Background: Inflammatory bowel disease is an autoimmune disease that affects the gut. T. spiralis larvae (E/S Ags) loaded on calcium-benzene-1,3,5-tricarboxylate metal-organic frameworks (Ca-BTC MOFs) were tested to determine whether they might prevent or cure acetic acid-induced murine colitis. Methods: T. spiralis larvae E/S Ags/Ca-BTC MOFs were used in prophylactic and therapeutic groups to either precede or follow the development of murine colitis. On the seventh day after colitis, mice were slaughtered. The effect of our target antigens on the progress of the colitis was evaluated using a variety of measures, including survival rate, disease activity index, colon weight/bodyweight, colon weight/length) ratios, and ratings for macroscopic and microscopic colon damage. The levels of inflammatory cytokines (interferon-γ and interleukin-4), oxidative stress marker malondialdehyde, and glutathione peroxidase in serum samples were evaluated. Foxp3 T-reg expression was carried out in colonic and splenic tissues. Results: T. spiralis larvae E/S Ags/Ca-BTC MOFs were the most effective in alleviating severe inflammation in murine colitis. The survival rate, disease activity index score, colon weight/length and colon weight/bodyweight ratios, and gross and microscopic colon damage scores have all considerably improved. A large decrease in proinflammatory cytokine (interferon-γ) and oxidative stress marker (malondialdehyde) expression and a significant increase in interleukin-4 and glutathione peroxidase expression were obtained. The expression of Foxp3+ Treg cells was elevated in colonic and splenic tissues. Conclusion: T. spiralis larvae E/S Ags/Ca-BTC MOFs had the highest anti-inflammatory, antioxidant, and cytoprotective capabilities against murine colitis and might be used to develop new preventative and treatment strategies.

Four species of the genus Longidorus were recovered from southern (Bushehr province) and southeastern (Southern Khorasan province) Iran. The first species, L. paratabrizicus n. sp. represents a new member to the genus and is characterised by 4.8–5.6 mm long females with anteriorly flattened lip region separated from the rest of the body by depression, amphidial fovea pocket-shaped without lobes, tail conical, dorsally convex, ventrally almost straight with bluntly rounded tip and males in population. By having similar lip region and tail shape, the new species most closely resembles five species viz. L. artemisiae, L. globulicauda, L. patuxentensis, L. sturhani, and L. tabrizicus. It represents the cryptic form of the last species. The second species belongs to L. mirus, recovered in both southern and southeastern Iran, representing the first record of the species after its original description. As an update to the characteristics of this species, it’s all juvenile developmental stages were recovered and described. The criteria to separate L. mirus from two closely related species, L. auratus and L. africanus, are discussed. The third species belongs to L. persicus, a new record in southern Iran. The fourth species, L. orientalis was recovered in high population density in association with date palm trees in Bushehr province. The phylogenetic relationships of the new species and recovered populations of L. mirus and L. persicus were reconstructed using two ribosomal markers and the resulted topologies were discussed.

Entomopathogenic nematodes (EPNs) are closely associated with Popillia japonica and potentially used as their biological control agents, although field results proved inconsistent and evoked a continual pursuit of native EPNs more adapted to the environment. Therefore, we surveyed the Azorean Archipelago to isolate new strains of Heterorhabditis bacteriophora and to evaluate their virulence against the model organism Galleria mellonella under laboratory conditions. Six strains were obtained from pasture and coastal environments and both nematode and symbiont bacteria were molecularly identified. The bioassays revealed that Az172, Az186, and Az171 presented high virulence across the determination of a lethal dose (LD50) and short exposure time experiments with a comparable performance to Az29. After 72 hours, these virulent strains presented a mean determination of a lethal dose of 11 infective juveniles cm-2, a lethal time (LT50) of 34 hours, and achieved 40% mortality after an initial exposure time of only 60 minutes. Az170 exhibited an intermediate performance, whereas Az179 and Az180 were classified as low virulent strains. However, both strains presented the highest reproductive potential with means of 1700 infective juveniles/mg of larvae. The bioassays of the native EPNs obtained revealed that these strains hold the potential to be used in biological control initiatives targeting P. japonica because of their high virulence and locally adapted to environmental conditions.

The Cyathocotylidae Mühling, 1898 is a family of primitive diplostomoid trematodes important for understanding the evolution of the superfamily Diplostomoidea. However, cyathocotylids remain poorly studied with the use of molecular techniques. In this study we sequenced the 5.8S + ITS2 region, 28S rRNA, and cox1 genes of two cyathocotylid species and obtained new morphological data on them. We propose Georduboisia nom. nov. instead of the preoccupied name Duboisia Szidat, 1936 (junior homonym of Duboisia Stremme, 1911). Adults of Georduboisia cf. teganuma (Ishii, 1935) and Paracoenogonimus ovatus Katsurada, 1914 were collected from fish-eating birds in the south of the European part of Russia. Georduboisia cf. teganuma was very similar to G. teganuma but differed from it in the shape of the testes. The 28S rRNA gene dataset provided the best-resolved phylogeny of the Cyathocotylidae to date. In the phylogram based on partial sequences of this gene, P. ovatus was close to members of Holostephanoides Dubois, 1983, Neogogatea Chandler & Rausch, 1947 and Gogatea Szidat, 1936. Georduboisia cf. teganuma clustered with members of Cyathocotyle Mühling, 1896 and Holostephanus Szidat, 1936. Phylogenetic analysis based on the 5.8S + ITS2 dataset showed that adults of P. ovatus examined in our study were conspecific with the metacercariae from the musculature of fish collected in Hungary and Italy. It also revealed probable misidentifications of larvae and adults of cyathocotylids whose sequences are deposited in GenBank NCBI.

This review summarises studies on distribution, diversity, and prevalence of gastrointestinal helminth infections in wild ruminants in sub-Saharan Africa. The results showed that 109 gastrointestinal tract (GIT) helminth species or species complexes were recorded in 10 sub-Saharan African countries. South Africa reported the highest number of species because most studies were carried out in this country. Eighty-eight nematode species or species complexes were recorded from 30 wild ruminant species across eight countries. The genus Trichostrongylus recorded the highest number of species and utilised the highest number of wild ruminant species, and along with Haemonchus spp., was the most widely distributed geographically. Fifteen trematode species or species complexes were reported from seven countries. The genus Paramphistomum recorded the highest number of species, and Calicophoron calicophoron was the most commonly occurring species in sub-Saharan African countries and infected the highest number of hosts. Six cestode species or species complexes from one family were documented from 14 wild hosts in seven countries. Moniezia spp. were the most commonly distributed in terms of host range and geographically. Impala were infected by the highest number of nematodes, whilst Nyala were infected by the highest number of trematode species. Greater kudu and Impala harbored the largest number of cestodes. The prevalence amongst the three GIT helminths taxa ranged between 1.4% and 100% for nematodes, 0.8% and 100% for trematodes, and 1.4% and 50% for cestodes. There is still limited information on the distribution and diversity of GIT helminths in wild ruminants in most sub-Saharan African countries.

A comparative analysis of taxonomic diversity on shrew cestodes among four islands in the Sea of Japan and the Sea of Okhotsk (Sakhalin, Kunashir, Hokkaido, and Moneron) was performed. Cestode species shared among the islands were identified and their host specificity was investigated. On Sakhalin Island, 33 species of the families Hymenolepididae, Dilepididae and Mesocestoididae were recorded in four shrew species (Sorex caecutiens, S. gracillimus, S. minutissimus and S. unguiculatus). In S. caecutiens, S. gracillimus, and S. unguiculatus on Kunashir Island, 22 species of the same families were found and, on Hokkaido Island, 23 species of the families Hymenolepididae and Dilepididae were recorded. On Moneron Island, three species of cestodes were registered in S. tundrensis. The Sakhalin–Hokkaido–Kunashir complex of shrew cestodes includes eastern-Palearctic, trans-Palearctic and endemic species. High endemism (~22%) of shrew tapeworms in the Sakhalin–Kunashir–Hokkaido Islands was noted as compared to continental territories. The different numbers of cestode species in S. unguiculatus (31), S. caecutiens (29), S. gracillimus (19) and S. minutissimus (1) were found. It was concluded that the cestodes species diversity of shrews of Sakhalin–Kunashir–Hokkaido depended primarily on the history of island formation, their modern physical and geographical features, the abundance of definitive and intermediate cestodes hosts and, to a lesser extent, on the size and remoteness of the islands from the mainland and the diversity of host species.

Relative to the numerous studies focused on mammalian schistosomes, fewer include avian schistosomatids particularly in the southern hemisphere. This is changing and current research emerging from the Neotropics shows a remarkable diversity of endemic taxa. To contribute to this effort, nine ducks (Spatula cyanoptera, S. versicolor, Netta peposaca), 12 swans (Cygnus melancoryphus) and 1,400 Physa spp. snails from Chile and Argentina were collected for adults and larval schistosomatids, respectively. Isolated schistosomatids were preserved for morphological and molecular analyses (28S and COI genes). Four different schistosomatid taxa were retrieved from birds: Trichobilharzia sp. in N. peposaca and S. cyanoptera that formed a clade; S. cyanoptera and S. versicolor hosted Trichobilharzia querquedulae; Cygnus melancoryphus hosted the nasal schistosomatid, Nasusbilharzia melancorhypha; and one visceral, Schistosomatidae gen. sp., which formed a clade with furcocercariae from Argentina and Chile from previous work. Of the physid snails, only one from Argentina had schistosomatid furcocercariae that based on molecular analyses grouped with T. querquedulae. This study represents the first description of adult schistosomatids from Chile as well as the elucidation of the life cycles of N. melancorhypha and T. querquedulae in Chile and Neotropics, respectively. Without well-preserved adults, the putative new genus Schistosomatidae gen. sp. could not be described, but its life cycle involves Chilina spp. and C. melancoryphus. Scanning electron microscopy of T. querquedulae revealed additional, undescribed morphological traits, highlighting its diagnostic importance. Authors stress the need for additional surveys of avian schistosomatids from the Neotropics to better understand their evolutionary history.

This article presents a checklist of metazoan parasites of snakes from Argentina, along with a comprehensive review of the relevant literature published between 1922 and June 2023, covering various aspects of interest. We compiled 34 species of metazoan endoparasites from 28 studies. The subclass Digenea showed the highest number of species (n = 22 species), followed by the phylum Nematoda (n = 8 species), and the subclass Pentastomida (n = 3 species and 1 taxa inquirenda). Dipsadidae was the family of snakes with the most species examined for metazoan endoparasites (n = 20 species). In contrast, Viperidae had the largest number of specimens surveyed (n = 343). Of 23 provinces, 15 (65.2%) presented at least one report of metazoan endoparasites in snakes. The northeastern provinces showed the highest richness of metazoan endoparasites and host diversity. Many articles focused on taxonomy, but studies on parasite ecology were not found. Although taxonomic accuracy was high in most reports, some records were correctly deposited in zoological collections or geo-referenced. This is the first attempt to include all groups of metazoan endoparasites of snakes from Argentina in a single checklist in the last century.

Chicken production has increased over the past decade, resulting in a concomitant rise in the demand for more humane options for poultry products including cage-free, free-range, and organic meat and eggs. These husbandry changes, however, have come hand-in-hand with increased prevalence of Ascaridia galli infection, which can cause clinical disease in chickens as well as the occasional appearance of worms in eggs. Additionally, development of anthelmintic resistance in closely related helminths of turkeys highlights the need for closely monitored anthelmintic treatment programs. Manual faecal egg counts (FECs) can be time-consuming and require specialist training. As such, this study sought to validate an automated FEC system for use in detection and quantification of A. galli eggs in chicken faeces. Automated counts using the Parasight System (PS) were compared to traditional manual McMaster counting for both precision and correlation between methods. Overall, ten repeated counts were performed on twenty individual samples for a total of 200 counts performed for each method. A strong, statistically significant correlation was found between methods (R2 = 0.7879, P < 0.0001), and PS counted more eggs and performed with statistically significant higher precision (P = 0.0391) than manual McMaster counting. This study suggests that PS is a good alternative method for performing A. galli FECs and provides a new tool for use in helminth treatment and control programs in chicken operations.

Three fish blood flukes (Aporocotylidae Odhner, 1912) infect mullets (Mugiliformes: Mugilidae): Cardicola mugilis Yamaguti, 1970 and Plethorchis acanthus Martin, 1975 infect striped mullet, Mugil cephalus Linnaeus, 1758 in the Central Pacific Ocean (Hawaiian Islands) and Brisbane River (Australia), respectively; Cardicola brasiliensis Knoff & Amato, 1992 infects Lebranche mullet, Mugil liza Valenciennes, 1836 from the Southwestern Atlantic Ocean (Brazil). White mullets were cast-netted from the mouth of Deer River, a coastal saltmarsh of Mobile Bay, in the north-central Gulf of Mexico and examined for blood fluke infections. Specimens of Mugilitrema labowskiae Warren & Bullard n. gen., n. sp. were found infecting the endocardial surface and inter-trabecular spaces of the atrium, ventricle, and bulbous arteriosus. The new genus and species differ from all other aporocotylids by having the combination of two post-caecal testes, a uterus with straight ascending and descending portions, and a common genital pore. The 28S analysis recovered the new species and P. acanthus as sister taxa and Aporocotylidae as monophyletic. Carditis associated with intense infections comprised endocardial hyperplasia, resulting in a thickened cardiac endothelium. Probable dead or deteriorating eggs in the myocardium were encapsulated by granulomas composed of epithelioid histiocytes. Live eggs infected the afferent artery of gill filaments and were associated with varied hyperplasia of the overlying epithelium and haemorrhaging from the afferent artery in high-intensity infections. The new species is the first aporocotylid infecting a mullet from the northwestern Atlantic Ocean and only the second description of demonstrable endocarditis attributed to an adult fish blood fluke infection.

Rhabdias are lung-dwelling parasites of anurans and some reptiles. Currently, 93 species are known to exist worldwide. The identification of Rhabdias species is based mainly on morphological traits of hermaphroditic females that generally have a very conserved morphology. However, different approaches, such as the combination of morphological, molecular, and ecological data, have provided advances in identifying and delimiting rhabdiasid species. Here, we describe a new species of Rhabdias from the south of Brazil, with morphological and molecular data. The new species is distinguished from its congeners by having an elongated body, evident cephalic dilation, larger buccal capsule, and large esophagus. In addition to morphological characteristics, we observed significant genetic divergence among the cytochrome oxidase subunit I (COI) sequence of the new species and the closest available sequence, Rhabdias fuelleborni (10.24%–10.87%). Furthermore, phylogenetic reconstructions based on the COI gene indicated that the new species represents a different lineage, constituting an outgroup of the species complexes Rhabdias cf. stenocephala and Rhabdias fuelleborni with Rhabdias sp. 4. Thus, Rhabdias megacephala is the 24th nominal species of the Neotropical region, the 14th Brazilian, and the fourth species described from south of Brazil.

Trematodes and their snail hosts have developed intimate parasite-host associations, with snails supporting a diverse and often species-specific trematode fauna. In the faucet snail, Bithynia tentaculata (Caenogastropoda, Littorinimorpha), a unique trematode fauna has been recorded recently. However, knowledge of the exact species identity, phylogenetic relationships, and geographical distribution remains limited as many of the species belong to groups with unclear or controversial taxonomical assignment. To contribute to our knowledge of the trematodes, we investigated the trematode fauna of B. tentaculata by examining a total of 556 snails from lakes in County Galway, Ireland. Using an integrative taxonomic approach including DNA sequence data analyses (28S rRNA gene, ITS1-5.8S-ITS2, ITS2, cox1, nad1) and morphological tools (taxonomical drawings and measurements), we identified nine trematode species of seven families, with seven species occurring as cercariae (Cyathocotyle prussica, Lecithodendrium linstowi, Lecithodendrium sp., Asymphylodora progenetica, Sphaerostoma bramae, Metorchis xanthosomus, and Notocotylus sp.) and three species occurring as metacercariae (A. progenetica, Parasymphylodora parasquamosa, and Sphaeridiotrema sp.). Except for S. bramae, all are new species records for Ireland and provide the most western distribution of these trematodes in Europe. The trematode species recorded are known to use a wide range of definitive hosts and have a wide geographical distribution; among them are species members of genera that are zoonotic (Metorchis) and pathogenic to wildlife (Cyathocotyle, Sphaeridiotrema, and Notocotylus). There remains an ongoing need for precise identification of the trematode species to ensure that wider ecological contexts are correctly understood and biodiversity and disease threats can be accurately evaluated.

Hybridization of parasitic species is an emerging health problem in the evolutionary profile of infectious disease, particularly within trematodes of the genus Schistosoma. Because the consequences of this hybridization are still relatively unknown, further studies are needed to clarify the epidemiology of the disease and the biology of hybrid schistosomes. In this article, we provide a detailed review of published results on schistosome hybrids of the haematobium group. Using a mapping approach, this review describes studies that have investigated hybridization in human (S. haematobium, S. guineensis, and S. intercalatum) and animal (S. bovis and S. curassoni) schistosome species in West Africa (Niger, Mali, Senegal, Côte d’Ivoire, Benin, Nigeria) and in Central Africa (Cameroon, Gabon, Democratic Republic of Congo), as well as their limitations linked to the underestimation of their distribution in Africa. This review provides information on studies that have highlighted hybrid species of the haematobium group and the regions where they have been found, notably in West and Central Africa.

Soluble Intercellular Adhesion Molecule-1 (sICAM-1) has emerged as an inflammatory biomarker of many essential functions. We investigated the level of sICAM-1 influenced by Clonorchis sinensis (C. sinensis) co-infection in chronic hepatitis B (CHB) patients to explore the degree of liver tissue inflammation and liver function damage after co-infection. The study included data from patients with C. sinensis mono-infection (n=27), hepatitis B virus (HBV) mono-infection (n=32), C. sinensis and HBV co-infection (n=24), post-hepatitis B liver cirrhosis (n=18), post-hepatitis B liver cirrhosis co-infected with C. sinensis (n=16), and healthy controls (n=39). The level of sICAM-1 was measured with specific enzyme-linked immunosorbent assay method. Compared to the healthy control group, all the experimental groups had significantly higher serum sICAM-1 levels. The levels of sICAM-1 in co-infected groups were significantly higher compared to the mono-infection groups and were positively correlated with the levels of glutamate aminotransferase (ALT) and aspartate aminotransferase (AST). Our research findings confirmed that co-infection could exacerbate liver tissue inflammation and liver function damage in patients, could raise the sICAM-1 level, and may lead to the chronicity of HBV infection. These results provide clues for pathological mechanism study and formulating treatment plans.

Two new species of the genus Allocreadium were isolated from the intestines of the Lake minnow Rhynchocypris percnura caught in the backwater of the Komissarovka River in the South of the Russian Far East. The morphology of A. anastasii n. sp. corresponds to that of Allocreadium sp. from Lake Khar (Mongolia) and Allocreadium sp. Belous, 1952 from the Primorsky region of Russia except for the preacetabular anterior border of the vitelline follicles in A. anastasii n. sp. from the Komissarovka River vs. at anterior half of ventral sucker in Allocreadium sp. Genetic analysis revealed the identity of A. anastasii n. sp. to Allocreadium sp. 1 from the Nezhinka River and Lake Khar. Allocreadium macrolecithum n. sp. was differentiated from Palaearctic Allocreadium spp. by having the following features: respectively large vitelline follicles extending from posterior extremity to anterior margin of the ventral sucker; relatively short caeca reaching the border of middle and posterior thirds of hindbody; and small testes in the middle of hindbody. Interspecific genetic p-distances between Allocreadium spp. were 0.16–7.23% in 28S gene and 18.62–31.54% in Cox1 mtDNA gene. In the phylogenetic tree reconstructed with Maximum parsimony and Bayesian Inference methods, A. anastasii n. sp. and A. macrolecithum n. sp. were nested into different species groups of the genus Allocreadium – sister to A. khankaiense and A. bursense, respectively. Modified dichotomous keys were prepared for 31 Palaearctic species of Allocreadium including A. crassum, A. dogieli, A. papilligerum, A. bursense, A. anastasii n. sp., and A. macrolecithum n. sp.

Species-level delineation of digenetic trematodes is complex and can be best achieved by integrative taxonomy using both genetic characterisation and morphological analysis. Two new Bucephalidae species of the genus Rhipidocotyle Diesing, 1858 are described here based on specimens collected from the intestine of Sphyraena putnamae Jordan & Seale following this approach. Adults of R. siphonyaka n. sp. and R. nolwe n. sp. possess tentacles and a tegument with scales. They are distinguished from their congeners by the arrangement of the digestive structures, the extent of the uterus relative to vitelline fields, and the arrangement of the reproductive structures. Rhipidocotyle siphonyaka n. sp. differs from R. nolwe n. sp. in having the pharynx and mouth positioned in the pre-uterine field, tandem testes, longer body length, and shorter pre-vitelline and post-testicular distance. Rhipidocotyle siphonyaka n. sp. differs from its congeners in having a tube-like intestinal caecum, pharynx and mouth opening positioned in the pre-vitelline field. Rhipidocotyle nolwe n. sp. appears to be similar, morphologically and morphometrically, to Rhipidocotyle khalili (Nagaty, 1937). Despite their similarities, R. nolwe n. sp. has a shorter body length and egg size. Moreover, the molecular analysis of 28S and ITS rDNA fragments indicate that R. siphonyaka n. sp. and R. nolwe n. sp. are closely related phylogenetically but distinct from one another and other Bucephalidae for which molecular data are available.

Members of the genus Maritrema Nicoll, 1907 include endoparasites of aquatic birds and mammals, distributed worldwide. Adult specimens were collected from the intestines of three bird species (the great black hawks, Buteogallus urubitinga Gmelin; laughing gull, Leucophaeus atricilla Linnaeus; and the willet, Tringa semipalmata Gmelin) in three localities along the Gulf of Mexico. Photogenophores were sequenced for the large subunit (LSU) from nuclear rDNA, and the new sequences were aligned with other microphalloid sequences available in GenBank. The maximum likelihood and Bayesian inference analyses revealed three independent lineages, one corresponding to a previously described species, Maritrema corai Hernández-Orts, Pinacho-Pinacho, García-Varela & Kostadinova, 2016, and two representing two undescribed species. These two new species are described in the current study. Maritrema itzamnai n. sp. can be morphologically differentiated from its four congeneric species occurring in coastal areas of Mexico by having smaller oral (20–29 × 20–38 μm) and ventral (20–39 × 19–33 μm) suckers. In addition, Maritrema itzamnai n. sp. possess annular vitellarium instead of a horseshoe-shaped vitellarium. Maritrema kukulkanni n. sp. can be distinguished from its congeneric species reported from Mexico by possessing a larger oesophagus (44–117μm) and by having a vitellarium distributed in both the hindbody and forebody. Maritrema corai is the third species recorded in this study parasitizing the great black hawk (Buteogallus urubitinga); this represents a new host and locality record, expanding its distribution range from the Mexican Pacific Ocean to the Gulf of Mexico.

We describe a new species of the genus Alippistrongylus (Nematoda: Trichostrongylina) in the small intestine of Delomys dorsalis (Rodentia: Sigmodontinae) found in Itatiaia National Park (Parque Nacional do Itatiaia, PNI), state of Rio de Janeiro, Brazil. The new species can be distinguished between the other two species previously described by the following morphological characteristics: pattern of the rays from the caudal bursa rays in males and the spherical-shaped appendage in the female. Additionally, we provide molecular genetic data from the new species. The discovery of Alippistrongylus itatiaiaensis sp. n. expands our understanding of nematode diversity and underscores the importance of parasite studies in biodiversity conservation. Its occurrence in a preserved area like the PNI emphasises the role of such habitats in maintaining unique ecological interactions.

Active components from plants are an alternative therapy to parasite control, addressing the widespread multidrug resistance populations. Linalyl acetate (LA), an ester abundantly found in plants of the genus Lavandula, was tested in vitro against third-stage larvae (L3) of Haemonchus spp. and Trichostrongylus spp. using the larval migration test at 0.89, 2.24, 4.47, 8.95, 17.9, 35.8, 71.6, and 143.2 mg/ml. After an initial incubation of 18 h, the total content of each tube was transferred to a 24-well plate that allowed active L3 to migrate through a nylon mesh (second incubation). Although LA exhibited 100% efficacy in reducing larval migration at 8.95 and 17.9 mg/ml, it showed reduced activity (5%) at 143.2 mg/ml. The data revealed a hormetic biphasic response characterised by an inverted U-shaped concentration-response curve. While hormesis has been previously documented in insecticidal and allelopathic contexts, this study reports the occurrence of hormesis induced by a phytochemical component against two species of nematodes for the first time. This distinctive stimulation-and-inhibition effect should be considered when selecting new compounds for preclinical testing.

Ascaridoidea (Nematoda) is a widespread superfamily of nematodes that comprises gastrointestinal parasites from all major groups of vertebrates. Although this taxon probably emerged in the Carboniferous, its Brazilian fossil record includes mostly eggs, found in ancient remains, collected in paleontological and archeological sites from the Mesozoic and Cenozoic Eras. The Tremembé Formation (Oligocene of the Taubaté Basin) has become an important source for paleoparasitological studies in avian coprolites during the third decade of the 21st century, with reports of eggs only at only a single cell stage, of embryonic development. Here we present the first egg of Ascaridoidea preserved containing morula, from a bird coprolite recovered from the shales of the Tremembé Formation. Three coprolites, from the outcrop of Aligra Comércio de Argila S/A, Taubaté municipality (State of São Paulo), were rehydrated and subjected to spontaneous sedimentation. Based on morphological and morphometric features and diet and zoopaleontological context, the trace fossils were assigned to piscivorous birds. The egg found showed morphological characteristics typical of Ascaridoidea: namely spherical form, ornamented, and somewhat thick shell. Moreover, this superfamily includes several taxa that infect piscivorous birds and fish in heteroxenous life cycles and produce eggs with similar features as the egg found in the present study. The paleoparasitological information associated with the paleofaunistic diversity of birds and fish from the Tremembé Formation, reveal that the ancient Brazilian paleoenvironments provided subsidies for the rise and success of nematodes infecting these animals during the Paleogene.