Echinococcosis lacks sensitive serological diagnostic tools. The echinococcosis-specific antigens Eg95, AgB8/1 and the Em18 gene sequences were fused and expressed as the novel recombinant antigens rAgB8/1-Em18-Eg95 (T3) and rEm18-Eg95 (T2), used for the diagnosis of hydatid disease, prepared into an enzyme-linked immunosorbent reaction (ELISA) kit, and evaluated for their serological diagnostic value. The relative molecular weight of the T3 protein was 88.1 kDa, the purified concentration was 1.5 mg mL−1, and the purity was 80%. The relative molecular weight of T2 protein was 79.9 kDa, the total protein concentration was 0.5 mg mL−1, and the purity was less than 50%. The overall coincidence rate of T2 protein was low, and it was impossible to distinguish between negative and positive sera. The T3 antigen was coated at 1.0 μg mL−1, the cutoff value was 0.5271, and the serum dilution ratio was 1:400. A T3 ELISA kits (96 tests) was constructed to detect the serum of 272 clinically and pathologically confirmed cases. The sensitivity of T3 was 93.8%, and the specificity was 83.3%. The parasite cross-reaction was 30%. Satisfactorily, the Pearson correlation coefficient between the T3 OD value and lesion diameter was 0.707, showing a strong correlation. T3 exhibits better antigenicity than T2, and the prepared T3 ELISA diagnostic kits reached the laboratory diagnostic level of a commercial kits. T3 can distinguish human cystic echinococcosis (CE) and alveolar echinococcosis (AE) more significantly and predict the diameter of lesions according to the OD value, which provides practical value for drug or surgical efficacy.

Visceral leishmaniasis (VL) is a tropical disease that can be fatal if acute and untreated. Diagnosis is difficult, the treatment is toxic and prophylactic vaccines do not exist. Leishmania parasites express hundreds of proteins and several of them are relevant for the host's immune system. In this context, in the present study, 10 specific T-cell epitopes from 5 parasite proteins, which were identified by antibodies in VL patients’ sera, were selected and used to construct a gene codifying the new chimeric protein called rCHI. The rCHI vaccine was developed and thoroughly evaluated for its potential effectiveness against Leishmania infantum infection. We used monophosphoryl lipid A (MPLA) and polymeric micelles (Mic) as adjuvant and/or delivery system. The results demonstrated that both rCHI/MPLA and rCHI/Mic significantly stimulate an antileishmanial Th1-type cellular response, with higher production of IFN-γ, TNF-α, IL-12 and nitrite in vaccinated animals, and this response was sustained after challenge. In addition, these mice significantly reduced the parasitism in internal organs and increased the production of IgG2a isotype antibodies. In vivo and in vitro toxicity showed that rCHI is safe for the mammalians, and the recombinant protein also induced in vitro lymphoproliferative response and production of Th1-type cytokines by human cells, which were collected from healthy subjects and treated VL patients. These data suggest rCHI plus MPLA or micelles could be considered as a vaccine candidate against VL.

Brazil has the richest biodiversity of Ergasilidae on Earth, with 76 species in 19 genera. However, several authors suggested that there is still great potential for discoveries, especially regarding genetic data that are still scarce for ergasilids from this region. To expand our knowledge of this taxon, we conducted an integrative study involving morphological (light and scanning electron microscopy) and molecular analyses of ergasilids from fishes sampled in the Pardo River, São Paulo State, Brazil. Two ergasilid species were found, Gamispatulus schizodontis and Rhinergasilus piranhus parasitizing the nostrils of 5 fish species (native and exotic): (i) R. piranhus from Astyanax lacustris; Cyphocharax modestus; Coptodon rendalli; Psalidodon bockmanni; and (ii) G. schizodontis from Serrasalmus maculatus. Additionally, we redescribed R. piranhus herein based on novelties and discrepancies found in the antennules, antennae, body segments and ornamentation of the swimming legs. Novel molecular data of ribosomal (18S and 28S rDNA) and/or mitochondrial (cox 1) genes were provided for both species and the phylogenetic relationships among the ergasilids were tested. Relationships between species/genera are still uncertain in Ergasilidae, but it was possible to verify the formation of 5 well-supported terminal clades – i.e. including a clade formed only by Neotropical species. More molecular data are needed to test this hypothesis, but the clades observed here represent good targets for future taxonomic revisions. The occurrence of R. piranhus specimens in the introduced fish, Co. rendalli can indicate (for the first time) host switching in this parasite species and spillback from native to introduced hosts.

Austropotamobius pallipes complex is an endangered freshwater crayfish species in Europe and the assessment of the health status of its wild populations is essential for conservation purposes. The two microsporidia Astathelohania contejeani and Nosema austropotamobii have been reported to cause in A. pallipes complex a chronic parasitic infection, known as ‘porcelain disease’, which reduces population fitness and leads the host to death. Due to the similar macroscopic signs produced, molecular biology analyses are required to unambiguously distinguish between these microsporidia. Focusing on A. pallipes complex populations located in Northern and Central Italy, the present study provides an evaluation of prevalence and distribution of A. contejeani and N. austropotamobii, and investigates the variables affecting the probability of detecting infected specimens during a survey (e.g. sex, crayfish density, longitude). Microsporidia were identified in 12 populations among the 42 monitored from 2011 to 2017, with an average prevalence of 3.12% for A. contejeani and 3.60% for N. austropotamobii, the latter being reported in a wider area than previously documented (from Lombardy to Liguria Regions). Notably, crayfish co-infected by both microsporidia were also detected in 4 populations. Moreover, it was observed that the probability of detecting a crayfish with a microsporidian infection significantly increased eastwards in the studied area, especially for N. austropotamobii. Our distribution map for microsporidiosis, combined with molecular screening, will be useful for planning breeding and translocation efforts for A. pallipes complex populations.

Marine parasites remain understudied in South Africa with little information available on their diversity and the effects these parasites may have on their hosts. This is especially true for parasitic copepods within the family Ergasilidae. Among the 4 genera known in Africa, Ergasilus Nordmann, 1832 is the most speciose with 19 reported species. However, this represents only 12% (19/163) of the global diversity. Furthermore, only 5 known African species are reported from marine environments, and only 1 is reported from the South African coastline. Given the rich biodiversity along this coastline, a high marine parasite diversity could be expected from these shores. As a case study, the Evileye blaasop, Amblyrhynchote honckenii (Bloch), a marine and brackish fish species, was screened for parasites along the South African coastline. This resulted in the discovery of 2 species of Ergasilus new to science (Ergasilus arenalbus n. sp. and Ergasilus chintensis n. sp.), which makes them the second and third ergasilid species reported for tetraodontid pufferfishes worldwide. Although genetically distinct, the 2 newly described species clustered in the same subclade within the Ergasilidae based on 18S rDNA, 28S rDNA and COI mtDNA phylogenies. The newly described species differ morphologically from each other, and their respective congeners based on the size and armature of the antenna; body segmentation; and general ornamentation throughout the entire body. The addition of these 2 new species from a single host species indicates that South Africa's marine fishes contain most probably a hidden parasitic copepod diversity that is worth exploring.

This study presents the first detection of Taenia omissa metacestodes in guanaco (Lama guanicoe) within the Chilean Patagonia, marking the southernmost record of natural infection in an intermediate host on the continent. Taenia omissa was found in the continental part of the Magallanes region where the top predators are pumas (Puma concolor). Conversely, all metacestodes found in guanacos collected from Tierra del Fuego Island, where no pumas exist, were identified solely as Echinococcus granulosus sensu stricto. Additionally, this research highlights a tissue preference of T. omissa for liver, contrasting with E. granulosus, which predominantly affects the lungs in guanacos. We also report the infection of T. pisiformis in 1 guanaco. Our findings emphasize the need for accurate identification of metacestodes during meat inspection in an area where T. omissa and E. granulosus overlap. This research also contributes to increase the knowledge of parasite–host dynamics in wildlife and underscores the importance of considering broader spectrum intermediate hosts in the epidemiology of parasitic infections.

Wood mice (Apodemus sylvaticus) and bank voles (Myodes glareolus) are often employed as natural study models in infectious disease ecology. Yet the identities of some elements of their parasite fauna have been subject to long-standing confusion. One instance of this relates to 2 nominal species of the capillariid nematode genus Aonchotheca: Aonchotheca annulosa (Dujardin, 1845) and A. murissylvatici (Diesing, 1851). Through literature review, analysis of recorded host- and site-specificity and tracing of taxonomic precedence, it is possible to confirm that A. annulosa is a valid species with a spicule c. 1000 microns long, a small intestinal site of infection and a wide host range centred in murine rodents (with A. sylvaticus the most common host). On the other hand, tracing the provenance of A. murissylavtici through to the works of the early naturalists reveals it is best assigned as a nomen nudum (lacking sufficient establishing description) or a junior synonym of A. annulosa and does not have precedence for the other Aonchotheca morphotype commonly found in Eurasian rodents. The first description consonant with this other morphotype, which has a short spicule (200–250 microns in length) and occurs primarily in the stomach of bank voles and other cricetids, was as Capillaria halli by Kalantarian in 1924. We thus recommend the suppression of A. murissyvatici in favour of Aonchotheca halli (Kalantarian, 1924) for this gastric-specialist short-spicule morphotype, particularly as the use of the A. murissylvatici name and its variants has previously been associated with substantial inconsistency and misidentification with A. annulosa.

Specimens of Cloacina artemis, C. expansa, C. hera, C. hermes, C. hestia, C. magnipapillata, C. obtusa and C. selene, which occur in both of the closely related species of grey kangaroos, Macropus fuliginosus and M. giganteus, were found to differ genetically based on sequence data derived from the internal transcribed spacers (ITS-1, ITS-2) of ribosomal DNA. The extent of differences varied from a single base pair in C. expansa, to 32 in C. hestia. In the case of C. hera, C. hestia and C. magnipapillata, separate genotypes were found in M. fuliginosus and M. giganteus. With C. artemis, C. expansa, C. obtusa and C. selene, nematode genotypes did not correspond with host distributions. In C. hermes, two genotypes were detected but they were not related phylogenetically. The data provide evidence suggestive of genetic differentiation in most of the nematode species potentially associated with host speciation, but with differing degrees of genetic differentiation and different associations with the two host species possibly related to changes in the geographical distribution of the hosts over time.

Nosemosis, caused by microsporidian parasites of the genus Nosema, is considered a significant health concern for insect pollinators, including the economically important honeybee (Apis mellifera). Despite its acknowledged importance, the impact of this disease on honeybee survivorship remains unclear. Here, a standard laboratory cage trial was used to compare mortality rates between healthy and Nosema-infected honeybees. Additionally, a systematic review and meta-analysis of existing literature were conducted to explore how nosemosis contributes to increased mortality in honeybees tested under standard conditions. The review and meta-analysis included 50 studies that reported relevant experiments involving healthy and Nosema-infected individuals. Studies lacking survivorship curves or information on potential moderators, such as spore inoculation dose, age of inoculated bees, or factors that may impact energy expenditure, were excluded. Both the experimental results and meta-analysis revealed a consistent, robust effect of infection, indicating a threefold increase in mortality among the infected group of honeybee workers (hazard ratio for infected individuals = 3.16 [1.97–5.07] and 2.99 [2.36–3.79] in the experiment and meta-analysis, respectively). However, the meta-analysis also indicated high heterogeneity in the effect magnitude, which was not explained by our moderators. Furthermore, there was a serious risk of bias within studies and potential publication bias across studies. The findings underscore knowledge gaps in the literature. It is stressed that laboratory cage trials should be viewed as an initial step in evaluating the impact of Nosema on mortality and that complementary field and apiary studies are essential for identifying effective treatments to preserve honeybee populations.

Soil-transmitted helminth (STH) infections afflict people worldwide, especially in tropical and subtropical regions. Strongyloides stercoralis is distinctive from other STH nematodes by its complex life cycle features of autoinfection, parthenogenesis, and environmental reproduction. This scoping review aims to identify the structures, features, and techniques employed in existing STH models, emphasizing their potential application in describing S. stercoralis infection dynamics. A comprehensive search was conducted in the Medline, Embase, and Scopus databases for studies published until 14 June 2024. A total of 47 studies presenting a new model or novel adaptation of an existing model to human STH infection transmission were identified: only one described S. stercoralis transmission in humans. The identified models were predominantly deterministic and focused on the dynamics of mean worm load within hosts and the infectiousness of the environmental reservoir. One model addressed transmission in multi-host scenarios, as not all STH transmission cycles involve multiple hosts. Models were frequently used to simulate the effectiveness of mass drug administration, including drug efficacy and treatment coverage, while water, sanitation, and hygiene (WASH), health education, and vaccination were less explored. Given the limitation of individual-level data, compartmental models may be a reasonable starting point for S. stercoralis transmission. For a comprehensive understanding, incorporating parasite life cycle features into the model, exploring multi-host dynamics, including a diverse range of host heterogeneities, and assessing the impact of climatic factors like rainfall and land surface temperature on parasite survival in the environment may be beneficial, especially in settings where their importance is notable.

Ponto-Caspian gobies became highly abundant in many regions outside their native distribution range (e.g. in the Rhine River system). In the newly invaded habitats, the parasite communities of the invasive gobies are characterized by a lower species richness compared to their native range. Interestingly, acanthocephalans of the genus Pomphorhynchus are highly abundant, although they do not become mature and mostly remain encapsulated in the abdominal cavity as preadults. Thus, gobiids could either represent a dead-end host for Pomphorhynchus sp. declining its population (dilution effect) or act as a paratenic host that could increase the infection pressure if the infected gobies are preyed upon by appropriate definitive hosts (spill back). To determine which of the 2 scenarios the gobiids contribute to, we conducted 2 infection experiments using smaller and larger individuals of the definitive host chub (Squalius cephalus), infected with preadults of Pomphorhynchus sp. collected from the abdominal cavity of Neogobius melanostomus. The results showed that preadults were able to complete their development and mature in the definitive host with mean recovery rates of 17.9% in smaller and 27.0% in larger chubs. Successful infections were observed in 62.0% and 80.0% of the smaller and larger chubs, respectively. Our study demonstrated that gobies can theoretically serve as a paratenic host for acanthocephalans of the genus Pomphorhynchus, and that infection might spill back into the local fish community if infected gobies are preyed upon by suitable definitive hosts of Pomphorhynchus sp. such as large barbel or chub.

Cystic echinococcosis (CE), caused by Echinococcus granulosus s.l. is a neglected zoonosis posing a significant public health challenge. Little is known about human CE in Bhutan. This study was conducted to gain an understanding of the burden, distribution, and potential risk factors of CE in Bhutan. From January 2015 to December 2019 data from Jigme Dorji Wangchuck National Referral Hospital (JDWNRH) and 6 other district-level hospitals were reviewed. Descriptive statistics were used to summarize the data. DALYs and Poisson regression models were used to estimate the burden and explore the relationship between cases and possible risk factors. A total of 159 cases were recorded. Most cases (145) were admitted to the surgical ward and 14 cases were referred to India. The average annual incidence was 4.4 cases per 100 000 population. The burden of disease was estimated to be approximately 39 DALYs per year for treatment-seeking cases, or possibly 80 DALYs per year including non-treatment seeking cases. This translates to approximately to 5.2 DALYs and 10.2 per 100 000 per year respectively. The commonest sites of infection were the liver (78%) and lungs (13%). Most cases were treated with surgery (>82%), and more than 47% were admitted to the hospital for >4 days. Policy interventions targeting community engagement, awareness, education, high risk occupational groups, females, and those living in the endemic districts of the central and western regions may yield larger gains. More studies and the institution of a surveillance system can help better guide policy interventions.

Human alveolar echinococcosis is a hard-to-treat and largely untreated parasitic disease with high associated health care costs. The current antiparasitic treatment for alveolar echinococcosis relies exclusively on albendazole, which does not act parasiticidally and can induce severe adverse effects. Alternative, and most importantly, improved treatment options are urgently required. A drug repurposing strategy identified the approved antimalarial pyronaridine as a promising candidate against Echinococcus multilocularis infections. Following a 30-day oral regimen (80 mg kg−1 day−1), pyronaridine achieved an excellent therapeutic outcome in a clinically relevant hepatic alveolar echinococcosis murine model, showing a significant reduction in both metacestode size (72.0%) and counts (85.2%) compared to unmedicated infected mice, which revealed significantly more potent anti-echinococcal potency than albendazole treatment at an equal dose (metacestode size: 42.3%; counts: 4.1%). The strong parasiticidal activity of pyronaridine was further confirmed by the destructive damage to metacestode tissues observed morphologically. In addition, a screening campaign combined with computational similarity searching against an approved drug library led to the identification of pirenzepine, a gastric acid-inhibiting drug, exhibiting potent parasiticidal activity against protoscoleces and in vitro cultured small cysts, which warranted further in vivo investigation as a promising anti-echinococcal lead compound. Pyronaridine has a known drug profile and a long track record of safety, and its repurposing could translate rapidly to clinical use for human patients with alveolar echinococcosis as an alternative or salvage treatment.

The study aimed to assess the heterogeneity in the distribution of disease awareness, attitudes, and practices related to cystic echinococcosis (CE) in different subgroups and inform health authorities regionally and globally for future evidence-based tailored prevention practices in the region. A cross-sectional study was conducted with 242 participants from Kyrgyz Republic (KR), Issyk-Kul oblast, and utilized survey data to analyse demographics, household information, echinococcosis-related practices, and knowledge. Participants in high-risk environments (HRE) and engaging in high-risk behaviours (HRB) linked to CE contracting were identified. Out of 242 participants, 39% lived in HRE, with 22% engaging in HRB of contracting CE. 13% lived in HRE and engaged in HRB. Only 6% followed all preventive measures, while 56% followed some. 97.5% of participants had heard about CE, but only 6% identified all transmission routes, and 63.4% were unaware of dog contact as a route. Education reduced the odds of being in the highest risk group (HRE&HRB) (OR 0.5, 95% CI 0.23–0.80). The study's findings are alarming, emphasizing factors contributing to regional endemicity. We anticipated a similar pattern in the neighbouring countries, given the shared nomadic customs and historical parallels. Examination of the heterogeneity of disease awareness and practices allows tailored prevention strategies. Urgent prevention programmes focusing on echinococcosis awareness in the KR are crucial to addressing challenges posed by nomadic habits.

Cystic and alveolar echinococcosis are considered the second and third most significant foodborne parasitic diseases worldwide. The microscopic eggs excreted in the feces of the definitive host are the only source of contamination for intermediate and dead-end hosts, including humans. However, estimating the respective contribution of the environment, fomites, animals or food in the transmission of Echinococcus eggs is still challenging. Echinococcus granulosus and E. multilocularis seem to have a similar survival capacity regarding temperature under laboratory conditions. In addition, field experiments have reported that the eggs can survive several weeks to years outdoors, with confirmation of the relative susceptibility of Echinococcus eggs to desiccation. Bad weather (such as rain and wind), invertebrates and birds help scatter Echinococcus eggs in the environment and may thus impact human exposure. Contamination of food and the environment by taeniid eggs has been the subject of renewed interest in the past decade. Various matrices from endemic regions have been found to be contaminated by Echinococcus eggs. These include water, soil, vegetables and berries, with heterogeneous rates highlighting the need to acquire more robust data so as to obtain an accurate assessment of the risk of human infection. In this context, it is essential to use efficient methods of detection and to develop methods for evaluating the viability of eggs in the environment and food.

This study aimed to explore extracellular microRNA derived from Echinococcus multilocularis (EM) in the plasma of patients with alveolar echinococcosis (AE) and assess its potential as a diagnostic biomarker. EM-derived miRNAs were identified in plasma samples from 20 AE patients through miRNA sequencing. Three novel miRNA molecules (emu-miR-novel 1, 2 and 3) were predicted through bioinformatic analysis to elucidate their chromosomal locations, secondary structures and precursor forms. Subsequently, plasma samples from 30 AE patients and 30 controls were utilized to establish an assay via stem-loop reverse transcription PCR, optimizing primers, reaction systems, and conditions to assess cross-reactivity and sensitivity. Clinical validation revealed that emu-miR-novel 1 had the highest diagnostic accuracy, with an area under the curve (AUC) of 0.8994, a P value of less than 0.0001, a sensitivity of 83.3%, and a specificity of 86.7%. Statistically significant differences were observed between the groups for emu-miR-novel 1 (P < 0.05), whereas emu-miR-novel 2 and 3 showed AUC values of 0.7922 and 0.6883, with P values of 0.0001 and 0.012, respectively, indicating no significant difference between groups (P > 0.05). Furthermore, the assay showed no cross-reactivity with samples from 18 common viruses, 4 parasitic infections, and miRNAs from AE sequenced from 8 species, confirming its high specificity. Emu-miR-novel 1 exhibited a sensitivity of 1 femtomolar. Emu-miR-novel 1 holds promise as a key diagnostic tool for AE, offering a novel perspective and approach for disease diagnosis.

Cystic echinococcosis control in South American countries requires a comprehensive integrative ‘One Health’ approach. While insular nations have seen successful in their elimination programmes, South American countries face persistent challenges in hostile environments, with Echinococcus granulosus s.l., posing a significant public health concern. Vaccination of intermediate hosts has demonstrated the efficacy of the EG95 vaccine in reducing transmission rates. For example, since 2009, Rio Negro Province in Argentina has added, with marked success, the EG95 vaccine to the control programme, supplementing dog deworming. The Aysen Region of Chile has also reported encouraging preliminary results in reducing cyst prevalence in vaccinated sheep after 3 years of vaccination. The challenges in aligning control strategies with socio-cultural factors, especially in indigenous communities, underlines the need for context-specific strategies. The Rio Negro programme demonstrated commendable compliance, underlining the importance of community engagement in achieving lasting success. The most promising strategies for effective echinococcosis control involved dog deworming and the routine vaccination of sheep and/or goats, underscoring the importance of sustained implementation until all grazing animals have been replaced. For lasting success, these interventions need to be combined with a robust surveillance system.