Toxoplasmosis, caused by the obligate intracellular parasite Toxoplasma gondii, is one of the most prevalent zoonotic parasitic infections worldwide. When acquired during pregnancy, T. gondii can be transmitted to the fetus, with clinical outcomes influenced by gestational age at time of infection and the parasite’s genotype. Prenatal screening enables the detection of maternal seroconversion and offers a critical window for intervention. In Uruguay, despite mandatory serological screening during pregnancy, national data on T. gondii seroprevalence and maternal seroconversion have not been updated in two decades. In addition, the genetic diversity of local strains remains poorly characterized. In this study, we analysed publicly available serological data from pregnant individuals attending Uruguay’s largest public maternity hospital between 2019 and 2023. We found that seroprevalence has modestly declined from 50% (reported in 1998) to 45.5%, with a congenital transmission rate of 0.58%. Clinical analysis of affected newborns revealed chorioretinitis as the predominant manifestation. To investigate parasite diversity, we performed genotyping of T. gondii strains using in silico PCR-RFLP following molecular detection. Our findings revealed substantial genetic diversity, including novel allele combinations not previously described in the region. These results highlight both the continued public health burden and the evolving genetic landscape of T. gondii in Uruguay. Our findings underscore the need to strengthen surveillance and prevention strategies for congenital toxoplasmosis in South America.

The caryophyllidean tapeworm Khawia armeniaca has long been regarded as an exceptionally widespread species within its genus, notable for its significant morphological variability. However, with the accumulation of molecular data from different fish hosts, K. armeniaca was suspected to represent a species complex. To clarify the true identity of these parasites, a comprehensive morphological and molecular study (using 18S, 28S and ITS2 ribosomal regions) of K. armeniaca tapeworms from barbels (Barbinae) across the Iberian Peninsula and the Middle East has been conducted. The results revealed two genetically distinct lineages within the K. armeniaca complex. The first lineage, found in Arabibarbus grypus, Barbus lacerta, Capoeta birunii, Carassobarbus luteus, Luciobarbus barbulus, L. esocinus and L. kersin in Iraq and Iran, is genetically congruent with K. armeniaca (Cholodkovsky, 1915), originally described from the Sevan khramulya (Capoeta sevangi) in Armenia. The second lineage, identified in Luciobarbus bocagei (type host), L. comizo and L. guiraonis from Portugal and Spain, is described as Khawia iberica n. sp. In addition to clear molecular divergence, K. iberica can be distinguished from K. armeniaca by notable morphological differences, including variations in the shape, structure and size of the ovary, the anterior extension of the vitelline follicles, the testes and several morphometric parameters.

Transposable elements (TEs) have the ability to move and amplify inside the host genome, making them a pivotal source of genome plasticity. Presently, only 4 TE clades (all classified as Class I retrotransposons) have been identified in trypanosomatids. We predicted repeat content and manually curated TEs across the genomes of 57 trypanosomatids, shedding light on their proportions, diversity and dynamics. Our analysis yielded 214 TE consensus sequence models across the dataset, with abundance ranging from 0.1% to 7.2%. We found evidence of recent transposon activity in most species, with notable bursts in the Vickermania, Lafontella, Porcisia and Angomonas spp., along with Leishmania (Mundinia) chancei, L. (M.) orientalis and L. (M.) procaviensis. We confirmed that the 4 TE clades have colonized virtually all lineages of trypanosomatids, potentially playing a role in shaping their genome architecture. The effort of this work culminated in the establishment of the Trypanosomatid TE Database 1.0, a resource designed to standardize the TE annotation process that can serve as a foundation for future studies on trypanosomatid TEs.

This review article summarizes the history of amoebic dysentery (entamoebiasis) caused by Entamoeba histolytica. Initially, Entamoeba species were thought to be the most primitive extant eukaryotes, but more recent research revealed that they emerged relatively late in evolutionary history. Paleoparasitological data suggest that E. histolytica has been a parasite of humans since ancient times and was probably spread throughout the world by man during early human migration. By the end of the 19th century, it was established that E. histolytica was the etiological agent of amoebic dysentery and liver abscess. The issue over pathogenic and non-pathogenic strains of E. histolytica was resolved in the 1980s by the discovery of the morphologically indistinguishable harmless sister species Entamoeba dispar. Being mainly a disease of tropical and subtropical low-income countries, entamoebiasis cases have increased among travellers and immigrants arriving from endemic regions in recent years.

There is growing interest in using avermectins in livestock as a vector control tool for mosquitoes involved in the transmission of human malaria in sub-Saharan Africa (SSA). If implemented, the potential health and productivity impacts across the livestock sector would need to be considered, as avermectins are already commonly used in veterinary medicine to treat gastrointestinal helminths and parasitic insects. Here we present the results of a restricted systematic review that summarizes what is known about the effects of avermectins on cattle and swine productivity in SSA and the presence of avermectin resistance in endo- and ectoparasites of importance in these species. A total of 583 unique journal articles were identified using key search terms in 3 databases: Agriculture, Life, and Natural Sciences Databases from ProQuest, CAB Abstracts and Scopus. Ten articles met the criteria for inclusion on impacts on productivity and 4 met the inclusion criteria related to avermectin resistance. All studies documenting impacts of avermectins on productivity were performed using ivermectin in cattle. Generally, these showed a positive significant effect on growth rates. Resistance to avermectins was documented in 2 of the 4 included articles. Considering the extensive literature documenting resistance to avermectins in other areas of the world, our findings may reflect a paucity of studies on the subject in SSA. The authors conclude that additional research is needed to quantify the potential benefits and challenges to the livestock sector of using avermectins for malaria control across different production systems, and in a variety of ecological settings.

The present study was designed to report the prevalence of spotted fever group Rickettsia and Anaplasma in ticks from Pakistan. To address this knowledge gap, ticks were collected from October 2019 to November 2020 from livestock hosts. Three hundred ninety ticks from Punjab, Khyber Pakhtunkhwa and Islamabad were investigated for the presence of Rickettsia and Anaplasma. The collected ticks were subjected to molecular studies for detection and characterization of spotted fever group Rickettsia and Anaplasma in ticks from Pakistan. PCR amplification of the ompA gene was used for detection of Rickettsia and portions of the 16S rDNA gene for detection of Anaplasma. Nine species of ticks were tested. Of the 390 ticks tested, 7 (2.58%) ticks were positive for Rickettsia. Rickettsia spp. were detected in Haemaphysalis punctata, Hyalomma anatolicum, Hyalomma scupense, Rhipicephalus microplus and Rhipicephalus sanguineus. Unknown Rickettsia was detected in Hy. scupense. Fifty-seven (14.6%) ticks were also positive for Anaplasma spp. Anaplasma ovis was detected in Hy. anatolicum, Hy. scupense, Hy. excavatum, Rhipicephalus decoloratus, R. microplus and R. sanguineus. Anaplasma marginale was detected in Hy. anatolicum, Hy. scupense, R. microplus, R. decoloratus and R. sanguineus. The Anaplasma sequences obtained from this experiment were 99–100% similar to those of the documented strains. This study provides information and confirms the presence of spotted fever group Rickettsia and Anaplasma spp. in different tick species. It also highlights the need for control programs to prevent health risks. Further investigation to determine the prevalence and disease burden of these pathogens in Pakistan is necessary.

Avian trypanosomes (Trypanosoma, Kinetoplastea) are successful blood parasites occurring worldwide. These parasites are usually non-pathogenic to their avian hosts, thus neglected in studies regarding their life cycles and vectors. Several families of blood-sucking dipteran insects, including mosquitoes, have been identified as vectors of avian trypanosomes. Mosquitoes have been experimentally confirmed as vectors of Trypanosoma culicavium and Trypanosoma thomasbancrofti. In this study, we describe a third species of avian trypanosomes occurring in mosquitoes, designated as Trypanosoma tertium n. sp. This species can be distinguished from related trypanosome species based on morphology and small subunit rRNA gene sequence. Two isolates of T. tertium n. sp. obtained from a mosquito and a bird host were able to infect two subspecies of laboratory Culex pipiens mosquitoes, with infection rates reaching 60% and heavy infections in 90% of positive females. In infected mosquitoes, trypanosomes occurred as long epimastigotes in the midgut and short epimastigotes and rosettes in the hindgut. Putative infectious stages were detected in the diuretic liquid of infected mosquitoes, suggesting, besides transmission through ingestion of the infected vector, a possible transconjunctival infection. Among wild mosquitoes, avian trypanosomes were detected exclusively in Cx. pipiens with 3.3% total prevalence, while T. tertium n. sp. prevalence was only 0.08% among 1128 dissected Cx. pipiens individuals. In birds, T. tertium n. sp. was detected in 8 species within which the prevalence was 1.3% (686 birds), while it was 0.3% in total (3084 birds). We discuss the relationship of the newly described T. tertium n. sp. with other mosquito-transmitted trypanosomes.

In the Argentinian Atlantic Forest (AAF) of Misiones, opossums comprise 13% of the wild mammalian diversity. The white-eared opossum, Didelphis albiventris, and the southern black-eared opossum, D. aurita are sympatric marsupials, and the most frequent mammals in the northern Misiones. In this study, we describe the helminth assemblages from both D. albiventris and D. aurita in the northern AAF. We found a total of 15 species of helminths: 2 trematodes, 1 cestode, 11 nematodes and 1 acanthocephalan. The specific richness in D. albiventris was 12, while in D. aurita was it 13. Both opossum’s species share 10 helminth species; D. albiventris presented Capillaria sp. 2 and Globocephalus marsupials, absent in D. aurita; while D. aurita presented Trichuris didelphis, Capillaria sp. 1, and Travassostrongylus orloffi, absent in D. albiventris. Cruzia tentaculata registered the highest prevalence in both opossum species. Seven out of the 12 helminth species identified in D. albiventris have an indirect life cycle. Similarly, in D. aurita, 5 out of 13 helminth species exhibit an indirect life cycle. This suggests that nearly half of the assemblage of helminth in both opossum species need an intermediate host acquired through the diet. We also present new records for Argentina including Trichuris minuta, G. marsupialis, Viannaia viannai, T. orloffi and T. callis. This is the first time the helminth assemblage has been described for D. aurita in Argentina.

The Hippoboscidae are ectoparasites of birds and mammals, which, as a group, are known to vector multiple diseases. Avipoxvirus (APV) is mechanically vectored by various arthropods and causes seasonal disease in wild birds in the United Kingdom (UK). Signs of APV and the presence of louse flies (Hippoboscidae) on Dunnocks Prunella modularis were recorded over a 16·5-year period in a rural garden in Somerset, UK. Louse flies collected from this site and other sites in England were tested for the presence of APV DNA and RNA sequences. Louse flies on Dunnocks were seen to peak seasonally three weeks prior to the peak of APV lesions, an interval consistent with the previously estimated incubation period of APV in Dunnocks. APV DNA was detected on 13/25 louse flies, Ornithomya avicularia and Ornithomya fringillina, taken from Dunnocks, both with and without lesions consistent with APV, at multiple sites in England. Collectively these data support the premise that louse flies may vector APV. The detection of APV in louse flies, from apparently healthy birds, and from sites where disease has not been observed in any host species, suggests that the Hippoboscidae could provide a non-invasive and relatively cheap method of monitoring avian diseases. This could provide advanced warnings of disease, including zoonoses, before they become clinically apparent.

After its near eradication in the 1940s, the common bed bug (Cimex lectularius) experienced a global resurgence. Within a few years after, some populations displayed insecticide resistance. Two distinct lineages of bed bugs were identified, each associated with humans and bats, respectively. A strong genetic differentiation was identified between bugs from human and bat sites across Europe. This raises the question of whether the same pattern is found at a local scale. Moreover, because long-distance dispersal of bed bugs is essentially human-mediated, we investigated the spread of bed bugs within and among sites. Using mitochondrial (cytochrome oxidase unit I (COI) and 16S rRNA genes) and nuclear (10 microsatellite loci) markers, we compared the genetic composition of human- and bat-associated bed bugs from western Switzerland. We first conducted a median-joining analysis and compared it to European sequences to detect local-scale host-specific separation of haplotypes. We estimated levels of genetic diversity and structure between and within the two host-associated bed bugs. Our results reveal two genetic clusters associated with bats and humans and a strong structure among human sites (FSC = 0·579). An analysis of knock-down insecticide resistance gene variants (V419L, L925I, I936F) shows that bed bugs infecting humans in western Switzerland carry insecticide resistance (99%) whereas bed bugs infecting bats do not (0%). Our results show that at the scale of western Switzerland, bed bugs are structured by host association, thus supporting the hypothesis of host specialization in the common bed bugs. Moreover, human-associated bugs might have settled from multiple colonization events and/or undergone bottlenecks.

Spirometra is a genus of zoonotic cestodes with an ambiguous species-level taxonomic history. Previously, Spirometra mansonoides was considered the only species present in North America. However, recent molecular data revealed the presence of at least three distinct species in the USA: Spirometra sp. 2 and 3, and Spirometra mansoni. This study aimed to elucidate the diversity and potential host associations of Spirometra species among companion animals in the USA. Samples (N = 302) were examined from at least 13 host species, including mammals, amphibians and reptiles. Sample types included eggs isolated from faeces (n = 222), adult specimens (n = 71) and plerocercoids (n = 9) from 18 different states and 2 territories across the USA. Extracted genomic DNA was subjected to PCR targeting a fragment of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Generated sequences (n = 136) were included in a phylogenetic analysis. Spirometra mansoni was detected in domestic cats (n = 76), dogs (n = 12), a White’s tree frog (n = 1), a Cuban knight anole (n = 1), a green iguana (n = 1) and a serval (n = 1) across 15 states and Puerto Rico. Spirometra sp. 2 was found only in dogs (n = 3) from Florida and Spirometra sp. 3 was found only in cats (n = 41) from 17 states. All plerocercoid samples were consistent with S. mansoni. The results confirm that at least three distinct Spirometra species are present and established in companion animals, such as dogs and cats, and likely are using various native and exotic species as paratenic hosts within the USA.

Toxoplasma gondii non-archetypal strains have distinct virulence profiles and immunological activation in the host when compared with archetypal strains. The present work aims to perform an analysis of the inflammatory profile during acute and early chronic infection by T. gondii atypical strain in an experimental murine model. After euthanasia, blood was collected for the quantification of specific IgG antibodies and their subtypes (IgG1/IgG3) by ELISA; bronchoalveolar lavage (BAL) was realized and immunophenotyping of lymphocytes population was performed at 12- and 30-days post infection (dpi); the levels of IFN-γ, IL-12, IL-10, TNF-α, IL-6, IL-17, nitric oxide and total proteins were determined in the BAL supernatant. Tissue cyst burden was determined in the brain homogenate, and the parasite load in the lungs was assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Infection with the CK4 strain induced a lower brain cyst load similar parasite burden in the lungs, and higher levels of IgG1 and IgG3, when compared to ME49. The group infected with the CK4 strain presented higher levels of systemic IFN-γ, and both infected groups displayed similarly elevated levels of systemic TNF-α, IL-6 and IL-17 at 30 dpi, as well as higher numbers of CD4+ and CD8+ T lymphocytes in the acute stage of infection, followed by higher numbers of central and effector CD4+ T cells. IFN-γ levels in the BAL fluid were significantly higher in animals infected with the CK4 strain in both the acute and early chronic stage of infection, highlighting the involvement of the lung environment.

Haemosporidians constitute a monophyletic group of vector-borne parasites that infect a wide range of vertebrate hosts, including Neotropical lizards. The remarkable diversity of these host-parasite associations and inadequate research on certain parasite groups have resulted in controversial haemosporidian taxonomy. Herein, we rediscover erythrocytic and non-erythrocytic haemosporidians infecting golden tegus (Tupinambis teguixin) from Brazil and Colombia. The erythrocyte-inhabiting parasite belongs to Plasmodium sp., and the non-erythrocytic form was identified as Saurocytozoon tupinambi, previously attributed to the Family Leucocytozoidae. These non-pigmented haemosporidian parasites do not multiply in the blood. The relationships between the Saurocytozoon and Leucocytozoidae species were discussed for many years, especially during the 1970s. However, cytochrome b (cytb) sequences and the mitochondrial genomes recovered for this species strongly support classifying this parasite as a Plasmodium taxon. Therefore, we proposed a new combination for this parasite, Plasmodium (Saurocytozoon) tupinambi comb. nov., where Saurocytozoon is retained as a subgenus due to its distinct morphology. These results reinforce that a broader definition of Plasmodiidae must include saurian parasites that develop non-pigmented leucocytozoid-like gametocytes.

The objective of this study was to assess the potential role of aquatic biofilms as natural reservoirs for Blastocystis. For this purpose, surface water (n = 4) and biofilm samples (n = 8) were collected from a stream nearby an urban area characterized by limited sanitation infrastructure and a high prevalence of Blastocystis in humans. Blastocystis cysts were detected in three of the four water samples and seven of the eight biofilm samples using fluorescence microscopy. Furthermore, viable cysts were identified exclusively in biofilm samples (five of the eight), while no live cysts were detected in water samples. These findings indicate that aquatic biofilms provide a habitat where Blastocystis cysts can adhere and remain viable, potentially contributing to their environmental accumulation. In addition, molecular characterization of the five isolates identified subtypes ST8 (allele 21) and ST3 (allele 36). This study is the first to report the detection and identification of viable Blastocystis subtypes in aquatic biofilms. The analysis of biofilms by fluorescence microscopy, as demonstrated here, offers a promising approach for monitoring Blastocystis and could serve as an alternative to traditional water sampling methods.

We present four cases of male genital schistosomiasis (MGS) within children and adolescents opportunistically encountered as part of a wider screening programme for imported schistosomiasis in Germany and community outreach screening in Mali. Such genital manifestations in young children and adolescents are often overlooked but can include hydrocele, hypogonadism, varicocele, cutaneous granulomata on the penis and scrotum, echogenic spots in the prostate and the epididymis, alongside testicular masses. Though these cases appear sporadic, from our scoping literature review, they draw fresh attention on MGS in young children and highlight wider confusion with other congenital, neoplastic and infectious disease. These might include an insufficient closure of the tunica vaginalis, malignancies or lymphatic filariasis. Frequently haematuria is not present. One typical sign indicating MGS in adults, i.e. haematospermia is not present before puberty. Another reason of missing MGS cases may be that screening with scrotal or transabdominal ultrasonography are not easily accepted unless the reason for it is not extensively explained beforehand and that transabdominal ultrasonography is less sensitive for revealing prostatic lesions than transrectal ultrasonography.

Neurocysticercosis (NCC) is a neglected parasitic disease that causes neurological symptoms. However, little is known about the long-term impact of this infection on health. We contacted participants from a randomized controlled trial on albendazole treatment for NCC in Ecuador 12 years after trial completion (14–16 years after NCC diagnosis) about their long-term health. We described the symptoms experienced post-trial and investigated if albendazole treatment, the presence of calcified NC cysts, and cysts in extraparenchymal locations at last imaging predicted symptoms. All analyses were standardized by adjusting for participant age and sex. In the 12 years post-trial, 52.1% reported some health problem, with 48.9% reporting neurological symptoms such as seizures (16.6% of participants) and headaches (26.6% of participants). At the end of the trial, 11 participants had complete NCC cyst resolution, of whom 3 (27.3%) reported seizures and 1 (9.1%) reported headaches post-trial. Twenty-four participants had only calcified cysts (residual calcification sometimes left after the parasite dies) by trial end, of whom 8 (33.3%) reported seizures and 9 (37.5%) headaches post-trial. None of the predictors examined were significantly associated with long-term symptoms. A high proportion of people diagnosed with NCC continue experiencing symptoms years after treatment, and while slightly fewer people experienced continued symptoms in the albendazole group, the difference was not statistically significant. Eleven participants with no live parasites at last imaging (8 with residual calcifications) had seizures post-trial, which may be unprovoked and an indication of epilepsy risk. Research is urgently needed to improve NCC treatment to mitigate long-term outcomes.

Neurocysticercosis is a poorly understood infection of the central nervous system with Taenia solium larva, and the treatment often fails to kill all the parasitic larva. Most research on this infection has used patient-level data, looking at summaries of the encysted parasitic cysticercus burden. Cyst-level analysis is needed to identify factors that impact individual cyst trajectories and how that may vary based on characteristics of the patient, infection and cyst being followed. We disaggregated data on 221 cysts from 117 patients who participated in a trial evaluating the impact of albendazole treatment to identify factors that impact cyst evolution over time from the active to the degenerating and calcified phases, and eventual resolution. We found that having calcified cysts at baseline was associated with a faster rate of transition from the degenerative phase to calcified phase or resolution. Age and sex were not associated with cyst evolution in the main effect analysis, but after stratifying on treatment we found that the direction of some associations by patient age and sex was reversed for patients in the albendazole arm compared to those in the placebo arm. These findings suggest that differences in host immune response by sex and age as well as by past exposure, potentially indicated by having calcified cysts together with active cysts at baseline, are important to cyst evolution and may be modified by treatment. Future research is needed to assess if these differences suggest distinct treatment recommendations.

Elevated levels of IL-6 in plasma are associated with the severity of visceral leishmaniasis (VL). The clinical manifestations of VL vary among patients, influenced by host factors and the virulence of the Leishmania infantum parasite. Considering that severe VL may result from an exaggerated inflammatory response, this study investigated whether IL-6 could serve as a biomarker to identify pro-inflammatory virulence factors. We conducted a genome-wide association study (GWAS) analysis on L. infantum isolates from patients with VL, whose IL-6 concentrations were measured. The analysis revealed that the relationship between IL-6 levels and clinical outcomes (survival vs mortality) had an area under the curve (AUC) of 0.67 (95% CI 0.52–0.81). A cut-off of 391.7 pg mL−1 for IL-6 was established to conduct a logistic regression analysis. We identified 10 029 single nucleotide variants (SNVs) across 62 genomes, resulting in 6,948 SNVs after filtering, of which 6,341 are located in protein-coding regions. The association analysis with PLINK identified 722 variants, of which 35 showed significant associations, with odds ratios ≥3.3, primarily in coding regions. These findings demonstrate that IL-6 levels tended to be associated with the fatal outcome of VL and highlight 35 novel genetic variants that could serve as potential biomarkers for prognosis. Further research into the biological role of these variants may lead to new therapeutic targets and improve the clinical management of VL, especially in identifying high-risk patients.

Cestodiases, like echinococcoses and cysticercoses, represent a global health problem. Currently available anthelmintics, as benzimidazoles and praziquantel, have limited effectiveness against these cestodiases, creating a demand for the identification of new and more effective drugs. Here, the potential of statins (simvastatin and fluvastatin), for repositioning as novel anthelmintic is explored. Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, a main enzyme in the mevalonate pathway, which is vital for the synthesis of non-steroidal isoprenoids and the maintenance of normal cell functioning. A survey for HMG-CoA reductase encoding genes showed that they are present in a single copy in the genomes of parasitic helminths and their mammal hosts. Sequence alignments and phylogenetic analyses showed 20–95% overall identities among ortholog HMG-CoA reductases, with special conservation of their catalytic domains. The HMG-CoA reductase 3D-structure was predicted for orthologs from 3 cestodes of medical importance (Echinococcus multilocularis, Echinococcus granulosus sensu lato, and Taenia solium), and from a model cestode species (Mesocestoides corti). Molecular docking between cestode HMG-CoA reductase orthologs with simvastatin demonstrated that the Arg, Ser, Lys, and Glu residues in conserved positions of the active site interact with this drug, similarly to the interactions predicted for the human reference ortholog enzyme. Furthermore, in vitro assays demonstrated that simvastatin produced a significant reduction of M. corti viability, being able to reduce 100% of parasite viability at 150 μm. Fluvastatin was also assessed showing a lower, although significant anthelmintic effect. The predicted overall structures and interactions together with in vitro assays suggest that cestodes HMG-CoA reductases are inhibited by simvastatin, being a potential therapeutic target for the repurposing of simvastatin as anthelmintic drug. Furthermore, these results pave the way for the in vivo evaluation of the potential effects of simvastatin on cestode larvae.