Frontiers in parasitology最新文献

Alveolar echinococcosis (AE) caused by Echinococcus multilocularis, is a severe zoonotic disease in humans. One of the major metacestode antigens of E. multilocularis is the Em2 or Em2(G11) native purified antigen. The Em2 antigen is used for the serological and histopathological diagnosis of AE in humans and plays an important role in parasite-host interactions. As the Em2(G11) antigen is a mucin-type and glycosylated protein, the protein backbone has not been identified yet. We have targeted the protein backbone identification through mass spectrometry (LC-MS/MS) analysis of the Em2(G11) antigen. As a result, we evidenced that the Em2(G11) antigen consists of 33 unique protein candidates of which the most abundant was ''EmuJ_001105600.1''. This protein (889 amino acids) had 427 predicted glycosylation sites. Amino acid composition comparison was in agreement with earlier studies and further confirmed the candidate of interest as the most likely Em2(G11) protein backbone. NCBI BLAST revealed no other known protein homologues in related Echinococcus species nor helminths. After successfully producing this protein recombinantly (Em2rec), a monoclonal antibody (mAbEm2rec) was raised against it. Immunohistochemical stainings of liver tissue sections of AE patients showed that the mAbEm2rec reacts specifically with E. multilocularis antigens solely after deglycosylation with an O-glycosidase cocktail. Similarly, in ELISA, the mAbEm2rec recognized the recombinant and native antigens of E. multilocularis after deglycosylation. These results reveal the nature of this highly glycosylated and specific protein, where mucins are covering the proteomic backbone. For antibody detection in human patients, the native Em2(G11) antigen was superior compared to the Em2rec antigen, indicating the importance of glycosylated epitopes in this immuno-dominant antigen. Of note is the second most abundant protein in the Em2(G11) antigen, namely phosphoenolpyruvate carboxykinase (PEPCK; EmuJ_000292700.1). PEPCK is known to play an important part in the metabolic pathway of gluconeogenesis in E. multilocularis. However, whether this co-eluted protein has any functional importance in the parasite-host interplay of nutrients, growth, and diagnostic significance, is not explored. By combining various approaches, we were able to uncover and confirm the protein backbone of the diagnostic Em2(G11) antigen of E. multilocularis.

Parasites have a severe impact on animal and human health. Parasites like worms, ticks, mites, fleas, biting flies, mosquitoes, and pathogenic protozoa affect humans and their pets as well as their livestock globally, both in terms of severity and numbers. Parasitic infections are a global phenomenon, and they can be associated with severe or mild symptoms but represent a continuous risk of severe diseases for animals and humans. Therefore, effective treatment options and the prevention of infection are key for the wellbeing of pets, livestock, and humans, including the reduction of zoonotic risk of infection. The effective control of parasites in animals can greatly improve their quality of life and is also beneficial for humans; this is threatened by drug-resistant parasite populations. Today's key areas for improvement of parasite control are as follows: a) convenience of prevention and treatment, b) effectiveness against drug-resistant parasites, c) availability and reduced costs of treatment, and d) control measurements that are environmentally friendly.

Trichomonas vaginalis is the causative agent of trichomoniasis, the most prevalent neglected parasitic sexually transmitted infection worldwide. Cysteine peptidases (CPs) are the most abundant proteins in the parasite degradome. Some CPs are virulence factors involved in trichomonal pathogenesis, cytoadherence, hemolysis, and cytotoxicity. Few are immunogenic and are found in the vaginal secretions of patients with trichomoniasis. Legumains are CPs of the C13 family of clan CD. T. vaginalis has 10 genes encoding legumain-like peptidases, and TvLEGU-1 and TvLEGU-2 have been characterized. Both are immunogenic and found in the vaginal secretions of patients with trichomoniasis that could be considered as potential biomarkers. Thus, our goal was to evaluate the effects of glucose on the proteolytic activity and secretion processes of TvLEGU-1 and TvLEGU-2. We performed in vitro secretion assays using different glucose concentrations, examined the presence and proteolytic activity of secreted legumains by Western blot and spectrofluorometry assays, and analyzed the localization of TvLEGU-1 and TvLEGU-2 in the parasites by indirect immunofluorescence. Our results show that TvLEGU-1 and TvLEGU-2 were secreted in vitro in a time-dependent manner and had legumain-like proteolytic activity that could contribute to parasite pathogenesis, supporting their relevance during infection and potential as trichomoniasis biomarkers.

Introduction: Trypanosomatids are parasites widely distributed in nature, parasitizing several host species in single or co-infections. Campo Grande (CG), capital of Mato Grosso do Sul State, is characterized by several green areas and forest fragments where wild mammals have been reported infected by diverse trypanosomatid species. In this study, we evaluated the parasitism by trypanosomatids in the non-human primates (NHP) Sapajus cay and Alouatta caraya sampled in three different areas of CG.

Material and methods: For the detection of infections and identification of trypanosomatid species, we made hemoculture, blood smears, molecular and serological tests.

Results: We detected trypanosomatids in 37/55 (67.3%) of sampled animals, all by the molecular test. DNA sequencing analyzes were performed on 32 samples, resulting in the following species identification: Trypanosoma cruzi, T. minasense, T. rangeli, Leishmania (L.) infantum and L. (L.) amazonensis (species already recorded in primates in Latin America), and for the first time T. lainsoni, a parasite related to small mammals, and Trypanosoma sp. DID, originally reported in marsupials Didelphis sp.

Discussion: The detection of trypanosomatids of public health importance as L. infantum, L. amazonensis and T. cruzi (genotypes TcI, TcII/TcVI and TcIV) indicates the enzootic character of these species in the studied area. Also, the presence of T. cruzi TcIV and T. minasense in the conservation area supports previous studies that these parasites would be associated with the arboreal stratum. We conclude that (i) the NHP at CG participate in a complex reservoir system for parasites of great importance for Public Health in the studied area, such as L. infantum, L. amazonensis and T. cruzi, and (ii) there is a great diversity of trypanosomatids circulating in the urban area of this city located in the Brazilian Midwest.

Background: Resistance to antimalarial drugs remains a major obstacle to malaria elimination. Multiplexed, targeted amplicon sequencing is being adopted for surveilling resistance and dissecting the genetics of complex malaria infections. Moreover, genotyping of parasites and detection of molecular markers drug resistance in resource-limited regions requires open-source protocols for processing samples, using accessible reagents, and rapid methods for processing numerous samples including pooled sequencing.

Methods: Plasmodium falciparum Streamlined Multiplex Antimalarial Resistance and Relatedness Testing (Pf-SMARRT) is a PCR-based amplicon panel consisting of 15 amplicons targeting antimalarial resistance mutations and 9 amplicons targeting hypervariable regions. This assay uses oligonucleotide primers in two pools and a non-proprietary library and barcoding approach.

Results: We evaluated Pf-SMARRT using control mocked dried blood spots (DBS) at varying levels of parasitemia and a mixture of 3D7 and Dd2 strains at known frequencies, showing the ability to genotype at low parasite density and recall within-sample allele frequencies. We then piloted Pf-SMARRT to genotype 100 parasite isolates collected from uncomplicated malaria cases at three health facilities in Dschang, Western Cameroon. Antimalarial resistance genotyping showed high levels of sulfadoxine-pyrimethamine resistance mutations, including 31% prevalence of the DHPS A613S mutation. No K13 candidate or validated artemisinin partial resistance mutations were detected, but one low-level non-synonymous change was observed. Pf-SMARRT's hypervariable targets, used to assess complexity of infections and parasite diversity and relatedness, showed similar levels and patterns compared to molecular inversion probe (MIP) sequencing. While there was strong concordance of antimalarial resistance mutations between individual samples and pools, low-frequency variants in the pooled samples were often missed.

Conclusion: Overall, Pf-SMARRT is a robust tool for assessing parasite relatedness and antimalarial drug resistance markers from both individual and pooled samples. Control samples support that accurate genotyping as low as 1 parasite per microliter is routinely possible.

Background: Malaria is the most important parasitic illness causing morbidity and mortality with high prevalence in tropical regions.

Objective: This study was aimed at evaluating the 7-year malaria trend and community awareness at Jawi Health Center and primary Hospital in Northwest Ethiopia.

Methods: A retrospective and cross-sectional or prospective design were used for the study. The data was analyzed using SPSS version 22 software. The findings were considered significant at P < 0.05.

Results: Among 62,624 blood films between 2015 and 2021 at Jawi Health Center, 40.9% were positive. Plasmodium falciparum accounted for 85.8%. Women had more mixed infections (P. falciparum and P. vivax) (X² = 8.9, df = 2, P = 0.011) than men. A greater proportion (20.6%) of malaria cases was observed within the under 5 years age group and the number of malaria cases was higher in September, October, and June. The overall prevalence of malaria was found to be 25.2% and June had the highest proportion (75.6%). In total, 335 (80.9%) respondents recognized mosquito bites as the cause and fever (50%) as a clinical symptom of malaria. More than half of the respondents (60.1%) never sleep under mosquito nets.

Conclusion: Thus, these findings have substantial implications for the trend of malaria prevalence and patient awareness of the disease which support the existing malaria control efforts.

Cystic echinococcosis (CE) is a zoonotic disease caused by Echinococcus granulosus sensu lato, the metacestode of a tapeworm parasite of high medical importance. Infection of the parasite leads to the development of echinococcal cysts, and the spleen is a rarely infected organ. A 46-year-old woman who was born and who resides in Sardinia, Italy, was referred to the Echinococcosis outpatient clinic at the University Hospital of Sassari (Sardinia, Italy) for a pain in the left flank. She used to live in the countryside, in contact with several animals, and for 2 years, she had been working in a family garden, growing vegetables as a hobby. Ultrasounds and X-ray were performed, which evidenced a rounded formation in the upper third of the spleen, while a CT scan confirmed a parasitological cyst. Immunological examinations on serum samples did not detect specific antibodies against Echinococcus spp. Following surgical exportation, the whole spleen with the cystic lesion was delivered to the World Organisation for Animal Health (WOAH) and the National Reference Laboratory for Echinococcosis for further laboratory analyses. Moreover, characterization of the cyst fluid resulted dense and shiny. Observation under a light microscope at ×400 magnification revealed the formation of rectangular crystals and aggregates attributable to cholesterol molecules. Subsequently, through parasitological investigation, molecular biology investigations confirmed E. granulosus sensu stricto G1. We describe cholesterol crystals in a splenic echinococcal cyst for the first time. There is no clear explanation of how the cholesterol crystals formed in this case, but this was attributed to multifactorial causes, including atherosclerosis, chronic inflammation, parasite metabolism, and host responses.

Nematode parasitic infections continue to be a major health problem for humans and animals. Drug resistance to currently available treatments only worsen the problem. Drug discovery is expensive and time-consuming, making drug repurposing an enticing option. Emodepside, a broad-spectrum anthelmintic, has shown efficacy in the treatment of nematode parasitic infections in cats and dogs. It is now being considered and trialed for the treatment of onchocerciasis, trichuriasis (whipworm), and hookworm infections in humans. Its unique mechanism of action distinguishes it from traditional anthelmintics, positioning it as a promising candidate for combating resistance to other current drugs. Here, we provide a brief review of the available information on emodepside's pharmacokinetics, safety, and tolerability. We highlight the potential benefits and risks associated with its use, examining key toxicity effects. By exploring the literature, we aim to provide insights into the risks associated with emodepside that may impact its application in veterinary and human medicine. Although emodepside demonstrates a favorable safety profile, continued monitoring of its toxicity is crucial, particularly in vulnerable populations. This mini-review serves as a concise resource for researchers and clinicians interested in anthelmintic therapy.

Background: Schistosomiasis is caused by infection with parasitic Schistosoma worms and affects more than 250 million people globally. The detection of schistosome derived circulating cathodic and anodic antigens (CCA and CAA) has proven highly valuable for detecting active Schistosoma infections, causing both intestinal and urinary schistosomiasis.

Aim: The combined detection of CCA and CAA was explored to improve accuracy in detecting Schistosoma infections.

Methods: Parallel detection of CCA and CAA was performed on two banked sample sets with matching serum and urine samples from Schistosoma mansoni (Sm) and S. haematobium (Sh) infected individuals using the non-concentration based lateral flow (LF) test comprising the sensitive luminescent up-converting reporter particle (UCP) technology.

Results: Parallel detection of CCA and CAA increased the positivity rate for detecting both Sm and Sh infections compared to the detection of either antigen separately, demonstrating the added value of detecting both antigens in a single sample to confirm diagnosis, independent from the Schistosoma species. Significantly higher CCA concentrations in urine were observed in Sm infected individuals compared to Sh infected individuals, while serum CCA-concentrations were similar between species. CAA concentrations were higher in serum compared to those in urine, irrespective of species. When exploring the relationship of CCA and CAA in urine, the CCA/CAA ratio in Sm infected individuals was significantly higher than in Sh infected individuals, while no differences were observed in serum.

Discussion and conclusion: Parallel detection of CCA and CAA via the UCP-LF platform showed added diagnostic value through an increased positivity rate for the detection of Sm and Sh infections, compared to only detecting either of the antigens. The combined and quantitative detection of CCA and CAA is indicative for identifying the infecting species, but needs further exploration.

Schistosomiasis is a group of both acute and chronic parasitic trematode infections of the genus Schistosoma. Research into schistosomiasis has been minimal, leading to its classification as a neglected tropical disease, yet more than 140 million people are infected with schistosomes globally. There are no treatments available for early-stage infections, schistosomal dermatitis, or Katayama syndrome, other than symptomatic control with steroids and antihistamines, as the maturing organisms seem to be mostly resistant to typical antiparasitics. However, praziquantel (PZQ) has been the drug of choice for schistosomiasis for decades in the latter stages of the disease. Though it is effective against all three clinically relevant species, heavy reliance on PZQ has led to concerns of schistosome resistance, especially in areas that have implemented this drug in mass drug administration (MDA) programs. This article summarizes the available literature concerning the available evidence for and against a warranted concern for PZQ resistance, genomic studies in schistosomes, proposed mechanisms of resistance, and future research in alternative methods of schistosomiasis treatment.