Folia Parasitologica最新文献

In total 949 specimens of Trachinotus rhodopus (Gill) were collected over a 11-year period (from June 2013 to February 2024) from Acapulco Bay, Mexico. Parasite communities in T. rhodopus were quantified and analysed to explore two hypotheses related to their parasite species richness and diversity associated with the bentho-demersal and pelagic habits, and effects of the climatic fluctuations. Thirty-two metazoan parasite taxa/species were identified: three species of 'Monogenea', 14 Digenea, one Aspidogastrea, one Acanthocephala, two Cestoda, three Nematoda and eight Crustacea. The digeneans and copepods were the best represented groups. The component parasite communities were characterised by the numerical dominance of the acanthocephalan Rhadinorhynchus sp. Species richness (15-24 species) was similar to that reported for other species of carangid fish, but the richness of the digeneans was significantly higher. The parasite communities of T. rhodopus exhibited high variability in species composition, suggesting that each species of parasite may respond differently to environmental changes. However, the species richness and diversity were fairly stable over time. Climatic events of La Niña and El Niño probably generated notable changes in the structure of local food webs, thus indirectly influencing the transmission rates of several endoparasite species.

Chagas disease, caused by the kinetoplastid Trypanosoma cruzi (Chagas, 1909), and transmitted by triatomine bugs, poses a significant public health challenge. Variability in the susceptibility of different triatomine species to T. cruzi infection can profoundly influence disease transmission dynamics and control measures. In this study, we assessed the susceptibility to T. cruzi infection in the first and third nymphal stages across eight triatomine species to T. cruzi infection using experimental inoculation with the NINOA strain and optical microscopy. The evaluated species were Dipetalogaster maximus (Uhler), Triatoma bassolsae (Alejandre-Aguilar, Nogueda-Torres, Cortéz-Jiménez, Jurberg, Galvão, Carcaballo), T. infestans (Klug), T. lecticularia (Stål), T. mexicana (Herrich-Schaeffer), T. pallidipennis (Stål), T. phyllosoma (Burmeister) and T. picturata (Usinger). The results indicated that T. bassolsae exhibited the highest susceptibility to infection, followed by T. pallidipennis and D. maximus. Our analysis also revealed that T. cruzi (NINOA) infection was significantly associated with triatomine species rather than nymphal stage (p < 0.0001), with substantial variability observed in susceptibility among species (p < 0.001). We ranked triatomine species susceptibility to T. cruzi infection as follows: T. bassolsae > D. maximus = T. pallidipennis = T. picturata = T. mexicana > T. phyllosoma = T. lecticularia = T. infestans. These findings enhance our understanding of T. cruzi transmission dynamics and offer valuable insights for the development of effective control strategies against this neglected tropical disease.

Blood-sucking arthropods belonging to the order Diptera, encompassing mosquitoes, sandflies, midges, blackflies, horseflies and tsetseflies serve as vectors for a myriad of pathogens, inflicting substantial harm on both human and animal health globally. The analysis and visualisation of global hotspots and trends pertaining to vector-borne diseases, stemming from these six categories of arthropods, constituted a reliable reference for further delving into the research on Diptera insect vectors. To achieve this, we mined literature information from the Web of Science Core Collection (WoSCC), encompassing all publications related to these six arthropod groups, and leveraged VOSviewer software for bibliometric analysis and visualisation. This resulted in the construction of comprehensive relationship networks encompassing keywords, countries, institutions and authors. A comprehensive analysis encompassed 41,393 research publications, segmented into 34,363 studies on mosquitoes, 1,668 on sandflies, 3,665 on midges, 241 on blackflies, 336 on horseflies and 1,120 on tsetseflies. The bibliometric analysis, coupled with visual characterisation, offered a multifaceted synthesis of the gathered data from diverse angles. The scientometric analysis quantitatively assessed and identified the contributions of keywords, countries, institutions and authors pertaining to the research of each vector. The resulting visualisation knowledge maps elucidate collaborative network relationships within the respective vector research domains. This research endeavour stems from numerous driving forces, and a comprehensive grasp of its future trajectories and research hotspots can empower scientists with historical perspectives and forward-looking insights, fostering the formulation of innovative and impactful research ideas for the years ahead.

The first data on the neurochemical and ultrastructural organisation of the nervous system of the fish blood fluke, suckerless adult Sanguinicola plehnae Warren et Bullard in Warren, Poddubnaya, Zhokhov, Reyda, Choudhury et Bullard, 2023 (Digenea: Aporocotylidae) from the circulatory system of pike, Esox lucius Linnaeus are presented. Based on 5-HT-IP staining, the simple, uniformly developed orthogonal pattern of S. plehnae nervous system is revealed. The ventral and dorsal nerve cords originate from the brain lobes, but the lateral nerve cords originate from anterior nerves at the level of the large serotonergic neurons. In addition, several pairs of such large 5-HT-IP neurons (22-23.5 µm in diameter) are revealed along the ventral nerve cords. Unusual spindle-shaped 5-HT-IP perikarya (7.8-19.8 µm in diameter) are observed along each ventral and lateral nerve cords. The neuroblasts and developing neurons are seen between neurites in S. plehnae along with neuron somata scattered around neuropil periphery, evidencing the renewal of neuron somata population in adult digeneans. The morphological variability of both the orthogonal pattern and neuron somata and types of neurovesicles in adult digeneans are discussed.

Cercariae are motile infectious larval stages of digenetic trematodes that emerge from their molluscan first intermediate host to seek the next host in their life cycle. A crucial transmission strategy of trematodes involves releasing the maximum number of cercariae at times that coincide with the presence and activity of the next hosts, thereby increasing the likelihood of successful infection and continuation of the parasite's life cycle. We investigated the cercarial emergence of two furcocercous (with forked tail) trematodes Tylodelphys clavata (von Nordmann, 1832) and unidentified species of Sanguinicola Plehn, 1905 from naturally infected Ampullaceana balthica (Linnaeus) and Radix auricularia (Linnaeus) snails under natural light and constant temperature conditions. Both trematodes, which are important fish pathogens, showed distinct daily emergence rhythms influenced by light intensity, with emergence peaking at sunset and night for T. clavata and at night for Sanguinicola sp. The daily emergence rhythms of T. clavata cercariae were consistent in both summer and autumn, indicating adaptability to natural changes in seasonal photoperiods. The interspecific differences in emergence patterns are likely related to the behavioural patterns of upstream, i.e., next in the life cycle, fish hosts. Cercarial output also varied between trematode species and seasons, likely due to combined effects of snail size, intensity of trematode infection in snails and size of cercariae rather than seasonal temperatures. The trematodes were molecularly characterised using mitochondrial (cox1) and nuclear (28S rDNA and ITS1-5.8S-ITS2) regions to confirm their identity and facilitate future studies. This study highlights the importance of light-regulated and host-synchronised cercarial emergence rhythms for increased trematode transmission success and reveals significant variation in cercarial output influenced by environmental and biological factors, contributing to a deeper understanding of trematode ecology and disease management.

A new species of Acanthocephala is described based on specimens found parasitising the intestine of the gafftopsail pompano Trachinotus rhodopus Gill in the State of Oaxaca, off the Pacific coast of Mexico. Rhadinorhynchus villalobosi sp. n. differs from the other 25 species of the genus known from the Pacific Ocean by a combination of morphological traits, such as the fewer number of rows of hooks along the proboscis, the distribution of spines of the trunk forming two fields, the position of genital pore, subterminal in both sexes, a shorter neck and cement glands, among others. The phylogenetic analyses based on sequences of the nuclear 18S and 28S rRNA genes, as well as the mitochondrial cox1, all agree that R. villalobosi sp. n. is part of the genus, and closely related to Rhadinorhynchus trachinoti Grano-Maldonado, Sereno-Uribe, Hernández-Payán, Pérez-Ponce de León et García-Varela, 2025, a recently described Mexican species, despite the marked morphological differences between the two and being distributed in different areas.

The present study describes the morphology and phylogenetic position of two specimens of Bertiella Stiles et Hassall, 1902 (Cestoda, Anoplocephalidae) from Rattus tanezumi (Temminck) (Muridae) from Đồng Tháp Province in southern Vietnam. The phylogenetic analysis was based on sequences of the large subunit ribosomal RNA gene (28S). The specimens were described and shown to be morphologically similar to Bertiella anapolytica Baylis, 1934 from Rattus spp. from Indonesia (Sumatra, type locality) and Australia, except for a few quantitative differences. The identification was confirmed by the phylogenetic analysis, which showed a strong affinity and fairly limited genetic divergence between the specimens from Vietnam and Australia. This is the first verified case of Bertiella in murid rodents from continental Eurasia. The uterine pore and associated canal present in the posterolateral corners of gravid proglottids of B. anapolytica are considered to form a true, functional structure used for egg release prior to apolysis. The phylogenetic analysis suggested that B. anapolytica has diverged as a consequence of a shift from marsupials, which probably took place east of the Wallace's line, either in Wallacea or Australasia. The presence of B. anapolytica west of the Wallace's line (Vietnam, Sumatra), where marsupials are absent, may be explained by a westward dispersal in commensal rats, possibly Rattus exulans (Peale), a species transported throughout the Pacific and South-East Asia by prehistoric people.

Clinostomum complanatum (Rudolphi, 1814) is known as a food-borne zoonotic parasite using freshwater fish as intermediate host, although in its native distribution area in Europe, the Danube and Po basins and the northeast of Italy, no cases have been reported. This study reports a new geographic location outside the native distribution range of this parasite. We detected high infection levels of C. complanatum in wild perch (Perca fluviatilis Linnaeus) from the Doubs River in continental France. Clinostomum complanatum reached a prevalence of 97% and mean intensity of 5.8 cysts per fish in 33 fish examined, with most fish already infected by the age of two years. No correlations were observed between fish traits (standard length, weight, age and sex) and the number of parasites. The distribution of C. complanatum cysts in the fish body was not random. The tissue surrounding the opercula and branchial cavity, and muscles along the lateral line and near the pectoral, dorsal and caudal fins were the preferred sites of infection. Morphological identification was confirmed with molecular data. The French specimens shared identical mt cox1 haplotypes with specimens from Italy. The distribution of this exotic parasite in freshwaters in continental France deserves further research. Under the current French law, the parasite occurrence represents an economic loss for the local freshwater aquaculture industry, and a possible zoonotic risk for consumers if undetected, especially when raw or marinated fish is consumed. We provided a list of all reported hosts for C. complanatum from the western Palaearctic, discussed the knowledge gap regarding the zoonotic risk of C. complanatum in Europe, and highlighted the lack of policy that may increase the hazards posed by food-borne emerging parasites and their broader ecological impacts as alien species in freshwaters in Europe.

In this article, I recount the journey of discovering the effects of latent toxoplasmosis on human psychology, behaviour, morphology, and health as I observed it from the closest perspective over the past 30+ years, during which our laboratory has been intensely focused on this research. I trace how we moved from the initial observations of differences between infected and uninfected individuals in certain personality traits to the systematic study of similar differences in behaviour, both in the laboratory and in everyday life, as well as in physiological and even morphological traits. This eventually led us to investigate the causal relationships behind these observed associations and their molecular basis. I describe some of the unexpected discoveries our research revealed - whether it was the impact of toxoplasmosis on the human sexual index, the prenatal and postnatal development, the sexual preferences and behaviour, the modulatory effect of blood Rh factor on toxoplasmosis, or the discovery of sexual transmission of toxoplasmosis. In exploring whether the toxoplasmosis-associated effects were merely side effects of an ongoing latent infection, we gradually uncovered that seemingly asymptomatic toxoplasmosis has profound (and certainly not positive) effects on the mental and physical health of infected individuals. The article also includes three separate boxes that discuss some key methodological challenges we encountered along the way, such as how to distinguish the effect of infection from mere statistical association, or how to differentiate parasitic manipulation from a simple side effect.

We provide a supplemental description of the type species for Cryptogonimus Osborn, 1903 (Digenea: Cryptogonimidae), Cryptogonimus chili Osborn, 1903, based on newly-collected, heat-killed, formalin-fixed specimens infecting rock bass, Ambloplites rupestris (Rafinesque), and smallmouth bass, Micropterus dolomieu Lacepède (both Centrarchiformes: Centrarchidae), from the Duck River, Tennessee (USA). We emend Cryptogonimus to include features observed in the present specimens of its type species and in the descriptions of its congeners: a broad (wider than long) oral sucker, an intestine that bifurcates in the posterior half of the forebody, a bipartite seminal vesicle, a hermaphroditic duct that is dorsal to the ventral sucker, a preovarian seminal receptacle, and a Laurer's canal that opens dorsally at the level of the anterior testis. We describe Caecincola duttonae sp. n. (Cryptogonimidae) infecting largemouth bass, Micropterus salmoides (Lacepède), from Neely Henry Reservoir (Coosa River, Alabama, USA). The new species differs from its congeners by having a combination of a less elongate body, an intestine that bifurcates at the level of the ventral sucker, caeca that terminate at the level of the testes, diagonal testes in the middle of the hindbody, and a vitellarium predominantly distributed in the hindbody. We emend Caecincola Marshall et Gilbert, 1905 (type species Caecincola parvulus Marshall et Gilbert, 1905) to include features of the new species and recently-described congeners: an elongate body, an intestine that bifurcates in the posterior half of the forebody, caeca that extend posteriad beyond the testes, tandem testes, and a vitellarium that is wholly or primarily in the hindbody. Our 28S and ITS2 phylogenetic analyses recovered Caecincola and Cryptogonimus as sister taxa; Caecincola was recovered as paraphyletic with 28S but monophyletic with ITS2. This is the first phylogenetic study of Cryptogonimidae that includes a nucleotide sequence for a species of the type genus Cryptogonimus. We regard Cryptogonimus diaphanus (Stafford, 1904) Miller, 1941 as a species inquirenda.