Parasite最新文献

Tick-borne pathogens, particularly Babesia and Theileria species, are major threats to cattle production, causing economically significant diseases such as babesiosis and theileriosis. In this study, a real-time SYBR Green PCR assay was developed to detect Babesia and Theileria species in hard ticks (N = 65) and cattle blood samples (N = 143) from Thailand. Using primers targeting the mitochondrial cytochrome b gene for Babesia and the nuclear 18S rRNA gene for Theileria, the assay measured specific melting temperatures (Tm) for each species. The results showed distinct Tm values for Babesia bigemina (74.38 ± 0.04 °C), Babesia bovis (75.7 ± 0.06 °C), Theileria orientalis (74.61 ± 0.03 °C), Theileria sinensis (75.84 ± 0.03 °C), and Theileria annulata (74.06 ± 0.03 °C). The assay demonstrated high specificity, with a cutoff cycle threshold of < 35 cycles and a minimum detectable concentration of 10 copies/μL. Significant species differences in melting curves were confirmed using Tukey's HSD test (p < 0.05). Theileria orientalis was detected in 8.4% of cattle blood samples, while T. sinensis was found in 25.9%, and B. bigemina in 0.7%. Theileria orientalis was also detected in 7.7% of tick samples, T. sinensis in 16.9%, and B. bigemina in 6.1%. The assay returned negative results for all non-target blood and tissue pathogens tested for specificity. This robust, high-throughput assay is highly effective for monitoring Babesia and Theileria infections, facilitating close surveillance and intervention efforts against tick-borne diseases in cattle.

Gastrointestinal infections caused by protozoan parasites remain a significant public health concern worldwide, particularly during the health crisis caused by the COVID-19 pandemic, which led to severe economic and social crisis that highlighted the inadequacy of healthcare services in many countries. In this study, we analyzed changes in the incidence of cases of amebiasis, giardiasis, and other gastrointestinal protozoal infections before (2017-2019) and during (2020-2022) the pandemic. Our findings indicate a decrease in the incidence of these infections, with no significant variations in incidence by gender or age, and a higher incidence during months with elevated temperature and humidity. Sociodemographic factors, including residence in homes with earthen floors, poverty, limited access to healthcare services, inadequate nutrition, unemployment, and overcrowded living conditions, were associated with an increased risk of infection. Additionally, our results highlight the impact of public health policies on disease control, demonstrating that COVID-19 containment measures - such as international travel restrictions, workplace closures, event cancellations, stay-at-home mandates, and enhanced hand hygiene - also contributed to reducing parasitic infections. The persistent prevalence of protozoal infections in both periods underscores the urgent need to improve sanitation, personal hygiene, and public health education, particularly in developing countries, to mitigate their high burden.

The nematode Nematodirus oiratianus is associated with major economic losses in the livestock industry, as it is a common gastrointestinal parasites of cattle, sheep, and other ruminants. These parasites primarily obtain nutrients by consuming the blood of their host. This study aimed to investigate changes in the intestinal microbiota of lambs infected with N. oiratianus before and after infection, using 16S rDNA sequencing technology. We aimed to reveal the impact of N. oiratianus infection on lamb intestinal microecology and to provide scientific evidence for the prevention and control of related diseases. Compared with the infected group, the control group had more bacterial species. Chao, Ace, and Shannon indices were significantly lower in the infected group (p < 0.05), while the Simpson index showed no significant difference (p > 0.05). These findings collectively indicate significant divergence in the composition of bacterial taxa between the infected and control groups. The phylum with the highest relative abundance in both groups was Firmicutes, followed by Bacteroidetes. Linear Discriminant Analysis Effect Size (LEfSe) identified significantly enriched taxa, including Proteobacteria, Bacteroides, and Campylobacteria in the control group, and Clostridiales, Firmicutes, and Ruminococcaceae in the infected group. Functional predictions indicated that the altered microbiota was associated with metabolic pathways such as carbohydrate, amino acid, and vitamin metabolism. Infection with N. oiratianus led to significant alterations in the diversity and composition of the intestinal microbiota in lambs.

Acanthocephalans of the genus Rhadinorhynchus parasitize various marine fishes worldwide. However, the true diversity of Rhadinorhynchus is still unclear. In this study, we found an example of phenotypic variation in trunk spines of the poorly known rhadinorhynchid species R. cololabis Laurs & McCauley, 1964. According to the number and distribution of trunk spines, the present specimens of R. cololabis can be divided into two distinct morphotypes, which may erroneously be recognized as distinct taxa in the absence of molecular data. However, the Assemble Species by Automatic Partitioning (ASAP) and Bayesian inference (BI) analyses based on different nuclear and mitochondrial sequence data, all confirm that the two distinct morphotypes are conspecific, and do not represent two separate genetic lineages. Our ASAP and BI results of cox1 data also suggest that is R. villalobosi Martínez-Flores et al., 2025 is a synonym of R. trachinoti Grano-Maldonado et al., 2025, and challenge the validity of R. dorsoventrospinosus Amin et al., 2011, and R. hiansi Soota & Bhattacharya, 1981. The present findings also indicate that the number and distribution of trunk spines vary markedly in some species of Rhadinorhynchus, and care must be taken when differentiating Rhadinorhynchus species based on this feature. Additionally, the complete mitogenome of R. cololabis is presented for the first time, which has only 13,567 bp, and displays a very high level of similarity with the mitogenome of R. laterospinosus in both nucleotide sequences (94.6%) and amino acid sequences of 12 protein-coding genes (93.8%). However, comparative mitogenomics support R. cololabis and R. laterospinosus representing two separate taxa.

Canine monocytic ehrlichiosis (CME) is a globally prevalent disease with zoonotic potential primarily caused by the obligate intracellular bacterium Ehrlichia canis, transmitted by the ticks Rhipicephalus spp. to vertebrate hosts. In dogs, CME affects immune system cells, leading to subclinical infection or acute and chronic disease forms that impact multiple organs and potentially result in death if diagnosis is delayed. Diagnosis of canine ehrlichiosis is complex, typically involving cytology, polymerase chain reaction), and serological assays such as the indirect immunofluorescence antibody test (IFAT), considered the gold standard, and enzyme-linked immunosorbent assay (ELISA). Herein, we introduce EhrlichiaCHECK Ab ELISA, a novel rapid indirect ELISA for detecting anti-E. canis antibodies in canine serum or plasma samples. The assay's performance was validated using 112 canine samples (61 negative, 51 positive). Compared to IFAT, the ELISA exhibited high sensitivity (96.1%, 95% confidence interval [CI]: 85.4%-99.3%) and specificity (95.1%, 95% CI: 85.4%-98.7%). Furthermore, in comparison to the widely used commercial INgezim Ehrlichia ELISA (Gold Standard Diagnostics), EhrlichiaCHECK Ab ELISA demonstrated 98.0% agreement and enhanced specificity attributed to a more specific antigen, corroborated by bioinformatics analysis. The assay also demonstrated accuracy, with low percentage values of intra- and inter-assay coefficients of variation. In conclusion, our data suggest that the newly developed assay is a valuable tool for diagnosing E. canis infections in dogs.

Cryptosporidium spp. are zoonotic protozoan parasites that cause diarrheal disease worldwide. Rodents can harbor diverse Cryptosporidium spp. and facilitate their transmission to the environment and other hosts, including humans. However, data on Cryptosporidium infection in wild rodents in the Poyang Lake region, China's largest freshwater lake, remain scarce. Here, we investigated Cryptosporidium spp. in 273 wild rodents collected from seven sites adjacent to villages around Poyang Lake between 2022 and 2024. The rodents were identified by cytochrome c oxidase subunit I (COI) gene sequencing as Apodemus agrarius (n = 148) and Rattus losea (n = 125). Nested PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene revealed an overall Cryptosporidium spp. infection rate of 16.5% (45/273, 95% CI: 12.3-21.9%), with 20.3% (30/148, 95% CI: 14.2-27.8%) in A. agrarius and 12.0% (15/125, 95% CI: 6.9-19.0%) in R. losea. Sequence and phylogenetic analyses identified seven Cryptosporidium species/genotypes: C. apodemi, C. canis, C. muris, C. suis, C. ubiquitum, rat genotype II, and rat genotype III. Notably, the detection of four zoonotic species (C. canis, C. muris, C. suis, and C. ubiquitum) highlights the potential risk of zoonotic transmission of Cryptosporidium spp. from wild rodents to humans in this region. These findings underscore the need for systematic surveillance and control of Cryptosporidium spp. in wild rodent communities around Poyang Lake.

Surra is a vector-borne disease, caused by a flagellate protozoan, Trypanosoma evansi, infecting all domestic mammals, including herbivores and dogs, and, very rarely, humans. In Tunisia, it affects mainly dromedaries (Camelus dromedarius) in the southern part of the country, causing heavy economic losses due to high morbidity, abortions and mortality. Trypanosoma evansi is mainly transmitted by mechanical vectors (Stomoxyine flies and tabanids), but also vertically, orally (to carnivores) and iatrogenically. In the present paper, we review and discuss the studies published on surra in Tunisia and show that the antibody seroprevalence in Tunisian dromedaries varies between 22.2% and 37%. The review also highlights the absence of a comprehensive database containing the most relevant information on the occurrence of T. evansi in Tunisia. We also underscore the urgent need for data collection and analyses. These data should be related to different aspects: epidemiological data (spatial and temporal distribution) and entomological data (main vectors involved in the transmission and their activity dynamics).

Leishmaniasis is one of the most important zoonotic diseases. Recently, Leishmania (Mundinia) martiniquensis, Leishmania (Mundinia) orientalis, and Leishmania (Mundinia) chancei have been reported as new human pathogens. Trypanosomatids, apart from Leishmania spp., such as Crithidia spp., are also occasionally capable of infecting humans. Here, a one-step multiplex qPCR assay for the simultaneous identification and quantification of L. martiniquensis and L. orientalis/L. chancei and detection and quantification of trypanosomatids was developed using ITS1 as the molecular target and human RNase P as the internal control gene. The assay was evaluated using 44 positive residual DNA samples from leishmaniasis patients and 25 negative DNA samples. Results revealed that the limits of detection (LOD) of the assay for L. martiniquensis, L. orientalis, and Crithidia sp. (CLA-KP1) were 1.699 (0.0255), 1.717 (0.0292), and 1.763 (0.0882) fg/reaction (parasite equivalents/reaction), respectively. The assay had high analytical specificity. The mean Cq values of the intra-assays and inter-assays differed by less than 1, indicating the reliability of the assay. Evaluation results revealed that the assay could identify L. martiniquensis and L. orientalis in clinical samples with 100% sensitivity and 100% specificity. In conclusion, the ITS1/human RNase P multiplex qPCR assay offers a rapid and reliable diagnostic tool for identifying and quantifying L. martiniquensis and L. orientalis/L. chancei and detecting and quantifying trypanosomatids in clinical samples within a single reaction. This assay provides an advancement in the diagnostic capabilities for leishmaniasis and trypanosomatid infections, potentially improving patient management and surveillance efforts.

Leucocytozoon species are cosmopolitan and prevalent avian parasites, with some infections being lethal, mainly due to the exo-erythrocytic development of the parasite in bird tissues. The patterns of exo-erythrocytic development in Leucocytozoon spp. infections in wild birds remain poorly studied. This study investigated the development of Leucocytozoon spp. tissue stages in tits (Paridae). Great tits (Parus major), Blue tits (Cyanistes caeruleus), and Coal tits (Periparus ater) were screened for infections using an integrative approach that consisted of microscopic analysis of thin blood smears, histological techniques, chromogenic in situ hybridization (CISH), PCR-based methods, and phylogenetic analysis. In total, 41 individuals were analyzed (eight naturally infected that were selected and euthanized, and 33 found dead in the wild and opportunistically sampled). Among the naturally infected birds, all individuals that were microscopically positive for Leucocytozoon species were also PCR-positive for these parasites. Co-infections with Plasmodium spp. and Haemoproteus spp. were commonly found, mainly among the opportunistically sampled birds. Two morphotypes were identified, Leucocytozoon majoris (Laveran, 1902) and Leucocytozoon fringillinarum Woodcock, 1910. Tissue stages were present in three birds sampled exclusively during the non-breeding season, two of them with meronts developing in the kidneys and liver, and one individual with a megalomeront in the heart. All the exo-erythrocytic stages were confirmed to be Leucocytozoon spp. by CISH using a Leucocytozoon genus-specific probe. Phylogenetic analysis placed parasite lineages with different morphotypes in separate clades. The developmental patterns of exo-erythrocytic stages of Leucocytozoon spp. in naturally infected passerines are poorly understood, requiring further research.

The red-eared slider, Trachemys scripta elegans (Wied, 1938), has been introduced worldwide, partly because of the exotic pet trade in the 1980s and 1990s. When T. s. elegans is released or escapes into natural environments, it often establishes new feral populations due to its tolerance for a variety of aquatic ecosystems. Therefore, it is now considered one of the most invasive species in the world because it can compete with native turtle species. In the present study, our objectives were to identify the potential for polystome spillover and spillback resulting from the introduction of the red-eared slider into new environments in North America. Fieldwork investigations were thus conducted mainly in aquatic habitats in Florida and North Carolina, United States, but also in Connecticut, Indiana, Kansas, Maine, Nebraska and New York. Using DNA barcoding based on cytochrome c oxidase I (COI) sequences, we surveyed the species diversity of polystome within American freshwater turtles. These included T. s. elegans but also Apalone ferox, Apalone spinifera, Chelydra serpentina, Chrysemys picta, Kinosternon baurii, Pseudemys spp., Sternotherus minor and Sternotherus odoratus. Genetic evidence confirmed that invasive populations of T. s. elegans in southern Europe have transmitted their own polystomes to native host species following spillover effects, and revealed here that T. s. elegans in non-indigenous habitats in the United States acts as a new reservoir of infection for native polystomes following spillback effects, thus increasing indigenous parasite transmission in the wild. Together, these findings raise further concern about the spread of non-native turtles and their impact on parasite transmission.