Parasites, hosts and diseases最新文献

Perkinsus marinusis a major protozoan pathogen of oysters, responsible for severe mortality events and substantial economic losses in the global aquaculture industry. Rapid, sensitive, and reliable detection of this parasite is therefore essential for effective monitoring and timely control of dermo disease outbreaks. In this study, we developed and optimized a novel loop-mediated isothermal amplification (LAMP) assay, designated Pm-LAMP, for the specific detection of P. marinus in oyster tissues. The optimized Pm-LAMP assay, employing 5 primers and performed at 67°C, demonstrated high analytical sensitivity, consistently detecting DNA concentrations as low as 40 fg/µl and enabling accurate quantification down to 0.4 pg/µl. The assay exhibited linear amplification across a wide template range from 4 ng/µl to 0.4 pg/µl, with a strong inverse correlation between template concentration and threshold time. Specificity testing confirmed exclusive amplification of P. marinus, with no cross-reactivity observed for P. olseni, P. honshuensis, or P. chesapeaki. This study represents the first LAMP assay specifically designed for the detection of P. marinus. The Pm-LAMP assay was validated using Pacific oyster tissues and cultured P. marinusisolates originating from the USA and Korea and was benchmarked against quantitative real-time PCR (qPCR). Although qPCR exhibited higher sensitivity for detecting trace DNA levels, the Pm-LAMP assay produced results within 20 min while maintaining reliable detection at low DNA concentrations. Diagnostic performance evaluation showed 100% sensitivity and 90.91% specificity, with substantial agreement with qPCR (Cohen's κ=0.811). Overall, the Pm-LAMP assay provides a rapid, robust, and field-deployable diagnostic tool for P. marinus, supporting improved disease surveillance and sustainable oyster aquaculture management.

Naegleria fowleri is a free-living amoeba that can cause primary amebic meningoencephalitis (PAM), a very serious infection of the central nervous system. Early diagnosis of PAM is challenging, and the condition is almost always fatal. In this study, we conducted 2-dimensional gel electrophoresis (2-DE) analysis using N. fowleri trophozoite lysates and conditioned media to identify preferentially secreted proteins. As a result of the 2-dimensional gel electrophoresis analysis, 1 protein was found to increase, 5 proteins were found to decrease, 3 proteins showed a qualitative increase, and 15 proteins showed a qualitative decrease in the conditioned media compared to the proteins in the trophozoite lysates. Using cDNA from N. fowleri, Acanthamoeba castellanii, and Balamuthia mandrillaris, all of which can cause encephalitis, real-time PCR was performed on 5 genes corresponding to the p23-like domain-containing protein, cystatin-like domain-containing protein, fowlerpain-2, hemerythrin family non-heme iron protein, and an uncharacterized protein. The results showed that all 5 genes were highly expressed in N. fowleri. In animal models infected with N. fowleri resulting in PAM, real-time PCR analysis of brain tissue revealed significant overexpression of the p23-like domain-containing protein and fowlerpain-2. These results suggest that the 2 secreted proteins could provide valuable insights for developing antibody-based or molecular diagnostic methods to detect N. fowleri in patients with PAM.

The human gut is host to a diversity of microorganisms, including a parasite called Blastocystis. While there are increasing reports characterizing Blastocystis subtypes (STs) among healthy individuals, only a few studies have investigated the Blastocystis STs in renal or dialysis patients. This study investigates the Blastocystis prevalence and STs in hemodialysis patients. Fifty healthy controls and 100 chronic kidney disease patients undergoing dialysis participated in the study. Blastocystis infection was identified by using microscopic and molecular diagnosis using 18S rRNA-PCR. Then all positive samples were sent for sequencing to identify which ST they belong to. Phylogenetic and pairwise distance analyses were performed to confirm the validity of the STs. Thirty-four hemodialysis patients were infected with Blastocystis while 17 patients in the control were infected with the parasite. All positive samples were then confirmed using PCR. Genetic sequencing analysis subsequently revealed that 66% of Blastocystis infection belonged to ST1 and ST3 (33% each), followed by ST10 (20%), and ST6 (14%). The nucleotide sequence analysis of the 385 bp 18S rRNA gene revealed a >97% identity with previously identified Blastocystis isolates. The genetic analysis showed that the 8 identified isolates correspond to previously observed alleles. Six ST1 isolates produced a high frequency of Blastocystis isolates matching allele 4, with very low genetic divergence. ST3 isolates showed relatively increased genetic diversity and matching allele 34, which is the most common allele worldwide.

Plasmodium vivax merozoite surface protein-1 (PvMSP-1) is one of the major polymorphic markers for molecular epidemiological purposes. In particular, the interspecies conserved block 5-6 (ICB 5-6) of PvMSP-1 is a region exhibiting extensive genetic polymorphism. In this study, we analyzed polymorphic characters of the pvmsp-1 ICB 5-6 region from P. vivax isolates collected in 4 provinces of Vietnam (Dak Lak, Dak Nong, Gia Lai, and Khanh Hoa) between 2018 and 2022. A comparative analysis of pvmsp-1 ICB 5-6 sequences was also conducted between Vietnam and other endemic regions. A total of 139 pvmsp-1 ICB 5-6 sequences were obtained from 117 Vietnamese P. vivax isolates. Vietnam pvmsp-1 ICB 5-6 were clustered into 34 distinct haplotypes at the amino acid level, with the recombinant types being predominant. The pvmsp-1 ICB 5-6 from the Central Highlands, Dak Lak, Dak Nong, and Gia Lai, exhibited high genetic polymorphism, while the sequences from the South-Central region, Khanh Hoa, were less polymorphic. Highly diverse patterns of poly-glutamine (poly-Q) variants were identified in Vietnam pvmsp-1 ICB 5-6. Comparable features of genetic polymorphism were also identified in the global pvmsp-1 ICB 5-6 populations. Phylogenetic analysis of global pvmsp-1 ICB 5-6 revealed no significant country- or region-specific clustering. This study suggests that Vietnam pvmsp-1 ICB 5-6 exhibited a substantial genetic diversity with regional variations, implying the genetic heterogeneity of the Vietnamese P. vivax population. These findings emphasize the importance of continuous molecular surveillance to understand the genetic nature of the parasite in the country.

Vertical transfer of maternal antibodies can provide passive protection to offspring against specific pathogens. In this study, we detected antibodies in the sera of uninfected offspring born to chronically Trichinella spiralis-infected female mice. Immunoblotting consistently revealed a distinct band at ~38 kDa in both T. spiralis excretory-secretory products and total somatic extracts. This band was identified by MALDI-TOF/TOF mass spectrometry as a cystatin-like protein of T. spiralis (Ts-CLP). Structural modeling and domain analysis indicated a typical cystatin-like fold comprising a central α-helix and an antiparallel β-sheet core. To confirm antigen identity, recombinant Ts-CLP protein was expressed and used to generate a polyclonal anti-recombinant Ts-CLP protein antibody. This antibody specifically recognized a ~38 kDa band in T. spiralis excretory-secretory products and total somatic extracts, consistent with that detected by offspring sera. Collectively, these findings demonstrate that maternal antibodies specific to Ts-CLP are vertically transferred and detectable in uninfected offspring. Although the functional significance remains to be determined, this observation provides a basis for future studies on passive immunity and host-parasite interactions.

The Oriental stork (Ciconia boyciana Swinhoe, 1873) is an endangered species, with active restoration efforts ongoing in Korea. Despite the ecological importance of host-specific parasites, such as chewing lice (Phthiraptera), information on the chewing lice fauna associated with C. boyciana in Korea remains unclear. Previous records of 2 chewing louse species from the host have been questioned due to potential misidentification. To clarify the chewing lice fauna of the host, we conducted a survey of captive C. boyciana at Yesan Oriental Stork Park, Korea, in October 2022. Morphological identification of collected louse specimens revealed 3 species: Neophilopterus incompletes (Denny, 1842), Ardeicola ciconiae (Linnaeus, 1758) and Colpocephalum zebra Burmeister, 1838. These species are typical ectoparasites of Ciconiiform birds and represent the first verified louse records of chewing lice from C. boyciana in Korea. Unlike with a previous report, Cuclotogaster heterographus (Nitzsch, 1866) and Anaticola anseris (Linnaeus, 1758) were not detected. Our findings provide an updated checklist of chewing louse species for C. boyciana in Korea, contributing to a more accurate understanding of host-parasite associations and supporting future conservation efforts for both the host and its associated parasite fauna.

Toxoplasma gondii is an intracellular protozoan parasite capable of causing chronic infection by forming persistent cysts in the brain. Despite its global burden, no approved vaccine exists. Virus-like particle vaccines expressing microneme protein 8 (MIC8) or apical membrane antigen 1 (AMA1) of T. gondii have previously shown efficacy. In this study, we generated recombinant vaccinia viruses (rVVs) expressing MIC8 and AMA1 and evaluated their efficacy against T. gondii ME49 infection. BALB/c mice were intramuscularly immunized with a combination of MIC8 and AMA1 rVVs and challenged orally with T. gondii ME49. Immunization with MIC8+AMA1 rVVs produced a significant increase in T. gondii-specific IgG. Splenocyte analysis revealed robust activation of CD4+ and CD8+ T cells, as well as expansion of memory B cells. The immunized group exhibited an 89.6% reduction in brain cyst count, with significantly improved survival compared to the control group. These findings demonstrate that combining the antigens MIC8 and AMA1 using a vaccinia virus platform can effectively promote both humoral and cellular immunity, supporting its potential as a vaccine strategy against T. gondii ME49.

Caryophyllaeus brachycollis mainly parasitizes the intestines of globally distributed freshwater fishes, and infection causes significant economic losses to the aquaculture industry. However, data on the molecular epidemiology, population genetics, and systematics of C. brachycollis are scarce. In this study, we sequenced the complete mitogenome of C. brachycollis isolated from Beijing, China. This circular mitogenome comprised 14,273 bp, which was 231 bp shorter than that of C. brachycollis isolated from Wuhan, China. The mitogenome contained 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 2 noncoding regions. Bayesian inference revealed that C. brachycollis belonged to the family Caryophyllaeidae. The taxonomic status of C. brachycollis is controversial when based solely on morphological features. A comparative analysis of the mitogenome sequence obtained in this study revealed novel molecular markers for the accurate ascertainment of the phylogenetic position of this parasite.

The leopard cat (Prionailurus bengalensis) is a wild felid species that serves as a reservoir of zoonotic parasites. In this study, we investigated intestinal parasite taxa by reanalyzing previously published shotgun metagenomic sequencing data from fecal samples of wild leopard cats using a custom 18S rRNA gene reference database constructed from the NCBI nucleotide database. Among 11 metagenomic samples, 5 parasite species were identified: Toxoplasma gondii, Clonorchis sinensis, Strongyloides planiceps, Cylicospirura petrowi, and Pharyngostomum cordatum. These findings demonstrate that shotgun metagenomic analysis of fecal samples can be a useful tool for monitoring zoonotic parasite infections in this species and for investigating parasite life cycles. However, this approach is limited by its dependence on existing reference databases and requires experimental validation of the findings.

We present a nearly complete mitochondrial genome (mitogenome) of Hymenolepis diminuta from a Danish isolate, which was reassembled and comprehensively annotated using whole-genome sequencing data retrieved from the Sequence Read Archive (accession No. ERS056110). Although 2 mitogenomes of H. diminuta have previously been submitted to GenBank (accession No. AP017664, Danish isolate; NC_002767, putative German laboratory strain), the former lacks noncoding regions, while the latter harbors relatively short repeat units. Our newly reconstructed mitogenome is 14,090 bp long, comprising 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a 643-bp noncoding region containing 7 tandem repeat units. The annotated sequence has been deposited in the Third Party Annotation database in GenBank (accession No. BK071817). Phylogenetic analysis based on mitogenomic sequences confirmed a close relationship between H. diminuta and Hymenolepis nana. This improved mitogenome sequence represents a valuable resource for comparative mitogenomic and phylogenetic investigations within the families Hymenolepididae, Taeniidae, and Diphyllobothriidae.