Parasitology最新文献

Angiostrongylus cantonensis, the rat lungworm, is a zoonotic parasite mainly of rats which act as definitive hosts. If humans become accidentally infected, the nematode is capable of migrating to the brain causing meningoencephalitis. Intermediate hosts are snails and slugs. Although originating from mainland China, A. cantonensis has now spread to various countries and continents. The precise timing of its departure from mainland China remains uncertain although it is often associated with significant historical events or migratory movements. The exit of A. cantonensis from mainland China is believed to have occurred in a singular event, followed by its divergence into 2 distinct clades: clade I, originating from mainland China, and clade II, representing global spread. Angiostrongylus cantonensis was first identified in continental Europe in 2021, specifically in Valencia, Spain. Illumina genome sequencing of 7 individuals isolated from rats captured in 2 different districts in the city of Valencia was carried out. The complete mitochondrial genome was assembled and compared with published A. cantonensis mitochondrial genomes through Bayesian phylogenetic analysis, both for complete mitochondrial genomes and for the cytochrome c oxidase I gene, given its widespread use for identification of the species. The findings revealed the presence of 2 different A. cantonensis haplotypes in the rats studied in Valencia, both belonging to clade II. In 2 rats both clades were present.

Isopods infest fish worldwide, but their role as disease vectors remains poorly understood. Here, we describe infestation of Atlantic bonefish (Albula vulpes) in Belize with isopods in two of three locations studied, with infestation rates of 15 and 44%. Isopods fed aggressively, and infested fish showed missing scales and scars. Gross morphologic and molecular phylogenetic analyses revealed the isopods to cluster within the family Aegidae and to be most closely related to members of the genus Rocinela, which are globally distributed micro-predators of fish. Metagenomic analysis of 10 isopods identified 11 viruses, including two novel reoviruses (Reovirales) in the families Sedoreoviridae and Spinareoviridae. The novel sedoreovirus clustered phylogenetically within an invertebrate-specific clade of viruses related to the genus Orbivirus, which contains arboviruses of global concern for mammal health. The novel spinareovirus clustered within the fish-infecting genus Aquareovirus, which contains viruses of global concern for fish health. Metagenomic analyses revealed no evidence of infection of bonefish with the novel aquareovirus, suggesting that viremia in bonefish is absent, low, or transient, or that isopods may have acquired the virus from other fish. During field collections, isopods aggressively bit humans, and blood meal analysis confirmed that isopods had fed on bonefish, other fish, and humans. Vector-borne transmission may be an underappreciated mechanism for aquareovirus transmission and for virus host switching between fish and other species, which has been inferred across viral families from studies of deep virus evolution.

Communities living in African animal trypanosomiasis (AAT) endemic areas of Zambia use several control strategies to protect their livestock from the devastating effects of trypanosomiasis. Several studies have reported the effectiveness of trypanosomiasis control strategies based on retrospective data. In this study, we assessed incidence rates of AAT in cattle (n = 227) using a prospective cohort study comprising 4 treatment groups, i.e., Diminazene aceturate, Isometamidium chloride, Cyfluthrin pour-on and Cypermethrin treated targets. The study was conducted in Mambwe district in Eastern Zambia between February 2019 and March 2020. The endemic prevalence of AAT for each group was determined using ITS-PCR prior to application of treatments. High endemic trypanosome pre-treatment rates were found in all Groups (Diminazene aceturate (61%), Isometamidium chloride (48%), Cyfluthrin pour-on (87%) and Cypermethrin targets (72%)). The overall apparent prevalence for the Mambwe district was 67% (152/227) and true prevalence at 95%CI was 63–71%. Once treatments were implemented, 12 monthly follow-ups were conducted. The average monthly incidence rates without standardization recorded: Diminazene aceturate (67%) Isometamidium chloride (35%), Cyfluthrin pour-on (55%) and Cypermethrin targets (61%). Incidence rates were standardized considering the endemic level of disease for each Group and the average standardized monthly incidence rate in the Diminazene aceturate Group was 7%; the Isometamidium chloride Group −13%; the Cyfluthrin Group −26%; and the Cypermethrin target Group, −17%. All Groups showed a decrease in incidence of AAT over the period of the study with the Cyfluthrin group showing to be the most effective in reducing AAT incidence in cattle.

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease, routinely diagnosed by direct light microscopy. The sensitivity of this method is dependent on the number of parasites present in the lesion. Immunoexpression of CD1a surface antigen by Leishmania amastigotes and its application as a diagnostic tool has been recently demonstrated in several species including Leishmania major, Leishmania tropica and Leishmania infantum. Leishmania donovani is the only reported species in Sri Lanka primarily causing CL and its CD1a status remains unexplored. We studied CD1a expression by amastigotes of L. donovani in skin biopsies from 116 patients with suspected CL. The biopsy sections were stained with CD1a clones O10 and MTB1 separately. Slit skin smear (SSS) results were considered the gold standard for diagnosis of CL. 103 cases were confirmed through SSS where 73 of them showed positive parasite staining for CD1a clone MTB1 with 70.9% sensitivity. Positivity was seen mostly in parasites closer to the epidermis. CD1a clone O10 failed to detect any amastigotes. Test sensitivity improved to 74.1% when the analysis was applied only to patients with low/no discernible Leishman-Donovan (LD) bodies in histology. Our findings show that CD1a clone MTB1 successfully stains amastigotes of L. donovani species and can be used as a supplementary diagnostic tool in detecting CL, especially when LD bodies are low in number. This method could be validated to detect other forms of leishmaniasis caused by L. donovani in Indian and sub-Saharan regions.

This study investigates the molecular intricacies of the transmembrane protein TSP11 gene in Echinococcus strains isolated from livestock and patients in Yunnan Province afflicted with Echinococcus granulosus (E. granulosus) between 2016 and 2020. Gene typing analysis of the ND1 gene revealed the presence of the G1 type, G5 type and untyped strains, constituting 52.4, 38.1 and 9.5%, respectively. The analysis of 42 DNA sequences has revealed 24 novel single nucleotide polymorphic sites, delineating 11 haplotypes, all of which were of the mutant type. Importantly, there were no variations observed in mutation sites or haplotypes in any of the hosts. The total length of the TSP11 gene's 4 exons is 762 bp, encoding 254 amino acids. Our analysis posits the existence of 6 potential B-cell antigenic epitopes within TSP11, specifically at positions 49-KSN-51, 139-GKRG-142, 162-DNG-164, 169-NGS-171, 185-DS-186 and 231-PPRFTN-236. Notably, these epitopes exhibit consistent presence among various intermediate hosts and haplotypes. However, further validation is imperative to ascertain their viability as diagnostic antigens for E. granulosus in the Yunnan Province.

Amphalius spirataenius belongs to Arthropoda, Insecta, Siphonaptera, Ceratophylloidea, Ceratophyllinae, Amphalius. Only 2 species from the subfamily Ceratophyllinae have been sequenced for mitogenomes to date. The genus Amphalius mitogenome research was still blank. The A. spirataenius mitogenome was determined, annotated and analysed for the first time in this study. The 14 825 bp long genome has the typical metazoan of 37 genes with insect ancestral genome arrangement pattern. There was no significant difference in codon usage of 13 protein-coding genes: UUA, UCU, GUU, ACU and GCU were the most frequently used codons. It was found that the reason for codon preference mainly contributed to natural selection base on PR2, ENC-plot and neutrality curve analysis. Evolutionary rate, conserved sites, variable sites and nucleotide diversity analysis indicated that nad6 of A. spirataenius had the fastest evolutionary rate, while cox1 had the slowest evolutionary rate. Phylogenetic trees were reconstructed based on 13 protein-coding genes and 2 rRNA genes datasets using Bayesian inference and maximum likelihood method. The phylogenetic tree supported that both Siphonaptera and Mecoptera were monophyletic, and were sister groups to each other. This study filled gap of the genus Amphalius mitogenome sequences and was of great significance for understanding evolution of the order Siphonaptera.

We report a case of a suspected intestinal myiasis of a child from Southeast Argentina. Diptera larvae were sampled by a physician from the nappy worn by the child and submitted for examination and identification to the Laboratorio de Artrópodos (Universidad Nacional de Mar del Plata). Based on diagnosis of the anterior and posterior spiracles and mouthparts, the larvae were identified as the false stable fly Muscina stabulans (Fallén, 1817) (Diptera: Muscidae). A comparison of diagnostic characters between Argentinean and European third instars of this species is presented. Muscina stabulans is a prevalent species in the district of General Pueyrredón, Buenos Aires province, where the case occurred. Its abundance in the area coincidentally peaked at the time of the infestation. This is the 1st report of M. stabulans as a suspect of intestinal myiasis for the whole of the southern cone of South America (Chile and Argentina).

Haemoproteus bobricklefsi sp. nov. (Haemosporida, Haemoproteidae) was found in the dunnock Prunella modularis and represents the first blood parasite described in accentor birds of the Prunellidae. The description is based on the morphology of blood stages and includes information about a barcoding segment of the mitochondrial cytochrome b gene (lineage hDUNNO01) and the full mitochondrial genome, which can be used for identification and diagnosis of this infection. The new parasite can be readily distinguished from described species of haemoproteids parasitizing passeriform birds due to markedly variable position of nuclei in advanced and fully grown macrogametocytes. Illustrations of blood stages of the new species are given, and phylogenetic analyses based on partial mitochondrial cytochrome b gene sequences and the full mitochondrial genome identified the closely related lineages. DNA haplotype networks showed that transmission occurs in Europe and North America. This parasite was found in the dunnock in Europe and several species of the Passerellidae in North America. It is probably of Holarctic distribution, with the highest reported prevalence in the UK. The parasite distribution seems to be geographically patchy, with preference for areas of relatively cool climates. Phylogenetic analysis suggests that H. bobricklefsi sp. nov. belongs to the Parahaemoproteus subgenus and is probably transmitted by biting midges belonging to Culicoides (Ceratopogonidae). The available data on molecular occurrence indicate that this pathogen is prone to abortive development, so worth attention in regard of consequences for bird health.

Adults of the genus Posthodiplostomum, Dubois, 1936 are parasites of fish-eating birds, mainly of the family Ardeidae, and are globally distributed. The genus currently comprises 35 species, although recent molecular evidence has shown that the diversity of the genus is underestimated since several candidate species have been recognized. In the Neotropical region of Mexico, at least 6 Posthodiplostomum lineages have been detected with metacercaria stages recovered from unrelated fish hosts. Here, we obtained adult specimens of Posthodiplostomum from 6 fish-eating birds representing 2 families (Butorides virescens, Ardea herodias, Nycticorax nycticorax, Tigrisoma mexicanum – Ardeidae, and Rynchops niger and Leucophaeus atricilla – Lariidae) from 4 localities in southern Mexico. Specimens were sequenced for 2 nuclear (28S and ITS1–5.8S–ITS2) and 1 mitochondrial (cox1) molecular marker. Phylogenetic analyses allowed us to link metacercariae and adult specimens and recognized a lineage, which was described morphologically. The new species can be distinguished from its congeners by its prosoma morphology and body size; this is the first described species in the Neotropical region of Mexico. Additionally, new host and locality records for P. macrocotyle and P. pricei are presented, expanding their geographical distribution range in the Americas.