Parasites & Vectors最新文献

Background: We aimed to investigate whether substances secreted by Clonorchis sinensis excretory/secretory protein (CS-ESP) have an effect on the inflammation of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) and to identify specific peptides through related proteomic analysis to determine which proteins exhibit anti-inflammatory effects more specifically.

Methods: Peripheral blood mononuclear cells (PBMCs) were obtained from healthy controls (HCs), RA and AS patients. Cytotoxicity of CS-ESP at different doses was assessed by MTS and flow cytometry before performing experiments. Inflammatory cytokine producing cells were analyzed using flow cytometry. To determine the effect of CS-ESP in an arthritis mouse model, 8-week-old SKG mice were injected intraperitoneally with curdlan and treated with CS-ESP; body weight and paw swelling were checked twice a week. Inflammation was evaluated using immunohistochemistry. We conducted proteomic analysis on CS-ESP and identified specific Cs-GT and Cs-Severin proteins. In vitro effect of coculture with Cs-GT and Cs-Severin was determined by inflammatory cytokine measurements.

Result: Treatment with CS-ESP resulted in no reduced cell viability of PBMCs. In experiments culturing PBMCs, the frequencies of IL-17A and GM-CSF producing cells were significantly reduced after CS-ESP treatment. In the SKG mouse model, CS-ESP treatment significantly suppressed clinical score, arthritis and enthesitis. Treatment with Cs-GT and Cs-Severin resulted in no reduced cell viability of HC PBMCs. After Cs-GT and Cs-Severin treatment of HC PBMC, the frequencies of IL-17A and GM-CSF producing cells were significantly reduced.

Conclusions: We provide evidence showing that CS-ESP, Cs-GT and Cs-Severin can ameliorate clinical signs and cytokine derangements in AS.

Background: Hemozoin is considered a waste byproduct of heme detoxification following hemoglobin digestion; consequently, the biological functions of hemozoin in hemozoin-producing organisms have often been overlooked. However, recent findings indicate that Schistosoma hemozoin facilitates the transfer of iron from erythrocytes to eggs through its formation and degradation, thereby increasing interest in the role of malarial hemozoin.

Methods: Using transmission electron microscopy, we compared the formation of Schistosoma hemozoin and malaria hemozoin. Through transcriptome analysis of different stages of P. falciparum 3D7^WT and P. falciparum 3D7^C580Y,- where the latter serves as a control with reduced hemozoin production, -we analyzed expression patterns of genes related to DNA synthesis, iron, and heme utilization. Using light microscopy, we observed hemozoin aggregation following artemether treatment, and macrophage morphology after ingesting hemozoin in vivo and in vitro.

Results: Similar to Schistosoma hemozoin, malaria hemozoin consists of heme aggregation and a lipid matrix, likely involved in lipid processing and the utilization of heme and iron. Transcriptome analysis reveals that during the trophozoite stage, the expression levels of these genes in P. falciparum 3D7^WT and P. falciparum 3D7C580Y are higher than those during the schizont stage. Correspondingly, less hemozoin was detected at the trophozoite stage, while more was observed during the schizont stage. These results suggest that when more heme and iron are utilized, less heme is available for hemozoin formation. Conversely, when less heme and iron are utilized, they can accumulate for hemozoin formation during the schizont stage, likely benefiting lipid remodeling. Disruption of heme utilization and hemozoin aggregation may lead to parasite death. In addition, the hemozoin released by schizonts can impair macrophage functions, potentially protecting merozoites from phagocytosis. Furthermore, it may be carried by gametocytes into the next host, fulfilling their requirements for iron and heme during their development in mosquitoes.

Conclusions: Hemozoin is not a waste byproduct of heme detoxification but instead plays a crucial role in the parasite's life cycle.

Background: Histological alterations such as nuclear abnormalities are sensitive biomarkers associated with diseases, tissue injury and environmental insults. While visual inspection and human interpretation of histology images are useful for initial characterization, such low-throughput procedures suffer from inherent limitations in terms of reliability, objectivity and reproducibility. Artificial intelligence and digital morphometry offer unprecedented opportunities to quickly and accurately assess nuclear morphotypes in relation to tissue damage including skin injury.

Methods: In this work, we designed NoxiScore, a pipeline providing an integrated, deep learning-based software solution for fully automated and quantitative analysis of nucleus-related features in histological sections of human skin biopsies. We used this pipeline to evaluate the efficacy and safety of three dermato-cosmetic products massively sold at the time of the study in the Montpellier area (South of France): a sunscreen containing UV filters, a mosquito repellent (with synthetic active ingredient IR3535) and a product combining a natural insect repellent plus a sunscreen. Hematoxylin and eosin or hematoxylin-eosin saffron staining was performed to assess skin structure before morphometric parameter computation.

Results: We report the identification of a specific nuclear feature based on variation in texture information that can be used to assess skin tissue damage after oxidative stress or UV exposure. Our data show that application of the commercial sun cream provided efficient protection against UV effects in our ex vivo skin model, whereas application of the mosquito repellent as a single product exerted no protective or toxic effect. Notably, we found that concurrent application of the insect repellent with the sunscreen significantly decreased the UVB protective effect of the sunscreen. Last, histometric analysis of human skin biopsies from multiple donors indicates that the sunscreen-insect repellent combo displayed variable levels of protection against UV irradiation.

Conclusions: To our knowledge, our study is the first to evaluate the potential toxicity of combining real-life sunscreen and insect repellent products using ex vivo human skin samples, which most closely imitate the cutaneous physiology. The NoxiScore wet-plus-dry methodology has the potential to provide information about the pharmaco-toxicological profile of topically applied formulations and may also be useful for diagnostic purposes and evaluation of the skin exposome including pesticide exposure, air pollution and water contaminants.

Background: Toscana virus (TOSV; Phlebovirus toscanaense), a phlebovirus transmitted by sand flies, is a growing public health concern in the Mediterranean region, with infections often being asymptomatic but potentially leading to neuroinvasive disease. Despite its presence in neighboring countries, data on TOSV seroprevalence in Portugal are limited. This study aimed to estimate the national seroprevalence of TOSV among blood donors in mainland Portugal and explore associations with sociodemographic factors and Leishmania infection.

Methods: A cross-sectional study was conducted using serum samples from 3593 blood donors across mainland Portugal, collected between February and June 2022. Anti-TOSV antibodies were detected via microneutralization assay, and anti-Leishmania antibodies had previously been tested using ELISA. Sociodemographic data were obtained from self-administered questionnaires. Seroprevalence was estimated by region, and multivariate logistic regression was used to identify factors associated with TOSV infection.

Results: Overall, the estimated national true seroprevalence of TOSV was 2.6% (95% CI 2.1-3.1%). Regional seroprevalence varied significantly, with the highest values (up to 14.8%) in Alto Alentejo, Baixo Alentejo, Douro, Alto Tâmega e Barroso and Oeste regions. Multivariate analysis showed that age ≥ 50 years (aOR 1.70, 95% CI 1.04-2.77), residing in the Alentejo region (aOR 3.05, 95% CI 1.85-5.02) and positive/borderline Leishmania serology (aOR 2.31, 95% CI 1.29-4.15) were significantly associated with TOSV infection.

Conclusions: This study highlights new areas of TOSV circulation in Portugal, particularly in regions with higher Leishmania seroprevalence and visceral leishmaniasis incidence, suggesting co-circulation of these pathogens. Although a lower seroprevalence was obtained compared to neighboring countries, TOSV should still be considered in the differential diagnosis of viral meningitis and encephalitis in Portugal, especially in potentially high-risk regions. Further research is needed to better understand the ecological drivers of TOSV distribution in Portugal.

Background: Metabolic responses to infection differ based on arthropod and pathogen. Increased metabolic rates can result in faster depletion of energetic resources, and decreases may allow for energy conservation. Babesia bovis is a protozoan pathogen transmitted by the cattle fever tick, Rhipicephalus microplus. Adult female ticks acquire B. bovis by feeding on an infected animal. Babesia bovis undergoes development and invades the ovaries where it is transmitted transovarially to tick offspring. The effects of infection on R. microplus metabolic rate are not well studied.

Methods: We tested the hypothesis that R. microplus infected with B. bovis would have altered metabolic rates (volume of carbon dioxide [VCO₂]) across life stages using flow-through respirometry. Replete females from either an infected or naïve calf were measured across 3 days to determine differences in VCO₂. Hemolymph smears were used to categorize the number of B. bovis kinetes present in the hemolymph of replete females during egg oviposition. The VCO₂ for groups of their offspring were measured twice as eggs and once as larvae. The number of individuals and successfully hatched larvae in each group were enumerated at the end of the experiment to determine the average VCO₂ per individual.

Results: Infected replete females have decreased VCO₂ while their offspring have increased VCO₂ at the egg and larval stages. Interestingly, replete females had a 25% reduction in body mass compared to uninfected female tick controls. Uninfected larvae were twice as likely to hatch than larvae from infected replete female ticks.

Conclusions: VCO₂ varied between control and infected ticks depending on life stage. Infected replete females had lower VCO₂ and body mass while their offspring had higher VCO₂ than their control counterparts. Higher larval VCO₂ may promote earlier questing and a shorter lifespan. Changes in metabolic and hatch rates have implications that may promote disease spread.

Background: Angiostrongylus cantonensis, the rat lungworm, is a metastrongyloid parasite that uses rodents as definitive hosts, mollusks as intermediate hosts, and a wide range of invertebrate and vertebrate species as paratenic hosts. Although this parasite poses a significant public health concern in many regions of the world, it can also cause disease in numerous domestic and wildlife aberrant host species. When parasite larvae are ingested by one of these aberrant hosts, larval migration in the central nervous system causes extensive damage, resulting in spinal cord and/or brain damage and inflammation, leading to potentially fatal neurological disease. We describe A. cantonensis infection in a novel host, the Florida burrowing owl (Athene cunicularia floridana), on Marco Island, Collier County, Florida, USA. The Florida burrowing owl is a state-listed species that has experienced steep population declines across its range, primarily due to habitat loss and fragmentation. Many populations are now restricted to urban environments, which pose novel threats to the owls, such as exposure to anticoagulant rodenticides and novel pathogens, increased risk of predation, vehicular strike, and increased disturbance at nest sites.

Methods: Through diagnostic evaluation of carcasses and select tissues submitted to the Southeastern Cooperative Wildlife Disease Study from 2019 to 2023, we diagnosed nine confirmed or suspected cases of angiostrongylosis on Marco Island.

Results: Microscopic examination and polymerase chain reaction (PCR) testing confirmed parasite identification. In addition, ancillary testing ruled out other potential causes of neurological disease, such as rodenticides, West Nile virus, and highly pathogenic avian influenza virus.

Conclusions: This study underscores the importance of surveillance and monitoring efforts for A. cantonensis, particularly in regions where novel hosts may serve as indicators of public health risk. In addition, as urbanization and habitat fragmentation continue encroaching upon wildlife habitats, understanding the dynamics of host-parasite interactions becomes crucial for mitigating the spread of zoonotic diseases.

Background: Wolbachia is present in all life stages of Dirofilaria immitis. Wolbachia surface protein (WSP) can be highly immunogenic and induce acute inflammatory reactions in the host upon worm death. To avoid the abrupt release of Wolbachia and its antigens from deceased parasites, the American Heartworm Society (AHS) has recommended using doxycycline (DOXY) and having a 1-month wait period between the DOXY treatment and the adulticidal process for Wolbachia elimination. Studies have shown that the 28 day, 10 mg/kg twice daily (BID) administration of DOXY can effectively clear Wolbachia in the bloodstream of the host. The 1-month wait period is hypothesized to allow for further reduction of Wolbachia. However, the levels of Wolbachia in adult parasites after the DOXY treatment remain unknown.

Methods: Forty-five purposely bred dogs were intravenously transplanted with 20 Dirofilaria immitis adults, consisting of 12 females and 8 males. The dogs were divided into nine groups of five dogs each. Two groups each received 5, 7.5, or 10 mg/kg DOXY BID orally for 28 days, and ivermectin (IVM) monthly (6 µg/kg.) Three groups remained untreated as controls. Study animals were necropsied on day 0, day 30, and day 60, following the start of treatment. Adult worms were collected at necropsy and preserved for analysis. Quantitative polymerase chain reaction (qPCR) and immunohistochemistry for WSP were performed on worms collected at each time point. The data were analyzed using a linear mixed model (LMM). Multiple comparisons were adjusted using Tukey's test.

Results: The qPCR results showed that all treatment doses significantly reduced Wolbachia levels compared with the control groups at 30 and 60 days. The intradose comparison indicated a significant decrease on day 60 compared with day 30. No significant differences were found between different doses on the two examination dates. Immunohistochemistry indicated the markedly reduced presence of Wolbachia in treatment groups.

Conclusions: All DOXY dosages can be considered effective in reducing Wolbachia on both tested dates (30 and 60 days). On the basis of the further reduction of Wolbachia levels in adult D. immitis, the 1-month rest period in the AHS heartworm treatment guidelines is beneficial. Wolbachia can still be detected on day 60 in all dosage groups.

Background: The pin nematode, belonging to the genus Paratylenchus, parasitizes higher plants, often causing reduced or inhibited root tip development.

Methods: Pin nematodes were isolated from the roots and rhizosphere of blueberry plants and subsequently identified as representatives of Paratylenchus projectus based on morphological characteristics and molecular barcoding. The P. projectus draft genome was sequenced using the Illumina platform.

Results: Phylogenetic analysis based on 18S, 28S and ITS rRNA placed this species in highly supported clades alongside other P. projectus specimens. The draft genome of P. projectus was sequenced and assembled, representing the first genomic data for both the genus Paratylenchus and the family Tylenchulidae. The assembled genome, though fragmented, had a total length of 191.36 Mb and an estimated genome size of 64.9 Mb. Protein-coding genes were predicted using four different databases, with particular focus on carbohydrate-active enzymes from the GH5 and GH18 families. The recovered GH5 genes were distributed among three distinct clades: one forming a basal group relative to other nematodes, one as a sister clade to the fungivorous nematode Aphelenchus avenae and one nested within a fungal clade. The GH18 chitinase genes were grouped into two clades: one closely related to sedentary plant-parasitic nematodes of the genera Heterodera and Globodera and the other closely related to the fungivorous nematode Ditylenchus.

Conclusions: The draft genome of Paratylenchus projectus was sequenced and assembled, representing the first genomic data for both the genus Paratylenchus and the family Tylenchulidae to our knowledge.

Background: The Cacao Region spans several municipalities in the state of Bahia. It is one of the major foci of American tegumentary leishmaniasis (ATL) in Brazil. We report the findings of a pilot cross-sectional study describing the phlebotomine fauna found around living sites of newly diagnosed ATL cases in that area.

Methods: The sand fly fauna was studied from May 2018 to June 2019 via an entomological survey, as recommended by the Brazilian Ministry of Health.

Results: Six hundred nineteen phlebotomine sand flies of 20 species were captured: 272 males (44%) and 347 females (56%). Nyssomyia whitmani was the most prevalent (62.2%), followed by Nyssomyia intermedia (9.2%), Evandromyia bahiensis (6.3%), endemic to Bahia, and Trichophoromyia viannamartinsi (4.5%). Ninety-four percent of the female sand flies collected were screened for infection with Leishmania (Viannia) braziliensis by polymerase chain reaction (PCR). Of the 97 sand fly pools analyzed, seven were positive for L. (V.) braziliensis: three of Nyssomyia whitmani, two of Th. viannamartinsi and one each of Psychodopygus hirsutus hirsutus and Trichopygomyia longispina. The overall value of minimum infection rate (MIR) was 2.2%, and its stratification rates for the above species were 1.9, 10, 33 and 50%, respectively. All positive pools consisted of phlebotomine sand flies collected from the peridomiciles and extradomiciles of homes in the municipality of Taperoá in July 2018, resulting in an adjusted MIR of 7.8%, with 50% of the pools positive for L. (V.) braziliensis during that outbreak of ATL.

Conclusions: Our findings suggest that areas experiencing outbreaks of ATL in affected regions present high proportions of infected phlebotomine sand flies involving a variety of species, some not usually considered involved in the L. (V.) braziliensis transmission cycle, such as Th. viannamartinsi.

Background: Aedes aegypti is expected to invade previously unoccupied areas, mainly due to the climate change, the increase in travel and trade activities and the continuous transformation of the rural environment into urban areas. The sterile insect technique (SIT), which relies on the mass production and release of sterile males, is an environmentally friendly approach that can be applied for population control of Ae. aegypti. SIT programs can be greatly benefited by a genetic sexing strain (GSS) and a reliable sex sorting system to minimize any accidental female release. Visually detectable or conditionally lethal selectable markers can be used for the development of new GSSs. In this study, we evaluated the suitability and competence of a mutant Ae. aegypti ebony strain for the development of a new GSS. The ebony gene is known to be involved in the pigmentation pathway of several dipteran insects, including Ae. aegypti.

Methods: An ebony gene knockout was developed though CRISPR/Cas9 mutagenesis. G₀ individuals with the desired phenotype were crossed, and progeny were screened in every generation. PCR and sequencing were performed using gDNA from a pulled leg to determine the mutant genotype. Quality control tests, including pupae and adult recovery rates, male sex ratio and fecundity, were applied to the ebony mutant line to determine whether the mutation confers any fitness cost.

Results: An Ae. aegypti ebony knockout mutant carrying a 5-bp deletion was obtained, which presented darker head and siphon phenotypes at the larval stage. However, genetic analysis revealed that this ebony mutation results in incomplete penetrance and variable expressivity. The establishment of a pure ebony mutant line was not possible because of the fitness costs conferred by the mutation.

Conclusions: In this study, the adequacy and suitability of the ebony gene as a selectable marker for the development of a GSS in Ae. aegypti were assessed. Despite its clear phenotype early in larval development, the homozygous mutant line presented phenotypic inconsistency and loss of fertility. These drawbacks clearly indicate that this particular mutation is not suitable for the development of a new GSS. Nonetheless, it cannot be excluded that a different mutation will lead to a different expression and penetrance profile and a viable homozygous mutant line.