NDV targets the invasion pathway in malaria parasite through cell surface sialic acid interaction.

Merozoites utilize sialic acids on the red blood cell (RBC) cell surface to rapidly adhere to and invade the RBCs. Newcastle disease virus (NDV) displays a strong affinity toward membrane-bound sialic acids. Incubation of NDV with the malaria parasites dose-dependently reduces its cellular viability. The antiplasmodial activity of NDV is specific, as incubation with Japanese encephalitis virus, duck enteritis virus, infectious bronchitis virus, and influenza virus did not affect the parasite propagation. Interestingly, NDV is reducing more than 80% invasion when RBCs are pretreated with the virus. Removal of the RBC surface proteins or the NDV coat proteins results in disruption of the virus binding to RBC. It suggests the involvement of specific protein: ligand interaction in virus binding. We established that the virus engages with the parasitized RBCs (PRBCs) through its hemagglutinin neuraminidase (HN) protein by recognizing sialic acid-containing glycoproteins on the cell surface. Blocking of the HN protein with free sialic acid or anti-HN antibodies abolished the virus binding as well as its ability to reduce parasite growth. Interestingly, the purified HN from the virus alone could inhibit the parasite's growth in a dose-dependent manner. NDV binds strongly to knobless murine parasite strain Plasmodium yoelii and restricted the parasite growth in mice. Furthermore, the virus was found to preferentially target the PRBCs compared to normal erythrocytes. Immunolocalization studies reveal that NDV is localized on the plasma membrane as well as weakly inside the PRBC. NDV causes neither any infection nor aggregation of the human RBCs. Our findings suggest that NDV is a potential candidate for developing targeted drug delivery platforms for the Plasmodium-infected RBCs.

Integrated Eco-Health approach significantly reduces helminth infections in endemic Khong islands with emphasis on Schistosoma mekongi.

BACKGROUND: Helminth infections, including Opisthorchis viverrini, hookworm, and Trichuris trichiura, are prevalent in Khong district, Champasack province, southern Lao People's Democratic Republic (PDR). Schistosomiasis caused by Schistosoma mekongi is of public health concern on the islands of the Khong district. This study aimed to assess the impact of an Eco-Health/One-Health approach in combination with mass drug administration (MDA) to reduce these helminth infections. METHODS: We conducted a community intervention using a stepped-wedge trial approach on two endemic islands (Donsom and Donkhone) of the Khong district, Champasack province, Lao PDR, between April 2012 and March 2013. In each study village, 30-40 households were randomly selected. All members of selected households, who were at home during the study period were invited to participate in the study. A baseline study was conducted to assess helminth infections, knowledge attitudes and practices toward Schistosoma mekongi infection, behavior of open defecation and availability of latrine at home. After the baseline (T0), the Eco-Health/One-Health approach was implemented on Donsom (intervention) and Donkhone island (control). An assessment was conducted in 2014 (T1), one year after the completion of intervention implementation, to assess the short-term impact of the Eco-Health/One-Health approach on helminth infections and compare intervention and control islands. Later in 2015, the Eco-Health/One-Health approach was implemented on control island (Donkhone). After the implementation of intervention, the parasitological assessments were conducted annually in humans in 2015 (T2), in 2016 (T3) and in 2017 (T4), and in dogs in 2017 (T4) to evaluate the long-term impact of the intervention on helminth infections. Frequency was used to describe the prevalence of helminth infections. Logistic regression was applied to associate the KAP (knowledge, attitudes, and practices and open defecation behavior) and the reduction of helminth infections between intervention and control islands. The reduction in prevalence pre- and post-intervention was associated using a McNemar test. A two-independent sample t-test was applied to compare the mean eggs per gram (EPG) of helminth infections between control and intervention islands. A paired t-test test was used to compare the mean EPG of stool samples before (baseline) and after (follow-up) interventions for the two islands separately. A P-value lower than 0.05 was considered statistically significant. RESULTS: Eco-Health/One-Health approach appears to be associated with reduction in prevalence of S. mekongi by 9.0% [odds ratio (OR) = 0.49, P = 0.003] compared to the use of mass drug administration alone (control island). Additionally, this intervention package significantly reduced O. viverrini infection by 20.3% (OR = 1.92, P < 0.001) and hookworm by 17.9% (OR = 0.71, P = 0.045), respectively. Annual parasitological assessments between 2012 and 2017 showed that the Eco-Health/One-Health approach, coupled with MDA, steadily reduced the prevalence of S. mekongi on the intervention island from 29.1% to 1.8% and on the control island from 28.4% to 3.1%, respectively. CONCLUSIONS: The study findings suggest that the Eco-Health/One-Health approach appears to be associated with a significant reduction in prevalence of S. mekongi and helminth co-infections, particularly hookworm and T. trichiura. Therefore, implementing the Eco-Health/One-Health approach in schistosomiasis-endemic areas could accelerate the achievement of national goals for transmission interruption by 2025 and elimination by 2030.

The 26 S proteasome in Entamoeba histolytica: divergence of the substrate binding pockets from host proteasomes.

OBJECTIVE: Proteasomes are conserved proteases crucial for proteostasis in eukaryotes and are promising drug targets for protozoan parasites. Yet, the proteasomes of Entamoeba histolytica remain understudied. The study's objective was to analyse the differences in the substrate binding pockets of amoeba proteasomes from those of host, and computational modelling of ß5 catalytic subunit, with the goal of finding selective inhibitors. RESULTS: Comparative sequence analysis revealed differences in substrate binding sites of E. histolytica proteasomes, especially in the S1 and S3 pockets of the catalytic beta subunits, implying differences in substrate preference and susceptibility to inhibitors from host proteasomes. This was strongly supported by significantly lower sensitivity to MG132 mediated inhibition of amoebic proteasome ß5 subunit's chymotryptic activity compared to human proteasomes, also reflected in lower sensitivity of E. histolytica to MG132 for inhibition of proliferation. Computational models of ß4 and ß5 subunits, and a docked ß4-ß5 model revealed a binding pocket between ß4-ß5, similar to that of Leishmania tarentolae. Selective inhibitors for visceral leishmaniasis, LXE408 and compound 8, docked well to this pocket. This functional and sequence-based analysis predicts differences between amoebic and host proteasomes that can be utilized to develop rationally designed, selective inhibitors against E. histolytica.

On the host specificity and genetic diversity of Iodamoeba bütschlii: Observations from short amplicon-based next-generation sequencing.

Iodamoeba is a single-celled intestinal parasite, which is common in humans in certain parts of the world, and also in pigs. For the first time, we provide DNA-based evidence of goat, dromedary, fallow deer, and donkey as hosts of Iodamoeba and show that Iodamoeba-specific nucleotide sequences from these four hosts do not appear to overlap with those of humans, unlike those from pigs. We moreover show that similar strains of Iodamoeba can be found in Madagascar, Western Sahara, and Ecuador and that intra-sample diversity is typically extensive across even small fragments of DNA in both human and non-human hosts.

The macrophage polarization in Entamoeba histolytica infection modulation by the C fragment of the intermediate subunit of Gal/GalNAc-inhibitable lectin.

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis, with clinical outcomes ranging from asymptomatic infections to severe invasive diseases. The innate immune system, particularly macrophages, is of paramount importance in resisting the invasion of host tissues and organs by the trophozoites of E. histolytica. Parasite-derived pathogenic factors, such as lectins, play a pivotal role in the promotion of macrophage polarization phenotypes that have undergone alteration. Nevertheless, the precise mechanisms by which E. histolytica modulates immune polarization remain largely unknown. The current study focused on the immunomodulatory effects of the Igl-C fragment of E. histolytica Gal/GalNAc lectin on macrophage polarization. These results demonstrated that Igl-C could induce the secretion of IL-1ß, IL-6, and other cytokines, activating a mixed M1/M2 polarization state. M1 polarization of macrophages occurs in the early stages and gradually transitions to M2 polarization in the later stages, which may contribute to the persistence of the infection. Igl-C induces the macrophage M1 phenotype and causes the release of immune effector molecules, including iNOS and cytokines, by activating the NF-κB p65 and JAK-STAT1 transcription factor signaling pathways. Furthermore, Igl-C supports the macrophage M2 phenotype via JAK-STAT3 and IL-4-STAT6 pathways, which activate arginase expression in later stages, contributing to the tissue regeneration and persistence of the parasite. The involvement of distinct signaling pathways in mediating this response highlights the complex interplay between the parasite and the host immune system. These findings enhance our understanding of the Igl-C-mediated pathogenic mechanisms during E. histolytica infection.

Prevalence and molecular analysis of Toxocara cati in Baghdad Province.

Objective: This study aimed to detect Toxocara cati in cats by microscopic and molecular analysis using PCR, sequencing, and phylogenetic analysis. Materials and Methods: Randomly selected 200 cat feces samples were taken from various private veterinarian clinics in Baghdad. To identify eggs of T. cati by the flotation method, DNA from 100 cat feces was extracted, and one pair of ITS2 region-specific primers was used for polymerase chain reaction, followed by sequencing. Results: Toxocara cati infection rate was found to be 23 out of 100 fecal samples using PCR. Ten DNA product sequence data studies showed 98%-100% similarity to the 5.8S ribosomal RNA gene sequences found in the Gene Bank. The study incidence showed that the overall infection rate by microscopic examination was 23%, with no significant difference between stray cats (27%), and domestic cats (19%). After studying the effect of several epidemiological parameters on the infection rate, it was found that the infection rates of stray and domestic cats were higher in kittens under six months of age, at 46.1% and 27%, respectively, whereas rates were lower for the adult than six months was 11.5% of domestic cats and 14.7% of stray cats. The percentage of stray and domestic male cats that were registered was 35.5%, whereas the female cats registered were 20.6% and 17.5%, respectively. Conclusion: Cats are significant clinical reservoirs for zoonotic parasites. In Iraq, Baghdad has a high incidence of T. cati detections. Compared to conventional methods, PCR is thought to be a more sensitive, accurate diagnostic procedure that confirms the species' identity.

Evolutionary drivers of sex-specific parasite prevalence in wild birds.

Males and females often differ in ecology, behaviour and lifestyle, and these differences are expected to lead to sex differences in parasite susceptibility. However, neither the sex differences in parasite prevalence, nor their ecological and evolutionary drivers have been investigated across a broad range of taxa using phylogenetically corrected analyses. Using the most extensive dataset yet that includes 755 prevalence estimates from 151 wild bird species in a meta-analytic framework, here we compare sex differences in blood and gastrointestinal parasites. We show that despite sex differences in parasite infection being frequently reported in the literature, only Haemoproteus infections were more prevalent in females than in males. Notably, only seasonality was strongly associated with the sex-specific parasite prevalence of both Leucocytozoon and Haemoproteus, where birds showed greater female bias in prevalence during breeding periods compared to the non-breeding period. No other ecological or sexual selection variables were associated with sex-specific prevalence of parasite prevalence. We suggest that much of the variation in sex-biased prevalence could be idiosyncratic, and driven by local ecology and behavioural differences of the parasite and the host. Therefore, breeding ecology and sexual selection may only have a modest influence on sex-different parasite prevalence across wild birds.

A new vector of Xylella fastidiosa: The role of Mesoptyelus impictifrons as a vector in Israel.

In recent years, the bacterium Xylella fastidiosa has been spreading in almond orchards (causing almond leaf scorch) and in grapevines (causing Pierce's disease) in northern Israel. Sucking insects specialized for xylem sap-feeding transmit this plant pathogen but the identity of the vector(s) in Israel has not been determined. Hence, we sought to determine the main potential vector(s) of X. fastidiosa in Israel. In our surveys in northern Israel, we collected and identified four species of spittlebugs: Neophilaenus campestris, Philaenus arslani, Cercopis intermedia, and Mesoptyelus impictifrons. The first two species were found in very low numbers. Cercopis intermedia was found only in spring and did not transmit X. fastidiosa in controlled experiments. Mesoptyelus impictifrons was the most abundant and widely distributed species in our survey and was found in and around infected vineyards in northern Israel. In controlled experiments we found that 35%-39% of M. impictifrons adults acquire X. fastidiosa from infected vines and almonds and subsequently transmit it to vines and almonds. Taken together, this study suggests that M. impictifrons is an important new vector of X. fastidiosa in almond orchards and vineyards in northern Israel. Further studies are needed on M. impictifrons' biology, ecology, and role as a vector of X. fastidiosa.

Does host migration affect host-parasite interaction? Migrant birds harbor exclusive parasites but have similar roles in parasite-host networks.

Parasites comprise a substantial portion of global biodiversity and play critical roles in shaping ecosystems by modulating trophic networks and affecting their hosts' abundance and distribution. The dynamics of host migration introduce new complexity to these relationships. From the host perspective, migratory behavior can either act as a defense mechanism or augment exposure to a broader spectrum of pathogens. Conversely, for parasites, host migration represents a mechanism for their dispersion and an opportunity to infect new host species. This study investigates the complex interplay between migration and parasite-host interactions, focusing on the interaction between hosts and avian malaria and malaria-like parasites in the Brazilian Atlantic Rain Forest. We captured 1466 birds representing 70 different species, uncovering 322 infections with Plasmodium/Haemoproteus parasites. We observed variations in migration timing and fluctuations in host abundance across months. By comparing the observed patterns of interaction of migratory and non-migratory birds to patterns of interaction expected at random, we show that migration affects the roles hosts take in the parasite-host network. Interestingly, despite the fact migratory species hosted more exclusive and distinct parasites, migrants did not occupy central network positions, which are mostly occupied by resident birds. Overall, we highlight the role of resident birds as a key species within parasite-host communities and the high specialization among avian haemosporidians and their hosts.

Systematic risk ranking of microbiological hazards in infant foods.

Ensuring food safety, particularly for vulnerable groups, like infants and young children, requires identifying and prioritizing potential hazards in food chains. We previously developed a web-based decision support system (DSS) to identify specific microbiological hazards (MHs) in infant and toddler foods through a structured five-step process. This study takes the framework further by introducing systematic risk ranking (RR) steps to rank MH risks with seven criteria: process survival, recontamination, growth opportunity, meal preparation, hazard-food association evidence, food consumption habits of infants and toddlers in the EU, and MH severity. Each criterion is given a semi-quantitative or quantitative score or risk value, contributing to the final MH risk calculation via three aggregation methods: semi-quantitative risk scoring, semi-quantitative risk value, and outranking multi-criteria decision analysis (MCDA). To validate the criteria and ranking approaches, we conducted a case study to rank MH risks in infant formula, compared the results of the three risk ranking methods, and additionally evaluated the ranking results against expert opinions to ensure their accuracy. The results showed strong agreement among the three methods, consistently ranking Salmonella non-Typhi and Cronobacter spp. and Shiga-toxin-producing Escherichia coli as the top MH risks in infant formulae, with minor deviations. When MHs were ranked after an initial hazard identification step, all three methods produced nearly identical MH rankings, reinforcing the reliability of the ranking steps and the selected criteria. Notably, the risk value and MCDA methods provided more informative MH rankings compared to the risk scoring method. The risk value and risk scoring methods were implemented into an online tool, called the MIcrobiological hazards risk RAnking decision support system (Mira-DSS), available at https://foodmicrobiologywur.shinyapps.io/MIcrobial_hazards_RAnking/. In conclusion, our framework enables the ranking of MH risks, facilitating intervention comparisons and resource allocations to mitigate MH risks in infant foods, with potential applicability to broader food categories.

A case of tick bite on the perianal region.

Key Clinical Message: Tickborne diseases have become the threats to the health of people worldwide, accounting for nearly 80% patients with vectorborne diseases in the United States. Early diagnosis and proper treatment play a significant role in the management. Close contacts should be screened for delayed symptoms associated with tickborne diseases. Abstract: This study describes a rare case of a 72-year-old Chinese man presented with a 5-day history of painful nodules on the perianal region, indicating tick bite. Tickborne diseases become the threats to the health of people worldwide. Untreated cases may result in several serious inflammatory complications. Manual removal of ticks with fine forceps is effective for preventing the transmission of tickborne infections. People (who have been bitten by a tick) and close contacts should be screened for delayed symptoms associated with tickborne diseases.

Outbreak of parasite-induced limb malformations in a declining amphibian species in Colorado.

The detection of severe limb malformations in metamorphosing northern leopard frogs (Rana pipiens) from a Colorado pond in August 2022 prompted questions about the cause(s) and concern over the implications. Northern leopard frogs, which are a Tier 1 Species of Greatest Conservation Need in Colorado, have declined over much of their range in the state, particularly along the Front Range. Although malformations in amphibians have been reported in other parts of the USA, they are rare in Colorado, and the current case represents the most severe hotspot reported in the state for over 70 years. Across three survey events in late summer and early fall of 2022, approximately 68% of captured leopard frogs (late-stage larvae and metamorphic frogs) exhibited one or more malformations. Malformations exclusively affected the hind limbs and were dominated by skin webbings (51.7% of the total), bony triangles (32.2%), and extra limbs or digits (11%). Many animals had multiple malformations that limited the movement of one or both limbs (average of 2.3 malformations per malformed frog). Dissection of a subset of animals coupled with 28S rDNA genetic sequencing revealed the occurrence of the trematode Ribeiroia ondatrae at an average of 75.2 trematode cysts (metacercariae) per frog. The parasite was also detected in 2.6% of dissected snails (Helisoma trivolvis), which function as the trematode's first intermediate host. The relatively high loads of infection detected here - coupled with the similarity of observed malformations to those previously linked to R. ondatrae in experimental studies and from other malformation hotspots in the USA - offer compelling evidence that the current case is the result of parasite infection. Unresolved questions include why malformation prevalence was so high in 2022 and the degree to which such abnormalities will affect population persistence for local leopard frogs, particularly if malformations continue.

Four new species of Cichlidogyrus (Platyhelminthes, Monopisthocotyla, Dactylogyridae) from Lake Victoria haplochromine cichlid fishes, with the redescription of C. bifurcatus and C. longipenis.

African cichlids are model systems for evolutionary studies and host-parasite interactions, because of their adaptive radiations and because they harbour many species of monogenean parasites with high host-specificity. Five locations were sampled in southern Lake Victoria: gill-infecting monogeneans were surveyed from 18 cichlid species belonging to this radiation superflock and two others representing two older and distantly related lineages. We found one species of Gyrodactylidae, Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, and seven species of Dactylogyridae. Four are described herein: Cichlidogyrus pseudodossoui n. sp., Cichlidogyrus nyanza n. sp., Cichlidogyrus furu n. sp., and Cichlidogyrus vetusmolendarius n. sp. Another Cichlidogyrus species is reported but not formally described (low number of specimens, morphological similarity with C. furu n. sp.). Two other species are redescribed: C. bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Our results confirm that the monogenean fauna of Victorian littoral cichlids displays lower species richness and lower host-specificity than that of Lake Tanganyika littoral cichlids. In C. furu n. sp., hooks V are clearly longer than the others, highlighting the need to re-evaluate the current classification system that considers hook pairs III-VII as rather uniform. Some morphological features of C. bifurcatus, C. longipenis, and C. nyanza n. sp. suggest that these are closely related to congeners that infect other haplochromines. Morphological traits indicate that representatives of Cichlidogyrus colonised Lake Victoria haplochromines or their ancestors at least twice, which is in line with the Lake Victoria superflock being colonised by two cichlid tribes (Haplochromini and Oreochromini).

Title: Quatre espèces nouvelles de Cichlidogyrus (Plathelminthes, Monopisthocotyla, Dactylogyridae) parasites d'haplochrominés (Cichlidae) du lac Victoria, avec la redescription de C. bifurcatus et C. longipenis. Abstract: Les cichlidés africains sont des systèmes modèles pour les études évolutives et les interactions hôtes-parasites, en raison de leurs radiations adaptatives et parce qu'ils hébergent de nombreuses espèces de monogènes parasites avec une spécificité d'hôte étroite. Cinq sites ont été échantillonnés dans le sud du lac Victoria, les monogènes infectant les branchies ont été étudiés chez 18 espèces de cichlidés appartenant à ce superflock et de deux autres espèces représentant deux lignées plus anciennes et éloignées. Nous avons trouvé une espèce de Gyrodactylidae, Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, et sept espèces de Dactylogyridae. Quatre sont décrites ici : Cichlidogyrus pseudodossoui n. sp., Cichlidogyrus nyanza n. sp., Cichlidogyrus furu n. sp. et Cichlidogyrus vetusmolendarius n. sp. Une autre espèce de Cichlidogyrus est signalée mais non formellement décrite (faible nombre de spécimens, similarité morphologique avec C. furu n. sp.). Deux autres espèces sont redécrites : C. bifurcatus Paperna, 1960 et C. longipenis Paperna & Thurston, 1969. Nos résultats confirment que la faune des monogènes des cichlidés du littoral du lac Victoria présente une richesse en espèces et une spécificité d'hôte inférieures à celles des cichlidés du littoral du lac Tanganyika. Chez C. furu n. sp., les crochets V sont clairement plus longs que les autres, ce qui souligne la nécessité de réévaluer le système de classification actuel qui considère que les crochets III-VII sont plutôt uniformes. Certaines caractéristiques morphologiques de C. bifurcatus, C. longipenis et C. nyanza n. sp. suggèrent que ceux-ci sont étroitement liés aux congénères qui infectent les autres haplochrominés. Les traits morphologiques indiquent que les représentants de Cichlidogyrus ont colonisé les haplochrominés du lac Victoria ou leurs ancêtres au moins deux fois, ce qui concorde avec le fait que le superflock du lac Victoria a été colonisé par deux tribus de cichlidés (Haplochromini et Oreochromini).

Micro RNA profiles of host extracellular vesicles are modulated by Ascaris suum infection but parasite extracellular vesicle miRNAs are systemically undetectable using in-depth miRNA sequencing.

The intestinal helminth Ascaris lumbricoides infects over 800 million people. Infections are often chronic and immunity is not sterilizing due to host-immune modulation, therefore reinfection is common after antihelmintic treatment. We have previously demonstrated a role for Ascaris spp. extracellular vesicles (EVs) in host immune modulation but whether EVs are recognized by the adaptive immune system and are present systemically in the host remains unknown. Therefore, we employed a well-established trickle infection model in pigs to mimic natural Ascaris infection in humans. EVs were isolated from adult Ascaris suum followed by immunoblotting of EV and EV-depleted secretory fractions using plasma from infected and uninfected pigs. Next, EVs were isolated from pig plasma at day 56 post first infection and subjected to deep small RNAseq analysis. RNAs were aligned to A. suum and Sus scrofa miRNA complements to detect A. suum EVs and elucidate the host EV micro RNA (miRNA) response to infection, respectively. Infection generates robust antibody responses against A. suum EVs that is distinct from EV-depleted fractions. However, A. suum miRNAs were not detectable in EVs from the peripheral blood. Notably, host plasma-derived EV miRNA profiles showed significant changes between infected and uninfected pigs, indicating that Ascaris infection drives systemic changes in host EV composition.

Trypanosoma cruzi assembles host cytoplasmic processing bodies to evade the innate immune response.

Processing bodies (P-bodies, PBs) are cytoplasmic foci formed by condensation of translationally inactivated messenger ribonucleoprotein particles (mRNPs). Infection with the protozoan parasite Trypanosoma cruzi (T. cruzi) promotes PB accumulation in host cells, suggesting their involvement in host mRNA metabolism during parasite infection. To identify PB-regulated mRNA targets during T. cruzi infection, we established a PB-defective human fibrosarcoma cell line by knocking out the enhancer of mRNA decapping 4 (EDC4), an essential component of PB assembly. Next-generation sequencing was used to establish transcriptome profiles for wild-type (WT) and EDC4 knockout (KO) cells infected with T. cruzi for 0, 3, and 24 h. Ingenuity pathway analysis based on the differentially expressed genes revealed that PB depletion increased the activation of several signaling pathways involved in the innate immune response. The proinflammatory cytokine IL-1ß was significantly upregulated following infection of PB-deficient KO cells, but not in WT cells, at the mRNA and protein levels. Furthermore, the rescue of PB assembly in KO cells by GFP-tagged wild-type EDC4 (+WT) suppressed IL-1ß expression, whereas KO cells with the C-terminal-deleted mutant EDC4 (+Δ) failed to rescue PB assembly and downregulate IL-1ß production. Our results suggest that T. cruzi assembles host PBs to counteract antiparasitic innate immunity.

Contrasting alterations in brain chemistry in a crustacean intermediate host of two acanthocephalan parasites.

The dynamic properties of neural systems throughout life can be hijacked by so-called manipulative parasites. This study investigated changes in the brain chemistry of the amphipod Gammarus fossarum in response to infection with two trophically-transmitted helminth parasites known to induce distinct behavioral alterations: the bird acanthocephalan Polymorphus minutus and the fish acanthocephalan Pomphorhynchus tereticollis. We quantified brain antioxidant capacity as a common marker of homeostasis and neuroprotection, and brain total protein, on 72 pools of six brains. We analyzed the concentration of serotonin (5HT), dopamine (DA) and tyramine in 52 pools of six brains, by using ultrafast high performance liquid chromatography with electrochemical detection (UHPLC-ECD). Brain total protein concentration scaled hypo-allometrically to dry body weight, and was increased in infected gammarids compared to uninfected ones. The brain of gammarids infected with P. minutus had significantly lower total antioxidant capacity relative to total proteins. Infection with P. tereticollis impacted DA level compared to uninfected ones, and in opposite direction between spring and summer. Brain 5HT level was higher in summer compared to spring independently of infection status, and was decreased by infection after correcting for brain total protein concentration estimated from dry whole-body weight. The potential implication of 5HT/DA balance in parasite manipulation, as a major modulator of the reward-punishment axis, is discussed. Taken together, these findings highlight the need to consider both brain homeostatic and/or structural changes (antioxidant and total protein content) together with neurotransmission balance and flexibility, in studies investigating the impact of parasites on brain and behavior.

Analysis of bamboo fibres and their associated dye on a freshwater fish host-parasite system.

With the growth of the fashion and textile industries into the twenty-first century, associated pollution has become pervasive. Fibre-based microplastics are the most common types of plastics recovered from aquatic ecosystems encouraging the move towards organic fibre usage. Often marketed as biodegradable and 'environmentally friendly', organic textile fibres are seen as less harmful, but their impacts are understudied. Here, we assess the health effects of reconstituted bamboo-viscose fibres, processed bamboo-elastane fibres (both at 700 fibres/L) and their associated dye (Reactive Black-5, at 1 mg/L) on fish, with an emphasis on disease resistance utilising an established host-parasite system: the freshwater guppy host (Poecilia reticulata) and Gyrodactylus turnbulli (monogenean ectoparasite). Following 3 weeks exposure to the bamboo fibres and associated dye, half the experimental fish were infected with G. turnbulli, after which individual parasite trajectories were monitored for a further 17 days. Overall, exposures to reconstituted bamboo-viscose fibres, processed bamboo-elastane fibres or dye were not associated with any change in host mortality nor any significant changes in parasite infection burdens. When analysing the routine metabolic rate (RMR) of fish, uninfected fish had, on average, significantly impacted RMR when exposed to processed bamboo-elastane (increased RMR) and reconstituted bamboo-viscose (decreased RMR). Hosts exposed to reconstituted bamboo-viscose and the associated dye treatment showed significant changes in RMR pre- and post-infection. This study bolsters the growing and needed assessment of the potential environmental impacts of alternative non-plastic fibres; nevertheless, more research is needed in this field to prevent potential greenwashing.

Exploring the prevalence and impact of Ligula intestinalis infection across fish species in Sistan region, Iran.

Fisheries play a crucial role in aquatic ecosystems, a resource with ecological and economic importance. Measuring parasite prevalence is necessary to assess these fish species' health and well-being. Within the Sistan region, this study sought to estimate the prevalence and intensity of infection with plerocercoid Ligula intestinalis (L. intestinalis) in seven fish species and identify factors such as fish weight, seasonality, and fishing location that might influence infection rates. 2800 fish from seven species were obtained in the Sistan region throughout four seasons. Fish samples from three weight categories (<200gr, 200-400gr, 400gr<) were examined parasitologically. Ligula intestinalis was detected in 96/2800 (3.4%) of fishs. There was a variation in prevalence among fish species. Alburnus charusini (A. charusini), Hypophthalmichthys molitrix (H. molitrix), Hypophthalmichthys nobilis (H. nobilis), and Schizocypris altidorsalis (S. altidorsalis) showed no infection. Schizothorax zarudnyi (S. zarudnyi) showed a prevalence of 1.5% (6/400), Cyprinus carpio (C. carpio) 15% (60/400), and Ctenopharyngodon idella (C. idella) 7.5% (30/400). It was found that infection prevalence was significantly influenced by fish weight in C . carpio and C . idella. A higher prevalence was found in fish with lower weight. Infection rates significantly fluctuated with season across species, but fishing locations had no significant difference. The present study highlights the significant prevalence of L. intestinalis infections in fish populations within Iran's Sistan region, underscoring the need for ongoing monitoring and research to inform effective fishery management strategies. Future studies should focus on long-term monitoring efforts and consider the broader global context of fish parasitology to understand parasite-host interactions better and inform conservation measures worldwide.

Impact of water quality and morphometric indices on the spatio-temporal prevalence of fish endo-parasites and diversity in the Ase River, Niger-Delta, Nigeria.

Three stations along the Ase River, Delta State Nigeria provided water and 85 fish samples which were analyzed. The fish were measured and examined for endoparasites according to established protocol. All water quality parameters investigated were within the WHO-acceptable values for surface waters. Station variation of physicochemical parameters was not statistically significant (p > 0.05). Fish body conformation indices positively correlated with the prevalence of parasites in Clarias gariepinus, Heterobranchus longifilis, Parachana africana, Chromidotilapia guntheri guntherii, and Denticeps clupeodes. The overall parasite prevalence of 63.53% was established with the most abundant parasite being Trichodina mutabillis. The parasites had a predilection for the gastrointestinal tract with a high occurrence of 307 individuals. Stations 1, 2, and 3 had 326, 213, and 259 parasites, respectively, out of a total of 798 parasites detected. P. laevis was absent in station 1. All parasites were found in stations 2 and 3. Statistically, there was a significant difference (p < 0.05) in the prevalence in all stations. The correlation index of T. mutabillis and R. congolensis in stations 1 and 3 was positively strong (p < 0.05) with the concentrations of water quality. However, water conditions in stations 1 and 3 had a deleterious impact on P. laevis. T. mutabillis maintained a high positive correlation with physicochemical water quality in all three stations. Shannon-Weiner's index in station 3 (H = 1.337) shows that the parasites were more diverse. PCA and biodiversity indices have enabled us to comprehend how parasite-host-environment systems interact.

Synthesis and Anti-Trypanosoma cruzi Activity of New Pyrazole-Thiadiazole Scaffolds.

Chagas disease, a silent but widespread disease that mainly affects a socioeconomically vulnerable population, lacks innovative safe drug therapy. The available drugs, benznidazole and nifurtimox, are more than fifty years old, have limited efficacy, and carry harmful side effects, highlighting the need for new therapeutics. This study presents two new series of pyrazole-thiadiazole compounds evaluated for trypanocidal activity using cellular models predictive of efficacy. Derivatives 1c (2,4-diCl) and 2k (4-NO2) were the most active against intracellular amastigotes. Derivative 1c also showed activity against trypomastigotes, with the detachment of the flagellum from the parasite body being a predominant effect at the ultrastructural level. Analogs have favorable physicochemical parameters and are predicted to be orally available. Drug efficacy was also evaluated in 3D cardiac microtissue, an important target tissue of Trypanosoma cruzi, with derivative 2k showing potent antiparasitic activity and a significant reduction in parasite load. Although 2k potentially reduced parasite load in the washout assay, it did not prevent parasite recrudescence. Drug combination analysis revealed an additive profile, which may lead to favorable clinical outcomes. Our data demonstrate the antiparasitic activity of pyrazole-thiadiazole derivatives and support the development of these compounds using new optimization strategies.