Parasitology Research最新文献

Acanthamoeba species are responsible for serious human infections, including Acanthamoeba keratitis (AK) and granulomatous amoebic encephalitis (GAE). These pathogens have a simple life cycle consisting of an infective trophozoite stage and a resistant cyst stage, with cysts posing significant treatment challenges due to their resilience against harsh conditions and chemical agents. Current treatments for AK often involve combining diamines, such as propamidine, and biguanides, such as chlorhexidine (CLX), which exhibit limited efficacy and significant toxicity. Thus, the effect of new therapeutic molecules, such as multifunctional systems (e.g., carbosilane dendritic molecules), should be studied as potential alternatives due to their biocidal properties and lower toxicity. This study evaluates various dendritic compounds against trophozoites and cysts of two Acanthamoeba clinical isolates, both alone and in combination with CLX, and assesses their cytotoxicity on HeLa cells. The results indicated that certain dendritic compounds, especially BDSQ024, were effective against both trophozoites and cysts. Additionally, combinations of dendritic molecules and CLX showed enhanced efficacy in eliminating trophozoites and cysts, suggesting potential for synergistic treatments. The study underscores the promise of dendritic molecules in developing more effective and less toxic therapies for Acanthamoeba infections.

Antlers are bony structures that undergo regular annual growth, mineralisation and casting phases, representing only mammalian organs capable of full regeneration. Myiasis is infestation of live vertebrates with dipterous larvae. We sampled mineralised antlers from a red deer spiker stag 2 months after velvet shedding, divided it into three segments and fixed in 10% neutral buffered formalin. After demineralisation, samples were embedded in paraffin and sliced to a thickness of 6 µm. Tissue sections were stained with hematoxylin-eosin (HE), a modified staining to show the ossification process, toluidin blue and Masson's trichrome staining. Smears of liquid content from the antlers were made and stained with May-Grünwald Giemsa. Larvae were separated from segments and preserved in 70% ethanol for identification. Macroscopically, some parts of the antler tips were lacking the compact part. Microscopically, within the Haversian and Volkmann canals, a large number of bacteria, scarce protein content and remnants of red blood corpuscles were visible. In the area of cancellous bone, cross-sectioned larvae were present. A large quantity of bacteria and a few degraded red blood corpuscles were visible on the smear made of liquid from the antlers. For morphological identification, three larvae were examined: two were third-instar larvae (L3), while one was a first instar larva (L1). Based on the shape of the cephaloskeleton, L3 was identified as Prochyliza nigrimanus and confirmed using molecular tools. To the extent of the authors' knowledge, this is the first record of Prochyliza nigrimanus in non-casted hard red deer antlers and the first description of this species in Croatia.

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.