Parasitology International最新文献

Black-goggled tanagers Trichothraupis melanops (Vieillot, 1818) are passerine birds commonly observed in the Brazilian Atlantic Forest, Argentina and Paraguay. Tanagers are among the passerines with the highest prevalence and density of coccidian parasites, mainly due to their frugivorous feeding habits that favor fecal-oral transmission. In this context, the current study identifies a new species of Isospora Schneider, 1881 parasitizing black-goggled tanagers captured in the Itatiaia National Park, a protected area with a high degree of vulnerability in Southeastern Brazil. The oocysts of Isospora tiedetopetei Almeida-Berto & Berto n. sp. are subspheroidal to ovoidal, measuring on average 24 by 23 μm. Micropyle is absent. Oocyst residuum absent, but comma-like and splinter-like polar granules are present. Sporocysts are ovoidal to slightly pear-shaped, measuring on average 16 by 11 μm. Stieda and sub-Stieda bodies are present. Sporocyst residuum is present among the vermiform sporozoites, which have striations, refractile body and nucleus. This morphology was different from the other Isospora spp. recorded in the same subfamily as the host. Molecular identification was targeted by the amplification and sequencing of four loci of the mitochondrial genome and the small subunit ribosomal RNA (18S) gene. In molecular and phylogenetic analyses of concatenated sequences of 5 fragments, I. tiedetopetei n. sp. sat in monophyly and/or had high similarities with Isospora spp. from passerines. Finally, based on the morphological and molecular analyses of the oocysts recovered from black-goggled tanagers T. melanops in the current study, I. tiedetopetei n. sp. is established new to science, being the seventh species recorded in the host subfamily Tachyphoninae and the first to have a molecular characterization based on mitochondrial genes and the nuclear 18S gene.

Strongyloides stercoralis (S. stercoralis) is a soil-transmitted nematode that is endemic to tropical and subtropical regions. S. stercoralis has the ability to cause autoinfection, potentially leading to a chronic disease that can last for decades or result in severe hyperinfection especially in individuals who are taking corticosteroids or other immunosuppressive medications. Here, we report the case of a patient presenting a two-week history of symptoms including cough, fatigue, weight loss, pruritus, and rash. Due to a significant increase in the percentage of eosinophils, the patient was referred to the hematology clinic. The patient underwent a comprehensive evaluation that included an autoimmune panel, genetic testing, and imaging methods. The results of these investigations were found to be normal. The upper gastrointestinal system endoscopy revealed eosinophilic duodenitis and corticosteroid treatment was initiated. The commencement of corticosteroid therapy resulted in a worsening of the patient's symptoms. In the repeated endoscopy of the upper gastrointestinal tract, the presence of S. stercoralis larvae was observed between the crypts. Subsequently, stool tests for S. stercoralis diagnosis were also found to be positive. The patient was at risk of developing a hyperinfection syndrome. Corticosteroids are commonly used to reduce inflammation and manage symptoms associated with eosinophilic disorders. The immunosuppressive effects of corticosteroids are known to precipitate S. stercoralis hyperinfection syndrome, which can result in significant morbidity and mortality. This case highlights the importance of maintaining a high index of suspicion for S. stercoralis in patients undergoing immunosuppressive therapy, particularly when presenting with unexplained eosinophilia.

Through studies of new antimalarial drugs, we identified 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) as a potential drug candidate. Here, we analyzed the antimalarial action of a transdermal formulation (td) of N-89, designed for easy use by children, using Plasmodium berghei-infected mice as a model for malaria patients. The td N-89 or artemisinin (ART) formulation was transdermally administered to P. berghei-infected mice with 0.2-0.4 % parasitemia, twice daily for four days, at an effective dose of 90 % for malaria. Parasitemia was decreased in td N-89 and td ART groups during the drug treatment; then, three of the eight mice in td N-89 group were completely cured without relapse. Additionally, abnormal trophozoites in td N-89 group were observed 8 h after administration and increased up to 24 h. To study the change in endoplasmic reticulum-resident calcium-binding protein (ERC) gene expression with td N-89, we investigated the gene expression of P. berghei ERC (PbERC) after td N-89 treatment. PbERC gene expression was increased time-dependently in control group, and was statistically decreased at 4 and 8 h and then increased similar to that of control group at 12 h in td ART group. In contrast, the expression in td N-89 group was almost steady starting from 0 h. We also studied parasite egress-related genes expression after td N-89 treatment, plasmepsin X, subtilisin-like protease 1 and merozoite surface protein 1, were suppressed at 12 h compared to control group. These results suggest that N-89 affects function of endoplasmic reticulum via regulating gene suppression and subsequently parasite growth is inhibited.

The recent floods in Morocco, occurring from September 16 to September 30, 2024, have created significant public health challenges, particularly in the regions of Tata, Ouarzazate, and Errachidia. These flooding events have heightened the risk of epidemic diseases, including vector-borne diseases like malaria and leishmaniasis, as well as waterborne infections. This letter outlines critical recommendations to mitigate these risks, including enhanced epidemiological surveillance, distribution of insecticidetreated nets, targeted vector control programs, and community engagement. Additionally, improving sanitation and water access, along with promoting vaccination campaigns, will be essential in protecting public health in the affected areas. Implementing these strategies will strengthen Morocco's preparedness for future epidemic threats following natural disasters.

Dense granules (DG) are understudied apical organelles in merozoites, the malaria parasite stage that invades erythrocytes. Only six proteins have been identified which localize to DGs, despite that DG proteins play crucial roles in multiple steps of intraerythrocytic parasite development. To develop a tool for investigating DG structure and function, this study applied ultrastructural expansion microscopy (U-ExM) to visualize the ring-infected erythrocyte surface antigen (RESA) in Plasmodium falciparum merozoites. Merozoites were expanded to approximately four times their original size, allowing the identification of DGs without the need for electron microscopy. RESA localization in merozoite DGs was confirmed by staining with a combination of anti-RESA mAb and protein staining by NHS-ester. The translocation of RESA to the infected erythrocyte membrane was also observed in early ring-stage parasites. These results are in good agreement with the RESA localization reported using immunoelectron microscopy (IEM). By using U-ExM, the identification of novel DG proteins will be facilitated without time-consuming IEM, thereby enhancing our understanding of erythrocyte parasitism by P. falciparum.

This study aims to identify the most sensitive colorimetric test for assessing intracellular drug susceptibility of Leishmania tropica to conventional antileishmanial drugs. To this end, the efficacy of four colorimetric methods-MTT, XTT, MTS, and WST-8-was compared using reference L. tropica promastigotes. The intracellular drug susceptibility was further evaluated using the test with the widest absorbance range on isolates from Türkiye CL patients: two responsive to a single course of meglumine antimoniate (MA) and two that showed no clinical improvement after two treatments. CL isolates were identified via real-time PCR targeting the ITS1 region. Promastigote suspensions at standardized densities (0.08 × 10⁶ to 10 × 10⁶ promastigotes/well) were prepared in both RPMI (phenol red-containing) and RPMIØRP (phenol red-free) media, then analyzed with ELISA-based MTT, XTT, MTS, and WST-8 to identify the method with the broadest specific absorbance range. Intracellular drug susceptibility of CL isolates was subsequently assessed in a macrophage/amastigote model by infecting THP-1 macrophages with promastigotes from both reference and patient isolates, followed by treatment with MA, sodium stibogluconate (SSG), miltefosine (MTF), pentamidine (PMD), and amphotericin B (AmB). Promastigotes obtained from parasite rescue and transformation assays were analyzed using the most sensitive colorimetric method to determine IC₅₀ values. Species identification confirmed all four CL isolates as L. tropica, and the XTT assay provided the widest absorbance range in RPMIØRP media. IC₅₀ values for both treatment-responsive and unresponsive isolates were similar to those of the reference isolate, showing susceptibility to all tested drugs without statistically significant differences. Expanding the isolate set is necessary to further evaluate the predictive value of Sb^V (pentavalent antimonials) susceptibility for treatment outcomes. The identification of XTT as the most sensitive method for intracellular antileishmanial susceptibility testing is expected to aid in standardizing laboratory models and provide valuable insights for researchers and clinicians managing treatment-unresponsive CL cases.

The lifecycle of schistosomes must be continuously maintained to clarify and understand this parasite in various aspects in laboratory settings. In the previous studies by other researchers, preservation of schistosome larvae or eggs was attempted by freezing with liquid nitrogen or organic chemicals, but frozen schistosomes were substantially impaired. The present study was conducted to determine whether schistosome eggs can be preserved under a non-frozen condition. The results showed that Schistosoma mansoni eggs could be maintained in phosphate-buffered saline at 4 °C, with a high level of infectivity of miracidia to freshwater snails thereafter. Furthermore, the egg hatchability was maintained for up to 12 weeks with weekly exchanges of the medium. The cercariae derived from snails infected with miracidia from preserved eggs were highly infective to mice. This simple schistosome egg preservation method allow researchers to maintain the schistosome lifecycle without freezing or other special procedures.

Among mammals, bats stand out as important reservoirs for Bartonella spp., second only to rodents. In Brazil, out of the 182 species of bats described, three are hematophagous: Desmodus rotundus, Diphylla ecaudata and Diaemus youngii. Considering that Bartonella species have been increasingly associated to disease in humans, the search for such agents in animal reservoirs and ectoparasites is crucial for understanding the epidemiology of bartonelloses. The present study aimed to investigate the occurrence and genetic diversity of Bartonella spp. in vampire bats and Streblidae bat flies in the Brazilian Amazon. For this purpose, 228 spleen samples of D. rotundus and 1 of D. youngi were collected from four states in the northern region of Brazil (Pará (n = 206/D. rotundus; n = 1/D. youngii), Roraima (n = 18/ D. rotundus), Amapá (n = 3/D. rotundus) and Amazonas (n = 1/D. rotundus). Additionally, 142 Streblidae bat flies were collected from 54 D. rotundus (23 Strebla wiedemanni and 118 Trichobius parasiticus) and one D. youngii (1 Trichobius diaemi). Seventy-three (31.9 %; 73/228) spleen samples of D. rotundus (62 from Pará, 9 from Roraima and 2 from Amapá) and 45/142 (31.7 %) Streblidae bat flies (1 T. diaemi, 8 S. wiedemanni and 36 T. parasiticus) were positive in qPCR for Bartonella spp. based on the nuoG gene. Phylogenetic analyses based on the gltA and rpoB genes positioned the sequences obtained together with genotypes previously detected in D. rotundus and bat-associated flies. High genotypic diversity was found among sequences obtained from bats and Streblidae flies (6 gtlA and 11 rpoB genotypes). The genotypes identified in D. rotundus in the present study were exclusively shared with sequences from Bartonella spp. detected in vampire bats, not overlapping with genotypes previously detected in non-hematophagous bats from Brazil. Most of the sequences detected in Streblidae bat flies formed unique genotypes for each dipteran species analyzed. The present study expanded the knowledge regarding the diversity of Bartonella genotypes in vampire bats and associated Streblidae flies.

Schistosomiasis is the second most important tropical disease in terms of socio-economic and public health impact among human parasitic diseases. In China, Oncomelania hupensis is the only intermediate host of Schistosoma japonicum. Despite the significant progress made, the wide distribution of O. hupensis habitats remains a major challenge to eliminating S. japonicum across China. Therefore, it is important to understand the population genetics of O. hupensis in given environment in order to guide local snail control. In this study, O. hupensis snails were collected from five snail habitats/sites (i.e., DT, JC, XG, XP and YH) in Jiaxing city in Zhejiang province of China between 2022 and 2023, and population genetic analyses were conducted based on nine microsatellites. Results showed that four O. hupensis snail populations (i.e., JC, XP and YHs) from two proximity geographically distant districts clustered together, indicating genetic exchange. Snails collected in XG and YH showed significant temporal genetic variation between two years. However, bottleneck effects were only observed in snails from two sites (JC and YH). Although the hypothesis that snail control would greatly reduce the effective population size was not completely supported by our evidence, completely eradicating snails from XG site is possible. These findings will aid in the development of more practical guidelines for local snail monitoring and control.