Neotropical Helminthology

Canine multicentric lymphoma-derived Trichuris vulpis hyperinfection.

David F. Conga — 2025-05-27

Trichuris vulpis (Roederer, 1761) is a geohelminth in the large intestine of wild carnivores, including domestic cats and occasionally humans. However, canine lymphoma, one of the most aggressive neoplasms in the small animal clinic, tends as a direct consequence of the loss of immunological response. Moreover, such parasite-related infections could develop into more serious conditions. In this study, we report a T. vulpis hyperinfection case in a canine affected by multicentric lymphoma. Physical examinations revealed lymphadenomegaly, haematochezia, and hind limb oedema. Despite the obtained treatment, the patient died. Macroscopic and microscopic examinations revealed congested lungs and legs, splenomegaly, lymphadenomegaly with leukocyte infiltration, and bloody large intestine mucosa with 528 adult T. vulpis specimens. Periodic coproparasitological examinations and specific antiparasitic drug applications are considered important, beyond preventive examinations for neoplasias, mainly in vulnerable patients such as older dogs.

Monogenean fauna (Platyhelminthes, Monogenea) of Trachelyopterus galeatus (Linnaeus, 1766) in a region of the Brazilian western amazon.

Carine Damaceno Bezerra — 2025-05-27

The present study evaluated the Monogenea fauna parasitizing Trachelyopterus galeatus Linnaeus, 1766 (Cangati) and investigated the influence of environmental and morphometric factors on the abundance of these parasites. Six species of monogeneans were identified, with Ameloblastella sp. and Cosmetocleithrum sp. being the most prevalent and having the highest mean intensity. Ameloblastella sp. stood out significantly compared to the other species, suggesting greater adaptive and competitive efficiency. It was observed that 46% of the fish harbored two species of Monogenea, while 10% harbored four or five species, indicating the coexistence of these parasites. Despite variations in host weight, length, and condition factor, these characteristics showed no significant relationship with the abundance of Monogenea, suggesting that individual body factors are not determinants of the infestation pattern. On the other hand, a strong influence of environmental variables such as chlorophyll content, water temperature, and dissolved oxygen was identified on the abundance of these parasites. Favorable environmental conditions, such as higher temperatures and eutrophication, appear to promote the proliferation of Monogenea by enhancing reproduction and facilitating contact between hosts. The findings of this research expand the understanding of parasitic ecology in the Amazon, highlighting the importance of monitoring environmental factors to predict and mitigate parasitic outbreaks in freshwater fish.

Parasites of The White Mullet, Mugil curema Valenciennes, 1836 (Mugiliformes: Mugilidae), From Santa Catarina State, Southern Brazil.

Rosiléia Marinho de Quadros — 2025-05-27

This study investigates the parasitic fauna of Mugil curema Valenciennes, 1836 (Mugilidae) from Laguna, southern Santa Catarina, Brazil, being the first parasitological survey of this species in the region. A total of 52 specimens were examined for ecto- and endoparasites. The external examination revealed Ergasilidae specimens and copepod eggs on the gills, while the monogenean Metamicrocotyla macracantha (Alexander, 1954) was identified. Internal prospection showed the presence of the acanthocephalan Neoechinorhynchus curemai Noronha, 1973 and one unidentified digenean from the family Haploporidae. Histopathological analysis revealed hepatic lesions and mild inflammation in intestinal tissue. These findings underscore the importance of parasites in M. curema, contributing to the ecological understanding of parasitism in marine fish and its potential implications for human health and environmental monitoring.

Paraspidodera Uncinata (Rudolphi, 1819) (Spirurida: Spidoderidae) parasitizing Ctenomys Eileenae (Rodentia: Ctenomyidae) in San Juan province, Argentina

Gabriel N. Castillo — 2025-05-06

Paraspidodera Travassos, 1914 is a genus of nematodes that parasitize rodents from the order Rodentia in South America. The objective of the present study is to document the first record of nematodes in the rodent Ctenomys eileenae Teta, Jayat, Alvarado-Larios, Ojeda, Cuello & D'Elía, 2023 in the province of San Juan, Argentina. For this, the gastrointestinal content of a female specimen of C. eileenae from the department of Iglesia was analyzed. Examination of the long intestine revealed the presence of Paraspidodera uncinata (Rudolphi, 1819) (Spirurida: Aspidoderidae). This study provides novel information on parasitism in rodents in Argentina, representing the first record of this nematode species in C. eileenae in the country and the first mention for the province of San Juan.

Parasitic prevalence in Canis Latrans (Say, 1823) (carnivora: Canidae) of the Samalayuca dunes flora and fauna protection area, Mexico: seasonal risks

José Petters — 2025-05-06

Coyotes are the most widely distributed mesocarnivores in North America, and can be found in natural, rural, peri-urban and urban areas, thanks to their ability to adapt. Like the rest of wild carnivores, it is capable of carrying pathogens that can be harmful to wild populations, domestic animals and even humans. The aim of this investigation was to determine parasite prevalence in coyote feces from the Flora and Fauna Protected Area Médanos de Samalayuca (APFFMS) and to evaluate the season of greatest risk of elimination of parasitic forms. Were collected 180 feces from coyotes, in the period from September 2018 to October 2019. Feces were analyzed using coproparasitoscopic techniques. In the results, Toxocarapresented a higher prevalence of 29%, followed by Ancylostoma 28%, Strongyloides 16%, Taenia 6%, Hymenolepis 5%, Physaloptera 3%, Toxascaris 2% and Echinococcus 1%, seven protozoan taxa, Balantidium 8%, Cystoisospora 7%, Cyclospora 6%, Sarcocystis 6%, Eimeria 3%, Chilomastix 1% and Entamoeba 1%. The cold season presented a 2.71 higher risk of finding parasitized feces than the rest of the seasons. Several of these parasites are zoonotic, so a high prevalence represents a risk to public health in areas of human activity, as well as a health hazard for the population of coyotes, the rest of wildlife and domestic animals.

First report of Capillaria Plica Rudolphi, 1819 (Nematoda: Enoplida: Capillariidae) infection in a Puma, Puma concolor Linnaeus, 1771 (Carnivora: Felidae) from southern Brazil

Rosiléia Marinho de Quadros — 2025-04-29

Capillaria plica Rudolphi, 1819, a parasitic nematode, infects the urinary tract of both domestic and wild carnivores. Despite its global presence, clinical reports are rare in certain regions, including Brazil. This study documents the first occurrence of C. plica in a Puma concolor Linnaeus, 1771 (Puma) from Santa Catarina, southern Brazil, marking the first report of this parasite in the southern part of the country. Necropsy and urinary sediment analysis revealed the presence of C. plica eggs and adult nematodes. The parasite's diagnosis is challenging due to its subclinical nature and the difficulty in visualizing eggs and adults, especially in wild felids. This case highlights the importance of urinalysis in wild carnivores for diagnosing urinary capillariasis and emphasizes the need for heightened awareness of this parasitic disease, particularly in under-researched regions.

Rangelia Vitalii (Carini, 1908) (Apicomplexa, Piroplasmorida) in domestic dog in southern Brazil: a case report

Alexsander Ferraz — 2025-05-20

Rangeliosis is an extravascular hemolytic disease caused by the piroplasm Rangelia vitalii. This protozoan is transmitted by ticks of the species Amblyomma aureolatum and infects erythrocytes, endothelial cells, and leukocytes, leading to a variety of clinical signs such as anemia, thrombocytopenia, splenomegaly, hepatomegaly, jaundice, and bleeding from the nose, oral cavity, and ear tips. This study aims to report a case of rangeliosis in a domestic dog in southern Brazil. A female, adult, mixed-breed dog from a rural area was admitted to a Veterinary Hospital. Clinical examination revealed necrosis of the ear tips with active bleeding and abdominal hematomas. After a few days, the patient also developed jaundice, hematuria, bilirubinuria, subconjunctival hemorrhage, and epistaxis. Hematological analysis indicated anemia and thrombocytopenia, while biochemical tests revealed elevated serum urea levels. The definitive diagnosis was confirmed through a stained blood smear, which revealed the presence of R. vitalii inside leukocytes and free in plasma. In addition to supportive treatment, doxycycline and imidocarb dipropionate were administered. However, due to disease progression, the patient ultimately succumbed. Canine rangeliosis is likely an underdiagnosed disease; therefore, it is crucial to consider it as a differential diagnosis in patients presenting compatible clinical manifestations and laboratory findings, particularly in those from rural or forested areas or with access to such environments.

Occurrence of the ectoparasitic mite of the genus Ornithonyssus Sambon, 1928 (Mesostigmata: Macronyssidae) as a potential vector of zoonotic diseases in sigmodontinal rodents (Cricetidae: Sigmodontinae) of the Andean region, Peru

Carla Yauris S. — 2025-03-14

Mites of the Macronyssidae family (Oudemans, 1936) are ectoparasites of reptiles, birds, and mammals, especially bats and rodents. Despite being a family of zoonotic and veterinary importance, their study has not been addressed in some areas of Peru. Therefore, this research focused on the search for mites of the Macronyssidae family in Ancash. Rodents were captured in three districts: Huari, Huachis, and San Marcos, in the department of Ancash, using Sherman traps. The ectoparasites were manually extracted with entomological forceps, collected in 70% ethyl alcohol, and transported to the laboratory. For taxonomic identification, adult female Macronyssidae mites were selected, rinsed with lactophenol, and mounted on Hoyer's medium. Identification was based on morphological characteristics according to specialized references. A total of 118 rodents were captured, distributed across seven species, with Akodon mollis Thomas, 1894, being the most abundant rodent (82.2%) of the entire sample. Ornithonyssus sp. were found primarily on A. mollis in Huari and San Marcos, and in lesser numbers on Microryzomys altissimus (Osgood, 1933) in Huachis. All mites collected were female, with two protonymphs present.

A new species of Rhinoxenoides (Dactylogyridae) parasitizing Triportheus Angulatus (Spix & Agassiz, 1829) (Characiformes) from the Juruá river basin, Brazil

Simone Chinicz Cohen — 2025-04-10

A new species of Rhinoxenoides was described parasitizing the gill filaments of neotropical triportheid fishes. The new species was described from Triportheus angulatus (Spix & Agassiz, 1829) from the Juruá River, State of Acre, Brazil. Rhinoxenoides cruzeirensis n. sp. resembles Rhinoxenoides horacioschneideri Santos Neto, Costa, Soares & Domingues, 2018, mainly by presenting a coiled male copulatory organ (MCO) with clockwise rings; accessory piece with articulation process extending within the coils to the base of MCO; dorsal anchor with well-developed superficial root, and dorsal bar absent. However, it differs from this by number of the coils of the MCO; accessory piece formed by a straight piece that expands in the middle, where it folds over itself; ventral bar short and robust; dorsal anchor with a well-developed superficial root twice as long as the deep root, with a small wing-shaped extension in the distal portion.

Nematodes infecting Phyllopezus Pollicaris (Spix, 1825) (reptilia: Phyllodactylidae) in the Palmares national forest, Piauí state, Brazil

Brenda Milena Bezerra Costa — 2025-03-31

Parasitological studies are important to understand the host-parasite interaction, providing information on the coevolution, biogeography, morphology, and diet of the species. The present study describes the endoparasite fauna of the lizard Phyllopezus pollicaris (Spix, 1825) in the Palmares National Forest, Piauí State, Brazil, a tropical forest covered by transitional vegetation between the Caatinga and Cerrado biomes. Furthermore, we investigated the influence of lizards’ size and sex on endoparasite infection patterns. We analyzed 23 individuals of P. pollicaris, of which 18 were infected by at least one helminth, belonging to the Nematoda phylum: Spauligodon oxkutzcabiensis,Strongyloides sp., and Parapharyngodon sp. Overall, S. oxkutzcabiensis showed the highest prevalence (73.9), mean infection intensity (8.64 ± 12.7), and mean abundance (6.39 ± 11.5). We observed that the lizard size was positively related to the abundance of endoparasites, while the sex of individuals had a poor effect on parasitological descriptors. This study contributes information about the endoparasite fauna associated with P. pollicaris, composed exclusively of nematodes. As a pioneering study, it can be considered the starting point for parasitological studies involving lizards in Piauí State, Northeastern Brazil.

Clinical/paraclinical findings in dogs with Leishmania Infantum (Ross, 1903) in transmission areas, Uruguay

Zully María Hernández-Russo — 2025-03-31

Canine visceral leishmaniasis (CVL), caused by Leishmania infantum (Ross, 1903), is an emerging disease in Uruguay, posing significant public and animal health challenges. This study aimed to evaluate the relationship between clinical signs and hematological, hepatic, and renal alterations in dogs seropositive for L. infantum in Uruguay. Canids were classified according to the absence/presence of clinical signs as asymptomatic (no apparent signs of disease), oligosymptomatic (less than three clinical signs compatible with CVL), polysymptomatic (three to six clinical signs) and hypersymptomatic (with more than six clinical signs). Laboratory analysis revealed significant alterations in hematological, hepatic, and renal parameters as the number of clinical signs increased. Polysymptomatic and hypersymptomatic dogs exhibited significant decreases in erythrocytes, hemoglobin, hematocrit, mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC), alongside increased segmented neutrophils and decreased lymphocytes. Hepatic function tests showed reductions in total and direct bilirubin, albumin, and the albumin/globulins ratio, while renal parameters such as urea and creatinine increased significantly with clinical severity. The multidimensional analysis highlighted distinct clusters of clinical signs and laboratory parameters that reflect the systemic effects of the disease. These findings highlight the progressive nature of CVL, characterized by worsening of erythropoiesis, hepatic dysfunction, and renal impairment. The study emphasizes the importance of early diagnosis and monitoring of clinical and laboratory parameters to manage this emerging disease effectively. The emergence of CVL in Uruguay calls for increased surveillance and control measures to mitigate its impact on both canine and human populations.

Endoparasites associated with anuran amphibians in a conservation area in the Sete Cidades National Park, Piauí State, Brazil

Jacilene de Sousa Uchôa — 2025-02-28

Inventories are the basis of studies, essential for determining which and how many species are part of an ecosystem and important for understanding the diversity and functioning of organisms. Studies on parasitic fauna are based on the importance of these organisms as disease-causing agents that can influence the biosecurity of ecosystems and natural environments. Thus, research that investigates the relationship between helminths and anurans provides information that helps in the conservation of these species and their habitats. The aim of this study is to describe the parasitic community associated with anuran amphibians in the Sete Cidades National Park (PNSC), an important conservation area in the north of the state of Piauí, Brazil. We analyzed 318 anuran amphibians, distributed among 21 species and four families. Of these, 142 individuals were parasitized by at least one species of endoparasite, giving an overall prevalence of 44.65%. A total of 8056 parasite specimens were counted and identified in 26 parasite taxa, with an average infection intensity of 56.73 and abundance of 25.33. Among the most abundant species found were Raillietnema spectans Gomes, 1964 (3034), Schrankiana schranki (Travassos, 1925) (2383), and Aplectana hylambatis (Baylis, 1927) (1540). In this study, we expanded the parasite fauna of anurans in the PNSC, which previously consisted of 13 parasite taxa in just four anuran species. Here, we recorded 21 additional parasite taxa, with new records of infection in 17 anuran host species. We also added 19 new parasite taxa to the existing records for the state of Piauí, significantly expanding our knowledge of the region.

Fecal examinations of dogs and cats rescued and adopted from the flood in Porto Alegre, Rio Grande do Sul, Brazil

Sandra Márcia Tietz Marques — 2025-02-28

The objective of this work is to report gastrointestinal parasitism in dogs and cats abandoned during the May 2024 flood, rescued and adopted in Porto Alegre, Rio Grande do Sul, Brazil. From June to October 2024, fecal samples from 93 pets (15 dogs and 78 cats) were analyzed using five parasitological techniques. Of the total number of pets (15 dogs and 78 cats), the frequencies of positive samples were 46.6% (7/15) and 43.6% (34/78), respectively, for dogs and cats. The parasites present in dogs were: Ancylostoma caninum (Ercolani 1859), Trichuris vulpis (Frolich 1789), Cystoisospora felis (Wenyon, 1923 Frenkel 1977) and Toxocara canis (Werner, 1782); in cats they were: T. canis, C. felis, Giardia sp., larvae of Aelurostrongylus abstrusus (Railliet, 1898) and Strongyloides sp., A. caninum, Dipylidium caninum (Linnaeus, 1758) and Dioctophyma renale (Goeze, 1782). These results demonstrate the importance of parasitological diagnosis based on the identification of parasites that can affect not only animal health, but also human health.

Description of Labiduris Argentinensis sp. Nov. (Nematoda: Cosmocercoidea: Atractidae) a new species of nematode in Chelonoidis Chilensis gray, 1870 (Testudines: Testudinidae) for Argentina

Cynthia J. González-Rivas — 2024-12-26

We describe a new species of Labiduris (Thapar, 1925) (Cosmocercoidea: Atractidae) collected from the long intestine of the land turtle Chelonoidis chilensis Gray 1870 in Argentina. Labiduris argentinensis sp. nov. differs from Labiduris gulosa (Rudolphi, 1819) (the only valid species of the genus), by the type and geographic distribution of the host, position of the excretory pore, body size and tail of the male and female nematodes. The new species has an excretory pore at the level of the middle widening of the esophagus, smaller body size, short and truncated tail, and is found in a terrestrial turtle with restricted distribution in Argentina. These characteristics of the new species are different from those of L. gulosa, which has an excretory pore in front of the bulb and a long, pointed tail and a larger body. The new species L. argentinensis sp. nov. represents the second valid species for the genus Labiduris.

Helminths of two species of Bachia, B. dorbignyi (Duméril & Bibron, 1839) and B. bresslaui (Amaral, 1935) (Sauria: Reptilia)

Vitoria Hellen Holanda — 2025-02-28

Bachia is a widespread genus of lizard, endemic to the Neotropical region. Despite this huge distribution, little is known about aspects of their ecology, such as diet and parasitism. Herein, we present data on helminth infection of two species of the genus, B. dorbignyi (Duméril & Bibron, 1839) and B. bresslaui (Amaral, 1935). Thirty-one specimens were analyzed, two helminths were found to B. dorbignyi, cystacanths of Centrorhynchus sp. and the nematode Oswaldocruzia sp. For B. bresslaui one helminth was found, the cestode Oochoristica sp. Our study provides the first record of parasites infecting B. dorbignyi and B. bresslaui.

Clinostomum marginatum infestation in Poecilia reticulata guppy collected in the Peruvian amazon and the identification of the species involved in its life cycle

Germán Augusto Murrieta Morey — 2025-02-28

Poecilia reticulata (Peters, 1859) popularly known as guppy, is a small fish commonly confined to the shallow edges of pools and streams and also found in heavily polluted water bodies. In natural and artificial environments, this fish species can be infected by a wide range of pathogens and parasites. In the present study, we reported for the first time in the Peruvian Amazon, the infestation of metacercariae of Clinostomum marginatum (Rudolphi, 1819) in the body of specimens of P. reticulata. Between May and June 2024, fifty specimens of P. reticulata were collected from an urban stream in the city of Iquitos, Loreto-Peru. Samples were taken to the “Laboratorio de Parasitología y Sanidad Acuícola” from “Instituto de Investigaciones de la Amazonía Peruana” (IIAP) in Loreto, Peru. Metacercariae of C. marginatum were observed embedded in the muscle tissue of 100% of sampled guppies. The freshwater snail Pomacea maculata (Perry, 1810) was captured in the same stream of guppies, acting as the first intermediate host. Poecilia reticulata acts as the second intermediate host, while the striated heron Butorides striata (Linnaeus, 1758) was observed as the definitive host where the adult parasites feed and reproduce. This is the first record of C. marginatum parasitizing P. reticulata from the Peruvian Amazon.

First register of Contracaecum sp. And Eustrongylides sp. (Nematoda) in kinosternon scorpioides (Linnaeus, 1766) (Testudines: Kinosternidae) from northeastern, Brazil

Alana Lislea de Sousa — 2024-12-26

Kinosternon scorpioides (Linnaeus, 1766) popularly known in Brazil as “Jurará” is a species of chelon that serves as a food resource and source of income for some families in Northeastern Brazil. In that sense, the present study aimed to analyze the metazoan endoparasites infecting K. scorpioides from the Baixada Maranhense, Brazil. Fifteen adult specimens were captured using funnel traps in flooded fields around the Aurá River, close to the city of São Bento-Maranhão. Samples were transported to the Postgraduate Multi-User Research Laboratory- Laboratories in Postgraduate Research/Postgraduate in Animal Science located at the State University of Maranhão- UEMA for parasitological analyses. The results revealed the presence of larvae of Contracaecum sp. infecting the stomach, intestine, and liver, while Eustrongylides sp. was found encysted in the musculature, stomach, intestine, and inside an egg of a gravid female mud turtle. The findings of the present study constitute the first records of these nematodes parasitizing K. scorpioides. Since K. scorpioides is consumed as food for some families in the State of Maranhão, Brazil, and the presence of both parasites with hygienic-sanitary importance, complementary studies should be designed to allow us to understand the relationship between host parasites and whether they could have zoonotic relevance.

New species of the genus Protylenchus Wachek, 1955 (Tylenchida, Allantonematidae) parasitizing Harmonia Axyridis (Pallas, 1773) (Coleoptera, Coccinellidae) in Argentina

Nora B. Camino — 2024-12-26

Protylenchus bonaerensis n. sp. (Tylenchida, Allantonematidae) was found in the Horticultural Belt of Gran La Plata, Argentina. This genus is reported for the first time in our country and a new species is described parasitizing adults of Harmonia axyridis (Pallas, 1773) (Coleoptera, Coccinellidae). This new species is mainly characterized by the males having a thin bursa, females with a non-protuberant vulva, and a short and thin caudal appendage in both sexes. In addition, the life cycle is described.

Intestinal parasitism and competency achievement in students of the Margarita Santa Ana de Benavides educational institution, Ica, Peru

Danne Douglas Donayre-García — 2024-10-12

The high incidence of intestinal parasites compromises health and academic performance in regions with inadequate sanitation. The objective of this study was to describe the relationship between intestinal parasitosis and the achievement of competencies among students at the Margarita Santa Ana de Benavides educational institution in Ica, Peru. This quantitative, basic, non-experimental study employed a correlational design to evaluate 80 conveniently selected secondary school students. Three fecal samples were collected per student, and a questionnaire was administered to measure communication competencies. The statistical analysis included the Kolmogorov-Smirnov test for normality and Chi-square (X²) analysis to assess the relationship between parasitosis and competencies. Of the 80 students evaluated, 27 (33.8%) exhibited parasitosis, while 53 (66.2%) did not. Regarding communication competencies, 5% of the parasitized students achieved them compared to 25% of the non-parasitized students. The analysis revealed a significant relationship between parasitosis and competency achievement, indicating that parasitosis negatively affects academic performance in communication. These results underscore the necessity of implementing public health interventions in vulnerable school contexts to improve both the physical well-being and academic performance of affected students.

A new geographic distribution and morphologic revision of Mastophorus muris (Nematoda: Spirurida), a parasite of the stomach of Rattus norvegicus in Rio de Janeiro, Brazil

Ana Júlia Rapozo Dias — 2024-10-11

This study provides a comprehensive morphological redescription of Mastophorus muris Gmelin, 1790, a spirurid nematode, based on specimens collected from Rattus norvegicus Berkenhout, 1769 in Nova Iguaçu municipality, Rio de Janeiro, Brazil. Employing optical and scanning electron microscopy, we detailed morphological characteristics, including previously unreported features such as a pair of ad-cloacal papillae and details of pseudolabia teeth. Additionally, we report a new geographical distribution for M. muris in Brazil. The low prevalence of M. muris observed in this study highlights the potential impact of anthropic changes on parasite distribution. Further investigations, including molecular analyses, are necessary to elucidate the taxonomic complexity and host-parasite relationships within the genus Mastophorus

Denarycotyle bajacaliforniensis (Monogenea: Monocotylidae) of Rhinoptera steindachneri (Rhinopteridae) from Puerto Viejo, Baja California Sur, México

María del Carmen Gómez del Prado-Rosas — 2024-10-11

Rhinoptera steindachneri Evermann & Jenkins, 1891 is a myliobatid elasmobranch distributed in the Pacific Ocean, from Baja California, including the Gulf of California, to Peru and it has been subject of parasitological studies in several states of Mexico. In the present work, a new species of monogenenean monocotylid, obtained from the gills of R. steindachneri collected from Puerto Viejo, Baja California Sur (BCS), is described. Their morphological characteristics are very similar to those described for Denarycotyle gardneri Pulido-Flores, Monks and Violante-González, 2015; however, the new species is distinguished from it by the following characteristics: hooks of the posterior medial septa lack sclerosed accessory piece, in the anterior region there is a sucker-like muscular structure in the center of which the mouth is located, no lateral glands to the pharynx are observed, the ejaculatory bulb is different in shape (it is ovoid and in some specimens it looks like a muscular barrel with longitudinal muscle fibers), the terminal region of the male reproductive system is surrounded by a glandular mass that occupies the entire intercecal space, and the wall of the ootype is muscular and glandular tissue is observed inside. Puerto Viejo constitutes a new record of the geographical range for the Denarycotyle species. A modification is proposed in the diagnosis of the genus introducing the characters “hamuli with or without accessory piece. With or without glands lateral to the pharynx. Seminal vesicle and ejaculatory bulb with or without glandular tissue occupying the intercecal space. Ootype with or without glandular tissue inside”.

Helminths infecting the Bom Jardim toad Rhinella dapsilis from an Atlantic forest enclave at northeastern Brazil

Vitoria Hellen Holanda — 2024-12-16

Rhinella dapsilis (Myers and Carvalho, 1945) is widespread in Amazonia, from Colombia to Brazil. Despite its huge distribution, information on basic biological aspects is scarce, even more regarding helminths parasites. Herein, we present data on helminth infecting R. dapsilis from an Atlantic Forest enclave from Northeastern Brazil. Ten taxa were found, being nine nematodes and one acanthocephalan, Cosmocercidae and Rhabdias sp. was the most prevalent taxa. We reported six new host records and expanded the knowledge about parasitism in Neotropical anurans.

Predatory behavior of gambusia punctata (Poey, 1854) on Aedes aegypti (Linnaeus, 1762) larvae based on visual detection in a controlled experimental system

George Argota Pérez — 2024-09-18

The objective was to evaluate the predatory behavior of Gambusia punctata (Poey, 1854) on Aedes aegypti (Linnaeus, 1762) larvae given its visual detection in a controlled experimental system. Two males and eight females of G. punctata were placed in a plastic container with submerged aquatic plants in the first third of the container. For the first three days, 30 A. aegypti larvae were supplied daily. A device was designed to distribute the mosquito larvae uniformly across the container's surface. A vertical plastic sheet was introduced in the second third of the container, restricting the fish to the first third. Four millimeter mesh cylinders were placed near the vegetation, designed to confine two larvae within each cylinder. Predatory response was assessed based on detection time and near-total permanence of the fish close to the cylinders. The experiment was replicated twice. Detection times were similar between replicates (6.01±0.21 s and 6.04±0.18 s), but replicate 1 showed greater variability and lower precision compared to replicate 2, which demonstrated higher consistency. No statistically significant differences were found. It was concluded that G. punctata effectively detects A. aegypti larvae when visible, but detection decreases when larvae are hidden, suggesting the use of other senses. The variability in detection times highlights the influence of experimental factors.

Zoonotic foci of Toxocara sp.: comparison of two tourist regions in the state of Sucre, Venezuela

Erika Gomez-Martinez — 2024-12-16

Toxocariasis is a human infection caused by the larvae of the nematodes Toxocara canis (Werner, 1782) or Toxocara cati (Schrank, 1788), which are parasitic in animals, and represents a serious public health problem. The objective of this study was to investigate the information and prevalence of parasitic toxocariasis in the state of Sucre, Venezuela, particularly in the municipalities of Montes and Sucre, in communities considered vulnerable due to social and economic deficiencies within the epidemiological/sanitary monitoring. In these municipalities, there are many stray dogs living near homes and maintaining contact with other domestic dogs. The seroprevalence of T. canis was evaluated through the ELISA method. A seroprevalence of IgG anti-T. canis was obtained in the parish of San Juan of 90.12% and in the parish of Cumanacoa of 82.14%. In the parish of San Juan, when evaluating the prevalence of parasites by species, T. canis was present in 18.37% of the feces of the canines evaluated. On the other hand, in the parish of Cumanacoa, T. canis was present in 9.90% of the canine samples analyzed; similarly, the presence of Toxocara sp. in soils in both parishes. In summary, the determination of two zoonotic foci of Toxocara sp. in the state of Sucre, Venezuela, since all the factors necessary for the transmission of toxocariasis are present.

Synthesium pantoporiae and Synthesium tursionis (Digenea; Brachycladiidae Odhner, 1905) in Pontoporia blainvillei Gervais & d’Orbigny, 1844 (Cetacea, Pontoporiidae) in south of the state of Santa Catarina, Brazil

Rosiléia Marinho de Quadros — 2024-10-11

Parasitic susceptibility can occur indidually or in populations due to several factors, such as: parasite species, abundance, host health status (age, nutritional status) and competition between diferente types of parasites. This study reports the presence of Synthesium pontoporiae Raga, Aznar, Balbuena & Dailey, 1994 and Synthesium tursionis (Marchi, 1873) in Pontoporia blainvillei Gervais & D’Orbigny, 1844 found dead on the beaches of the mucipalities of Laguna, Imbituba and Garopaba, located on the southern coast of Santa Catarina, Brazil, between 2017 until 2020. A total of 144 specimens of trematodes were identified in 14 evaluated animals, with a prevalence of 35,71%, mean abundance of 10.28 and mean intensity of infection of 28.80. The average intestinal lenght was 8.96 meters, ranging from 1.90 to 29.10 meters. The occurence of parasites can be indicative of the relationship between feeding habits and the dispersion of animals in the ocean and, in the case of the presence of the Synthesium trematode, this knowledge is fundamental in the research for more information about the evolutionary cycle of this parasite. In this study, although the beaches where the animals were found are geographically very close, there were significant diferences, mainly between the intensity and parasite abundance, which demonstrates the need for further studies to understand the relationship between the findings in this study with the diet and the presence of possible intermediate hosts of this parasite in these regions.