Frontiers in parasitology最新文献

Introduction: Human African trypanosomiasis (HAT), caused by Trypanosoma brucei rhodesiense, is categorized as acute due to rapid disease progression but presents varying clinical outcomes. Although the mechanisms underpinning differential clinical progression are poorly understood, both host and parasite factors are implicated. Therefore, we sought to elucidate roles of primate host factors in mediating varying T. b. rhodesiense infection outcomes.

Methods: Here, we assessed the roles of selected host cytokines in disease progression using a tsetse-mediated infection in a non-human primate (NHP) vervet monkey model that closely mimics HAT and natural infection. We quantified eight cytokines, including TNF-α, IFN-γ, IL-10, IL-6, IL-12, and IL-1β, as well as the brain injury biomarker S100b and clinical data, and compared acute and chronic infections. In addition.

Results: Monkeys infected with KETRI 3801 and KETRI 3928 had mean survival times of 28 and 95 days, respectively. In both infected groups, cytokine levels were significantly higher than those in uninfected controls (p < 0.05). IL-12, IL-6, and IL-1β cytokines were significantly elevated (p < 0.05) from early-stage disease to the onset of late-stage disease. IL-1β, IL-6, IL-12, and IL-10 are implicated in pro- and counter inflammatory responses. In addition, cerebrospinal fluid parasite and white blood cell levels were higher in KETRI 3801 infections compared with KETRI 3928 infections.

Discussion: We conclude that cytokines play roles in modulating disease progression and severity in an NHP model of HAT, which is important for understanding varying infection outcomes.

The genome of Echinococcus multilocularis, one of the most dangerous endoparasites for humans in the northern hemisphere, has been studied for decades, but its global genetic diversity has not yet been fully deciphered. Yet, our understanding of the diversity of this parasite has recently improved significantly due to the development of new genotyping methods. However, the use of different methods and markers has made it difficult-and in some cases impossible-to compare existing studies directly. As a result, accurate information on the global genetic diversity of E. multilocularis remains unavailable, although such knowledge is essential from both clinical and epidemiological perspectives. Here we provide an overview of the state of knowledge on the genetic diversity of E. multilocularis, and the methods used for genotyping this parasite and provide an outlook on needed future research to understand the diversity of this fascinating parasite.

Introduction: Guinea worm (GW) is a nematode that causes a neglected tropical disease that is targeted for eradication. GW emergence in animals, particularly dogs, has hampered eradication efforts. Currently, there is no method for diagnosing GW infection in animals during the prepatent period. Previous work has identified two immunoreactive antigens, TRXL-1 (TRX) and DUF148.

Methods: This study developed and assessed the performance of an indirect ELISA using these antigens.

Results: Using serum samples from experimentally exposed dogs, TRX and DUF148 showed reactivity at 9- and 11-weeks post-exposure, respectively. These antigens were further assessed using sera of dogs from GW-endemic villages in Chad (n=47) and shelter dogs from the non-endemic United States (n=492). DUF148 showed better reactivity and sensitivity of 76.6.% in detecting GW infection in prepatent sera compared to TRX. However, DUF148 cross-reacted with a Brugia pahangi experimental infection serum sample and several shelter dog sera. To mitigate this cross-reaction, we produced 3 peptides that spanned different regions of DUF148. Peptide 3 from the C-terminal was more reactive with prepatent sera and had a sensitivity of 83%; however, the specificity was not superior to whole antigen.

Discussion: Our findings could facilitate the development of diagnostic methods for early detection of GW infection in dogs in endemic countries.

Trichuris trichiura remains a major global public health concern, particularly in low-resource settings where standard anthelmintic regimens are limited. This study evaluated the diagnostic performance of real-time PCR (qPCR) compared to the Kato-Katz (KK) method in assessing the efficacy of a fixed-dose combination (FDC) of albendazole and ivermectin versus albendazole for the treatment of T. trichiura. The study was embedded within the ALIVE clinical trial (NCT05124691), a phase 2/3 trial conducted in Kenya, Mozambique, and Ethiopia. Stool samples were collected at baseline and 21 ± 7 days post-treatment, with KK performed on fresh samples and qPCR on ethanol-preserved aliquots. In total 534 participants were selected based on positive KK and qPCR at baseline and complete data post-treatment. The primary endpoint was cure rate (CR) by KK and qPCR; secondary endpoints included egg reduction rate (ERR) and cycle threshold (Ct) value incrementation rate (CtIR). Additionally, machine learning algorithms were used to predict infection intensity from qPCR Ct-values and demographic variables. qPCR confirmed the superior efficacy of FDC compared to albendazole as previously shown by KK, but discrepancies were observed in CRs between qPCR and KK, particularly lower qPCR CRs for FDC×1 and FDC×3. Concordance between stool egg counts and Ct-value decreased post-treatment, likely due to reduced KK sensitivity in low-intensity infections. ERR and CtIR showed parallel patterns of efficacy across treatment arms. Machine learning models showed good performance for predicting baseline infection intensity. While not interchangeable, qPCR complements KK and enhances the precision of drug efficacy evaluation in helminth clinical trials.

Introduction: Malaria remains a major public health challenge across sub-Saharan Africa, with Plasmodium falciparum responsible for the vast majority of cases and deaths. In Rwanda, although control measures have led to significant progress, malaria continues to be endemic, with urban centers like Kigali experiencing continuous transmission. With the recent rollout of malaria vaccines such as RTS,S and R21, understanding the genetic variability of vaccine-targeted antigens is essential for anticipating and enhancing vaccine performance.

Methods: This study investigated the genetic diversity of the Plasmodium falciparum circumsporozoite protein (Pfcsp) gene among 245 clinical isolates collected between October 2021 and June 2023 at King Faisal Hospital, a referral center in Kigali, Rwanda. PCR amplification of the csp locus was performed, and the resulting amplicons were sequenced using Oxford Nanopore Technology (ONT) employing the R10.4 flow cell chemistry, allowing for high-resolution haplotype reconstruction and detection of polymorphic sites across the gene.

Results: A total of 48 distinct haplotypes were identified, indicating high haplotype diversity (Hd = 0.8899) but moderate nucleotide diversity (p = 0.00834), suggesting immune-driven balancing selection. The N-terminal region was highly conserved across isolates, including full conservation of the KLKQP motif, reinforcing its functional importance in hepatocyte invasion. In contrast, the central repeat region exhibited substantial variability in NANP/ NVNP tetrapeptide repeat numbers, and the C-terminal region, particularly the Th2R and Th3R epitopes showed extensive polymorphism. Notably, fewer than 1% of sequences matched the 3D7 vaccine strain, and several key amino acid positions associated with vaccine escape showed high mutation frequencies.

Discussion: Our findings suggest that the genetic divergence of circulating csp variants in Kigali could be a factor influencing vaccine performance, underscoring the importance of ongoing molecular surveillance to guide eventual vaccine implementation in Rwanda and other endemic regions.

[This corrects the article DOI: 10.3389/fpara.2025.1523113.].

Background: Hydatid disease is a zoonosis caused by the larval stage of Echinococcus granulosus, most often affecting the liver and lungs. Disseminated hydatidosis is rare, accounting for <10% of cases.

Case presentation: We present a 28-year-old man with paraplegia and abdominal pain. He was first diagnosed with hydatid disease at a government hospital 3 years earlier and presented to us with only an ultrasound (US) report. No serology reports were furnished. He had deferred surgery due to financial constraints. At current presentation, US, computed tomography (CT), and magnetic resonance imaging (MRI) demonstrated multiple cysts across the pelvis, retroperitoneum, spine, mediastinum, neck, and extremities. Imaging morphology was consistent with the WHO-IWGE (Informal Working Group on Echinococcosis) CE1-CE3 hydatid cysts. Differentials including abscess, cysticercosis, necrotic metastases, and lymphangioma were ruled out based on the absence of contrast enhancement, calcification pattern, and clinical correlation.

Treatment and outcome: Surgery was advised, but was declined. PAIR (puncture, aspiration, injection, re-aspiration) was contraindicated due to multivesicular bone and spinal cysts. The patient was managed with oral albendazole. Follow-up data are currently unavailable.

Conclusion: This case highlights disseminated hydatid disease with an unusual spinal and soft tissue involvement. Multimodality imaging is pivotal for diagnosis and treatment planning. Awareness of the imaging features is essential for timely recognition and management.

Introduction: Trichomoniasis, the most common non-viral sexually transmitted disease, is caused by the protozoon Trichomonas vaginalis. T. vaginalis can establish a symbiosis with two bacteria, Mycoplasma hominis and Candidatus Mycoplasma girerdii, whose intracellular presence may modulate several characteristics of the protozoan, including its sensitivity to 5-nitroimidazoles, the only class of drugs currently effective in treating trichomoniasis. The rising prevalence of T.vaginalis strains resistant to metronidazole, the most commonly used antitrichomonal drug, underscores the need for therapeutic alternatives active against the protozoon.

Methods: In this study, we evaluate the antimicrobial activity of essential oils extracted from three plants cultivated in Vietnam - Cymbopogon citratus, Citrus grandis, and Mentha arvensis - against thirty T. vaginalis strains isolated from symptomatic women in Italy and Vietnam. We also assess the influence of M. hominis and Ca. M. girerdii on T. vaginalis susceptibility to essential oils and metronidazole, through dedicated susceptibility assays. Additionally, given the importance of lactobacilli in maintaining vaginal health, we investigate the effects of the essential oils on Lactobacillus gasseri and Lactobacillus crispatus. The cytotoxic activity of the oils against HeLa cells was also tested in vitro.

Results: All three essential oils showed effective antitrichomonal activity without inhibiting lactobacilli growth. Among them, C. citratus oil exhibited the strongest inhibitory effect on T. vaginalis, including strains harboring bacterial symbionts. Moreover, the oils demonstrated no cytotoxic activity against HeLa cells at the concentrations effective against the protozoan.

Discussion: The results support the potential of C. citratus essential oil as a natural antitrichomonal agent. Its effectiveness against both free and symbiont-infected T. vaginalis strains positions it as a promising candidate for developing alternative therapies against drug-resistant trichomoniasis.

Chagasic megaesophagus is a relatively uncommon clinical manifestation in individuals with chronic Chagas disease (CD), and it has not been extensively documented in literature. However, individuals may exhibit negative or inconclusive serology for CD. This study aimed to assess the performance of molecular diagnostics for CD in participants with these conditions. This was a prospective cohort study that included 26 participants with negative or inconclusive conventional CD serology (Group I), 33 participants with positive CD serology and megaesophagus (Group II), and 10 participants with negative serology and no CD epidemiological history (Group III). Blood samples were collected for serological tests (ELISA and IFAT), blood cultures, and molecular tests like nested PCR (nPCR) targeting Sat-DNA and kDNA, as well as quantitative PCR (qPCR) of T. cruzi. Statistical analyses applying the Composite Reference Standard (CRS), showed that diagnosis by Sat-DNA nPCR had a sensitivity of 95% (95% CI: 82%-99%), a specificity of 81% (95% CI: 64%-93%), an accuracy of 88%. When considering a positive result from at least one molecular test, 20 out of 26 participants with megaesophagus and negative or inconclusive conventional serology were identified (76.9%). This study reinforce the greater detection capacity of Sat-DNA nPCR compared to the diagnostic methods tested. This emphasizes the importance of employing molecular diagnosis to clarify the etiology in megaesophagus cases.