Parasitology Research最新文献

Triatoma species from the phyllosoma subcomplex are sympatrically distributed and include some of the main vectors of Chagas disease in Mexico. Species within this subcomplex, including Triatoma pallidipennis, T. mazzottii, T. picturata, and T. longipennis, have shown resistance to pyrethroid insecticides, associated with mutations in the para gene of the voltage gate sodium channel (VGSC) and the activity of detoxifying enzymes such as β-esterases and glutathione s-transferases (GST). In this study, we evaluated resistance to deltamethrin in hybrids of T. pallidipennis × T. mazzottii (T.pal × T.maz) and T. pallidipennis × T. picturata (T.pal × T.pic) under laboratory conditions, and the inheritance was determined based on the degree of dominance (DO). Additionally, associated resistance mechanisms were analyzed, including detoxifying enzymes and knockdown resistance (kdr) mutations. High levels of resistance to deltamethrin were found in the hybrids of T.pal × T.maz when compared with the susceptible strain of T. mazzottii (RR₅₀ = 17.50). Dominance levels calculated for each hybrid showed values <  - 1, confirming that resistance to deltamethrin was recessive. Hybrids exhibited reduced α-, β-esterases, and cytochrome P₄₅₀ mixed-function oxidases (MFO) activity. However, both hybrids showed significantly increased GST activity, particularly in T.pal × T.pic, suggesting enhanced detoxification through this pathway. The kdr mutation A943V, present in T. mazzottii, was found in T.pal × T.maz hybrids. These results emphasize the importance of considering hybridization in resistance management programs and its potential impact on the success of insecticide-based control measures.

The immunomodulatory activity of parasites has been extensively investigated in multiple immune-related diseases. However, dermatological diseases have been off the list for a long time despite their vast incidence and the deleterious consequences of some of them. This study explored the immunomodulatory role of autoclaved Trichinella spiralis (T. spiralis) larvae antigen (ATSLA) as a psoriasis immunotherapeutic candidate in a mice model. Psoriasis was induced in Swiss albino mice using commercial imiquimod cream (IMQ). Mice were randomly divided into the IMQ untreated control group and the IMQ treated group that was treated with ATSLA twice, on day 0 and day 3. Additional mice served as normal controls. Assessment of skin thickness, erythema, and scales was recorded. Total skin scores were calculated. Skin MDA levels, splenic indices, serum and skin IL-23, and tumor necrosis factor alpha (TNF-α) were measured. Skin sections were stained with H&E and immune stained for CD68-positive cells using immunohistochemistry. Treatment with ATSLA significantly reduced skin thickness, erythema, scales, and total skin scores in the IMQ-treated group compared to the untreated control. This was accompanied by a reduction in the splenic index, skin MDA levels, IL-23, and TNF-α in both the skin and serum of the treated group. Pathologically, skin sections of the treated group showed less epidermal thickness, acanthosis, hyperkeratosis, and CD68 cell count. The study concluded the immunotherapeutic activity of ATSLA in experimental psoriatic skin lesions. This will enrich the psoriasis immunotherapeutic list with novel candidates of parasitic origin.

Sparganosis is a parasitic zoonotic disease that poses a serious threat to public hygiene and human health. Annexin is a phospholipid-binding protein with calcium ion binding activity, serving various important functions, including interaction with the parasite and regulation of the host's immune response. In this study, two annexin (ANX) family genes, Spirometra erinaceieuropaei (S. erinaceieuropaei) Annexin B8 (SeANXB8) and E1 (SeANXE1), isolated from spargana, were cloned and immunologically characterized. Both recombinant S. erinaceieuropaei Annexin B8 (rSeANXB8) and E1 (rSeANXE1) were specifically recognized by serum from rats immunized with the recombinant proteins, displaying strong immunoreactivity. They are also among the major components of sparganum excretion/secretion products (ESPs). SeANXE1 was identified in the parasite's tegument, testis, genital pore, ovary, and eggs, while SeANXB8 was found in the parasite's tegument and eggs. Plasminogen (PLG)-binding assays revealed that the two annexins could bind to human PLG in a concentration-dependent manner, which was blocked by the corresponding antibodies. These findings suggest that SeANXB8 and SeANXE1 may be involved in host-parasite interaction and may influence the host's immune response during sparganosis. They could be potential diagnosis and vaccination targets for sparganosis.

Yellow grub disease is a parasite infection, caused by Clinostomum spp. Metacercariae and affecting axial muscles and internal organs of freshwater fish. Killifishes live in seasonal ponds and are short-lived; in the Neotropical region they are among the most vulnerable vertebrates. The current study analyzes the possible injury and inflammatory reaction caused by parasitic infection with Clinostomum spp. metacercariae in testes, ovaries, liver, intestine and mesentery in the seasonal killifishes Trigonectes aplocheiloides and Titanolebias monstrosus. Apparently, this parasite could migrate through the circulatory system to different organs, since a cercaria was found in the lumen of a hepatic sinusoid. In all organs the inflammatory response showed dilated, congested vascular areas and infiltration of numerous inflammatory cells, mainly composed of lymphocytes, eosinophilic granular cells and macrophages. However, the most affected organs were the pancreas, ovaries and testes. In these organs, severe pancreatitis with degranulation of the pancreatic acini, scarce ovarian follicles and spermatocysts dilated with few or no seminiferous cells were observed. In seasonal killifish, yellow grub disease could cause low fertility rates or even sterility by reducing or impairing their reproductive capacity. Therefore, this type of parasitism has a considerable impact on the perpetuation of this species due to the short periods they have to breed before their habitats dry out.

A species set in a site comprises species that are present (realized diversity) and species that could inhabit this site but are absent (dark diversity; DD). DD can be both species-driven (a species' traits preclude its presence, independently of site features) and site-driven (site features preclude the species' presence, independently of its traits). DD affinity (DDA) is a measure of species' tendencies to be absent from sites that they could inhabit or of sites' tendencies to lack species that could be present. Decomposition of DDA into DDA for species (dda_sp) and for sites (dda_site) allows (a) disentangling these two mechanisms and (b) detecting species traits and site features contributing to their DDA. The species-site unified model is a Bayesian statistical model aimed at simultaneously estimating dda_sp and dda_site. We applied it to flea and mite assemblages (a) within a host species across regions (component metacommunities; CtM; dda_site = dda_region) and (b) within a region across host species (compound metacommunities; CdM, dda_site = dda_host). In CtMs, dda_sp and dda_region equally contributed to DD, whereas the relative contributions of dda_sp and dda_host to DD in CdMs varied from the former being higher than the latter and vice versa. In CtM and CdM, dda_sp increased in low-abundance ectoparasites exploiting a restricted number of hosts. In CtMs, dda_region was associated with the regional environment, but we failed to find host traits affecting dda_host in CdMs. We conclude that ectoparasite species and either regions in CtMs or host species in CdMs independently contribute to DD.

The life-cycle of Amblyomma calcaratum was evaluated experimentally under laboratory conditions using birds (Serinus canaria, Gallus gallus) and rodents (Calomys callosus) as hosts for immatures and a rabbit (Oryctolagus cuniculus) as host for adults. Developmental periods of the non-parasitic stages were observed in an incubator at 27 °C and 90% RH. The passerine S. canaria was the most suitable host for larvae and nymphs whereas the rodent C. callosus was not suitable to both immatures; only one engorged larva was recovered. The suitability of S. canaria for larvae and nymphs of A. calcaratum supports field data regarding passerine birds as main hosts for A. calcaratum immatures. Among the Amblyomma species which life cycle has been evaluated under laboratory conditions, A. calcaratum is one with the longest off-host developmental periods.

The aim of this study was to assess the changes in strongylid communities of domestic horses after two decades of regular anthelmintic treatments; the changes in prevalence and relative abundance of individual strongylid species and their contribution to the observed alterations were estimated. The study was conducted in 2023; data collected in 2004 were used for comparison; 39 horses from two farms in Ukraine (22 horses in 2004 and 17 in 2023) were examined. In total, 18,999 strongylid specimens were collected by in vivo diagnostic deworming method before (in 2004, 9119 specimens) and after (in 2023, 9880 specimens) frequent application of anthelmintics. Strongylids were identified morphologically. Thirteen strongylid species were found in horses in 2023; only small strongylids (Cyathostominae) were recorded. In 2004, 21 species were found: 6 species of large strongylids (Strongylinae) and 15 of cyathostomins. Species richness (Margalef's index) and species diversity (Shannon's and Simpson's indexes) decreased over two decades on both farms; the Berger-Parker dominance index for C. nassatus dramatically increased up to 74.4. The dissimilarity of strongylid communities of 2023 and 2004 was primarily connected with the disappearance of large strongylids and rare cyathostomin species after two decades of regular anthelmintic treatments. SIMPER analysis revealed that C. nassatus and C. catinatum mostly contributed to this dissimilarity. A trend of gradual transformation of the strongylid community structure from multimodal (in 2004) to bimodal (in 2023) was observed on both farms.

A case of polyparasitism in an 8-year-old female cat from Southern Brazil is reported. Among the described clinical signs, both gurltiosis and lagochilascariasis are of rare occurrence, being categorized as neglected diseases. The diagnosis of feline crural parasitic paraplegia was established through clinical signs, necropsy lesion observations, and the presence of Gurltia paralysans in histological sections of the spinal cord. Lagochilascaris minor was diagnosed with an ulcerated wound in the cervical region and further confirmed by coprology. In addition, other gastrointestinal parasites (i.e., Trichuris spp., Diphyllobothriidae, Toxocara cati, Ancylostoma spp., Cystoisospora spp., and Entamoeba spp.) were diagnosed through fecal examination and Sarcocystis felis by molecular analysis of muscle cysts. Aelurostrongylus abstrusus was detected in histological sections of lung parenchyma and confirmed by molecular analyses. The multiple parasitism detected in this case represents a unique report in terms of the number of parasites in the same individual, indicating the risk represented by stray cats as spreaders of zoonotic agents.

NLRP3 inflammasome-mediated inflammatory responses play pivotal functions in innate immunity. However, its homeostatic regulation still needs to be better understood. Here we explore the effect and potential mechanism of IL-33 on NLRP3 inflammasome upon Toxoplasma gondii infection through a series of molecular biology and immunological experiments, including western blot, qRT-PCR, and ELISA. We demonstrated that T. gondii infection induces the expression of IL-33, and IL-33-deficient (IL-33^-/-) mice exhibit longer survival time than wild-type (WT) mice upon T. gondii infection. IL-33 deficiency promotes the expression of NLRP3 and ASC and the secretion of IL-1β, while exogenous IL-33 inhibits NLRP3 inflammasome. Furthermore, T. gondii infection results in the M2 polarization of macrophages, exacerbated by exogenous IL-33, which also promotes the proliferation of T. gondii. These findings showed that IL-33 deficiency attenuates T. gondii infection by promoting NLRP3 inflammasome, advancing the understanding of the role of IL-33 in inflammation.

Haematophagous leeches rely on a broad variety of bioactive compounds to secure a sufficient blood meal from their vertebrate prey. Both the primary (platelet aggregation) and secondary (blood coagulation) haemostasis are the main targets of action. The platelet aggregation inhibitor decorsin was first described in the North American leech, Macrobdella decora Say, 1824, whereas the bivalent thrombin inhibitor hirudin was originally identified in the European medicinal leech, Hirudo medicinalis Linnaeus, 1758. Hirudin blocks both the catalytic site and the fibrinogen-binding site (exosite I) of thrombin. Haemadin of the Indian land leech Haemadipsa sylvestris Blanchard, 1894, is also a highly efficient bivalent thrombin inhibitor but blocks exosite II of thrombin. So far, only the archetypal form of haemadin from H. sylvestris has been purified and functionally characterized, and two putative haemadins have been identified in the salivary transcriptome of Haemadipsa interrupta Moore, 1835, a terrestrial leech inhabiting mainly the Malayan peninsula. Here, we describe the identification of ten additional putative haemadins in the transcriptomic data set of H. interrupta, first generated by another study. Furthermore, we identified a putative oligomeric decorsin, which represents the first finding of this anticoagulant in a haemadipsid leech. Both the putative decorsin and a selection of haemadins were expressed, purified, and functionally characterized. The putative haemadins displayed a broad spectrum of thrombin-inhibitory potencies, whereas the putative oligomeric decorsin was indeed a weak inhibitor of platelet aggregation.