Folia Parasitologica最新文献

The genus Maxvachonia Chabaud et Brygoo, 1960 (Ascaridomorpha: Cosmocercidae) is a poorly known group of parasitic nematodes. Species of Maxvachonia are native to Madagascar-Australo-Papuan Region, where they are known to parasitise frogs, snakes and skinks. Unfortunately, most of Maxvachonia species have been inadequately described. In the present study, we report the native species Maxvachonia chabaudi Mawson, 1972 from the intestine of the invasive marine toad Rhinella marina (Linnaeus) in Australia for the first time. We speculate that the marine toads infected with M. chabaudi are likely related to their eating skinks or the similarity in diet/habitat/ecology between the toad and the skinks. The detailed morphology of M. chabaudi was studied using light microscopy and, for the first time, scanning electron microscopy, based on the newly collected specimens. Some characters important for the specific diagnosis of M. chabaudi are reported for the first time, including each lip with distinct inner flanges, the location of vulva varying from anterior to posterior of the oesophageal bulb and the presence of single medio-ventral precloacal papilla. An identification key to the species of Maxvachonia is provided.

Species of Acanthamoeba Volkonsky, 1931 are the commonest among free-living amoebae that are widespread in different water resources but with lacking phylogenetic data. This study aims at detecting molecular prevalence and genetic diversity of Acanthamoeba isolates in Kafrelsheikh Governorate, Egypt. Forty-eight water samples were collected from 12 swimming pools; four samples during each season over one year. Samples were filtered, cultivated on non-nutrient agar plates and examined microscopically. Polymerase chain reaction (PCR) and sequence analysis of positive samples targeting diagnostic fragment 3 (DF3) of the small subunit rRNA gene were done. Cultivation succeeded to detect 14 (29%) positive samples while PCR missed three positive samples. The obtained sequences were phylogenetically analysed. The phylogenetic tree was constructed for them with sequences of reference species from the NCBI database. The identified species were Acanthamoeba castellanii Douglas, 1930 (T4), A. astronyxis (Ray et Hayes, 1954) (T9) and A. hatchetti Sawyer, Visvesvara et Harke, 1977 (T11). The prevalence of species of Acanthamoeba was higher during summer and fall. Therefore, the control of the presence of Acanthmoeba spp. in swimming pools needs immediate, effective and practical measures to prevent and control infection with species of Acanthamoeba.

Species of Blastocystis Alexieff, 1911 are anaerobic intestinal protists found in humans and many kinds of animals that mainly cause diarrhea, abdominal pain and other clinical symptoms. At present, data on the prevalence and subtype diversity of species of Blastocystis in domestic rabbits are very limited. The purpose of this study was to characterise the infection rate and gene subtype distribution of Blastocystis sp. in domestic rabbits in Henan Province, Central China, and provide foundation for prevention and control of the disease caused by Blastocystis sp. in domestic rabbits. DNA was extracted from 286 fresh rabbit faecal samples collected from four areas of Henan Province, Central China. All DNA samples were screened using PCR and positive samples were sequenced to identify individual subtypes based on the small ribosomal subunit (SSU rRNA) gene. The overall infection rate of Blastocystis sp. in domestic rabbits in Henan Province was 15% (43/286). Three subtypes were identified, including ST1 (26/43, 60%), ST3 (5/43, 12%) and ST7 (12/43, 28%), all of which belonged to potentially zoonotic subtypes, ST1 was the dominant gene subtype. These results showed that infection with Blastocystis sp. was common in domestic rabbits in Henan Province, Central China, and was represented by zoonotic subtypes. Therefore, special attention should be paid to reduce the risk of transmission of Blastocystis sp. from domestic rabbits to humans.

Taxonomic issues within Trypanorhyncha, e.g., the inaccurate light microscopic visualisation of the hook patterns, are solvable by confocal laser scanning microscopy (CLSM). We applied CLSM imaging to study Trygonicola macropora (Shipley et Hornell, 1906) and Dollfusiella michiae (Southwell, 1929) from Neotrygon caeruliopunctata Last, White et Séret from Bali, Indonesia. To illustrate the strength and limitations of CLSM, images of Otobothrium cysticum (Mayer, 1842) and Symbothriorhynchus tigaminacantha Palm, 2004, both permanent mounts from a collection, were also processed. The CLSM created image stacks of many layers, and edited with IMARIS Software, these layers resulted in three-dimensional images of the armature patterns and internal organs of both species. BABB (benzylalcohol and benzylbenzuolate) clearing was applied to T. macropora. We conclude that trypanorhynch cestodes stained with Mayer-Schuberg's acetic carmine permanently mounted in Canada balsam are suitable for CLSM, allowing detailed analyses of museum type-material as well as freshly collected and processed worms. BABB resulted in imaging the testes in detail, suggesting other stains to be used for CLSM in trypanorhynch cestode research. Application of CLSM for studies of other cestode groups is highly recommended.

Salmincola markewitschi Shedko et Shedko, 2002 (Copepoda: Lernaeopodidae) is an ectoparasitic copepod mainly infecting the buccal cavities of white-spotted charr Salvelinus leucomaenis (Pallas) (Salmonidae). This species has only been recorded from Northeast Asia, where a morphologically similar congener Salmincola carpionis (Krøyer, 1837) is also distributed, using the same host species. These copepods are hard to distinguish from each other because of their similarities. We thus examined the newly collected specimens morphologically and genetically from five populations of white-spotted charr in Japan. Most of the specimens were morphologically consistent with S. markewitschi but showed great variations in the numbers of spines on the exopods of the antennae, shape of the maxilliped myxal palps, and the bulla diameter. Consequently, some specimens shared characteristics with S. carpionis. In addition to the mophological continuities, genetic analyses of 28S rDNA and COI mitochondrial DNA confirmed that all specimens belong to a single species. Further taxonomic revisions are required to draw conclusions of whether S. markewitschi is a valid species different from S. carpionis, by collecting samples from across their wide distributional ranges, such as Europe, North America, and Northeast Asia. A key to identification of species of Salmincola Wilson, 1915 occurring in Japan is also provided.

Recently, based on a limited morphological characterisation and partial 18S rRNA gene sequence, Jiang et al. (2019) described Trypanosoma micropteri Jiang, Lu, Du, Wang, Hu, Su et Li, 2019 as a new pathogen of farmed fish. Here we provide evidence based on the expanded sequence dataset, morphology and experimental infections that this trypanosome does not warrant the establishment as a new species, because it is conspecific with the long-term known Trypanosoma carassii Mitrophanow, 1883, a common haemoflagellate parasite of freshwater fish. The former taxon thus becomes a new junior synonym of T. carassii.

Congenital toxoplasmosis is reportable disease in Europe. To prevent it antibody serological tests were introduced in several European countries as a part of screening programmes. Immunoglobulin G (IgG) avidity index testing is one of these tests for diagnosing acute infection with Toxoplasma gondii (Nicolle et Manceaux, 1908) in pregnant women. However, a low or moderate IgG avidity index can give inconclusive results for predicting woman's status. From June 2012 until the end of 2014, 17,990 women were included in the national screening program to prevent congenital toxoplasmosis. One hundred and twenty-six women were consecutively included in the study because they had low or moderate IgG avidity. Every woman with possible acute toxoplasmosis was followed up every month till delivery. Fifty-eight of 126 (46%) women got infected in months before current pregnancy, 39 women (31%) were infected early in pregnancy. Twenty-nine pregnant women of 126 (23%) got infected in the second/third trimester of pregnancy. New cut off for IgG avidity index was 0.11. With this cut off, we were able to exclude T. gondii acute infection in the first trimester with very good diagnostic accuracy (area under the curve (AUC) = 0.95, 95% confidence Interval (CI) 0.91-0.99, sensitivity 0.95, specificity 0.86). If an IgG avidity index above 0.11 is measured in a woman's serum and she is in the first trimester of pregnancy, then a odds ratio (OR) for acute infection with T. gondii is below 1 (OR 0.11, 95% CI 0.05-0.25, P < 0.0001). If we measure IgG avidity index that is ≥ 0.11 in the first trimester of pregnancy, we can exclude infection with T. gondii with good diagnostic accuracy in our cohort of women. With a new cut off we could reduce number of invasive procedures such as amniocentesis and put less pregnant women in distress.

Trichodina centrostrigeata Basson, Van As et Paperna, 1983 from Oreochromis mossambicus (Peters) and O. niloticus (Linnaeus) from different host populations from Argentina, Mexico and South Africa was reviewed. Although T. centrostrigeata has a distinct denticle structure that makes morphological taxonomic inferences uncomplicated, variation of the denticles within and among individuals and populations were still observed. While traditional taxonomy of mobilines is heavily reliant on morphometrics, and recently even more so on molecular analysis, this paper proposes the use of geometric morphometry, specifically elliptical Fourier analysis, to address morphological conflicts that arise when comparing different populations. By applying this technique, combined with traditional taxonomy, it was found that T. centrostrigeata in this study can be grouped into two separate morphotypes, the first (type a) from aquaculture farms in Argentina and Mexico and the second (type b) from a natural habitat in Glen Alpine Dam, South Africa. This study supports the validity of geometric morphometry as an additional technique to distinguish not only between species but also evolutionary plasticity of the same species from different localities and habitats.

Toxoplasma gondii Nicolle et Manceaux, 1909, the etiologic agent of toxoplasmosis, was considered a clonal population with three distinct genetic lineages (I, II and III); however, sequence analysis of different strains has revealed distinct atypical genotypes. Macrophages are essential for immunity against toxoplasmosis and differential cell regulation may affect the course of the disease. In this context, our study aims to investigate the infection by TgChBrUD2, a highly virulent atypical Brazilian strain of T. gondii, on the activation and polarisation of human macrophages. Human macrophage-like cells obtained from THP-1 cells were infected with TgChBrUD2, RH or ME49 strains of T. gondii to evaluate the impact of parasite infection on macrophage polarisation. Our results indicate that the TgChBrUD2 and ME49 strains of T. gondii induced a classic activation of human macrophages, which was confirmed by the high rate of spindle-shaped macrophages, low amount of urea and increase in the levels of nitrite, as well as the down-regulation of M2-markers. In contrast, RH strain promoted an alternative activation of macrophages. The polarisation of human macrophages towards an M1 subtype mediated by TgChBrUD2 and ME49 strains resulted in a low parasite burden, with high levels of IL-6 and MIF. Finally, the M2 subtype triggered by the RH strain culminated in a lower intracellular proliferation index. We concluded that the atypical (TgChBrUD2) and clonal (ME49) strains are able to elicit an M1 subtype, which results in parasitism control, partially explained by the high levels of IL-6 and MIF produced during the infection by these genotypes. In contrast, the clonal (RH) strain promoted a macrophage polarisation towards an M2 subtype, marked by a high parasite burden, with a weak modulation of pro-inflammatory cytokines. Thus, atypical strains can present different mechanisms of pathogenicity and transmissibility compared to clonal strains, as well as they can use distinct strategies to evade the host's immune response and ensure their survival.

Dactylogyrus Diesing, 1850 is the most species-rich genus in Platyhelminthes, with over 900 documented species, that are mostly strictly specific to freshwater cyprinoids. The morphological Dactylogyrus groups afrobarbae-type, carpathicus-type, pseudoanchoratus-type, and varicorhini-type are known to occur in Africa. This study describes a new species of Dactylogyrus of the varicorhini-type from the gills of the endemic smallmouth yellowfish Labeobarbus aeneus (Burchell) from the Vaal River, Free State Province, South Africa. Dactylogyrus matlopong sp. n. is unique among its varicorhini-type congeners mainly by the accessory piece of the male copulatory complex that presents a hook-shaped subunit with defined round base not reaching the male copulatory organ, combined with the presence of a conspicuous medial projection on the anterior margin of the ventral bar. Sequences of the partial 28S and 18S rRNA genes, together with entire ITS1 region, were generated for the first time for a species of Dactylogyrus from South Africa. Concatenated phylogenetic analyses of selected Dactylogyrus spp. showed that these parasites group according to their morphological types.