Rhipicephalus (Boophilus) microplus is an obligate hematophagous ectoparasite that primarily infests cattle, transmitting diseases and causing economic, health, and productive problems in tropical and subtropical regions worldwide. Scanning Electron Microscopy (SEM) has become a tool with great potential for use in various studies involving this parasite. Although some studies affirm the importance of the sample coating process for good image quality, others report this same process hides the visualization of ultra-structures. This study aimed to compare images of R. (B.) microplus larvae using SEM with and without gold coating. Larvae aged 21 days after hatching were sampling this research. There were generated images by SEM and they were visually compared one another. Samples coated with gold for 20 s showed balanced contrast, but also exhibited artifacts due to metal agglomeration, which made it difficult to visualize details of the parasite's morphology. Those coated for 40 s showed cracking surface and structural disruption. Samples prepared without coating showed high contrast but rich fine details. In general, when deciding whether perform or not coating samples, the researcher should consider the study objectives, alternative conductors, and the availability of financial resources.
Neocalceostomatidae comprises a small group of monogenoids parasitizing marine catfishes (Siluriformes, Ariidae), with species reported exclusively from the Australian and Oriental regions. Despite their taxonomic relevance within Dactylogyridea, the evolutionary relationships within the group remain uncertain. In this study, we describe a new Neocalceostomoides species from the gills of Cathorops spixii using an integrative taxonomic approach that combines morphological and molecular evidence. Additionally, Calceostomella herzbergii Zambrano, Dezón & León, 2004 is redescribed and transferred to Neocalceostomatidae as Neocalceostomoides herzbergii n. comb. Furthermore, finding Neocalceostoma elongatum Tripathi, 1957 infecting Genidens barbus in southeastern Brazil is the first record of Neocalceostomatidae in Neotropical ariid hosts, expanding the family's known range. We propose the first molecular phylogeny for the Neocalceostomatidae based on partial 28S rDNA, 18S rDNA, ITS1, 5.8S rDNA, and ITS2 sequences. Our results recover Neocalceostomatidae as a nested lineage within Dactylogyridae and closely related to lineages parasitizing ariid catfishes. This contradicts previous hypotheses that the group is a derived lineage of Calceostomatinea or an independent Dactylogyridea lineage. Although our results indicate Neocalceostomatidae may represent a derived lineage of Dactylogyridae, the family is provisionally retained pending broader taxonomic sampling and additional molecular data.
During a parasitological investigation conducted in Italy on domestic reptiles, a motile proglottid was macroscopically observed in a fecal sample from a Yucatán spiny-tailed iguana (Cachryx defensor). Subsequent analysis using the quali-quantitative flotation technique (Mini-FLOTAC®) revealed the presence of cestode eggs. DNA was extracted from the sample and amplified using conventional PCR. Sequence comparison with those available in GenBank showed the highest similarity (98%) with Oochoristica hemidactyli, supporting identification at the genus level (Oochoristica sp.). To our knowledge, this represents the first molecularly supported detection of Oochoristica sp. in a captive reptile in Italy, highlighting the importance of parasitological surveillance in domestic reptile populations and the potential role of exotic pets in the introduction and spread of parasites.
Haemosporidians are vector-borne parasites that infect vertebrates and are commonly detected in captive birds, causing infections ranging from mild to severe and may be fatal, especially those involving Plasmodium and Haemoproteus species. Blood samples from 17 Anseriformes, including 15 captive Ruddy Shelduck (Tadorna ferruginea) and two black-necked swans (Cygnus melancoryphus), were analyzed in this study. An integrative approach identified Haemoproteus infection in one female of each species, with genetic sequences showing 100% similarity to Haemoproteus macrovacuolatus, based on a 478 bp fragment of the mitochondrial cytochrome b (cytb) gene. However, the morphology observed in these birds differed slightly from the parasite's original description, particularly in the absence of large vacuoles, which are considered characteristic of the species. Combined with the molecular findings, this morphological divergence supports the interpretation of the detected parasite as a H. macrovacuolatus-like lineage and underscores the importance of integrative taxonomy for accurate haemosporidian identification, especially when infections are detected in newly reported avian hosts. Traditional diagnostic and species delimitation criteria may vary due to host-related factors, physiological conditions, and host-parasite interactions, all of which may contribute to morphological variation in these parasites.
Alveolar echinococcosis (AE), caused by the larval stage of Echinococcus multilocularis, is a severe zoonosis requiring prolonged anthelmintic therapy. Albendazole (ABZ) remains the treatment of choice; however, its poor aqueous solubility and low systemic bioavailability limit therapeutic efficacy and necessitate prolonged high-dose regimens. Improving the delivery of existing antiparasitic drugs therefore represents a valuable therapeutic strategy. This study evaluated the in vivo chemoprophylactic and therapeutic efficacy of an innovative nanomedicine formulation comprising ABZ encapsulated in poly(hydroxybutyrate) (PHB) nanoparticles synthesized by electrospraying. The resulting formulation demonstrated high reproducibility, adequate drug loading, and stable physicochemical characteristics suitable for in vivo evaluation. Efficacy was assessed in an experimental murine model of intraperitoneal alveolar echinococcosis using chemoprophylactic and therapeutic protocols. In the chemoprophylactic study, ABZ-loaded PHB nanoparticles significantly reduced cyst weight compared with the untreated control group and induced extensive ultrastructural damage to the germinal layer, outperforming the ABZ suspension. In the therapeutic protocol, the polymeric nanocarrier system significantly impaired metacestode tissue viability relative to the untreated control. Notably, despite the lack of a statistically significant difference in the cyst weights compared to the ABZ suspension, the nanoparticle treatment induced far more pronounced ultrastructural alterations in the germinal layer. This severe damage, characterized by a marked reduction in germinative cells, effectively compromised the regenerative capacity and proliferative potential of the metacestode tissue. In conclusion, the electrosprayed PHB nanocarrier system represents a promising biopharmaceutical strategy to optimize ABZ delivery, enhancing its therapeutic performance against experimental alveolar echinococcosis without requiring increased drug dosages.
Leishmaniasis remains a major public health challenge due to the limited therapeutic options available and the increasing emergence of drug-resistant parasites. Membrane transporters play essential roles in parasite physiology and drug susceptibility; however, the biological functions of glycosomal ATP-binding cassette (ABC) transporters remain poorly understood in Leishmania. In this study, we investigated the role of glycosomal ABC transporter 3 (GAT3) in Leishmania infantum by generating knockout mutants using CRISPR-Cas9-mediated gene editing. Successful deletion of GAT3 was confirmed in two independent knockout clones, which were subsequently characterized with respect to growth, drug susceptibility, oxidative stress tolerance, and infectivity in THP-1-derived macrophages. GAT3 deletion resulted in a modest reduction in promastigote proliferation. Notably, GAT3-knockout promastigotes displayed a 2.3-fold increase in resistance to trivalent antimony and a 3.4-fold increase in resistance to miltefosine compared with control parasites. This phenotype was accompanied by decreased transcript levels of aquaglyceroporin 1 (AQP1) and the miltefosine transporter (MT), two membrane transporters known to mediate the uptake of these antileishmanial drugs. In contrast, GAT3 deletion did not alter susceptibility to amphotericin B or tolerance to hydrogen peroxide-induced oxidative stress. Furthermore, loss of GAT3 had no detectable effect on macrophage infectivity. Collectively, our findings demonstrate that GAT3 is a non-essential glycosomal ABC transporter that contributes to antileishmanial drug susceptibility in L. infantum. The association between GAT3 deletion and reduced expression of AQP1 and MT suggests a previously unrecognized link between glycosomal transport processes and pathways involved in drug uptake and resistance, expanding current knowledge of glycosomal transporter function in Leishmania.
OBJECTIVES:To describe changes in intestinal parasitic infections in Santa Catalina, Bolívar (Caribbean Colombia) between 2014 and 2015 and 2022, and to assess sociodemographic, hygiene, sanitation, and drinking-water factors associated with infection. METHODS:We analyzed two community-based cross-sectional surveys conducted in the same municipality. In 2014-2015, an age-stratified household sample was recruited; in 2022, adults were recruited by convenience during community ascariasis screening activities. Participants provided two stool samples examined by Kato-Katz and direct microscopy. Using 2014-2015 data, we fitted multivariable logistic regression models for parasitic infection outcomes including a composite household sanitation score and drinking-water exposures. Because the 2022 survey differed in sampling frame and age structure, between-wave comparisons were primarily descriptive and complemented by a restricted analysis among adults residing in the municipal head town. RESULTS:In 2014-2015 (N = 685), prevalence was 88.5% for any intestinal parasite, 79.9% for protozoa, and 71.1% for helminths. Poorer household sanitation was strongly associated with helminth infection, whereas protozoan infection was more consistently associated with drinking aqueduct water; residence in the municipal head town was protective. In 2022 (N = 209), infection frequency decreased to 26.3% for protozoa and 11.0% for helminths. In the restricted head-town adult comparison, any intestinal parasite declined from 84.7% (2014-2015; N = 137) to 27.0% (2022; N = 185) CONCLUSIONS: Intestinal parasitic infections declined markedly between 2014 and 2015 and 2022 despite persistent structural constraints. Remaining risk was patterned by household sanitation and, for protozoa, by drinking-water exposure, underscoring the need to strengthen safe drinking water and sustain basic sanitation in rural Caribbean Colombia.
Description of a new species of Myxobolus parasitizing the freshwater fish Rhamdia quelen, in the municipality of Cachoeira do Arari, Marajó Island, Pará, Brazil. Thirty specimens were analyzed, with 60% exhibiting rounded or ovoid, whitish plasmodia containing mature myxospores, scattered across the palate and the lower lip of the hosts. These myxospores measured 13.9 ± 0.3 μm in length and 9.9 ± 0.3 μm in width, in valvar view. Two pear-shaped polar capsules were observed in the anterior region, each containing 6 to 7 turns of the polar tube. Histological analysis revealed the development of plasmodia within the submucosal layer, causing compression of adjacent tissues and exhibiting features suggestive of bone loss. Myxospores were identified diffusely distributed in the vicinity of the plasmodia, possibly because of the rupture of a plasmodium, and were associated with an intense local inflammatory response. In the molecular phylogeny, the new species can be positioned in a clade with high nodal support, predominantly formed by species that infect fish of the order Siluriformes, with M. marajoensis, an intestinal parasite, identified as its sister species. The combined morphological and phylogenetic evidence confirm the description of the new species, Myxobolus cachoeirensis n. sp. and contribute to the knowledge of myxozoan fish parasite biodiversity and phylogenetic relationships in the Amazon biome.
Partial worm replacement (PR), consisting of the elimination of an anthelmintic-resistant parasite population from the host but not from the environment, was evaluated as a tool to improve anthelmintic treatment efficacy in White Dorper (DO), Santa Inês (SI), and Texel (TX) sheep breeds. Artificially infected ewes were kept either in a nematode-free paddock (total replacement - TR) or in a paddock naturally contaminated with resistant helminth larvae (PR) and compared with untreated ewes harboring resistant helminths kept in a naturally contaminated paddock (control - C) over two breeding seasons. In the third breeding season, because of reestablishment of resistance, ewes from the PR and TR groups were reinfected with the susceptible isolate, and their lambs were evaluated every 21 days for fecal egg count (FEC), packed cell volume (PCV), live body weight, FAMACHA© score, and body condition score (BCS). Benzimidazole (F200Y) and levamisole (S168T) resistance-associated polymorphisms were genotyped in Haemonchus contortus larvae. Lambs in the C group had higher FEC and lower PCV than lambs in the other groups, in addition to lower final weight than in the TR group (p < 0.05). DO lambs showed higher FEC, lower PCV, and higher final weight, whereas SI lambs showed higher PCV (p < 0.05). FAMACHA© 3 predominated in the C group and in DO lambs (p < 0.05), which also required significantly more anthelmintic treatments. Reinfection reduced the allele frequencies associated with benzimidazole and levamisole resistance, mainly in the PR group, positively affecting the evaluated parameters. Although reversion of anthelmintic efficacy was transient, strategic reinfection at the end of the dry season may offer an alternative for producers unable to implement TR. When combined with the use of resistant breeds, this approach may help reduce production losses in countries where effective drug classes are unavailable.
Trypanosoma evansi, the causative agent of Surra, remains a major constraint to livestock production in arid and semi-arid regions. In Algeria, numerous studies have investigated T. evansi infection in domestic animals; however, reported prevalence estimates vary widely and are influenced by study design and diagnostic approach. Following PRISMA 2020 guidelines, we conducted a systematic review to synthesize available data and provide an updated overview of T. evansi epidemiology in Algeria. Twelve peer-reviewed studies reporting prevalence data were included. Data were extracted on host species, geographic region, diagnostic method, and number of animals examined and infected. Pooled prevalence estimates were calculated separately according to diagnostic method, and prevalence patterns were described according to host species and geographic region within each diagnostic category. Overall, 4449 animals from various host species were included. Pooled prevalence estimates varied markedly by diagnostic method: serological assays yielded a pooled prevalence of 14.29% (95% CI: 9.36-20.07%), molecular methods 6.64% (95% CI: 3.20-11.21%), and parasitological examination 2.53% (95% CI: 0.68-5.51%), confirming the well-known hierarchy of diagnostic sensitivity. Dromedary camels and equids consistently showed the highest seroprevalence, whereas lower infection rates were observed in cattle, small ruminants, and dogs. Marked regional differences were evident, with higher seroprevalence reported in southwestern and southeastern Algeria. These findings confirm that T. evansi remains endemic in Algeria and that reported prevalence is strongly influenced by the diagnostic method employed, emphasizing the need for standardized surveillance protocols using sensitive tools, particularly in camels and equids.
Oncomelania hupensis quadrasi is the obligate intermediate host of Schistosoma japonicum in the Philippines and is central to sustaining environmental transmission. Although its distribution and infection dynamics have been well characterized, parasite-host interactions at the cellular level remain largely unexplored due to the lack of suitable in vitro systems. This study describes the establishment and optimization of primary embryonic cell cultures of O. h. quadrasi embryonic cell primary culture, providing foundational tools for cellular and molecular investigations. Morphologically identified embryos at the onset of shell formation were enzymatically dissociated using collagenase, and trypsin-EDTA and maintained under a range of conditions, including varying osmolalities (∼125-275 mOsm/kg H₂O), basal media (Roswell Park Memorial Institute medium and Schneider's Insect Medium), and nutritional supplements, particularly fetal calf serum (FCS). Culture performance was assessed by trypan blue exclusion and resazurin and XTT reduction assays. Culture conditions using Schneider's Insect Medium (SIM) supplemented with lactalbumin hydrolysate (LH) and 20% fetal calf serum (FCS) at approximately 200 mOsm/kg H₂O and 27 °C supported the maintenance of viable embryonic cell populations and metabolic activity. Under minimally disturbed conditions, viable cell populations were maintained for up to approximately 30 days. Although this observation was derived from limited biological replication, it establishes experimental conditions that warrant independent validation. Increases in viable cell counts were observed during early culture but did not correspond to doubling of total cell numbers, and no direct evidence of cell division was obtained. These findings define culture conditions that supported the establishment and maintenance of O. h. quadrasi embryonic cell populations under the experimental conditions evaluated. Further studies incorporating increased biological replication and orthogonal assays for cell division are needed to confirm reproducibility and characterize long-term culture performance. This work provides a methodological foundation for the development of species-specific in vitro systems to support schistosomiasis and molluscan biology research.
Giardia duodenalis is a common intestinal parasite that infects children and adults worldwide. Of its eight known assemblages (A-H), assemblages A and B are the predominant genotypes infecting humans. The infection ranges from asymptomatic to chronic diarrhea, but whether disease severity depends on parasite strain or host factors remains unclear. This study analyzed Giardia isolates from non-Inflammatory Bowel Disease (non-IBD) and Inflammatory Bowel Disease (IBD) patients at PGIMER, Chandigarh, to explore link between assemblage type and symptom severity. A total of 180 non-IBD and 80 IBD patients were enrolled categorized into mild, moderate, and severe groups based on symptom severity scores. Detection was done by microscopy and nested PCR, followed by assemblage specific conventional and real-time PCR. The present study revealed that among non-IBD patients, 20 cases were identified as assemblage A, 25 as assemblage B, and 2 as mixed assemblages. Among IBD patients, 4 cases each were classified as assemblage A and assemblage B. Assemblage B predominated in the severe symptom group among non-IBD patients. In IBD patients, a possible association of assemblage A with severe symptoms was observed, although this finding remains preliminary due to the limited sample size. In non-IBD cases, assemblage A was frequent in females and B in males, while in IBD cases, assemblage A dominated in males and B showed equal distribution. This study reveals novel association between Giardia assemblages and symptom severity, highlighting the value of assemblage-level detection for better diagnosis and treatment, and the role of host factors in disease outcome.
Despite the government's and numerous organizations' efforts, Opisthorchis viverrini infection continues to prevail. This literature review aims to explore the relationship between socioeconomic and cultural factors and O. viverrini infection, which is a significant contributor to neglected tropical diseases in the Mekong River Basin, including Thailand, Lao PDR, Myanmar, Cambodia, and Vietnam. This review presents evidence of a positive correlation between lower socioeconomic status and higher O. viverrini infection rates, with specific studies highlighting increased risks among individuals with lower education and income levels. The identification of potential interventions to reduce O. viverrini infection and cholangiocarcinoma risk is a key focus of this review, including health education programs, budget for improved sanitation, and annual mass drug administrations. This review underscores the significant influence of socioeconomic factors on O. viverrini infection in Thailand and emphasizes the necessity of targeted interventions to address these disparities and reduce the public health burdens associated with O. viverrini infection.
Cryptosporidium is a zoonotic protozoan parasite of humans and animals and an important waterborne pathogen worldwide. In the Republic of Korea, Cryptosporidium infection has been reported in humans, livestock, companion animals, and water sources, but the available epidemiological data remain limited and fragmented across studies. This study summarized the prevalence, species distribution, and epidemiological characteristics of Cryptosporidium in Korea. Relevant publications were retrieved from PubMed, Web of Science, Google Scholar, and the Korea Citation Index from June 1991 to July 2025, and a meta-analysis was conducted to estimate pooled prevalence by host group. The overall pooled prevalence was 7.1% (95% CI, 4.6-11.0%), with significant differences among host groups. In humans, prevalence was relatively high in rural areas in the 1990s but generally decreased in later studies. In cattle, prevalence varied widely and remained substantial, particularly in young calves. In pigs, earlier studies mainly reported C. parvum, whereas recent molecular studies identified C. scrofarum and C. suis. Limited studies in goats reported relatively high prevalence, whereas data in chickens remained scarce. In companion animals, prevalence was generally low to moderate, with C. canis and C. felis predominating in dogs and cats, respectively. Cryptosporidium oocysts were also detected in environmental water sources, and a waterborne outbreak caused by C. parvum was reported in Seoul in 2012. Overall, Cryptosporidium remains relevant to both veterinary and public health in Korea. Continued surveillance and further molecular epidemiological studies are needed to better understand transmission patterns and zoonotic risk.
An integrative reassessment of Tetrancistrum polymorphum (Paperna, 1972) Kritsky, Galli & Yang, 2007 (Monogenoidea: Dactylogyridae) was conducted based on specimens collected from the gills of Siganus luridus (Rüppell) (Acanthuriformes: Siganidae) from the Egyptian Red Sea. Although this species has been previously reported and morphologically described using light microscopy, its ultrastructural features, molecular identity, and pathological impact on the host have remained unexplored. In the present study, detailed morphological and morphometric analyses were performed using light microscopy to confirm species identification. Scanning electron microscopy (SEM) provided complementary information on the external morphology, allowing improved visualization of surface topography of the tegument, copulatory complex, and haptor. SEM observations revealed longitudinal tegumental folds, small dome-shaped papillary structures, subtle cephalic elevations, and the external configuration of haptoral structures, with anchors visible at the surface while bars remained embedded within deeper tissues. Molecular characterization based on partial 28S rDNA sequences provided crucial genetic data for this species and supported its phylogenetic placement within Dactylogyridae. Histopathological examination of infected gills demonstrated that T. polymorphum induces epithelial necrosis, lamellar fusion, vascular congestion, and inflammatory cell infiltration, leading to marked disruption of normal gill architecture. By integrating morphological, ultrastructural, molecular, and histopathological data, this study moves beyond traditional redescription and provides an integrative reassessment of T. polymorphum based on these complementary approaches, contributing to a better understanding of its taxonomy, phylogenetic relationships, and host-parasite interactions.
Bromodomains (BRDs) are protein interaction modules that exclusively recognize acetylation motifs, and are evolutionarily conserved and present in diverse nuclear proteins. Toxoplasma gondii is the causative agent of toxoplasmosis, with the tachyzoite stage driving pathogenesis through rapid invasion and replication within nucleated cells. Bromodomain-containing protein 4 (BDP4) is a conserved BRD protein across apicomplexans. To address the roles of T. gondii bromodomain-containing protein 4 (TgBDP4) in the lytic circle of T. gondii, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 and an auxin-inducible degron-based conditional knockdown strategy were used to construct a conditional knockdown parasite line. Phenotypic analysis revealed a growth defect in parasite replication when TgBDP4 was depleted conditionally. TgBDP4 localized in the parasite's nucleus. Depletion of the TgBDP4 led to changes in the expression level of 874 genes. The loss of TgBDP4 resulted in widespread dysregulation of gene expression, highlighting its involvement in both transcriptional activation and repression. Notably, perturbation in the expression of seven APiAP2 transcription factors was accompanied by the down-regulation of specific secretory proteins, such as ROP37, ROP15, ROP30, MIC3, and MIC12. These findings suggest that TgBDP4 may be implicated in the regulatory network controlling secretory protein expression.
Chromist parasites of the genus Eimeria are the causative agent of coccidiosis, an economically important disease of poultry characterized by enteritis, reduced growth performance and decrease in egg production. In the Philippines, Eimeria infections have largely been reported through conventional coproparasitological techniques; however, molecular investigations on the distribution of specific Eimeria species and quantitative assessments of infection intensity are lacking. In the present study, molecular surveillance of Eimeria infections was conducted in various commercial poultry farms in the Philippines to better characterize the epidemiology of the disease. Eimeria oocysts were detected in 24 of 42 poultry houses (57.1%) across 9 of 16 examined commercial farms (56.3%). The positivity rates among different poultry production systems were 60% (6/10) in broilers, 100% (6/6) in broiler breeders; 47.8% (11/23) in layer pullets, 50% (1/2) in egg layers and 0% (0/1) in fighting cocks. The mean oocyst per gram (OPG) across investigated farms was 7211.9 with values ranging from 19.6 to 44,933.3. PCR analysis of the 24 positive poultry houses identified four Eimeria species, namely E. tenella, E. necatrix, E. acervulina, and E. mitis. These findings indicate that Eimeria infections, especially the highly pathogenic species, are widely distributed in commercial poultry operations in the Philippines. The results provide baseline data on the current distribution and infection intensity of Eimeria species in the country, which will be helpful in the prevention, management and control of coccidiosis.
Leishmaniasis is a vector-borne parasitic disease transmitted by female sandflies of the genus Phlebotomus and affects approximately 1.2 million people annually in more than 90 countries worldwide. Morocco remains one of the most affected countries in North Africa, where the disease continues to represent a major public health concern. This study aimed to analyze the spatial and temporal trends of leishmaniasis incidence across all municipalities of Errachidia Province between 2010 and 2025 and to assess the influence of ecological, demographic, and socio-economic factors on its distribution. Also, the study aimed to predict the monthly CL cases using the Seasonal Autoregressive Integrated Moving Average (SARIMA) model. Epidemiological data on parasitologically confirmed cases obtained from the Errachidia Provincial Health Delegation were processed using geographic information system (GIS) tools and statistical methods to explore spatial patterns and correlations with environmental and socio-demographic variables. The models are trained and evaluated using monthly CL cases collected from 2010 to 2025, with the optimal model selected based on Akaike Information Criterion (AIC). During 16-years study period, 7034 cases were recorded in Errachidia Province, with the highest incidence reported in 2010 (860 cases per 100,000 inhabitants). Overall, the incidence showed marked temporal fluctuations but demonstrated a general decreasing trend over the study period. A pronounced spatial heterogeneity was observed between rural municipalities (Sid Ali, Melaab, and Ferkla) and urban municipalities (Errachidia, Arfoud, and Goulmima) (p < 0.01). The disease was slightly more frequent in females (54.41%) than in males (45.59%), and a significant difference was observed among age groups (p = 0.019), with the 0-9 and 10-19-year groups being the most affected. Seasonal analysis revealed a peak incidence during winter. In addition, higher incidence was associated with low- to medium-altitude municipalities, while no significant association was observed with poverty or vulnerability indices. The SARIMA (0,0,1)12 model demonstrated the best predictive performance. These findings highlight the heterogeneity and ecological determinants of leishmaniasis in southeastern Morocco and may support targeted surveillance and control strategies in high-risk areas.
Caprine theileriosis is an economically important tick-borne disease caused by various Theileria species, particularly Theileria lestoquardi, Theileria luwenshuni, and Theileria uilenbergi, in goats (Capra hircus). Goat farming plays an economically and culturally important role on Tarama Island, Okinawa, Japan. Because goats on the island are mainly managed under an extensive grazing system, tick infestation is common. However, Theileria infections have not previously been investigated in goats on Tarama Island. To address this, archived DNA samples prepared from blood collected from 44 goats on Tarama Island were screened using a universal PCR assay targeting 18S rRNA sequences of Theileria and Babesia species. Two DNA samples were positive, and sequencing analysis of the amplicons identified T. luwenshuni. To further investigate the epidemiology of T. luwenshuni on Tarama Island, blood samples were subsequently collected from 96 goats across 19 farms. From each blood sample, a thin blood smear was prepared and genomic DNA was extracted. Microscopic examination of Diff-Quik-stained smears detected intraerythrocytic Theileria-like organisms in 35 (36.5%) goats. In addition, screening of DNA samples using a newly developed T. luwenshuni-specific PCR assay detected 77 (80.2%) positive goats, and the subsequent sequencing analysis confirmed the PCR results. Given that T. luwenshuni can cause severe disease in small ruminants, our findings highlight the importance of managing T. luwenshuni infection in goats on Tarama Island.
Mass mortality events occurred in cultured Japanese whiting (Sillago japonica) in Japan between 2018 and 2025. Dead fish exhibited severe skin erosion, ulceration, and hemorrhaging, with numerous ciliates observed in affected lesions. Histopathological examination revealed epidermal detachment, ulceration, and extensive parasite infiltration into connective and muscle tissues. The causative agent was identified as Miamiensis avidus through 18S rRNA gene analysis. PCR detected parasite DNA in multiple organs, confirming systemic infection. To clarify the role of temperature in disease occurrence, in vitro proliferation and in vivo experimental infection trials were conducted at different temperatures. In vitro, M. avidus exhibited optimal growth at 20-25 °C, while growth was markedly reduced at ≤15 °C and ≥ 30 °C. Experimental infection trials at 12, 18, 24, and 28 °C showed that high mortality occurred at 12 °C and 28 °C in both control and infected groups, suggesting that these temperatures impose significant thermal stress. At 18 °C, mortality was observed only in infected fish, indicating that Japanese whiting were susceptible to M. avidus infection under this thermal condition. At 24 °C, mortality remained low despite high growth potential observed in vitro, suggesting that Japanese whiting were less susceptible to disease at this temperature. These findings suggest that scuticociliatosis in Japanese whiting may be influenced by the balance between temperature-dependent growth of M. avidus and host physiological condition. Maintaining rearing water at approximately 24 °C may reduce the risk of scuticociliatosis under the experimental and rearing conditions examined in this study.
