of molluscs that can be propagated in vitro in a defined culture medium, in the absence of host cells. We previously reported that P. marinus trophozoites can be transfected with high efficiency by electroporation using a plasmid based on MOE, a highly expressed gene, and proposed its potential use as a “pseudoparasite.” This is a novel gene expression platform for parasites of medical relevance for which the choice of the surrogate organism is based on phylogenetic affinity to the parasite of interest, while taking advantage of the whole engineered surrogate organism as a vaccination adjuvant. Here we improved the original transfection plasmid by incorporating a multicloning site, an enterokinase recognition sequence upstream of GFP, and a His-tag and demonstrate its potential suitability for the heterologous expression of Plasmodium sp. genes relevant to the development of anti-malarial vaccines. Plasmodium berghei HAP2 and MSP8, currently considered candidate genes for a malaria vaccine, were cloned into p[MOE]:GFP, and the constructs were used to transfect P. marinus trophozoites. Within 48 hr of transfection we observed fluorescent cells indicating that the P. berghei genes fused to GFP were expressed. The expression appeared to be transient for both P. berghei genes, as florescence of the transfectants diminished gradually over time. Although this heterologous expression system will require optimization for integration and constitutive expression of Plasmodium genes, our results represent attainment of proof for the “pseudoparasite” concept we previously proposed, as we show that the engineered P. marinus system has the potential to become a surrogate system suitable for expression of Plasmodium spp. genes of interest, which could eventually be used as a malaria vaccine delivery platform. The aim of the present study was to test the ability of marine protozoan parasite P. marinus to express genes of P. berghei.

The filarial nematode Setaria bidentata was found in 10 of 31 fetuses of the red brocket deer (Mazama americana) from the Loreto region of the Peruvian Amazon. A total of 25 specimens were collected and morphologically identified as S. bidentata. Filarial nematodes were found in the peritoneal cavity of 9 deer fetuses and the thoracic cavity of 1 fetus. Most specimens were adult stage. In this report, we provide morphometric data for these filarial specimens. This is the first study to demonstrate prenatal S. bidentata infection in cervid fetuses. Also, the finding of S. bidentata in Peru expands the geographic range of this parasite.

As a part of an ongoing project to inventory the helminth parasites of rodents in Mexico, 85 specimens of 2 families of rodents were collected from the Mexican Plateau: Cricetidae (Neotoma sp., Neotoma leucodon, Onychomys arenicola, Peromyscus sp., Peromyscus eremicus, and Reithrodontomys sp.) and Heteromyidae (Chaetodipus sp., Chaetodipus eremicus, Chaetodipus hispidus, Dipodomys merriami, Dipodomys ordii, Dipodomys ornatus, Dipodomys spectabilis, Liomys irroratus, Perognathus sp., and Perognathus flavus). A total of 13 taxa of helminths were found: Heteromyoxyuris longejector, Heteromyoxyuris otomii, Heteromyoxyuris sp., Onchocercidae gen. sp. 1 and sp. 2, Physalopteridae gen. sp., Protospirura dipodomis, Pterygodermatites dipodomis, Subulura sp., Syphacia sp., Trichuris dipodomis, Vexillata liomyos, and Vexillata armande. The highest species richness was recorded in D. merriami (7 taxa). This study is the first report of nematodes from O. arenicola (Physalopteridae gen. sp.) and C. eremicus (H. longejector) and for V. liomyos from D. merriami. All reports of these species of nematodes represent new collection localities in Mexico.

Metacercarial stages of digeneans were collected from decapod crustaceans inhabiting intertidal rocky zones in central Chile. The digeneans were identified through a molecular analysis based on the V4 region of the 18S ribosomal RNA gene. We analyzed 356 crustaceans belonging to 10 species, 115 intertidal fish belonging to 6 species, and 4 specimens of 1 coastal bird species. In total, 74.1% of crustaceans were parasitized with metacercariae. We found 1 species of Opecoelidae. This species showed low genetic divergence (0% and 0.1%) with adult digeneans found in intertidal fish and with the species Helicometrina labrisomi infesting a subtidal fish from northern Chile (Labrisomus philippii). Additionally, we found 2 species of Microphallidae, 1 closely related to Maritrema (1.3% genetic distance) and the other related to Microphallus (5% genetic distance). Therefore, our findings showed that the decapod crustaceans are relevant hosts in food webs from the southeastern Pacific coast. Furthermore, we found 5 species of crustaceans as second intermediate hosts for H. labrisomi and 2 species as secondary intermediate hosts for 2 Microphallidae, which contribute to elucidate parts of their life cycles through molecular markers and extended the host distribution of H. labrisomi in the southeastern Pacific coast.

The study of fossil parasites can provide insight into the antiquity of host–parasite relationships and the origins and evolution of these paleoparasites. Here, a coprolite (fossilized feces) from the 1.2-million-yr-old paleontological site of Haro River Quarry in northwestern Pakistan was analyzed for paleoparasites. Micromorphological thin sectioning and Fourier-transform infrared spectrometry (FTIR) analysis confirms the coprolite belonged to a bone-eating carnivore, likely the extinct giant short-faced hyena (Pachycrocuta brevirostris). Parasitological analysis shows the coprolite to be positive for Toxocara sp. To our knowledge, this is the earliest evidence for Toxocara sp. found.

Thirty-five adult waterfowl (14 males and 21 females) representing various orders and species were sampled during the hunting season from 2015 to 2016. Antibodies to Neospora caninum were detected by IFAT on blood samples, while heart and brain were subjected to molecular analysis for the detection of Neospora caninum DNA. Twelve birds (34.3%) (6 Anas crecca, 3 Anas platyrhynchos, 2 Anas penelope, 1 Anas acuta) showed antibodies versus N. caninum, while 10 animals out of 35 (4 A. crecca, 2 A. platyrhynchos, 2 A. penelope, 1 A. acuta, and 1 Vanellus vanellus) scored positive for at least 1 DNA sample, with an overall prevalence of 28.6%. The present report shows for the first time the occurrence of antibodies and N. caninum DNA in waterfowl. The avian species investigated in the present report, which feed directly from the soil and/or water, would be able to ingest oocysts excreted by final canid hosts and could contribute to parasite transmission in the sylvatic cycle. To achieve a definitive result about the role of these avian species in the epidemiology of this protozoan, the presence of viable parasites should be demonstrated by bioassay and/or culture, as well as histological evidence of N. caninum cysts in avian tissues.