Parasite最新文献

In addition to the ribosomal internal transcribed spacer (ITS) locus, four loci (MS1, MS3, MS4, and MS7) have been identified to develop multilocus sequence typing tools for high-resolution genotyping of Enterocytozoon bieneusi in previous studies. However, the use of only five loci was insufficient for population genetic analysis of E. bieneusi from diverse hosts. In this study, comparison of a clinical genome sequence (C44566) with the whole genome sequence of an E. bieneusi isolate (H348) in GenBank led to the selection of the hypothetical protein 1 (hp1) and tubulin 1 (tub1) loci. Further analysis of the two loci with 156 E. bieneusi-positive samples showed high sequence polymorphisms in ITS Groups 1-6 and 10. Altogether, 30 and 23 sequence types were identified at hp1 and tub1, respectively. Genotyping based on the two loci confirmed the lack of genetic differentiation between Group 1 and Group 2 genotypes, as previously reported. Moreover, the genotypes in Groups 4 and 5 are more divergent from other genotypes within Groups 1-10. However, isolates in Group 11 and 12 could not be amplified at the hp1 and tub1 loci, supporting the previous conclusion of genetic uniqueness of the two genotype groups. The identified genetic markers and generated data could be used to develop a multilocus sequence typing tool for high-resolution genotyping of E. bieneusi, which would also have implications for understanding the taxonomy of Enterocytozoon spp., the public health significance of E. bieneusi in animals, and sources of E. bieneusi infections in humans.

Dactylogyrus Diesing, 1850 is the most speciose genus of platyhelminths with more than 900 species, and over a hundred species recorded from Africa. Of the latter, six are from the straightfin barb, Enteromius paludinosus (Peters). Dactylogyrus teresae Mashego, 1983 and Dactylogyrus dominici Mashego, 1983 were collected from E. paludinosus in the Vaal River system, Gauteng, South Africa and their taxonomic data revised using standard protocols and modern approaches, alongside the type material. Whole worms were mounted on glass slides with glycerine ammonium picrate (GAP) and studied using light microscopy (LM). For scanning electron microscopy (SEM), whole worms were placed on concavity slides and the soft tissue digested to release the sclerotised copulatory organs and haptoral sclerites. A combination of these approaches (LM and SEM) was employed for the first time to study the sclerotised structures of GAP-mounted material. Soft tissues of SEM analysed specimens were genetically characterised using CO1 mtDNA, 18S-ITS1-5.8S rDNA and partial 28S rDNA fragments. Phylogenetic topologies were constructed using Bayesian inference. Results confirmed the morphologic and genetic distinctness of D. dominici and D. teresae, highlighting the importance of studying the varying orientations of specifically the vagina and transverse bar. This study presents a new locality record, the first SEM study of isolated sclerotised structures, as well as the first molecular data for the Dactylogyrus afrobarbae-like species. The multifaceted approaches applied to the same specimen in this study enabled improved resolution of individual specimens, showing promise for studies where limited specimens are available.

Giardia duodenalis and Cryptosporidium spp. are significant zoonotic parasites that cause diarrhea and affect a diverse range of hosts. This study aimed to investigate the infection rates of these parasites in captive wildlife at Beijing Zoo. A total of 445 fecal samples were collected and analyzed using PCR. The infection rate of G. duodenalis was 3.82% (17/445), with assemblage A (n = 1), assemblage B (n = 13), and assemblage E (n = 3) identified. The infection rate of Cryptosporidium spp. was 0.22% (1/445), with only one instance of C. ryanae identified from cattle (Bos taurus). To the best of our knowledge, this study enhances the understanding of the host range of G. duodenalis in captive wildlife within China, highlighting infections in Corsac Fox (Vulpes corsac), Indian Rhinoceros (Rhinoceros unicornis), and Giraffe (Giraffa camelopardalis). These findings indicate that the infection rates of G. duodenalis and Cryptosporidium spp. in captive wildlife at Beijing Zoo are low, while showing that the known host range of G. duodenalis is expanding.

The aim of this study was to clarify the taxonomic identification of a hemoflagellate and assess the effect of trypanosome infection on Larimichthys crocea. Giemsa staining showed the presence of three morphotypes of trypomastigotes. The trypanosomes had the following morphological characteristics: a slender body with a long flagellum at the front; body size 12.30-30.90 × 1.13-2.33 μm; elongated oval nucleus situated in the median region; kinetoplast small, oval, located at the posterior end. The parasite had significant morphological differences from Trypanosoma epinepheli Su, Feng, Jiang, Guo, Liu & Xu, 2014 and Trypanosoma carassii (Mitrofanov) Doflein, 1901. The 18S rDNA sequences of the trypanosome from L. crocea had the highest homology (98.4%) with T. carassii. Phylogenetic analysis indicated that the parasite clustered with freshwater fish trypanosomes. Based on the differences in morphological characteristics and molecular data, it is considered a new species, Trypanosoma larimichthysi n. sp. Trypanosome infection had no effect on the growth of L. crocea, but significantly increased the concentration of blood urea nitrogen (BUN), and induced pathological changes in the gills, liver, spleen and kidney. The pro-inflammatory immune genes, including TNF-α, IFN-γ, IL-1β, CXCL8 and iNOS, were significantly upregulated in the L. crocea infected with trypanosomes. These results suggest that the trypanosome has negative impacts on host health.

The fluke Clinostomum complanatum, a parasite of piscivorous birds, but also reptiles and rarely mammals, has established several foci in the western Palaearctic regions. Previous studies pointed out the complicated taxonomy of the genus, but broader population genetic analysis of C. complanatum has not yet been carried out. The aim of this study was to determine the structure, intraspecific variability, and diversity of mitochondrial cox1 haplotypes of C. complanatum from different localities in Slovakia (Danube floodplain forests) and Italy (Emilia-Romagna and Tuscany), as well as to evaluate the interrelationships among populations from Europe, the Middle East, and North Africa. The genetic structure of C. complanatum from Slovakia and Italy was represented by a great number of haplotypes, showing stable populations with high intraspecific diversity. The haplotypes of samples from other localities (Romania, Turkey, Egypt, and Iran) showed possible gene flow among the populations from Central Europe down to the Mediterranean region, North Africa, and the Middle East. The genetic homogeneity of these samples can be linked to the distribution and migratory routes of the definitive hosts, aquatic piscivorous birds, mainly herons and cormorants, that spread parasite eggs among the continents.

Culicoides biting midges (Diptera: Ceratopogonidae) have been reported as potential vectors for haemoparasites. Information about host-vector-parasite specificity is required to confirm their status. Here, molecular detection of haemosporidians, Leishmania, trypanosomatids, and filarial nematodes in biting midges was conducted to understand their potential role as vectors, and their host preference was determined. Wild-caught biting midges were collected from six different localities of Chiang Mai and Nakhon Si Thammarat provinces, Thailand. A total of 6,578 individual Culicoides (170 males, 6,408 females) comprising 15 species of six sub-genera and two groups were collected. Also, 738 parous females and 29 engorged females were examined for parasites and host blood meals, respectively. Culicoides arakawae, C. mahasarakhamense, C. peregrinus and C. innoxius in Chiang Mai province, and C. innoxius and C. peregrinus in Nakhon Si Thammarat province were the most dominant species. Leucocytozoon spp., Leucocytozoon caulleryi and Plasmodium juxtanucleare were identified in five Culicoides species including C. mahasarakhamense, C. arakawae, C. oxystoma, C. fulvus, and C. guttifer. This study is the first record of L. caulleryi in the biting midge C. arakawae in Thailand. Blood meal analysis revealed that Culicoides primarily fed on cattle (17/29, 58.6%), followed by chickens (10/29, 34.5%), and humans (2/29, 6.9%). Our findings confirmed the existence of several Culicoides species in Thailand, which might be potential vectors for transmission of haemosporidians (Leucocytozoon and Plasmodium). Information from host blood meal analyses underlined their preference for large mammals, followed by domestic chickens. More anthropophilic Culicoides species remain to be discovered.

Diarrhea caused by zoonotic pathogens is one of the most common diseases in dairy calves, threatening the health of young animals. Humans are also at risk, in particular children. To explore the pathogens causing diarrhea in dairy calves, the present study applied PCR-based sequencing tools to investigate the occurrence and molecular characteristics of three parasites (Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi) and three bacterial pathogens (Escherichia coli, Clostridium perfringens, and Salmonella spp.) in 343 fecal samples of diarrheic dairy calves from five farms in Lingwu County, Ningxia Hui Autonomous Region, China. The total positive rate of these pathogens in diarrheic dairy calves was 91.0% (312/343; 95% CI, 87.9-94.0), with C. perfringens (61.5%, 211/343; 95% CI, 56.3-66.7) being the dominant one. Co-infection with two to five pathogens was found in 67.3% (231/343; 95% CI, 62.4-72.3) of investigated samples. There were significant differences (p < 0.05) in the positive rates of Cryptosporidium spp. and diarrheagenic E. coli among farms, age groups, and seasons. Two Cryptosporidium species (C. parvum and C. bovis) and five gp60 subtypes of C. parvum (IIdA15G1, IIdA20G1, IIdA19G1, IIdA14G1, and a novel IIdA13G1) were identified. Two assemblages (assemblage E and zoonotic assemblage A) of G. duodenalis and six ITS genotypes of E. bieneusi (J, Henan-IV, EbpC, I, EbpA, and ESH-01) were observed. Four virulence genes (eaeA, stx1, stx2, and st) of diarrheagenic E. coli and one toxin type (type A) of C. perfringens were detected. Our study enriches our knowledge on the characteristics and zoonotic potential of diarrhea-related pathogens in dairy calves.

The Heteracanthocephalidae Petrochenko, 1956 is a rare family of acanthocephalans mainly parasitic in fishes. The pattern of mitogenomic evolution of the Heteracanthocephalidae is still unknown, and the phylogenetic relationships of the Heteracanthocephalidae with the other 14 families within the order Echinorhynchida remain unclear. In the present study, the complete mitochondrial genome of Aspersentis megarhynchus (von Linstow, 1892) Golvan, 1960 was sequenced and annotated for the first time, which represents the first mitogenomic data for the genus Aspersentis and also for the family Heteracanthocephalidae. The mitogenome of A. megarhynchus has 14,661 bp and includes 36 genes, containing 12 protein-coding genes (PCGs) (missing atp8), 22 tRNA genes, and 2 ribosomal RNAs (rrnS and rrnL), plus two non-coding regions. Comparative mitochondrial genomic analysis revealed that the presence of translocations of several tRNA genes (trnV, trnE, and trnT) and the gene arrangement in the mitogenome of A. megarhynchus represents a new type in Acanthocephala. Moreover, the mitogenomic phylogenetic results based on concatenated amino acid sequences of 12 protein-coding genes strongly supported the validity of the Heteracanthocephalidae and suggested close affinity between the Heteracanthocephalidae and Echinorhynchidae in the order Echinorhynchida.

Schistosomiasis is an endemic disease in Côte d'Ivoire. We compared the conventional Kato Katz (KK) test and a more sensitive but rarely used method, the point-of-care circulating cathodic antigen (POC-CCA), in order to contribute to the development of a more appropriate strategy for the control and elimination of intestinal schistosomiasis in western Côte d'Ivoire. A cross-sectional epidemiological survey was conducted in eight elementary schools in the Guémon and Cavally regions from February to December 2020. Selected schoolchildren provided stool and urine samples to detect the presence of Schistosoma mansoni eggs and parasite antigen using the KK and POC-CCA tests, respectively. A total of 554 schoolchildren were included in the study. The overall prevalence of intestinal schistosomiasis was 10% and 67% for KK and POC-CCA, respectively. The POC-CCA detected an infection rate of 100%, while the KK yielded a rate of 42%. In schools, prevalence ranged from 27 to 100% with POC-CCA and from 0 to 42% with KK. Swimming, fishing, washing clothes, and dishwashing were significantly associated with the onset of infection and high intensities. The epidemiological risk factors for intestinal schistosomiasis updated here using KK and POC-CCA diagnostic methods showed that prevalence was much higher than previously estimated using the KK. The POC-CCA is more sensitive and ways should be considered to improve its specificity in order to improve the diagnosis.

Feline pulmonary capillariosis is a significant disorder due to its distribution and clinical impact. This study evaluated the safety and efficacy of two administrations 28 days apart of a topical solution containing esafoxolaner, eprinomectin and praziquantel (NexGard^® Combo) in treating Eucoleus aerophilus (syn. Capillaria aerophila) infection in naturally infected cats. Cats were allocated to two groups: G1 cats (n = 23) received two treatments at study days (SDs) 0 and 28 (±2) and were evaluated for 6 weeks, and G2 cats (n = 17) served as a negative control for 6 weeks and were then treated twice on SDs 42 (±2) and 70 (±2), allowing for an additional 6-week assessment of efficacy. Each cat was subjected to McMaster coproscopy at SDs -7/0, 28 (±2) and 42 (±2) for both groups, 70 (±2) and 84 (±2) only for G2. Clinical examination and chest radiographic images were performed at SDs 0, 28 (±2) and 42 (±2) for G1 and G2, 70 (±2) and 84 (±2) only for G2. The comparison of EPG (eggs per gram of feces), clinical (CS), and radiographic scores (RS) at each time-point was used as a criterion. The efficacy based on the EPG reduction was 99.5% (G1) and 100% (G2) after two administrations of NexGard^® Combo 2 weeks apart. At SD 0, no significant differences for CS and RS were recorded between G1 and G2, while a significant reduction (p < 0.05) was observed post-treatment for CS, RS, oculo-nasal discharge, auscultation noises, and cough. Two doses of NexGard^® Combo 28 days apart stopped egg shedding and significantly improved clinical alterations in cats infected by E. aerophilus.