Parasitologia, Volume 5, Issue 2 (June 2025) – 8 articles

Metacyclogenesis is a critical process in the Trypanosoma cruzi life cycle. This transition naturally occurs in an insect vector’s gut. Although Triatomine Artificial Urine (TAU) medium is the widely adopted approach to metacyclogenesis in vitro, its efficiency decreases with prolonged epimastigote culture, limiting the availability of metacyclic trypomastigotes for study. We aimed to establish a practical and efficient method for generating high concentrations and purities of metacyclic trypomastigotes in vitro. Epimastigotes of the Dm28c strain were exposed to pH shifts in nutrient-rich (MT-LIT) and nutrient-poor (M16) media, under static or agitated conditions. Both media promoted higher metacyclogenesis rates than TAU, with epimastigotes’ adherence to the substrate being a crucial factor. Metacyclogenesis efficiency varies depending on the strains and culture conditions. Notably, both LIT and M16 at pH 6 produced metacyclic trypomastigotes with infective capacity on Vero cells. Under these conditions, a variety of intermediate forms were observed compared to those induced by TAU metacyclogenesis. Our findings further emphasize the strain-dependent nature of optimal in vitro metacyclogenesis conditions and offer new opportunities for studying the intermediate forms involved in this essential process. Full article

Dogs harbour a wide range of endoparasites, many of which pose a significant risk to public health globally due to their zoonotic potential. Addressing the dynamics of zoonotic parasites comprehensively requires epidemiological studies under the One Health paradigm, incorporating multidisciplinary methodologies to explore the complex interactions among humans, animals and the environment. The present study aimed to investigate the presence of canine parasites in public green places (PGPs) in Tandil, Argentina, using epidemiological and geographical tools to enhance efforts towards the prevention and control of canine parasitic diseases impacting public health. Between August 2024 and January 2025, 893 canine faecal samples were collected through a randomised two-stage sampling process from 92 public green places. The overall prevalence of intestinal parasites was 29.9% and the identified parasites were Trichuris vulpis, Ancylostoma caninum, Eucoleus spp., Uncinaria stenocephala, Toxascaris leonina, and Cystoisospora sp. Risk factors identified included the presence of playgrounds and a higher dog density, while protective factors comprised sampling during spring vs. winter and presence of areas of bare soil on the public green places. Spatial analysis revealed clusters of high prevalence in areas with lower socioeconomic status, and clusters of low prevalence in higher socioeconomic areas. These findings emphasise the need for targeted preventive measures, including responsible pet ownership policies. Moreover, the methodological approach adopted could be replicated in other regions to enhance public health protection and mitigate the risks associated with zoonotic parasitic diseases. Full article

Strongyloidiasis represents a public health problem in tropical and subtropical regions. The medicinal plants demonstrate the potential of plants as a source of molecules with helminthic activity. In this research, we assessed the potential of five extracts medicinally used in Mexico against Strongyloides venezuelensis third-stage infective larvae (L3). Plant methanol (MeOH) extracts of Argemone mexicana (chicalote), Jatropha dioica (Sangre de Drago), Lippia graveolens (oregano), Thymus vulgaris (tomillo), and Kalanchoe daigremontiana (aranto) were prepared by the maceration technique. The toxicity of the extracts was evaluated in human red blood cells by the hemolysis test and in monkey kidney epithelial cells (Vero cells) using the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In addition, we showed their antioxidant potential by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The methanolic extracts of A. mexicana, J. dioica, L. graveolens, and T. vulgaris exhibited significant activity against L3 cultures at 72 and 96 h post-incubation. None of the extracts showed hemolytic effects on red cells or Vero cells. L. graveolens demonstrated the strongest antioxidant activity, with an EC₅₀ of 19.80 µg/mL. Plant MeOH extracts used in this study showed a promising anthelmintic effect in vitro, making it a suitable candidate for future research in nematocidal therapies. Full article

The genus Polystoma includes parasites with direct life cycles that involve a short-lived free-living, aquatic oncomiracidia, post-larvae infecting the gill chambers of tadpoles, and adults parasitizing the urinary bladder of adult anurans. Despite the high diversity of anurans in the South American sub-continent, less than 20 species of Polystoma have been reported to date, and, particularly, in Argentina, only five species have been described from adult frogs. The aim of this work was to describe and characterize taxonomically the specimens found parasitizing tadpoles and frogs living in a well in Chicoana, Salta province, Argentina. Parasites were observed under optical and scanning electron microscopy and characterized genotypically by sequencing ITS1 and COI fragments. Frogs and tadpoles were characterized by morphology and sequencing a partial fragment of the cytochrome B region, confirming that the hosts corresponded to Pleurodema borellii. Given their morphology and the strict specificity of Polystoma species for their hosts, the identity of the parasites was established as P. borellii. The morphology of oncomiracidia and post-larvae was described, expanding adults’ description with insights provided by COI and ITS1 molecular analysis. The present work summarizes a complete description of the life cycle, with the genetic characterization of Polystoma borellii in Salta, Argentina. Full article

The Gran Acuario Mazatlán (GAM), Mexico’s largest aquarium, is located at the entrance of the Gulf of California. In April 2023, fish in the Ocean Tank (OT) began exhibiting disease symptoms, followed by significant mortality, primarily affecting Caranx caninus, Chaetodipterus zonatus, and Lutjanus colorado. Parasitological examinations identified heavy infestations of Neobenedenia sp. (Monogenea: Capsalidae), with parasites extensively covering body surfaces and gills of some individuals. To control the outbreak, an environmental management strategy was implemented, involving a gradual reduction in water temperature (from 26 °C to 22 °C) and salinity (from 35 ppt to 26 ppt), increased cleaning frequency, and parasite egg abundance monitoring. Over time, egg abundance declined, and by July, fish behavior and feeding rates had returned to normal, with parasite-associated mortality dropping below 2%. Preventive measures, including strict quarantine protocols for new fish, have been implemented to maintain optimal conditions in the OT. This case highlights the challenges of managing parasite outbreaks in large, multi-species aquaria and underscores the importance of environmental control strategies in marine animal care. Full article

A significant portion of women encounter vaginal infections at some point in their lives. These infections have many effects such as infertility, pelvic inflammatory disease (PID), severe disseminated infections, and complications affecting fetal health during pregnancy. Vaginal infections can be symptomatic or asymptomatic, thereby concealing their presence. This study aimed to determine the frequency and causative agents of vaginal infections in symptomatic and asymptomatic women in Konya. The study included 200 patients aged > 18 years who visited the gynecology clinic for any reason and provided informed consent. Patients who reported at least one of the symptoms of vaginal discharge, burning, or itching were categorized into the symptomatic group, while those without any of these complaints were categorized into the asymptomatic group. Vaginal swab samples collected from the patients were evaluated for bacterial vaginosis (BV) using the Nugent scoring method on Gram-stained smears. Trichomonas vaginalis was investigated through Giemsa-stained microscopic examination and polymerase chain reaction (PCR) analysis. Samples were also cultured on routine media to analyze fungal and bacterial growth. A total of 74% of the patients were symptomatic, and 26% were asymptomatic and were admitted to the gynecology outpatient clinic for reasons other than vaginitis. According to the Nugent scoring system, BV was observed in 21.6% of the symptomatic group and 13.5% of the asymptomatic group. T. vaginalis was detected in only seven patients (3.5%) through microscopic examination and PCR. Among the patients with T. vaginalis, five were in the symptomatic group, and two were in the asymptomatic group. The rate of vaginal candidiasis was found to be 34.5% in the symptomatic group and 21.2% in the asymptomatic group. Aerobic vaginitis was observed in 12.8% of the symptomatic group and 7.7% of the asymptomatic group. The positivity rates for BV, vaginal candidiasis, and trichomoniasis in asymptomatic patients are concerning. Considering the fetal complications and chronic effects of vaginal infections, the decision to establish screening programs in the asymptomatic patient group should be based on national data, considering the prevalence of the pathogen in the region and its outcomes. Full article

Equine Piroplasmosis (EP) is a significant tick-borne disease affecting horses, and one of the causative protozoan parasites is Theileria equi, hence the need to understand the prevalence and associated factors influencing it. Considering the population of horses in the study areas, a sample size of 272 horses comprising 171 and 101 horses from Taif and Jeddah was estimated. Thin and thick blood smears were made from the animals’ whole blood for microscopic examination. At the same time, serum samples were prepared and examined for antibodies to antigens using commercial Theileria equi antibody test kit ELISA. The relationships of gender and age with the presence or absence of T. equi parasite infection were determined using the chi-square test. The results revealed no significant association between gender and T. equi prevalence using both microscopic (χ² = 2.748, p = 0.07) and ELISA (χ² = 2.412, p = 0.096) diagnostic methods. In Taif, the microscopic results revealed that 86% of female horses tested negative, while 14% tested positive. In contrast, 75% of male horses tested negative, with 25% testing positive for T. equi. In terms of age groups of horses, a significant association (χ² = 31.966, p = 0.032) between age groups and the prevalence of T. equi in samples from Jeddah using the ELISA method was recorded. Understanding the relationship between the prevalence of T. equi and factors such as gender and age is crucial for developing effective control measures and improving equine health management, especially in Saudi Arabia. Full article

Introduction: Freshwater snails, particularly snails from the genus Biomphalaria, play a key role in the transmission of schistosomiasis, a parasitic disease prevalent in tropical regions. Schistosomiasis poses a significant public health challenge in these regions, leading to chronic illness, reduced productivity, and impaired childhood development, particularly in communities with limited access to healthcare and sanitation. Understanding the seasonal and spatial variations in snail populations and infection rates is crucial for controlling schistosomiasis, especially in areas like Southwest Ethiopia, where the disease burden is high. Methods: This study was conducted in Mizan Aman, Southwest Ethiopia, across two seasons, dry and wet. A total of 1150 snail samples were collected from 20 freshwater sites, and their species, abundance, and infection status were assessed. Environmental parameters, including temperature, pH, salinity, and conductivity, were measured to analyze their impact on snail populations. Results: Four snail species were identified, Biomphalaria pfeifferi, Biomphalaria sudanica, Lymnaea natalensis, and Bulinus globosus, with B. pfeifferi and B. sudanica being the most prevalent. Snail abundance varied by site and season, with 598 in the dry season and 552 in the wet season. Snail abundance and species composition showed significant spatial variation, with higher counts in sites like Sasin and Agu 1, while some sites had no snails. Biomphalaria snails, particularly B. pfeifferi, are the principal intermediate host for Schistosoma mansoni. The overall prevalence of Biomphalaria snails exceeded 85% in both seasons, and their average infection rate in Mizan Aman was 13.5%. This infection rate showed a strong correlation (r = 0.733, p < 0.001) with the incidence of schistosomiasis cases in the community. Seasonal variation in environmental factors, such as temperature and pH, had no significant effect on snail abundance; however, water salinity showed to be correlated with snail abundance during the dry season. Furthermore, community-led vegetation clearance at selected sites significantly reduced snail abundance. Conclusions: This study highlights the seasonal and spatial dynamics of freshwater snails, particularly Biomphalaria species, in relation to schistosomiasis transmission in Mizan Aman, Southwest Ethiopia. The findings confirm that B. pfeifferi species is the predominant intermediate host for schistosoma in this region and that schistosomiasis infection rates among snails significantly correlate with human cases in the community. While environmental factors such as temperature and pH showed no significant influence on snail abundance, water salinity had an impact during the dry season. Additionally, community-led vegetation clearance was an effective intervention in reducing snail populations. These results emphasize the need for targeted, site-specific control measures integrating ecological and community-based interventions to sustainably reduce schistosomiasis transmission. Full article