Folia Parasitologica最新文献

Ixodes inopinatus Estrada-Peña, Nava et Petney, 2014 was described in 2014 from the Iberian Peninsula and later reported from Algeria, Morocco, Tunisia, Germany, Austria and Romania. However, recent studies raised serious doubts about the presence of I. inopinatus in Central Europe and reported hybridisation between the Ixodes ricinus (Linnaeus, 1758) and I. inopinatus. In this study, we selected a locally common rodent host, the edible dormouse Glis glis (Linnaeus) (Rodentia: Gliridae), to study the prevalence of these two tick species and their hybrids in a Central European woodland. The TROSPA nuclear gene and the COI mitochondrial gene were used for tick identification. Overall, 581 dormice were screened and 383 I. ricinus, 17 I. ricinus/inopinatus hybrids and no I. inopinatus were found. Co-infection of I. ricinus and hybrids was found on 11 dormice with the overall prevalence of I. ricinus 28.8% and hybrids 2.5%. Seasonal occurrence of I. ricinus and hybrids reached a peak in August. Edible dormouse males were more frequently infected than females and larvae of both tick taxa greatly outnumbered the nymphs. Detection of a large number of hybrid larvae on this mammal host demonstrates that tick hybridisation likely occurs further north and outside the originally described distribution range of I. inopinatus.

Toxoplasma gondii (Nicolle et Manceaux, 1908), an intracellular parasite that causes toxoplasmosis, infects a third of the human population. Latent toxoplasmosis has been linked to altered immune responses, including elevated proinflammatory cytokines. In early pregnancy, the immune system adapts to balance inflammation and foetal tolerance. This study assessed whether pregnant women in the first trimester infected with Toxoplasma gondii have different cytokine levels than uninfected women. This study also examined whether women with discordant test results for toxoplasmosis represent a distinct group or a mixed group composed of infected women with unusually low levels of anti-Toxoplasma antibodies and uninfected women with high levels of cross-reacting antibodies. We measured 18 cytokines (IL-1β, IL-1ra, IL-2, IL-4, IL-7, IL-9, IL-17A, Eotaxin, FGF basic, G-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α) in 78 pregnant women, classified as Toxoplasma-positive, Toxoplasma-negative or Toxoplasma-discordant (negative by IgG ELISA, positive by complement fixation test [CFT]). Using exploratory factor analysis, we identified two factors, the first explaining 29.6% and the second 24.9% of the total variability in cytokine concentrations. Toxoplasma-positive women scored significantly higher in the second factor, primarily associated with cytokines linked to Th1-driven inflammation and cellular immunity. Specifically, these women exhibited elevated levels of IL-1β, IL-1ra, IL-2, FGF basic and PDGF-BB compared to Toxoplasma-negative women. This finding suggests that pregnant women with latent toxoplasmosis experience some degree of chronic inflammation. Additionally, our results indicate that Toxoplasma-discordant women are likely Toxoplasma-negative individuals with detectable anti-Toxoplasma IgM antibodies. However, as this study focused on pregnant women, further research is necessary to validate these conclusions in broader populations.

During November of 2007, parasitic nematodes were collected from 161 specimens of 32 freshwater fish species in the Lacantún River of the Lacandon rain forest of Chiapas, southern Mexico. Recent detailed morphological and taxonomic studies of this material revealed the presence of 17 nematode species (12 adult and 5 larval) of nine families, including Cucullanus potamarii sp. n. from the intestine of the ariid catfish Potamarius usumacintae Betancur-R et Willink, which is endemic to the Usumacinta River basin to which the Lacantún River belongs. This new species is mainly characterised by deirids and the excretory pore located far posterior to the level of the oesophago-intestinal junction, which is an almost unique feature among its congeners. Most parasites are briefly described and illustrated, and problems concerning their morphology, taxonomy, hosts and geographical distribution are discussed. Some findings represent new host and geographical records. Cucullanus oaxaquensis Caspeta-Mandujano, Salgado-Maldonado et Martínez-Ramírez, 2010 is considered a junior synonym of Cucullanus angeli Cabañas-Carranza et Caspeta-Mandujano, 2007, and Neocucullanus marcelae Ramallo, 2012 a species inquirenda. Based on absence of relevant morphological differences, Rhabdochona ictaluri Aguilar-Aguilar, Rosas-Valdez et Pérez-Ponce de León, 2010 is considered a synonym of Rhabdochona kidderi Pearse, 1936.

Herein, we explore the potential influence of Schistosoma mansoni Sambon, 1907 soluble egg antigen (SmSEA) on the immunopathology of COVID-19 in K18-hACE2 mice infected with an Omicron BA.5 isolate of SARS-CoV-2. SmSEA treatment was delivered in a single dose by intraperitoneal injection, shortly after intrapulmonary inoculation of SARS-CoV-2. RNA-seq identified 36 differentially expressed genes in the spleens of virus-infected mice treated with SmSEA vs. PBS on day 5 post infection. Ingenuity Pathway Analysis of these genes suggested marginal modulation of cytokine responses, with upregulation of the IL-10 and IL-4 signatures and downregulation of the IFNγ signature. However, cytokine responses and histopathology in the lungs were largely unaffected. Future work will require purification of active helminth compounds and dosing and scheduling optimisation.

Opegaster Ozaki, 1928 is one of the most species-rich genera of the trematode family Opecoelidae, commonly found in marine teleost fishes. This study describes a new species of Opegaster of the intertidal fish species Labrisomus xanti Gill (Labrisomidae) (type host) and Tomicodon zebra (Jordan et Gilbert) (Gobiesocidae) from the coast of Oaxaca, Mexican Pacific. Opegaster mezcal sp. n. is characterised by the absence of papillae on the ventral sucker and the size and shape of the testes. Sequences of the D1-D3 domains from large subunit from nuclear DNA (28S) were generated for the new species and for another opecoelid species, Opecoelus adsphaericus Manter et Van Cleave, 1951. The new sequences of Opegaster mezcal sp. n. formed a clade, which is sister to O. adsphaericus. However, the phylogenetic relationships among genera of Opecoelinae remain unresolved because few species have been analysed; the addition of further taxa is necessary to better understand the evolution of the subfamily.

Species richness and similarity in metazoan parasite communities of fish can be influenced by several biotic (age, body size, vagility, social and feeding behaviour, among others), and local abiotic factors (temperature, salinity, climatic events, etc.). The parasite communities of ten species of the family Carangidae from Acapulco Bay, Mexico, were quantified and analysed between May 2014 and August 2024. A total of 1,148 fish specimens were examined and 78 parasite species were identified (44 endoparasites and 34 species of ectoparasites). At the component community level, species richness ranged from 11 in Euprepocaranx dorsalis (Gill) to 27 in Caranx caninus Günther. Parasite communities were dominated mainly by monogenean species. The richness and parasite species composition differed between the ten species of host. The habitat type, body size and host diet variety were the main factors responsible of these differences. Similarity in species composition varied even between hosts of the same genus, suggesting that phylogenetic relatedness and sympatry were not important determinants of parasite communities in these carangid fish. Therefore, host ecology has a greater influence on the structure and species composition of parasite communities than its phylogenetic history.

Here I recount my research journey on the coccidian protist Toxoplasma gondii (Nicolle et Manceaux, 1908), a ubiquitous parasite capable of infecting all warm-blooded animals as intermediate or secondary host, but with only members of the Felidae as its definitive host. I describe my initial studies into its epidemiology and persistence within the UK, and how this led on to a series of biologically and ethically appropriate studies into T. gondii's apparent specific manipulation of its rat intermediate host to facilitate transmission to its feline definitive host. I then describe how this prompted searches into the potential mechanisms of action behind such manipulation and what this raises in terms of behavioural changes, from the subtle to severe, across other secondary hosts including humans.

Latent infection with Toxoplasma gondii (Nicolle et Manceaux, 1908) has been repeatedly correlated with behavioural and physiological changes in both humans and animals. While classically regarded as a parasite transmitted via ingestion or vertical (transplacental) transmission, accumulating evidence suggests that sexual transmission may also contribute to its epidemiology. This review explores the hypothesis that some behavioural effects of toxoplasmosis - especially those related to attraction, sexual activity, and mate choice - may have evolved to facilitate sexual transmission of the parasite. We summarise findings from animal models and human studies that show modified sexual preferences, altered sexual activity, enhanced attractiveness in infected individuals, and elevated prevalence of T. gondii in groups exhibiting high sexual activity or non-traditional sexual behaviour patterns. Particular attention is given to the role of testosterone, which may mediate both behavioural changes and reproductive consequences, such as shifts in offspring sex ratios and fertility outcomes. Direct detection of the parasite in semen and evidence of transmission through insemination in non-human species further support the plausibility of this route. The observed behavioural effects may also intersect with mechanisms previously thought to enhance predation risk, such as altered fear responses to felid odours. Taken together, these findings point to the possibility that sexual transmission, while likely secondary in humans, may have played a more substantial role in the evolutionary history and current ecology of T. gondii than previously appreciated. This perspective also provides an alternative interpretative framework for understanding the broad spectrum of phenotypic changes associated with latent toxoplasmosis. Further interdisciplinary research is required to clarify the relative contribution of sexual transmission to the parasite's life cycle and to assess its implications for public health and theory of host-parasite coevolution.

While the identification of adult monogeneans primarily relies on morphological criteria, the morphology of a number of monogenean larvae (oncomiracidia) is to this day scarcely described. Yet, oncomiracidium plays a crucial role in the life cycle of the parasite, being responsible for the detection and localisation of its host, as well as for its attachment to this host. Few studies investigated the external morphological structures related to these functions, especially in Monopisthocotylea. The present study focuses on the early life stages (egg and oncomiracidium) of Lamellodiscus erythrini Euzet et Oliver, 1967, which are accurately described for the first time by light and scanning electron microscopy. Eggs of L. erythrini are smooth, tetrahedral and extended by a long polar filament. Freshly laid, the egg is brown, opaque, impermeable and becomes transparent as it matures, revealing the larva and its eye spots. When the egg matures, the egg casing exhibits functional weak points all around the operculum through which the larva emerges. The larva of L. erythrini is elongated, cylindrical and has a highly developed ciliation covering three areas: an anterior zone, a pleural zone, and a posterior cone. The ciliated cells are contiguous and are organised in a structured mosaic of spherical droplets, each cilium inserted into one. The larval tegument presents microvilli as well as 9 pairs of dorsal sensilla. The haptor is a closed structure consisting of 14 sclerotised hooklets, 12 arranged in a circle, and one pair positioned at the centre of the haptor. The possible link between these morphological structures and larval behaviour is discussed.

The zoonotic marine nematodes of the genus Anisakis Dujardin, 1845 are the causative agents of anisakiasis, a parasitosis that has been increasingly reported in Europe over the past decade due to the more frequent consumption of lightly processed or raw seafood. While the life cycle in the marine environment is relatively well-known, an in vitro life cycle has recently been established with the goal to serve as a model for a better understanding of the functional biology of the nematode and consequent devising of strategies for its detection and inactivation. However, the reproductive capacity of the nematode has not been investigated so far, although it is an important parameter for epidemiological modelling or risk assessment studies. To measure the fecundity of Anisakis pegreffii Campana-Rouget et Biocca, 1955, type I larvae were obtained from naturally infected blue whiting Micromesistius poutassou (Risso) from the Adriatic Sea (Croatia) and cultured to the adult stage in Schneider's insect Drosophila medium supplemented with 10% chicken serum (n = 30 in triplicate). Larvae reached stage 4 (L4) by day 4 post-incubation (dpi), followed by molting to the stage 5 (L5) after 15 days and transition to the adult stage, characterised by production and expulsion of eggs on day 17 dpi. The fecundity of the adults was quantified by the daily number of eggs expelled per female, as well as their hatchability. Eggs were detected from 17 to 133 dpi but started hatching only from 44 dpi. Over the next 51 days, the eggs typically hatched into L2 larvae within 5-7 days. Average fecundity peaked at 100 dpi with 44,125 eggs/day/female and a sex ratio of 1 : 2 to 1 : 3. Cumulative mortality of cultured animals reached 60, 50 and 53% for the triplicates at 133 dpi, whereupon the experiment was terminated as only unfertilised eggs were produced.