Acta Parasitologica最新文献

Background

Myxosporeans infecting amphibians, particularly Asian salamanders, remain poorly investigated. I conducted a parasitological survey of Japanese salamanders to investigate the occurrence of myxosporean infections.

Materials and Methods

A parasitological survey was conducted on 132 individuals representing 27 taxa (26 species and one hybrid taxon) of Japanese salamanders belonging to three families. The parasites obtained were examined morphologically using light microscopy and scanning electron microscopy (SEM), and molecular analyses were performed using partial sequences of the small subunit (SSU) and large subunit (LSU) rDNA genes.

Results

Myxosporean parasites belonging to the genus Cystodiscus were identified from the gallbladders of three hynobiid salamanders: Hynobius kimurae, H. tagoi, and H. utsunomiyaorum. Based on morphological and molecular evidence, the parasite is herein described as a new species, Cystodiscus uptoni n. sp. The species is characterized by its myxospore morphology and the presence of motile plasmodia. This represents the first record of a myxosporean infection in salamanders in Asia and the first record of the genus Cystodiscus from Japan. Molecular phylogenetic analyses supported the distinctiveness of the new species from previously sequenced congeners. Myxosporeans were not detected in the remaining 23 salamander taxa, although plasmodia-like structures lacking mature spores were observed in H. hirosei.

Conclusion

This study provides the first evidence of myxosporean infection in Asian salamanders and expands the known host and geographic ranges of Cystodiscus. The results highlight the need for further investigations of myxosporean diversity and host associations in Asian salamanders.

Purpose

The present study investigated clinico-pathological alterations associated with naturally occurring Babesia gibsoni infection in dogs from Mizoram, India.

Methods

Diagnosis was established using rapid antibody detection, microscopic blood smear examination, and polymerase chain reaction (PCR). Blood samples were collected to study the haemogram, and serum samples were used for the evaluation of serum biochemical profile and oxidant-antioxidant indices. Abdominal ultrasonography was performed in the infected dogs.

Results

Of 138 samples screened, 43 (31.15%), 70 (50.72%), and 85 (61.59%) were positive by rapid antibody test, blood smear examination, and PCR, respectively. The most consistent clinical signs included depression/lethargy, inappetence/anorexia, and pyrexia. Splenomegaly and splenic lesions were the most consistent ultrasonographic findings noticed. Major haemato-biochemical alterations comprised anaemia, leukocytosis with neutrophilia and eosinophilia, thrombocytopaenia, hypoproteinaemia, hypoalbuminaemia, hyperbilirubinaemia, azotaemia, and increased alanine aminotransferase (ALT), alkaline phosphatase (ALP), and C-reactive protein (CRP) levels. Dogs with B. gibsoni infection exhibited significantly (P < 0.001) higher lipid peroxide (LPO) levels and significantly (P < 0.001) lower total antioxidant capacity (T-AOC) and reduced glutathione (GSH). Red blood cell (RBC) count showed a negative correlation with LPO (r = − 0.741; P < 0.01) and a positive correlation with GSH (r = 0.714; P < 0.01) and T-AOC (r = 0.828; P < 0.01), indicating a role of oxidant–antioxidant imbalance in the severity of anaemia.

Conclusion

These findings underscore the multiorgan involvement of the disease and suggest a potential role of oxidative stress in the pathogenesis of B. gibsoni–induced anaemia in dogs.

Background

The introduction of host-associated symbionts by invasive species threatens native aquatic biodiversity through symbiont spillover and host switching. This study investigated the experimental host-specificity and transmission potential of Diceratocephala boschmai from invasive Cherax quadricarinatus to the native giant freshwater prawn Macrobrachium rosenbergii.

Methods

Briefly, temnocephalid-infested C. quadricarinatus were exposed to symbiont-free M. rosenbergii and C. quadricarinatus for 30 days. Thereafter, symbiont transmission was assessed, and host hemolymph parameters, including total hemocyte count (THC), differential hemocyte count (DHC), glucose, and protein concentration, were evaluated.

Results

Successful transmission was observed in 93.33% of C. quadricarinatus, with both adult worms and egg capsules detected, whereas no transmission was observed in M. rosenbergii. THC was significantly higher in experimentally infested C. quadricarinatus (TCq) than in non-infested C. quadricarinatus (NCq) (p<0.05). DHC and glucose concentrations differed among host populations. Total protein concentration also differed significantly among host populations, with NMr exhibiting higher concentrations than the other groups, whereas no significant difference was detected between TCq and NCq.

Conclusion

The results demonstrate successful infestation of C. quadricarinatus but not in M. rosenbergii under the experimental conditions, suggesting differences in host compatibility. Increased THC in experimentally infested C. quadricarinatus indicates a cellular response to symbiont exposure, although experimental stress may also have contributed. Overall, the findings provide restricted host compatibility and highlight that invasive C. quadricarinatus may serve as a reservoir for D. boschmai, facilitating its persistence and dissemination in freshwater ecosystems.

Background

Bovine anaplasmosis reduces livestock productivity in cattle, making timely and accurate diagnosis essential for epidemiological surveillance.

Purpose

To explore alternative primers for pathogen detection beyond the reference 19A/19B set targeting the single-copy msp5 gene and to update epidemiologic data we evaluated analytical and field performance of primers designed for the multicopy msp2 gene, using conserved terminal regions (msp2A/B). We also described the prevalence of A. marginale in specific sampled herds from several regions of Venezuela.

Methods

PCR conditions were standardized, and the analytical sensitivity of msp2A/B and 19A/B was evaluated. Field evaluations involved 208 cattle from small farms in four distinct geographical regions of Venezuela (Aragua, Cojedes, Guárico, and Miranda), divided into two groups with different clinical characteristics.

Results

Both primer sets detected the pathogen at concentrations as low as 0.01 ng. In a herd of 24 cattle experiencing an anaplasmosis outbreak, positivity rates were 12.5% and 66.67% using primers msp2A/B and 19A/B, respectively. One of the positive field-sample amplicons was cloned and sequenced to confirm bacterial identity, yielding a 97% BLAST identity with complete coverage to the reference strain Florida. Additionally, 10 and 5 nucleotide substitutions were detected at the 5′ and 3′ ends, respectively, compared to the reference isolate. This suggests terminal heterogeneity in the gene that may contribute to the reduced diagnostic performance of msp2A/B. Additionally, 184 clinically healthy cattle analyzed solely with 19A/B revealed a subclinical prevalence of 41.85%.

Conclusion

In a country with limited recent molecular reports, these findings underscore the epidemiological relevance of persistent infections. This study also constitutes the first report of an msp2 sequence from a Venezuelan A. marginale isolate, providing preliminary insights of the genetic diversity of A. marginale and support using msp5-based PCR for routine field detection and surveillance in Venezuela.

Introduction

Colpodella spp., a group of predatory protists closely related to the phylum Apicomplexa, are primarily known as free-living organisms associated with aquatic and terrestrial ecosystems. Although Colpodella-related DNA has increasingly been detected in vertebrate-associated samples, its distribution and ecological significance remain poorly understood. This study aimed to investigate the occurrence, molecular characteristics, and genetic diversity of Colpodella spp. DNA detected in human fecal samples and Haemaphysalis longicornis ticks from Hebei Province, China.

Materials and Methods

A total of 2,448 human fecal samples and 215 tick samples were collected from Hebei Province, China. The presence of Colpodella spp. DNA was investigated using PCR targeting the 18S rRNA gene, followed by sequencing, phylogenetic analysis, and genetic diversity assessment based on partial Colpodella spp. 18S rRNA sequences.

Results

Colpodella spp. DNA was detected in 136 human fecal samples and 11 tick samples, with detection rates of 5.56% and 5.12%, respectively. Sanger sequencing successfully detected high-quality 18S rRNA sequences from all PCR-positive samples. Because identical sequences were detected among tick-derived samples, one representative sequence derived from H. longicornis ticks and 21 representative human-derived sequence types were selected for downstream analyses. Phylogenetic analysis based on 22 representative sequences showed that the sequences obtained in this study clustered within previously reported Colpodella spp. lineages. Genetic diversity analysis identified 3 haplotypes among the analyzed sequences.

Conclusions

This study provides molecular evidence for the occurrence and genetic variation of Colpodella spp. DNA in human fecal and tick-associated samples from Hebei Province, China. However, PCR-based detection alone cannot determine active infection, colonization, pathogenicity, or biological activity of the detected organisms. Further studies using additional molecular markers, culture systems, and biological approaches are required to clarify the ecological and potential health significance of Colpodella spp.

Background

African animal trypanosomosis remains a persistent constraint on livestock production in sub-Saharan Africa, yet the combined influence of parasite species, inoculation route and host immune response on disease severity has rarely been examined within a single controlled experiment. We compared Trypanosoma congolense and Trypanosoma brucei infections in BALB/c mice following intraperitoneal or intramuscular inoculation. Four infected groups of fifteen mice and five uninfected controls were followed for parasitaemia, body weight, rectal temperature and survival. Packed cell volume, endpoint haematological indices, serum IFN-γ and IL-10 concentrations, and semi-quantitative liver, spleen and kidney pathology scores were assessed.

Results

Survival differed markedly between groups (log-rank p < 0.0001). Intraperitoneal T. congolense infection had the shortest median survival of nine days, whereas intramuscular T. brucei infection showed the longest survival among the infected groups. Patency and peak parasitaemia were broadly comparable, indicating that parasite burden did not correspond to the observed survival differences. Infected animals showed anaemia and thrombocytopenia. IFN-γ was higher in infected animals than in controls but did not distinguish the four infected groups. IL-10 showed a stronger species-associated pattern, with higher concentrations in T. congolense-infected mice than in T. brucei-infected mice. Liver, spleen and kidney pathology scores were significantly higher in infected animals than in controls but did not differ significantly among the infected groups.

Conclusions

Parasite species and inoculation route influenced the tempo of experimental murine trypanosomosis. These discordances between survival, parasitaemia, lesion severity and cytokine profiles suggest that species-associated host responses may contribute to disease outcome, although further mechanistic investigation is required.

Background

Cryptosporidium spp. are obligate intracellular apicomplexan parasites causing gastroenteritis and diarrhea in many vertebrates, including small ruminants. This study aimed to determine the occurrence and perform molecular characterization of Cryptosporidium spp. in healthy Akkaraman sheep across three provinces (Nevşehir, Sivas, and Kayseri) in the Central Anatolia Region of Türkiye.

Methods

Fresh fecal samples were collected from 300 healthy Akkaraman sheep (100 per province) randomly selected from various small-scale farms. Following gDNA extraction, the presence of Cryptosporidium spp. was determined via polymerase chain reaction (PCR). To identify specific species, sequence analysis of the 18S ribosomal RNA (rRNA) gene was performed.

Results

The overall prevalence of Cryptosporidium spp. in sheep was 6.0% (18/300). Positivity differed significantly across age groups (p < 0.0001), but no significant difference was observed between genders (p = 0.548). Sequence analysis identified three Cryptosporidium species: C. parvum (2.3%; 7/300), C. bovis (2.3%; 7/300), and C. xiaoi (1.3%; 4/300). These sequences were registered in GenBank (Accession numbers: MZ027074-MZ027078). Phylogenetic analysis revealed that our isolates clustered within the same clades as reference sequences reported from different hosts and geographic regions.

Conclusions

To the best of our knowledge, this is the first report of sheep infected with C. bovis in Türkiye. The findings provide detailed insights into the molecular epidemiology of ovine cryptosporidiosis in the region and highlight the critical importance of controlling Cryptosporidium infections in sheep due to their potential public health relevance.

Background

The genus Caryospora Léger, 1904 comprises facultatively heteroxenous coccidia that predominantly parasitize snakes, with seven nominal species recorded in vipers (Viperidae). In the Neotropical region, the Jararaca Bothrops jararaca (Wied-Neuwied, 1824) and the Common Lancehead Bothrops atrox (Linnaeus, 1758) were previously the only recorded viperid hosts for Caryospora jararacae (Carini, 1939). This study aimed to provide a morphological redescription and the first molecular characterization of C. jararacae, alongside a global taxonomic review of Caryospora spp. in viperids.

Methods

Fecal samples from B. jararaca and Cascabel Rattlesnakes Crotalus durissus Linnaeus, 1758 were analyzed for oocyst morphology. Molecular characterization of C. jararacae was performed using a multilocus approach combining three mitochondrial loci and the nuclear 18S rDNA gene. Additionally, an integrative review synthesizing global data on geographic distribution, host specificity, and genotypic similarities of viperid Caryospora spp. was conducted.

Results

Caryospora jararacae was identified and redescribed from B. jararaca and C. durissus. By reidentifying previous morphometric reports from C. durissus as C. jararacae and providing the first genetically confirmed records for both host species, this study establishes C. jararacae as the sole Caryospora species known from Neotropical vipers and only the second genotypically characterized Caryospora species in the family Viperidae worldwide. The integrative review revealed that five of the seven nominal species reported in vipers belong to the Caryospora simplex species complex, representing five morphologically indistinguishable geotypes distributed across different continents.

Conclusions

Molecular evidence primarily supports a scenario of recent common ancestry and incipient speciation among geotypes of the Caryospora simplex species complex, wherein high genetic similarity reflects shared ancestral characters, rather than active ongoing genetic exchange. Despite their morphological indistinguishability, retention of the five nominal species within the complex is recommended, as they can be delimited through an integrative framework combining biogeographical, host, and molecular data.

Background

Lymphatic filariasis (LF) remains endemic in several island communities in Indonesia despite mass drug administration (MDA) campaigns. Investigating the spatial relationship between human cases and potential mosquito breeding sites may help explain the persistence of LF transmission.

Methods

A cross-sectional survey was conducted in 2019 across four sub-villages in two LF-endemic villages in Belitung Regency, Indonesia: Suak Gual village (Suak Gual sub-village) and Lasar village (Batumana, Dudat, and Ulin sub-villages). Thick blood smears were collected at night from 671 participants and were examined microscopically. GPS coordinates were recorded for the residence of all study participants, regardless of their infection status, as well as for each water body exhibiting characteristics consistent with a potential Mansonia habitat. Distance analysis, buffer zone evaluation, the Clark-Evans test, and cross-K function analysis were used to characterize the spatial relationship between cases and habitats.

Results

Case clustering was robust in two of the four sub-villages, Suak Gual (R = 0.380, p < 0.001) and Batumana (R = 0.432, p < 0.001), with significance maintained after Bonferroni correction across all boundary-window widths tested. Ulin showed nominally significant clustering (R = 0.654, p = 0.026) that did not survive Bonferroni correction (p = 0.106) or a narrower boundary window and is reported as a weaker, less consistent finding. Dudat showed no deviation from spatial randomness (R = 0.856, p = 0.434), which is consistent with its comparatively dense and widespread habitat. Just over three-quarters of cases, 76.5% (n = 26), lived within 500 m of the nearest habitat, indicating a geographic link between residence and vector breeding sites.

Conclusions

Filariasis cases in Belitung tend to cluster near potential Mansonia habitats. These findings provide programme planners with a quantitative basis for prioritizing habitat-focused interventions alongside ongoing mass drug administration. Direct entomological surveys are still needed to confirm vector presence and test the effectiveness of spatially targeted control.