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Visceral leishmaniasis (VL) is a severe infectious disease caused by protozoan parasites of the Leishmania donovani complex. Blood cytokine concentrations in VL patients can inform us about underlying immunopathogenesis and may serve as a biomarker for treatment effectiveness. However, cytokine levels have not yet been studied in VL patients from Kenya, where case load is high. This study measured the serum cytokine profile, blood parasite load and clinical and haematological features of VL patients from West Pokot County, Kenya, over the course of treatment with sodium stibogluconate and paromomycin (SSG-PM). VL patients recruited at the hospital presented with splenomegaly and weight loss, and frequently had pancytopenia and anaemia. Median Leishmania parasite load in blood, determined with real-time polymerase chain reaction, was 2.6 × 104 parasite equivalents mL−1. Compared to endemic healthy controls, serum interferon gamma (IFN-γ), interleukin 5 (IL-5), IL-6, IL-10, IL-12p70, IL-17A and IL-27 were significantly elevated in untreated VL patients. Severe VL was associated with higher IL-10 and lower IFN-γ levels. After 17 daily injections with SSG-PM, disease symptoms disappeared, leukocyte and thrombocyte counts significantly increased, and blood parasite load decreased to undetectable levels in all VL patients. There was a significant decrease in IL-10 and IL-6, whereas IL-17A levels increased; the remaining cytokines showed no significant concentration change during treatment. In conclusion, the results suggest that SSG-PM treatment of VL patients from West Pokot was effective. Moreover, both inflammatory and regulatory immune responses appeared to decrease during treatment, although the increase in IL-17A could reflect a partial continuation of immune activation.

Understanding which factors make an individual susceptible to parasitism provides insight on how a parasite infects a host. Numerous factors such as habitat characteristics, body size, and sex have shown differential impacts on parasitism rates. Trends in parasitism rate often exist for similar taxonomic groups, so expanding research to new species helps test the robustness of such trends. A chelonian-specific ectoparasite, Cistudinomyia cistudinis (Diptera: Sarcophagidae), has been documented in case studies dating back a century. Almost all reports of infection by this flesh fly are of a single or few turtles, so there is a lack of information regarding the population dynamics of infection. This lack of information means little is known about which factors make a turtle more or less likely to be parasitized. In this work, we compared the occurrences of parasitism in ornate box turtle (Terrapene ornata) populations across multiple seasons from 2 different habitats in northeastern Kansas (North Topeka and Lawrence). At the population level, we found a significantly higher number of parasitized turtles in the Lawrence population. Within the Lawrence population, we found females were more likely to be parasitized. This study sets baseline infection rates for a long-lived vertebrate host that can help better understand the reasons for parasitism both among and within populations. [ABSTRACT FROM AUTHOR]

Slugs are important agricultural pests causing yearly yield losses. However, parasitizing helminths potentially could affect the size of the slug population. Here, a survey of terrestrial slug-parasitic helminths (nematodes and trematodes) was conducted for the first time in Sweden. In total, 268 terrestrial slugs were collected from 27 agricultural field edges in three seasons over 2020 and 2021 and dissected for presence of helminth parasites. Slugs belonging to the genus Arion were molecularly identified by mitochondrial DNA cytochrome c oxidase subunit I (COI) while parasites were identified using ribosomal RNA (18S). Overall, 13% of the collected slugs had helminth parasites and the likelihood of a slug being parasitized was highest in autumn. Slugs identified as Arion vulgaris were more likely to be parasitized than native slug species. The prevalence of nematodes and trematodes were similar; the dominant species found were Alloionema appendiculatum and Brachylaima thompsoni, respectively. This is the first record of the presence of these two species in Sweden.

Background: Paramphistomosis, a parasitic condition caused by Calicophoron microbothrioides in domestic ruminants, has garnered limited attention among cattle breeders in the Cajamarca Valley, Peru. Despite its status as an endemic affliction with considerable risk, scant investigations have been conducted on this parasite within this region. Objective: This study aimed to assess the correlation between the population of adult parasites (referred to as "number of adult parasites" or NAP) in rumen and reticulum of naturally infected cows and the number of eggs per gram of feces (EPG). Methods: A sample of twenty-two cattle harboring adult parasites in their rumen and reticulum was selected for analysis. Fecal samples were collected from these animals to establish a correlation between NAP and EPG. Data analysis included linear regression, the Shapiro-Wilk normality test, and the nonparametric Mann-Whitney test. Results: The study revealed a remarkably strong and directly proportional association between the number of adult parasites in rumen and reticulum and the coproparazitologic EPG (r = 0.971). Conclusion: According to the linear model (NAP = 60.381 ± 3.37; EPG - 22.979) increasing EPG by one lead to an increase by 60 NAP in rumen and reticulum (p<0.01). [ABSTRACT FROM AUTHOR]

Anti-helminthic drugs (Albendazole and Levamisole) trials were conducted on Indian Peafowls (n = 20) kept at Jallo Wildlife Park, Lahore, Pakistan for 15. Sampling was conducted on days 7 and 15 of treatments. The results showed that the WBC count was significantly (P

Inbreeding depression (ID) occurs when inbreeding negatively impacts fitness. Understanding ID in wildlife is crucial for conservation and management, but obtaining good estimates of inbreeding and fitness to study ID on such systems can be challenging. Furthermore, the possible modulation of ID by various intrinsic and extrinsic variables can make its detection and interpretation uncertain in the absence of detailed individual and environmental information. Here we tested for ID in the culturally important population of feral horses (Equus ferus caballus) of Sable Island, Canada, using inbreeding coefficients derived from ~ 30,000 Single Nucleotide Polymorphisms (SNPs) and individual-based data for three fitness-related traits (body condition [BC], strongyle fecal egg count [FEC], and age at first reproduction [AFR]). We further assessed whether the expression of ID in this population was modulated by intrinsic (age, sex, reproductive status) and extrinsic (location, year) variables. ID was detected for all traits but mediating variables differed. For both BC and FEC, ID varied among years and was greater in the western portion of the island. In contrast, ID for BC was strongest in juveniles and lactating mares while for FEC it was strongest for reproductive-aged horses and males. Lastly, ID for AFR was mediated by cohort effects. Our study indicates that ID is impacting the fitness and welfare of Sable Island horses, but that its intensity varies among traits and ecological contexts. This illustrates the importance of considering both intrinsic and extrinsic variables to understand the expression of ID in the wild. [ABSTRACT FROM AUTHOR]

Hysterothylacium aduncum is a parasitic nematode that infects mainly marine fish. The information on the heterogeneity in the aggregation of macroparasites in fish species is still limited, particularly for the Raphidascarid nematode H. aduncum that infects exploitable marine fish species including horse mackerel (Trachurus trachurus). This study aimed to investigate the heterogeneity of the distribution of H. aduncum to better understand macroparasite aggregation in marine fish. Weibull tests comprising Maximum likelihood were used to analyze the frequency distribution of parasites within a fish host population over the three years period. The parasite, H. aduncum (third larval stage) prevalence was found to be 88% and the condition factor was 1.30∓0.029 in un-infected fish and 1.12∓0.022 in infected fish. The clustered pattern was observed in H. aduncum in horse mackerel. The relation between parasite load and the fish condition factor was found to be significant and conformity of length and weight was affected by parasite load. It is the first time that aggregation has been observed in H. aduncum distribution and forecasts of nematode intensity in horse mackerel. The findings related to the large individual variations suggest that this pattern is significant and should be considered for host-parasite dynamics. [ABSTRACT FROM AUTHOR]

The reintroduction of captive animals to the wild helps restore endangered species, but it risks pathogen transmission, harming wild populations. Such transmission can impact the genetic diversity and long-term viability of these populations. This study assessed parasite diversity and load in captive Pecari tajacu, a species native to the Americas and culturally significant to Brazilian indigenous culture, prior to reintroduction. Samples from 24 peccaries were analyzed for ectoparasites, hemopathogens, and stool parasites with direct and molecular analysis. Findings showed that various parasites were present. Two peccaries (8.3%) were infested by the adult tick Amblyomma sculptum. Six (25.0%) tested positive for Trypanosoma evansi, four (16.7%) for hemobacteria of the family Anaplasmataceae, twelve (50.0%) for hemotropic Mycoplasma, and seven (29.2%) for Leishmania braziliensis. Stool samples indicated multiple parasites, with sixteen (66.7%) peccaries infected by Strongylida order parasites, Spiruridae in three (12.5%), and Ascaris suum in one (4.2%) animal. Cysts of Balantidium sp. were found in twenty (83.3%), Entamoeba polecki in five (20.8%), and Iodamoeba bütschlii in two (8.3%) peccaries. To our current knowledge, this is the first global report of Leishmania braziliensis, Iodamoeba bütschlii, and Entamoeba polecki in P. tajacu, irrespective of the environment, including both captivity and wild conditions. Some of these parasites are common in domestic animals, and others are zoonotic, indicating potential interspecies pathogen transmission. [ABSTRACT FROM AUTHOR]

Anti-helminthic drugs (Albendazole and Levamisole) trials were conducted on Indian Peafowls (n = 20) kept at Jallo Wildlife Park, Lahore, Pakistan for 15. Sampling was conducted on days 7 and 15 of treatments. The results showed that the WBC count was significantly (P < 0.05) higher in both samples in response to Levamisole treatment. Haemoglobin (HGB) and Mean Corpuscular Haemoglobin Concentration (MCHC) concentration increased significantly (P < 0.05) in response to both treatments; however, Mean Corpuscular Haemoglobin (MCH) decreased significantly (P < 0.05) in Albendazole-treated birds on both the sampling days compared to the control. Red Blood Cell Distribution Width-Standard Deviation (RDW-SD) decreased significantly (P < 0.05) in all treatment groups. On the other hand, the prevalence of eggs per gram (EPG) was reduced by 20% after the application of Levamisole on days 7 and 15. It was concluded that both drugs had significant effects on WBCs, HGB, MCH, MCHC and RDW-SD. [ABSTRACT FROM AUTHOR]

Background Focused efforts of the visceral leishmaniasis elimination program have led to a drastic decline in cases, and the present challenge is disease monitoring, which this study aimed to assess. Methods A Leishmania kinetoplastid-targeted qPCR quantified parasite load at disease presentation, and following treatment completion (n=49); an additional 80 cases were monitored after completion of treatment. Results The parasite load at disease presentation was 13 461.00 (2560.00–37764.00)/µg gDNA, which upon completion of treatment reduced in 47 of 49 cases to 1(1–1)/µg gDNA, p<0.0001. In 80 cases that presented >2 months post-treatment, their parasite burden similarly decreased to 1(1–1)/µg gDNA except in 6 of 80 cases, which were qPCR positive. Conclusion In 129 cases of visceral leishmaniasis, qPCR by quantification of parasite burden proved effective for monitoring treatment. [ABSTRACT FROM AUTHOR]

Abstract In urban environments, domestic dogs (Canis familiaris) are a major reservoir for the parasite Leishmania infantum. Miltefosine has been used as the standard treatment for canine visceral leishmaniasis in Brazil. However, therapeutic failures have been reported. In the present study, two dogs (CG03 and CG06) with a diagnosis of infection by L. infantum underwent two cycles of treatment with miltefosine (Milteforan™ - Virbac®). Analyses showed increases in the parasite load of both CG03 and CG06, even after treatment. The clinical score of CG03 dropped from 1 to 0 (after one round of treatment), such that this dog became asymptomatic. CG06 showed clinical worsening, such that its score increased from 1 to 2. After the second therapeutic round, the parasite load in CG03 was found to have decreased, but it was still higher than before drug treatment even though this dog was physically asymptomatic. There was no decrease in the parasite load in CG06 and there was clinical worsening. The clinical response of these dogs to the treatment differed, but the parasite load remained high in both cases, which poses a risk to public health, making it essential take measures to prevent the sandfly vector from accessing the dog.

BackgroundLeishmaniasis is an infectious disease caused by protozoa of the genus Leishmania. There are still no vaccines, and therapeutic options are limited, indicating the constant need to understand the fine mechanisms of its pathophysiology. An approach that has been explored in leishmaniasis is the participation of microRNAs (miRNAs), a class of small non-coding RNAs that act, in most cases, to repress gene expression. miRNAs play a role in the complex and plastic interaction between the host and pathogens, either as part of the host’s immune response to neutralize infection or as a molecular strategy employed by the pathogen to modulate host pathways to its own benefit.MethodsMonocyte-derived macrophages from healthy subjects were infected with isolates of three clinical forms of L. braziliensis: cutaneous (CL), mucosal (ML), and disseminated (DL) leishmaniasis. We compared the expression of miRNAs that take part in the TLR/NFkB pathways. Correlations with parasite load as well as immune parameters were analyzed.ResultsmiRNAs -103a-3p, -21-3p, 125a-3p -155-5p, -146a-5p, -132- 5p, and -147a were differentially expressed in the metastatic ML and DL forms, and there was a direct correlation between miRNAs -103a-3p, -21-3p, -155-5p, -146a-5p, -132-5p, and -9-3p and parasite load with ML and DL isolates. We also found a correlation between the expression of miR-21-3p and miR-146a-5p with the antiapoptotic gene BCL2 and the increase of viable cells, whereas miR-147a was indirectly correlated with CXCL-9 levels.ConclusionThe expression of miRNAs is strongly correlated with the parasite load and the inflammatory response, suggesting the participation of these molecules in the pathogenesis of the different clinical forms of L. braziliensis.

Leishmaniasis is a zoonotic disease with worldwide distribution. In the Americas, the causative agent of the visceral form is the protozoa Leishmania (Leishmania) infantum. Transmission to the host or vertebrate reservoir occurs through the bite of infected arthropod females like Lutzomyia longipalpis. The epidemiological connection between the infection in dogs and humans generate constant studies about the relationship between the parasite and the canine host, including the development of methods and tests for the detection and quantification ofLeishmania (L.) infantum. Both conventional PCR (cPCR) and quantitative PCR (qPCR) can be used in the diagnosis of the parasite. Dropet Digital PCR (ddPCR) is another useful tool. Knowing the parasite load and its relationship with the clinical signs of naturally infected dogs is useful in research development and for establishing treatments that reduce the transmission of the disease. In this study, thirty-nine clinical samples of spleen from dogs naturaly infected by L. infantum were collected after necropsy. Two molecular tools were used to quantify the parasite load (qPCR and ddPCR) and there was 100% agreement in the results of the them. The tools developed in this work are important for the detection of L. infantum in dogs and humans. Droplet Digital PCR does not require a standard curve and is easy to standardize. In such manner, this new tool can generate more in-depth information in the broad debate about parasitic loads and the pathogenesis of leishmaniasis. [ABSTRACT FROM AUTHOR]

Despite the enormous morbidity attributed to schistosomiasis, there is still no vaccine to combat the disease for the hundreds of millions of infected people. The anthelmintic drug, praziquantel, is the mainstay treatment option, although its molecular mechanism of action remains poorly defined. Praziquantel treatment damages the outermost surface of the parasite, the tegument, liberating surface antigens from dying worms that invoke a robust immune response which in some subjects results in immunologic resistance to reinfection. Herein we term this phenomenon Drug-Induced Vaccination (DIV). To identify the antigenic targets of DIV antibodies in urogenital schistosomiasis, we constructed a recombinant proteome array consisting of approximately 1,000 proteins informed by various secretome datasets including validated proteomes and bioinformatic predictions. Arrays were screened with sera from human subjects treated with praziquantel and shown 18 months later to be either reinfected (chronically infected subjects, CI) or resistant to reinfection (DIV). IgG responses to numerous antigens were significantly elevated in DIV compared to CI subjects, and indeed IgG responses to some antigens were completely undetectable in CI subjects but robustly recognized by DIV subjects. One antigen in particular, a cystatin cysteine protease inhibitor stood out as a unique target of DIV IgG, so recombinant cystatin was produced, and its vaccine efficacy assessed in a heterologous Schistosoma mansoni mouse challenge model. While there was no significant impact of vaccination with adjuvanted cystatin on adult worm numbers, highly significant reductions in liver egg burdens (45-55%, P

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In the absence of validated biomarkers to control the cure of Chagas disease, PCR-based diagnosis is being used as the main tool for an early indication of therapeutic failure. However, since it is considered a technique of complex reproducibility, mainly due to difficulties in establishing accurate controls to guarantee the quality of the reaction, the use of PCR for Chagas disease diagnosis is restricted to specialized centers. In an effort to disseminate the molecular diagnosis of Chagas disease and its applications, new diagnostic kits based on qPCR have been made available in the market in recent years. Here, we show the results of the validation of the NAT Chagas kit (Nucleic Acid Test for Chagas Disease) for the detection and quantification of T. cruzi in blood samples of patients suspected of Chagas disease infection. The kit, composed of a TaqMan duplex reaction targeting the T. cruzi satellite nuclear DNA and an exogenous internal amplification control, presented a reportable range from 104 to 0.5 parasite equivalents/mL and a limit of detection (LOD) of 0.16 parasite equivalents/mL of blood. In addition, the NAT Chagas kit detected T. cruzi belonging to all six discrete typing units (DTUs—TcI to TcVI), similarly to the in-house real-time PCR performed with commercial reagents, which has been selected as the best performance assay in the international consensus for the validation of qPCR for Chagas disease. In the clinical validation presented here, the kit showed 100% sensitivity and 100% specificity when compared to the consensus in-house real-time PCR assay. Thus, the NAT Chagas kit, which is produced entirely in Brazil under the international standards of good manufacturing practices (GMP), appears as an excellent alternative to enable the molecular diagnosis of Chagas disease in public and private diagnostic centers, as well as to facilitate the monitoring of patients under etiological treatment participating in clinical trials. [ABSTRACT FROM AUTHOR]

Modulation of brain serotonin (5-HT) signalling is associated with parasite-induced changes in host behaviour, potentially increasing parasite transmission to predatory final hosts. Such alterations could have substantial impact on host physiology and behaviour, as 5-HT serves multiple roles in neuroendocrine regulation. These effects, however, remain insufficiently understood, as parasites have been associated with both increased and decreased serotonergic activity. Here, we investigated effects of trematode Euhaplorchis californiensis metacercariae on post-stress serotonergic activity in the intermediate host California killifish (Fundulus parvipinnis). This parasite is associated with conspicuous behaviour and increased predation of killifish by avian end-hosts, as well as inhibition of post-stress raphe 5-HT activity. Until now, laboratory studies have only been able to achieve parasite densities (parasites/unit host body mass) well below those occurring in nature. Using laboratory infections yielding ecologically relevant parasite loads, we show that serotonergic activity indeed decreased with increasing parasite density, an association likely indicating changes in 5-HT neurotransmission while available transmitter stores remain constant. Contrary to most observations in the literature, 5-HT activity increased with body mass in infected fish, indicating that relationships between parasite load and body mass may in many cases be a real underlying factor for physiological correlates of body size. Our results suggest that parasites are capable of influencing brain serotonergic activity, which could have far-reaching effects beyond the neurophysiological parameters investigated here.

Giardiasis and other protozoan infections are major worldwide causes of morbidity and mortality, yet development of new antimicrobial agents with improved efficacy and ability to override increasingly common drug resistance remains a major challenge. Antimicrobial drug development typically proceeds by broad functional screens of large chemical libraries or hypothesis-driven exploration of single microbial targets, but both strategies have challenges that have limited the introduction of new antimicrobials. Here, we describe an alternative drug development strategy that identifies a sufficient but manageable number of promising targets, while reducing the risk of pursuing targets of unproven value. The strategy is based on defining and exploiting the incompletely understood adduction targets of 5-nitroimidazoles, which are proven antimicrobials against a wide range of anaerobic protozoan and bacterial pathogens. Comprehensive adductome analysis by modified click chemistry and multi-dimensional proteomics were applied to the model pathogen Giardia lamblia to identify dozens of adducted protein targets common to both 5'-nitroimidazole-sensitive and -resistant cells. The list was highly enriched for known targets in G. lamblia, including arginine deiminase, α-tubulin, carbamate kinase, and heat shock protein 90, demonstrating the utility of the approach. Importantly, over twenty potential novel drug targets were identified. Inhibitors of two representative new targets, NADP-specific glutamate dehydrogenase and peroxiredoxin, were found to have significant antigiardial activity. Furthermore, all the identified targets remained available in resistant cells, since giardicidal activity of the respective inhibitors was not impacted by resistance to 5'-nitroimidazoles. These results demonstrate that the combined use of click chemistry and proteomics has the potential to reveal alternative drug targets for overcoming antimicrobial drug resistance in protozoan parasites.

The impacts of parasites on hosts and the role that parasites play in ecosystems must be underlain by the load of parasites in individual hosts. To help explain and predict parasite load across a broad range of species, quantitative theory has been developed based on fundamental relationships between organism size, temperature and metabolic rate. Here, we elaborate on an aspect of that scaling theory for parasitism, and test a previously unexplored prediction, using new data for total ectoparasite load from 263 wild birds of 42 species. We reveal that, despite the expected substantial variation in parasite load among individual hosts, (i) the theory successfully predicts the distinct increase of ectoparasite load with host body size, indicating the importance of geometric scaling constraints on access to host resources, (ii) ectoparasite load appears ultimately limited by access-not to host space-but to host energy, and (iii) there is a currency-dependent shift in taxonomic dominance of parasite load on larger birds. Hence, these results reveal a seemingly new macroecological pattern, underscore the utility of energy flux as a currency for parasitism and highlight the promise of using scaling theory to provide baseline expectations for parasite load for a diversity of host species.

Within the theoretical framework of the small population paradigm, we investigated the population genomics and parasite load of two bumblebee species across the UK and Ireland. Bombus pratorum is widespread and common throughout its range while Bombus monticola is restricted to higher altitudes and shows a more fragmented distribution.Bombus monticola showed stronger population structuring, isolation‐by‐distance, and a deficit of heterozygotes in the most isolated population in the south of its range (Dartmoor). Heterozygosity and inbreeding coefficients (FIS) were comparable between both species, but the proportion of polymorphic sites was much greater in B. pratorum. Notably, both species have suffered significant declines in Ne over the last 100 generations and estimates and declines for both species were of similar orders of magnitude. No pattern of increased parasite prevalence in populations of lower heterozygosity was observed. Instead, ecological and demographic factors (age, latitude, date, habitat suitability) were the main drivers of parasite prevalence.Distinct patterns of selection were observed in both species in regions involved in regulation of transcription and neurotransmission and in particular pathways targeted by neonicotinoid insecticides.Our results highlight the pressing need for monitoring to include common as well as rare species. This should not focus solely on census population counts, but include estimates of Ne. We also highlight the need for further work to establish adaptive shifts in globally important pollinator communities. [ABSTRACT FROM AUTHOR]

Systemic control uses the vertebrate hosts of zoonotic pathogens as "Trojan horses," killing blood‐feeding female vectors and short‐circuiting host‐to‐vector pathogen transmission. Previous studies focused only on the effect of systemic control on vector abundance at small spatial scales. None were conducted at a spatial scale relevant for vector control and none on the effect of systemic control on pathogen transmission rates. We tested the application of systemic control, using Fipronil‐impregnated rodent baits, in reducing Leishmania major (Kinetoplastida: Trypanosomatidae; Yakimoff & Schokhor, 1914) infection levels within the vector, Phlebotomus papatasi (Diptera: Psychodidae; Scopoli, 1786) population, at the town‐scale. We provided Fipronil‐impregnated food‐baits to all Psammomys obesus (Mammalia:Muridae; Cretzschmar, 1828), the main L. major reservoir, burrows along the southern perimeter of the town of Yeruham, Israel, and compared sand fly abundance and infection levels with a non‐treated control area. We found a significant and substantial treatment effect on L. major infection levels in the female sand fly population. Sand fly abundance was not affected. Our results demonstrate, for the first time, the potential of systemic control in reducing pathogen transmission rates at a large, epidemiologically relevant, spatial scale. [ABSTRACT FROM AUTHOR]

Background: Schistosomiasis is endemic in Cameroon and continues to cause serious public health problems, especially among populations in rural areas. This study aimed at determining the prevalence and risk factors of urinary and intestinal schistosomiasis in Manjo. Method: A cross-sectional study was conducted in the city of Manjo in 2020. Stool and urine samples were collected from 400 participants. These stool and urine samples were examined by the Kato Katz, and centrifugation methods respectively. Results: The results obtained showed an overall prevalence of 6.25%, with 5% and 1.25% for S. mansoni and S. haematobium respectively. A significant difference (p

The reintroduction of captive animals to the wild helps restore endangered species, but it risks pathogen transmission, harming wild populations. Such transmission can impact the genetic diversity and long-term viability of these populations. This study assessed parasite diversity and load in captive Pecari tajacu, a species native to the Americas and culturally significant to Brazilian indigenous culture, prior to reintroduction. Samples from 24 peccaries were analyzed for ectoparasites, hemopathogens, and stool parasites with direct and molecular analysis. Findings showed that various parasites were present. Two peccaries (8.3%) were infested by the adult tick Amblyomma sculptum. Six (25.0%) tested positive for Trypanosoma evansi, four (16.7%) for hemobacteria of the family Anaplasmataceae, twelve (50.0%) for hemotropic Mycoplasma, and seven (29.2%) for Leishmania braziliensis. Stool samples indicated multiple parasites, with sixteen (66.7%) peccaries infected by Strongylida order parasites, Spiruridae in three (12.5%), and Ascaris suum in one (4.2%) animal. Cysts of Balantidium sp. were found in twenty (83.3%), Entamoeba polecki in five (20.8%), and Iodamoeba bütschlii in two (8.3%) peccaries. To our current knowledge, this is the first global report of Leishmania braziliensis, Iodamoeba bütschlii, and Entamoeba polecki in P. tajacu, irrespective of the environment, including both captivity and wild conditions. Some of these parasites are common in domestic animals, and others are zoonotic, indicating potential interspecies pathogen transmission.

Dornelor Basin is characterised by numerous high quality water sources, which is proven by the fact that the main mineral waters on the Romanian market come from this area. The study aimed to provide data on the occurrence and human infective potential of Giardia and Cryptosporidium, as the most important water-borne parasites, from Bistrița river tributaries of Dornelor basin, North-Eastern Romania. Water samples were collected from 10 tributaries of the Bistrita river, from the level of sampling stations set upstream and downstream from the anthropic communities. The harvested water samples were further processed using non-molecular methods in order to isolate (oo)cysts. Subsequently, the isolated Cryptosporidium and Giardia (oo)ccyst were molecularly characterized through PCR and genomic sequencing, which led to the identification of Giardia in order to identify them at species level. The outcomes revealed the fact that the waters of the emissaries under study have a low parasite load and that, upstream from the human settlements, the water is highly pure when related to the protozoa under study. The increased load of Giardia spp. and Cryptosporidium spp. corresponded to important animal husbandry activity. The obtained results underline a potential public health risk.

Toxoplasma gondii is the causative agent of toxoplasmosis, a disease that affects warm-blooded animals and one third of the human population worldwide. Pregnant women who have never been exposed to the parasite constitute an important risk group, as infection during pregnancy often leads to congenital toxoplasmosis, the most severe form of the disease. Current therapy for toxoplasmosis is the same as it was 50 years ago and has little or no effect when vertical transmission occurs. Therefore, it is urgent to develop new strategies to prevent mother-to-fetus transmission. The implementation of experimental animal models of congenital toxoplasmosis that reproduces the transmission rates and clinical signs in humans opens an avenue of possibilities to interfere in the progression of the disease. In addition, knowing the parasite load in maternal and fetal tissues after infection, which may be related to organ abnormalities and disease outcome, is another important step in designing a promising intervention strategy. Therefore, we implemented here a murine model of congenital toxoplasmosis with outbred Swiss Webster mice infected intravenously with tachyzoites of the ME49 strain of T. gondii that mimics the frequency of transmission of the parasite, as well as important clinical signs of human congenital toxoplasmosis, such as macrocephaly, in addition to providing a highly sensitive quantitative real-time PCR assay to assess parasite load in mouse tissues. As the disease is not restricted to humans, also affecting several domestic animals, including companion animals and livestock, they can also benefit from the model presented in this study. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is one of the most common parasitic zoonoses that affects all vertebrates. The drugs most commonly used against toxoplasmosis have many side effects, making the development of new antiparasitic drugs a big challenge. The present study evaluated the therapeutic effectiveness of novel herbal treatments, including propolis and wheat germ oil (WGO), against acute toxoplasmosis. A total of 50 albino mice were divided into five groups: group 1 (G1) (non-infected and non-treated); group 2 (G2) (infected without treatment); group 3 (G3) (treated with propolis); group 4 (G4) (treated with WGO); group 5 (G5) (treated with a combination of propolis and WGO). The effects of the herbal substances on different organs, mainly liver, spleen, and lungs, were investigated using parasitological, molecular, and histopathological examinations. The results of parasitological examination demonstrated statistically significant (p < 0.05) differences in the parasitic load between treated groups (G3, G4, and G5) compared to the control positive group (G2). These differences were represented by a significant reduction in the parasite load in stained tissue smears from the liver obtained from the animals treated with propolis (G3) compared to the parasite load in the positive control group. Similarly, animals (G4) treated with WGO exhibited a significant reduction in the parasite load versus the positive control group, while the lowest parasite load was found in G5, treated with propolis and WGO. Quantification of the parasite burden through molecular methods (PCR) revealed similar findings represented by reduction in the parasite burden in all treated groups with WGO and propolis as compared to the control group. Importantly, these previous parasitological and molecular findings were accompanied by a marked improvement in the histopathological picture of the liver, spleen, and lungs. In conclusion, propolis and WGO showed a good combination of therapeutic efficacy against acute toxoplasmosis. [ABSTRACT FROM AUTHOR]

Background: The adjuvants' optimal dose and the administration route can directly influence the epitope recognition patterns and profiles of innate response. We aimed to establish the effect and the optimal dose of adjuvant systems for proposing a vaccine candidate to be employed with Leishmania (Viannia) braziliensis. Methods: We evaluated the adjuvants saponin (SAP), monophosphoryl lipid A (MPL) and resiquimod (R-848) isolated and combined as adjuvant systems in a lower dose corresponding to 25%, 33%, and 50% of each adjuvant total dose. Male outbred BALB/c mice were divided into 13 groups, SAP, MPL, and R-848 isolated, and the adjuvant systems SAP plus MPL (SM), SAP plus R-848 (SR), and MPL plus R-848 (MR). Results: SM50 increased levels of all chemokines analyzed and TNF production, while it presented an increased inflammatory cell infiltrate in the skin with macrophage recruitment. Thus, we proposed a vaccine candidate employing L. (V.) braziliensis antigen associated with the SM adjuvant system against experimental L. (Leishmania) infantum challenge. We observed a significant increase in the frequency of cells expressing the central and effector memory CD4+ T cells phenotype in immunized mice with the LBSM50. In the liver, there was a decreased parasite load when mice received LBSM50. Conclusions: When combined with L. (V.) braziliensis antigen, SM50 increases TNF and IFN-γ, which generates central and effector memory CD4+ T cells. Therefore, using an adjuvant system can promote an effective innate immune response with the potential to compose future vaccines. [ABSTRACT FROM AUTHOR]

The transmission cycles of Trypanosoma cruzi, the causative agent of Chagas disease, include a wide variety of mammals and hematophagous triatomine insects. Infection with this blood parasite has been confirmed in many armadillo species; however, information on infection in Zaedyus pichiy, a small armadillo that inhabits areas endemic to Chagas disease, is scarce. Our objective was to determine the infection frequency and parasite load of T. cruzi in 49 wild Z. pichiy confiscated dead from poachers in Mendoza, Argentina, 2010–2017. We detected T. cruzi DNA in 32 of 49 armadillos (65%) using real-time PCR, confirming infection with T. cruzi in a high proportion of confiscated pichis. No differences were found related to sex, age, or ecoregion origin of the assessed pichis. Parasite loads ranged between <0.1 and 8.88 parasite equivalents/microgram cardiac tissue. Additional studies on the infection status of Z. pichiy are needed to determine their role in the maintenance of the sylvatic transmission cycle and the potential zoonotic risk from hunted pichis. [ABSTRACT FROM AUTHOR]

Amniotic fluid DNA samples were genotyped by multilocus-nested-PCR-RFLP, but only three of 11 markers amplified 113 of 122 (92.6%) samples, resulting in 12 untyped and 101 partial non-archetypal genotypes. The 101 typed samples were subdivided into four groups: G1 with 73 samples (5'and 3' SAG2 allele I + SAG3 allele III + GRA6 allele III), 53 had parasite load = 102 parasites/mL (43 asymptomatic, 10 mild infections), 17 had load > 102 and = 103 (one mild, 13 moderate and three severe), and three had load > 103 parasites/mL (three severe); G2 with 22 samples (5'and 3' SAG2 allele I + SAG3 allele III), all parasite load levels = 102 parasites/mL (18 asymptomatic and four mild); G3 with five samples (5' and 3' SAG2 allele I + SAG3 allele II), parasite load = 102 parasites/mL (three asymptomatic and two mild); G4 with one sample (5' and 3' SAG2 allele II + SAG3 allele II + GRA6 allele I), a parasite load < 102 parasites/mL in an asymptomatic infant. After DNA sequencing, restriction sites confirmed SAG2, SAG3 and GRA6 alleles in 98.7%, 100% and 100% of the cases, respectively, while single nucleotide polymorphisms confirmed 90% of 5'-SAG2 allele I; 98.7% of 3'-SAG2 allele I; 98% of SAG-3 allele III, but only 40% of GRA6 allele III results. For the moment, partial non-archetypal genotypes of parasites did not show any relationship with either parasite load in amniotic fluid samples or clinical outcome of infants at the age of 12 months. [ABSTRACT FROM AUTHOR]

Gastrointestinal (GI) parasites may impose detrimental consequences on wildlife populations due to their capacity to cause mortality and reduce fitness. Additionally, wild animals play an important role in the transmission of zoonoses. Despite this importance, information on GI parasites of tropical wild mammals is critically lacking. The present study aimed to document GI parasites of six wild-dwelling large mammal taxa in Sri Lanka: Asian elephant (Elephas maximus), Sloth bear (Melursus ursinus), civet (Paradoxurus sp.), Leopard (Panthera pardus), Grey langur (Semnopithecus priam) and buffalo (Bubalus sp). Fresh faecal samples (n = 56) collected from the Wasgomuwa National Park, Sri Lanka were subjected to coprological examination using faecal smears, and the brine floatation technique followed by microscopic identification; quantitative data were accrued using the formol-ether method. The survey revealed a high prevalence of GI parasites, where 86% (48/56) of faecal samples screened positive for parasitic infections. Faecal samples of the civet, buffalo and Leopard recorded 100% prevalence, while the lowest (40%) was recorded for the Grey langur. Eight types of GI parasites were documented: protozoan cysts, platyhelminth ova (three types of digenean and a single cyclophillidean type), nematode ova (strongyle, strongyloid, ascarid, and trichuroid types) and rhabditiform larvae. The buffaloes and civets had a comparatively high number and diversity of GI parasites (buffalo: 7 types, H’ = 1.02; civet: 6 types, H’ = 1.52), whilst only a single type (digenean) was detected in the Grey langur. Likewise, parasite loads were also highly variable; highest in the bear (486 per g faeces) and lowest in the monkey (10 per g faeces). The outcome of this survey is important on two accounts; i) to fill the knowledge gap on GI parasites of tropical wild mammals, and ii) the revelation of many first-time parasite-host records for some of the threatened wild-dwelling large mammals in Sri Lanka.

Abstract Background Counting parasite transmission stages in faeces is the classical measurement to quantify “parasite load”. DNA-based quantifications of parasite intensities from faecal samples are relatively novel and often validated against such counts. When microscopic and molecular quantifications do not correlate, it is unclear whether oocyst counts or DNA-based intensity better reflects biologically meaningful concepts. Here, we investigate this issue using the example of Eimeria ferrisi (Coccidia), an intracellular parasite of house mice (Mus musculus). Methods We performed an infection experiment of house mice with E. ferrisi, in which the intensity of infection correlates with increased health impact on the host, measured as temporary weight loss during infection. We recorded the number of parasite transmissive stages (oocysts) per gram of faeces (OPG) and, as a DNA-based measurement, the number of Eimeria genome copies per gram of faeces for 10 days post-infection (dpi). We assessed weight loss relative to the day of experimental infection as a proxy of host health and evaluated whether DNA or oocyst counts are better predictors of host health. Results Absolute quantification of Eimeria DNA and oocyst counts showed similar but slightly diverging temporal patterns during 10 dpi. We detected Eimeria DNA earlier than the first appearance of oocysts in faeces. Additionally, Eimeria OPGs within each dpi did not explain parasite DNA intensity. Early dpi were characterized by high DNA intensity with low oocyst counts, while late infections showed the opposite pattern. The intensity of Eimeria DNA was consistently a stronger predictor of either maximal weight loss (1 value per animal during the infection course) or weight loss on each day during the experiment when controlling for between-dpi and between-individual variance. Conclusions Eimeria ferrisi oocyst counts correlate weakly with parasite intensity assessed through DNA quantification. DNA is likely partially derived from life-cycle stages other than transmissive oocysts. DNA-based intensities predict health outcomes of infection for the host more robustly than counts of transmissive stages. We conclude that DNA-based quantifications should not necessarily require validation against counts of transmissive stages. Instead, DNA-based load estimates should be evaluated as complementary sources of information with potential specific biological relevance for each host-parasite system. Graphical Abstract

Abstract Background The distribution of parasite load across hosts may modify the transmission dynamics of infectious diseases. Chagas disease is caused by a multi-host protozoan, Trypanosoma cruzi, but the association between host parasitemia and infectiousness to the vector has not been studied in sylvatic mammalian hosts. We quantified T. cruzi parasite load in sylvatic mammals, modeled the association of the parasite load with infectiousness to the vector and compared these results with previous ones for local domestic hosts. Methods The bloodstream parasite load in each of 28 naturally infected sylvatic mammals from six species captured in northern Argentina was assessed by quantitative PCR, and its association with infectiousness to the triatomine Triatoma infestans was evaluated, as determined by natural or artificial xenodiagnosis. These results were compared with our previous results for 88 humans, 70 dogs and 13 cats, and the degree of parasite over-dispersion was quantified and non-linear models fitted to data on host infectiousness and bloodstream parasite load. Results The parasite loads of Didelphis albiventris (white-eared opossum) and Dasypus novemcinctus (nine-banded armadillo) were directly and significantly associated with infectiousness of the host and were up to 190-fold higher than those in domestic hosts. Parasite load was aggregated across host species, as measured by the negative binomial parameter, k, and found to be substantially higher in white-eared opossums, cats, dogs and nine-banded armadillos (range: k = 0.3–0.5) than in humans (k = 5.1). The distribution of bloodstream parasite load closely followed the “80–20 rule” in every host species examined. However, the 20% of human hosts, domestic mammals or sylvatic mammals exhibiting the highest parasite load accounted for 49, 25 and 33% of the infected triatomines, respectively. Conclusions Our results support the use of bloodstream parasite load as a proxy of reservoir host competence and individual transmissibility. The over-dispersed distribution of T. cruzi bloodstream load implies the existence of a fraction of highly infectious hosts that could be targeted to improve vector-borne transmission control efforts toward interruption transmission. Combined strategies that decrease the parasitemia and/or host–vector contact with these hosts would disproportionally contribute to T. cruzi transmission control. Graphical Abstract

Toxoplasma gondii is the causative agent of toxoplasmosis, a disease that affects warm-blooded animals and one third of the human population worldwide. Pregnant women who have never been exposed to the parasite constitute an important risk group, as infection during pregnancy often leads to congenital toxoplasmosis, the most severe form of the disease. Current therapy for toxoplasmosis is the same as it was 50 years ago and has little or no effect when vertical transmission occurs. Therefore, it is urgent to develop new strategies to prevent mother-to-fetus transmission. The implementation of experimental animal models of congenital toxoplasmosis that reproduces the transmission rates and clinical signs in humans opens an avenue of possibilities to interfere in the progression of the disease. In addition, knowing the parasite load in maternal and fetal tissues after infection, which may be related to organ abnormalities and disease outcome, is another important step in designing a promising intervention strategy. Therefore, we implemented here a murine model of congenital toxoplasmosis with outbred Swiss Webster mice infected intravenously with tachyzoites of the ME49 strain of T. gondii that mimics the frequency of transmission of the parasite, as well as important clinical signs of human congenital toxoplasmosis, such as macrocephaly, in addition to providing a highly sensitive quantitative real-time PCR assay to assess parasite load in mouse tissues. As the disease is not restricted to humans, also affecting several domestic animals, including companion animals and livestock, they can also benefit from the model presented in this study.

Helminths have coevolved with their hosts, resulting in the development of specialized host immune mechanisms and parasite-specific regulatory products. Identification of new pathways that regulate helminth infection could provide a better understanding of host-helminth interaction and may identify new therapeutic targets for helminth infection. Here we identify the endocannabinoid system as a new mechanism that influences host immunity to helminths. Endocannabinoids are lipid-derived signaling molecules that control important physiologic processes, such as feeding behavior and metabolism. Following murine infection with Nippostrongylus brasiliensis, an intestinal nematode with a life cycle similar to that of hookworms, we observed increased levels of endocannabinoids (2-arachidonoylglycerol [2-AG] or anandamide [AEA]) and the endocannabinoid-like molecule oleoylethanolamine (OEA) in infected lung and intestine. To investigate endocannabinoid function in helminth infection, we employed pharmacological inhibitors of cannabinoid subtype receptors 1 and 2 (CB1R and CB2R). Compared to findings for vehicle-treated mice, inhibition of CB1R but not CB2R resulted in increased N. brasiliensis worm burden and egg output, associated with significantly decreased expression of the T helper type 2 cytokine interleukin 5 (IL-5) in intestinal tissue and splenocyte cultures. Strikingly, bioinformatic analysis of genomic and transcriptome sequencing (RNA-seq) data sets identified putative genes encoding endocannabinoid biosynthetic and degradative enzymes in many parasitic nematodes. To test the novel hypothesis that helminth parasites produce their own endocannabinoids, we measured endocannabinoid levels in N. brasiliensis by mass spectrometry and quantitative PCR and found that N. brasiliensis parasites produced endocannabinoids, especially at the infectious larval stage. To our knowledge, this is the first report of helminth- and host-derived endocannabinoids that promote host immune responses and reduce parasite burden.

Simple Summary: The consumption of fish represents a healthy and affordable alternative for a large sector of the population; among the species with the highest consumption worldwide are tilapia. However, its consumption may be associated with health risks of a parasitic type. Through the analysis of the available scientific literature on parasitic prevalence in tilapia, it was observed that fish obtained from the wild and aquaculture represent a risk of parasitosis in human populations. Additionally, a high prevalence of cestodes and a greater diversity of trematodes were found. Finally, the presence of the genus Gnathostoma must stand out. This synthesis of information can be useful as a platform for the develCopment of intervention programs for parasite control, and it also suggests continuing with the study of zoonotic parasites related to the consumption of tilapia in geographical areas of high consumption. Tilapia has a high socioeconomic value in many countries worldwide. However, it has been identified as a zoonotic parasite reservoir. A systematic literature search and meta-analysis were carried out in order to estimate the global prevalence of zoonotic parasites that affect tilapia. The search was performed by three field experts to avoid reviewer bias. Polled prevalence was estimated using a logistic-normal random-effect regression model in the R software. We dealt with the heterogeneity among studies through subgroup analysis, taking into account the continent, country, genus of the host, parasite taxonomic group, sample origin, and type of diagnostic test as moderator variables. Fifty-two eligible articles were identified covering five tilapia genera with a pooled prevalence of 0.14 (95% CI: 0.10–0.20) showed significant heterogeneity (I2 = 98.4; p < 0.001). The subgroup analysis revealed that the most affected host was Sarotherodon, with a prevalence of 0.42 (95% CI: 0.22–0.65). Cestode was the taxonomic group with the largest prevalence (0.40; 95% CI:0.32–0.48), followed by amoeba (0.24; 95% CI: 0.16–0.35) and nematode (0.22; 95% CI: 0.11–0.38), among which, Schyzocotyle spp., Opistorchis spp., Gnathostoma spp. and Vermamoeba spp. have an impact on public health. Significant differences (p < 0.004) were found among continents and countries, with the highest value of prevalence detected in the African continent (0.28; 95% CI: 0.20–0.37), specifically in Tanzania (0.56; 95% CI: 0.22–0.87) and Egypt (0.43; 95% CI: 0.20–0.55). The origin of samples had a significant effect (p < 0.0001) on the detected prevalence, especially from those that showed the highest prevalence (0.24; 95% CI: 0.17–0.33). Finally, there were no differences in prevalence according to the diagnostic test (p = 0.97). Our results provide useful information on the development of epidemiological programs for the control of zoonoses associated with parasites in tilapia and in the design, planning, and implementation of future research. [ABSTRACT FROM AUTHOR]

Simple Summary: Intestinal nematodes were analyzed in three small rodent species: Apodemus sylvaticus, Apodemus flavicollis, and Myodes glareolus. In total, 15 species of nematodes were identified. We studied the relationship between the parasitological parameters (individual parasite species richness IndPSR and individual parasite load IndPL) and morphological characteristics (body mass, body condition index BCI, and spleen mass). In all of the studied species, our results showed that animals in a better condition (BCI) had significantly higher parasite species richness, as we had expected. Furthermore, we showed that females of the same BCI as males were parasitized with more parasite species in A. flavicollis. Contrary to our expectations, the spleen mass did not reflect changes in the level of parasitism, but in M. glareolus, a smaller spleen was related to a higher parasite load. Since the spleen is just part of the complex immune response, it is possible that the presence of nematode parasite species provokes, in small rodent species, a response at the other levels of the immune system. Nematode burdens and variation in morphological characteristics were assessed in eighty-eight animals from three host species (Apodemus sylvaticus, Apodemus flavicollis, and Myodes glareolus) from eight localities in Serbia. In total, 15 species of nematodes were identified, and the overall mean parasite species richness (IndPSR) was 1.61 per animal (1.98 in A. flavicollis, 1.43 in M. glareolus, and 0.83 in A. sylvaticus). Furthermore, the studied host species significantly differed in individual parasite load (IndPL) and in the following morphological characters: spleen mass, body condition index (BCI), and body mass. We aimed to analyze the relationship between the burden of intestinal nematodes, on one hand, and the body conditions of the host and its capability to develop immune defends on the other. Spleen mass was considered as a measure of immune response. In all host species, larger animals with a better condition (higher BCI) were infected with more parasites species (IndPSR), while parasite load was not related to BCI. Only in A. flavicollis were males significantly larger, but females of the same sizes were infected with more parasite species. This female-biased parasitism is contrary to the theoretical expectation that males should be more parasitized, being larger, more active, with a wider home range. Although the spleen size was significantly correlated with body condition and body mass, IndPSR was not related to spleen mass in any studied species, but in M. galareolus, we found that a smaller spleen was related to higher infection intensity (IndPL). [ABSTRACT FROM AUTHOR]

Objective. To identify the abundance and prevalence in infection by digestive parasites (DPs) and their seasonal distribution in dogs from Aguascalientes, Mexico. Materials and Methods. A statistically representative sample (n=927) systematically selected (first in each 10), of stray or owners-surrendered dogs at a local animal control and welfare center was examined. Immediately after legal euthanasia (pre-anesthetic plus anesthetic overdose), the entire intestine was removed, and intestinal contents were sieved; macroscopically visible helminths were collected; a stool sample was then examined in duplicate by flotation, McMaster, and Lugol's-stained smear. Results. The prevalence of DPs was 42.8%. Elevated prevalence values were detected among puppies (60.6%), in dogs with lower body weight (72.7%), also in stray dogs (57.5%) compared with those voluntarily surrendered by their owners (37.5%; p<0.01); additionally, more cases were found during temperate seasons (51.0 vs 33.1%; p<0.01). The DPs prevalence values were determined: Dipylidium caninum (26.2%), Taenia spp. (4.0%), Giardia spp. (13.6%), Cystoisospora spp. (7.8%), Sarcocystis spp. (5.3%); Toxocara canis (14.0%), Ancylostoma caninum (12.9%), Uncinaria stenocephala (4.2%), Toxascaris leonina (0.5%), and Oncicola canis (0.1%). The DPs reached a high prevalence with hundreds of adult forms in the intestine and thousands of eggs or oocysts per gram of feces. Conclusions. These results indicated a high prevalence of DPs in dogs of central Mexico, especially in the population segment constituted by stray, young and underweight animals, which is relevant in public health due to its recognized zoonotic capacity. [ABSTRACT FROM AUTHOR]

Trypanosoma cruzi , the causative agent of Chagas disease, can be congenitally transmitted by crossing the placental barrier. This study investigates the role of T. cruzi -derived exovesicles (TcEVs) in facilitating parasite infection and the consequent tissue damage and apoptotic cell death in human placental explants (HPEs). Our findings demonstrate that TcEVs significantly enhance the parasite load and induce tissue damage in HPEs, both in the presence and absence of the parasite. Through histopathological and immunohistochemical analyses, we show that TcEVs alone can disrupt the placental barrier, affecting the basal membrane and villous stroma. The induction of apoptotic cell death is evidenced by DNA fragmentation, caspase 8 and 3, and p18 fragment immunodetection. This damage is exacerbated when TcEVs are combined with T. cruzi infection. These findings suggest that TcEVs play a critical role in the pathogenesis of congenital Chagas disease by disrupting the placental barrier and facilitating parasite transmission to the fetus. This study provides new insights into the mechanisms of transplacental transmission of T. cruzi and highlights the potential of targeting TcEVs as a therapeutic strategy against congenital Chagas disease., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Fernández-Moya, Oviedo, Liempi, Guerrero-Muñoz, Rivas, Arregui, Araneda, Cornet-Gomez, Maya, Müller, Osuna, Castillo and Kemmerling.)

The European badger (Meles meles) is a common mustelid species known as a significant reservoir for various human and animal diseases. Studies investigating Leishmania infection in European badgers across Mediterranean regions have yielded inconsistent findings. In Spain, results are particularly controversial: some studies confirm the presence of Leishmania in badgers, while others do not. Our study aimed to conduct a retrospective histopathological and immunohistochemical analysis to detect Leishmania in tissues of nine European badgers from northeastern Spain, a region previously unevaluated for Leishmania infection in this species. Microscopic examination revealed lesions indicative of leishmaniosis in the lymph nodes and spleens of six badgers. In one of them, Leishmania-like structures were identified in multiple organs and confirmed via immunohistochemistry. Parasites were detected in the lymph nodes, spleen, adrenal glands, and pancreas. The parasite load was high in the adrenal glands, moderate in the lymph nodes and spleen, and low in the pancreas. No parasites were found in other examined organs. This finding represents a frequency of 11.11% (1/9) of Leishmania infection among the badgers we studied. Further investigation of wildlife and atypical reservoirs can enhance our understanding of the pathogenesis of this significant zoonotic disease., (© 2024. The Author(s).)

Leishmaniasis is a parasitic disease spread by the bite of an infected sandfly and caused by protozoan parasites of the genus Leishmania. Currently, there is no vaccine available for leishmaniasis in humans, and the existing chemotherapy methods face various clinical challenges. The majority of drugs are limited to a few toxic compounds, with some parasite strains developing resistance. Therefore, the discovery and development of a new anti-leishmanial compound is crucial. One promising strategy involves the use of nanoparticle delivery systems to accelerate the effectiveness of existing treatments. In this study, Amphotericin B (AmB) was incorporated into functionalized carbon nanotube (f-CNT) and evaluated for its efficacy against Leishmania major in vitro and in a BALB/c mice model. The increase in footpad thickness was measured, and real-time PCR was used to quantify the parasite load post-infection. Levels of nitric oxide and cytokines IL-4 and IFN-γ were also determined. We found that f-CNT-AmB significantly reduced the levels of promastigotes and amastigotes of the Leishmania parasite. The nanoparticle showed strong anti-leishmanial activity with an IC 50 of 0.00494 ± 0.00095 mg/mL for promastigotes and EC 50 of 0.00294 ± 0.00065 mg/mL for amastigotes at 72 h post-infection, without causing harm to mice macrophages. Treatment of infected BALB/c mice with f-CNT-AmB resulted in a significant decrease in cutaneous leishmania (CL) lesion size in the foot pad, as well as reduced Leishmania burden in both lymph nodes and spleen. The levels of nitric oxide and IFN-γ significantly increased in the f-CNT-AmB treated groups. Also, our results showed that the level of IL-4 significantly decreased after f-CNT-AmB treatment in comparison to other groups. In conclusion, our results demonstrate that AmB loaded into f-CNT is significantly more effective than AmB alone in inhibiting parasite propagation and promoting a shift towards a Th1 response., (© 2024 John Wiley & Sons Ltd.)

Interleukin 27 (IL-27) is a cytokine that regulates susceptibility to Leishmania infantum infection in humans and experimental models. This cytokine has not yet been described in canine leishmaniasis (CanL). Therefore, we investigated whether IL-27 has a regulatory role in CanL. The EBI3 and p28 subunits of IL-27 were measured in splenic leukocytes culture supernatant from dogs with CanL and compared to control dogs. We also correlated EBI3 and p28 levels with IL-21, anti-L. infantum antibodies and parasite loads. We performed functional assays followed by IL-27 blockade and measured parasite loads, production of cytokines in splenic leukocytes culture supernatant, and the expression of PD-1, CTLA-4, phospho-Stat-1/3, T-bet, GATA3 and nitric oxide production (NO). Both IL-27 subunits increased in the supernatant of dogs with CanL compared to control dogs. EBI3 and p28 levels showed a moderate positive correlation with IL-21 (r = 0.67, p < 0.0001 and r = 0.45, p < 0.012, respectively), and the EBI3 subunit was positively associated with anti-L. infantum IgG antibodies (r = 0.38, p < 0.040) and parasite load (r = 0.47, p < 0.009). IL-27 and IL-21 participate of immune responses in CanL. IL-27 may be associated with the failure of immunity to control parasite replication via upregulation of the expression of PD-1, CTLA-4, T-bet and NO in splenic leukocytes from dogs with CanL. These findings suggest that the pathways regulated by IL-27 are involved in CanL pathogenesis in the host, and may be targets for new therapies., (© 2024 John Wiley & Sons Ltd.)

Toxoplasma gondii (T.gondii) is an obligate intracellular protozoan that infects warm-blooded animals and has a global distribution. Acute toxoplasmosis is commonly reported in patients with acquired/congenital toxoplasmosis and immune deficiency. New methods are needed to prevent the sideffects of classical treatment. In this study, Rosuvastatin loaded chitosan nanoparticle (CH-NP-ROS) were synthesized and zeta potential and size were determined, and an MTT assay was performed to evaluate the cell toxicity on Macrophage cells (MQ) and anti-Toxoplasma activity using Trypan-blue staining by different concentrations of Rosuvastatin (ROS), and Rosuvastatin loaded chitosan nanoparticle (CH-NP-ROS). The cell viability assay demonstrated that CH-NP-ROS had lower cell toxicity (<15 %) compared to ROS (<30 %). Statistical analysis showed that CH-NP-ROS significantly killed 98.950 ± 1.344; P < 0.05) of Toxoplasma gondii tachyzoites. In vivo results of perituneal fluid showed that CH-NP significantly reduced the parasite load in the CH-NP-ROS group, compared to that in negative control group (P < 0.001). Growth inhibition rates of tachyzoites in mice receiving free ROS and CH-NP-ROS (injection and oral form) were found to be 166.125 + 4.066, 118.750 + 4.596 and 124.875 + 2.652, respectively, compared to mice in Sulfadiazine/Pyrimethamine treated group (positive control). In the infected untreated mice (control +), the mean tachyzoite counts per oil immersion field in the spleen was 8.25 respectively. The mean survival time in all the groups treated with ROS and CH-NP-ROS was longer than that in the negative control group Therefore, nanoformulation is a promising approach for the delivery and is safe for using therapeutic effects in acute toxoplasmosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Leishmaniasis is one of the most important neglected tropical parasitic diseases, manifesting various clinical forms depending on the parasite species and the genetic background of the host. In order to elucidate the underlying mechanisms of reptilian defense against pathogenic Leishmania species and to delineate the global gene expression profile alterations during host-pathogen interaction, we established experimental animal and cell models using both heterothermic lizards (Phrynocephalus przewalskii) and homothermic mammals (BALB/c mice) infected with pathogenic Leishmania infantum (high virulence HCZ strain) and Leishmania donovani (low virulence 801 strain). Overall, the lizards didn't show any obvious clinical symptoms or immune responses in vivo. Using RNA-seq methodology, differentially expressed genes identified in the HCZ and 801-comparison groups of P. przewalskii were primarily associated with arginine biosynthesis, the MAPK signaling pathway and the PI3K-Akt signaling pathway. In contrast, higher parasite loads, exacerbated hepatic inflammatory lesions and enhanced immune responses were observed in BALB/c mice, with DEGs predominantly associated with immunological diseases, innate and adaptive immune responses. By integrating transcriptional data from reptile and mammalian hosts, we elucidated the pivotal role of amino acid metabolism and lipid metabolism in parasite control. In contrast to findings from animal experiments, Leishmania parasites effectively infected peritoneal macrophages of lizards in vitro, demonstrating a high infection rate. Furthermore, we used RT-qPCR to detect changes in cytokine expression in macrophages and found that Th1-type cytokines were significantly upregulated in lizards, facilitating the clearance of the HCZ strain 24 hours post-infection. Conversely, cytokine expression was generally suppressed in BALB/c mice, allowing immune evasion by the parasites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: Toxoplasma gondii is an intracellular opportunistic pathogenic protozoan that poses serious threats, particularly in immunocompromised individuals. In the absence of a robust prophylactic measure, the mitigation and management of toxoplasmosis present formidable challenges to public health. We recently found that GRA72 plays an important role in parasitophorous vacuole (PV) morphology, growth and virulence of T. gondii. However, whether gra72-deficient strain can be used as a vaccine remains unknown., Methods: We first examined the attenuated virulence of gra72 gene knockout strain (PruΔgra72) and the parasite load in organs of the infected mice. Subsequently, we evaluated the immune-protective effects of the PruΔgra72 vaccination against challenge with various types of T. gondii tachyzoites and Pru cysts. Furthermore, levels of antibodies and cytokines induced by PruΔgra72 vaccination were examined. Statistical analysis was conducted by Student's t-test or Mantel-Cox log-rank test based on data obtained from three independent experiments with GraphPad Prism 8.0., Results: We found that PruΔgra72 strain exhibited a significantly attenuated virulence even at the highest dose of 5 × 10 7 tachyzoites in Kunming mice model. The significant decrease of brain cyst burden and parasite load in the organs of the PruΔgra72-infected mice suggested its potentiality as a live-attenuated vaccine. Hence, we explored the protective immunity of PruΔgra72 vaccination against toxoplasmosis. Results showed that vaccination with 5 × 10 6 PruΔgra72 tachyzoites triggered a strong and sustained Th1-biased immune response, marked by significantly increased levels of anti-T. gondii IgG antibodies, and significantly higher levels of Th1 type cytokines (IL-2, IL-12 and IFN-γ) compared to that of Th2 type (IL-4 and IL-10). Vaccination with 5 × 10 6 PruΔgra72 tachyzoites in mice conferred long-term protection against T. gondii infection by less virulent tachyzoites (ToxoDB#9 PYS and Pru strains) and Pru cysts, provided partial protection against acute infection by high virulent Type I RH tachyzoites and significantly decreased brain cyst burden of chronically infected mice., Conclusions: The avirulent PruΔgra72 induced strong protective immunity against acute and chronic T. gondii infection and is a promising candidate for developing a safe and effective live-attenuated vaccine against T. gondii infection., (© 2024. The Author(s).)

The spotted seatrout, Cynoscion nebulosus, is a popular game fish in the southeastern USA. It is estimated that nearly 90% of the adult population in South Carolina estuaries are infected in their skeletal muscle by the myxosporean, Kudoa inornata. However, little is known about this parasite's biology, including the distribution and densities of myxospores within tissues of infected fish, which we expect affect the physiology of their hosts. In order to correlate densities with physiological parameters in future studies, we quantified the myxospores density in muscle and characterized the variation among individual fish. Naïve juvenile seatrout was experimentally infected via presumed K. inornata actinospores exposure to raw seawater. A plug of muscle was extracted from two bilaterally symmetrical regions in the epaxial fillet from fresh and frozen carcasses. Variation in density data was calculated both within and among individuals. Within individuals, density counts were compared between left- and right-side biopsies. There was no significant difference between fresh and frozen plugs, and variation among individuals accounted for the greatest proportion of variation at 68.8%, while variation within individuals was substantial at 25.6%. Simulation and correlation tests confirmed that bilaterally symmetrical replicates varied significantly within individuals. When sampled from areas surrounding the initial biopsies, myxospore density estimates were more similar than between sides. Our findings have important implications for sampling design, particularly for studies investigating physiological parameters at the cellular or molecular level in association with parasite infection., (© 2024. The Author(s).)

Purpose: The influence of two key factors, host length and infection site, on the host-parasite interaction in Ompok bimaculatus (Butter catfish) from Mukutmanipur Dam Lake, were investigated., Methods: Present study involved 192 specimens of Ompok bimaculatus with varying body lengths, subjected to diverse statistical analyses. One-way analysis of variance (ANOVA) was performed for the parasite numbers for three groups (cestode, nematode and trematode). Subsequently, we conducted one-way permutational multivariate analysis of variance (PERMANOVA) followed by pairwise test to assess parasite numbers across three body sites (intestine, mesentery, and bodycavity), employing the Bray-Curtis index. Additionally, Principal Coordinate Analysis (PCoA) for the same dataset was performed using the same index. Linear regression analysis was performed for the fish length-cestode number, fish length-nematode number, fish length-trematode number and fish length-total parasite number., Results: One-way ANOVA revealed no significant differences in parasite numbers among the three endo-helminth groups (cestode, nematode, and trematode). The results of PERMANOVA revealed significant differences in parasite numbers across the three body sites of the host fishes (groups) (F = 9.41, p = 0.0001). Pairwise tests further demonstrated significant differences between the intestine-mesentery, intestine-body-cavity, and mesentery-body-cavity. Additionally, Principal Coordinate Analysis (PCoA) unveiled a significant relationship between infection site and parasite number. However, linear regression analysis examining the relationship between fish length and parasite abundance indicated no significant associations., Conclusions: Through a detailed exploration of the statistical analyses, we provide insights into the host-parasite interaction, elucidating both established knowledge and novel findings in fish parasitology., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Purpose: This study describes the composition and infection patterns of macro endoparasites associated with the lizard Phyllopezus periosus., Methods: We collected 115 P. periosus over 12 expeditions on the rocky cliffs of the Missão Velha waterfall canyon in northeastern Brazil. Specimens were collected by hand, during active searches conducted between 18:00 h and 23:30 h. The infection patterns were estimated using prevalence, total abundance, and mean intensity of infection for all parasites found., Results: A total of 4256 parasites were collected from 104 hosts, resulting in an exceptionally high overall prevalence of 90.4%. No significant ontogenetic difference in the prevalence of infection was detected. Although juveniles exhibited a high parasite prevalence their parasite loads were significantly lower compared to adults. Six species of endoparasites were found; among these, the nematode Spauligodon oxkutzcabiensis was the most common endoparasite in the digestive tract, while the pentastomid Raillietiella mottae was the only species found in the respiratory tract., Conclusions: Infection rates in Gekkota species appear to correlate with body size, with larger individuals generally exhibiting a higher prevalence. This pattern was also observed across separate populations of P. periosus and other geckos from distinct ecological domains. The dominance of the monoxenous S. oxkutzcabiensis highlights potential transmission mechanisms, suggesting that behaviors such as limb licking after feeding may contribute to its prevalence. The occurrence of Physalopteroides venancioi, Oswaldocruzia sp., Parapharyngodon sp., Physaloptera sp., infecting P. periosus are new records for this host. These findings significantly contribute to the knowledge of host-parasite dynamics in geckos., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Chagas disease affects millions of people in Colombia and worldwide, with its transmission influenced by ecological, environmental, and anthropogenic factors. There is a notable correlation between vector transmission cycles and the habitats of insect vectors of the parasite. However, the scale at which these cycles operate remains uncertain. While individual triatomine ecotopes such as palms provide conditions for isolated transmission cycles, recent studies examining triatomine blood sources in various habitats suggest a more intricate network of transmission cycles, linking wild ecotopes with human dwellings. This study aims to provide further evidence on the complexity of the scale of Trypanosoma cruzi transmission cycles, by exploring the different blood sources among developmental stages of infected triatomines in different habitats. We evaluated infection rates, parasite loads, feeding sources, and the distribution of Rhodnius prolixus insects in Attalea butyracea palms across three distinct habitats in Casanare, Colombia: peridomestics, pastures, and woodlands. Our results show that there is no clear independence in transmission cycles in each environment. Analyses of feeding sources suggest the movement of insects and mammals (primarily bats and didelphids) among habitats. A significant association was found between habitat and instar stages in collected R. prolixus. The N1 stage was correlated with pasture and woodland, while the N4 stage was related to pasture. Additionally, adult insects exhibited higher T. cruzi loads than N1, N2, and N3. We observed higher T. cruzi loads in insects captured in dwelling and pasture habitats, compared with those captured in woodland areas. Effective Chagas disease control strategies must consider the complexity of transmission cycles and the interplay between domestic and sylvatic populations of mammals and vectors., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)