The placenta plays a critical role in host-pathogen interactions. Thus, ex vivo infection of mammalian placental explants is an excellent and simple method to study the mechanisms of cellular and tissue invasion by different pathogens in different mammalian species. These explants can be maintained in culture for several days, preserving the tissue architecture and resembling in-utero conditions under more physiological conditions than their isolated counterparts in isolated cell culture models. In addition, placental explants not only allow us to study how the placenta responds and defends itself against various infections but also provide a versatile platform for advancing our understanding of placental biology and the immune response. Furthermore, they serve as powerful tools for drug discovery, facilitating the screening of potential therapeutics for placental infections and for the identification of diagnostic markers. This review highlights the utility of mammalian placental explants in studying the host-pathogen interaction of two relevant protozoan parasites, Trypanosoma cruzi, the causative agent of Chagas disease, and Toxoplasma gondii, the etiological agent of Toxoplasmosis. Here, we discuss the different methodologies and technical aspects of the model, as well as the effect of both parasites on placental responses in human, canine, and ovine explants.

BACKGROUND: It is well-documented that using immunosuppressive drugs such as corticosteroids or cytokine blockers in treating coronavirus disease 2019 (COVID-19) increases the risk of co-infections. Here we systematically summarized the cases of COVID-19-associated parasitic infections (CAPIs) in Iran.
METHODS: From 19 February 2020 to 10 May 2023, all studies on Iranian patients suffering from CAPIs were collected from several databases using a systematic search strategy.
RESULTS: Of 540 records, 11 studies remained for data extraction. In this research, most of the studies were related to Lophomonas and Toxoplasma. Of 411 cases of CAPIs, toxoplasmosis (385 [93.7%]) had the highest rate of infection among Iranian patients, followed by blastocystosis (15 [3.6%]), fascioliasis (4 [0.97%]), leishmaniasis (3 [0.7%]), lophomoniasis (3 [0.7%]) and strongyloidiasis (1 [0.2%]). In general, Blastocystis enhanced diarrhoea in patients with COVID-19. Lophomonas, Toxoplasma and Strongyloides increased the severity of COVID-19, but Fasciola decreased its intensity. Patients with a history of cutaneous leishmaniasis showed mild symptoms of COVID-19. Also, patients with a prior history of hydatid cysts were not affected by COVID-19.
CONCLUSIONS: Due to the similar symptoms of some parasitic diseases and COVID-19 and immunosuppressive treatment regimens in these patients that may cause the reactivation or recurrence of parasitic infections, early diagnosis and treatment are required.

BACKGROUND: Healthy eating habits are essential for improving nutritional status and strengthening immunity against infectious diseases. This study examined the relationship between diet quality and stunting in school-aged children in an infectious disease-endemic area of western Kenya.
METHODS: This cross-sectional study included 260 school-aged children (age 9-17 years) enrolled in primary schools in Mbita Sub-county, western Kenya. The nutritional status was assessed using anthropometric measurements. Dietary intake was measured using food frequency questionnaires and evaluated using the Food Pyramid (FP) score, which indicates adherence to the Kenyan food-based dietary guideline. Information on the children\'s age, sex, maternal education, and household wealth index was collected using a household-based questionnaire. Infections with the predominant parasites, such as Schistosoma (S.) mansoni, were detected via microscopy. The trend associations of the FP score with food group intake were examined to characterize the dietary intake of this population. Logistic regression analysis was performed to investigate the relationship between stunting and FP score tertiles, adjusted for sociodemographic and economic indicators and parasitic infection status.
RESULTS: Among the studied schoolchildren, 15.0% exhibited stunting, while 76.2% were infected with S. mansoni. The mean FP score was 25.6 out of 50 points. A higher FP score was characterized by a high intake of roots and tubers, dairy products, pulses, and fruits and a low intake of cereals and animal-source foods. The analysis revealed a trend: a lower risk of stunting was evident in groups with elevated FP scores (p for trend = 0.065). However, these trend associations were observable among subjects with either negative or light S. mansoni infection (p for trend = 0.016).
CONCLUSIONS: A higher quality diet, as evaluated by FP scores, was associated with a low risk of stunting among school-aged children. Notably, this association seemed to weaken in the presence of a high burden of S. mansoni infection. It highlights the importance of enhancing dietary quality through the promotion of diverse nutrient-dense foods alongside effective S. mansoni infection control for improved growth. This study contributes fundamental knowledge for understanding the diet-malnutrition relationship in areas endemic for S. mansoni infection.

Understanding how microbes interact with each other is key to revealing the underlying role that microorganisms play in the host or environment and to identifying microorganisms as an agent that can potentially alter the host or environment. For example, understanding how the microbial interactions associate with parasitic infection can help resolve potential drug or diagnostic test for parasitic infection. To unravel the microbial interactions, existing tools often rely on graphical models to infer the conditional dependence of microbial abundances to represent their interactions. However, current methods do not simultaneously account for the discreteness, compositionality, and heterogeneity inherent to microbiome data. Thus, we build a new approach called \"compositional graphical lasso\" upon existing tools by incorporating the above characteristics into the graphical model explicitly. We illustrate the advantage of compositional graphical lasso over current methods under a variety of simulation scenarios and on a benchmark study, the Tara Oceans Project. Moreover, we present our results from the analysis of a dataset from the Zebrafish Parasite Infection Study, which aims to gain insight into how the gut microbiome and parasite burden covary during infection, thus uncovering novel putative methods of disrupting parasite success. Our approach identifies changes in interaction degree between infected and uninfected individuals for three taxa, Photobacterium, Gemmobacter, and Paucibacter, which are inversely predicted by other methods. Further investigation of these method-specific taxa interaction changes reveals their biological plausibility. In particular, we speculate on the potential pathobiotic roles of Photobacterium and Gemmobacter in the zebrafish gut, and the potential probiotic role of Paucibacter. Collectively, our analyses demonstrate that compositional graphical lasso provides a powerful means of accurately resolving interactions between microbiota and can thus drive novel biological discovery.

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Neuroschistosomiasis is a rare manifestation of schistosomal infections presenting with cerebral and spinal cord involvement. We reported a case of a 31-year-old woman who presented with a history of headache, dizziness, and nausea. Brain MRI with contrast showed features suggestive of brain lesion with edema, and a serology test for Schistosoma was positive. She was diagnosed with neuroschistosomiasis and treated with intravenous steroids followed by praziquantel resulting in a significant regression of the brain mass. Cerebral neuroschistosomiasis is a rare complication of Schistosoma infection, and clinicians should consider it among the differential diagnosis of unexplained brain lesions.

We investigated the occurrence of organochlorine pollutants (OCs) in the muscle of brown trout and evaluated their potential modulation of parasite infection. The toxicological risk for consumer health was assessed, too. Trout were collected from the Sila National Park (Calabria region, South of Italy). The highest concentrations emerged for the sum of the 6 non-dioxin-like (ndl) indicator polychlorinated biphenyls (Σ6ndl-PCBs), followed by the 1,1,1-trichloro-2,2-di(4-chlorophenyl)-ethane (DDT), dioxin-like PCBs, hexachlorobenzene (HCB), and dieldrin. Measured on lipid weight (LW), the mean value of Σ6ndl-PCBs amounted to 201.9 ng g-1, that of ΣDDTs (the sum of DDT-related compounds) to 100.2 ng g-1, with the major contribution of the DDT-metabolite p,p\'-DDE which was detected in all sample units (97.6 ng g-1 on average). Among dioxin-like congeners, PCB 118 showed the highest mean concentration (21.96 ng g-1 LW) and was detected in all sample units. Regression analysis of intestinal parasites on OC concentration was performed, controlling for two potential confounding factors, namely sex and sexual stage. The results evidenced the existence of interactions between the dual stressors in the host-parasite system in the wild. A negative and statistically significant correlation was estimated, suggesting that OCs may decrease parasite infection degree. Regarding the toxicological risk evaluation, OC concentrations were consistently below the current European Maximum Residue Limits.

BACKGROUND: Quantifying infection intensity is a common goal in parasitological studies. We have previously shown that the amount of parasite DNA in faecal samples can be a biologically meaningful measure of infection intensity, even if it does not agree well with complementary counts of transmission stages (oocysts in the case of Coccidia). Parasite DNA can be quantified at relatively high throughput using quantitative polymerase chain reaction (qPCR), but amplification needs a high specificity and does not simultaneously distinguish between parasite species. Counting of amplified sequence variants (ASVs) from high-throughput marker gene sequencing using a relatively universal primer pair has the potential to distinguish between closely related co-infecting taxa and to uncover the community diversity, thus being both more specific and more open-ended.
METHODS: We here compare qPCR to the sequencing-based amplification using standard PCR and a microfluidics-based PCR to quantify the unicellular parasite Eimeria in experimentally infected mice. We use multiple amplicons to differentially quantify Eimeria spp. in a natural house mouse population.
RESULTS: We show that sequencing-based quantification has high accuracy. Using a combination of phylogenetic analysis and the co-occurrence network, we distinguish three Eimeria species in naturally infected mice based on multiple marker regions and genes. We investigate geographical and host-related effects on Eimeria spp. community composition and find, as expected, prevalence to be largely explained by sampling locality (farm). Controlling for this effect, the novel approach allowed us to find body condition of mice to be negatively associated with Eimeria spp. abundance.
CONCLUSIONS: We conclude that amplicon sequencing provides the underused potential for species distinction and simultaneous quantification of parasites in faecal material. The method allowed us to detect a negative effect of Eimeria infection on the body condition of mice in the natural environment.

The influence of diet on immune function and resistance to enteric infection and disease is becoming ever more established. Highly processed, refined diets can lead to inflammation and gut microbiome dysbiosis, whilst health-promoting dietary components such as phytonutrients and fermentable fibres are thought to promote a healthy microbiome and balanced mucosal immunity. Chicory (Cichorium intybus) is a leafy green vegetable rich in fibres and bioactive compounds that may promote gut health.
Unexpectedly, we here show that incorporation of chicory into semisynthetic AIN93G diets renders mice susceptible to infection with enteric helminths. Mice fed a high level of chicory leaves (10% dry matter) had a more diverse gut microbiota, but a diminished type-2 immune response to infection with the intestinal roundworm Heligmosomoides polygyrus. Furthermore, the chicory-supplemented diet significantly increased burdens of the caecum-dwelling whipworm Trichuris muris, concomitant with a highly skewed type-1 immune environment in caecal tissue. The chicory-supplemented diet was rich in non-starch polysaccharides, particularly uronic acids (the monomeric constituents of pectin). In accordance, mice fed pectin-supplemented AIN93G diets had higher T. muris burdens and reduced IgE production and expression of genes involved in type-2 immunity. Importantly, treatment of pectin-fed mice with exogenous IL-25 restored type-2 responses and was sufficient to allow T. muris expulsion.
Collectively, our data suggest that increasing levels of fermentable, non-starch polysaccharides in refined diets compromises immunity to helminth infection in mice. This diet-infection interaction may inform new strategies for manipulating the gut environment to promote resistance to enteric parasites.

Interest in host epigenetic changes during apicomplexan infections increased in the last decade, mainly due to the emergence of new therapies directed to these alterations. This review aims to carry out a bibliometric analysis of the publications related to host epigenetic changes during apicomplexan infections and to summarize the main studied pathways in this context, pointing out those that represent putative drug targets. We used four databases for the article search. After screening, 116 studies were included. The bibliometric analysis revealed that the USA and China had the highest number of relevant publications. The evaluation of the selected studies revealed that Toxoplasma gondii was considered in most of the studies, non-coding RNA was the most frequently reported epigenetic event, and host defense was the most explored pathway. These findings were reinforced by an analysis of the co-occurrence of keywords. Even though we present putative targets for repurposing epidrugs and ncRNA-based drugs in apicomplexan infections, we understand that more detailed knowledge of the hosts\' epigenetic pathways is still needed before establishing a definitive drug target.