Characteristics of changes in the structures of the anterior eye of rabbits at acute opisthorchosis and paracoenogonymosis

The purpose of the research is studying changes in the structures of the anterior eye of rabbits at acute opisthorchosis and paracoenogonymosis in experiment.Materials and methods. The studies were performed on sexually mature male rabbits. The first group consisted of animals infected with 50 metacercariae Opisthorhis felineus (Rivolta, 1884) (n = 3), and the second consisted of animals infected with 50 metacercariae Paracoenogonimus ovatus (Katsurada, 1914) (n = 3). The animals from the third group were control (n = 3). The study at opisthorchosis was performed at 1, 2, 3, 4 and 5 weeks after infection, and the study at paracoenogonymosis was only performed at 1 and 2 weeks in connection with rapidly proceeding infection. These groups were compared within 1 and 2 weeks and according to specific changes. The clinical study included the upper and lower eyelids turned outwards in animals, and examination of the conjunctival surface of the eyelids, epicanthus (third eyelid), cornea, limbus and sclera of the eyeball, and eyelash less edge of the eyelids at all periods of observation. The measurements were carried out with a millimeter ruler along the longest part of the formation. The data were processed statistically by calculating the arithmetic mean (M) with the standard error of mean (σ) using the Microsoft Excel 2007 software package, and changes in characteristics were assessed at follow-up by the Wilcoxon rank sum test.Results and discussion. In the acute phase of opisthorchosis, the structures of the anterior eye are damaged, which occurs after the first week of infection in the form of allergic conjunctivitis, episcleritis. We found follicular formations in the upper eyelid, in the outer corner of the eye with further synulosis by the 5th week, and vascular enhancement of the upper eyelid. Conjunctival and corneal changes a month later were of the type of trachomatous pannus with conjunctival hyperemia of both eyelids, edema, and reddening of the free eyelash less edge. The infection by P. ovatus showed no follicular formations or eyelid edema for two weeks. Thus, at opisthorchosis, we observed the phenomena of combined pathology of the visual organ with a specific component for which an independent name can be distinguished, specific parasite-associated ophthalmitis.

PALEOPARASITOLOGICAL ANALYSES OF CAVE BEAR (URSUS KANIVETZ VERESHCHAGIN, 1973) COPROLITES FROM THE IGNATIEVSKAYA CAVE (SOUTHERN URAL)

The first paleoparasitological analysis of coprolites of a cave bear (Ursus kanivetz Vereshchagin, 1973) was performed. Material for research was obtained from different deeps at the excavation of Ignatievskaya Cave (Chelyabinsk Region, Southern Urals, Russia, 54°53’N 57°46’E). Fossil coprolites were find from the excavations N 1-2, situated et the 120 meters from the entry of cave. The depth of excavations was 1.9 m. Radiocarbon analysis show that the age of cave bear bones was more than 27500 years. Coprolites were analyzed by combine method and sedimentation. Slides were viewed under the Meiji microscope with Х100 and Х400 magnification and made a pictures by the Vision camera. Eggs were defined using scientific descriptions available in the national and foreign literature. As a result from the paleoparasitological analysis, the presence Nematodes eggs was detected. Eggs are belonged to Baylisascaris transfuga Rudolphi, 1819 – specific parasite of Ursidae. Obviously, that helminth infected different species of bears already at the Late Pleistocene period and had a wide spreading. This is the first finding of the nematode B. transfuga of Pleistocene age and the first finding of parasites in the cave bear coprolites.

Paleoparasitological study of Holocene South American camelids (ca. 8970–470 years 14C BP) from an archaeological site, Southern Puna of Argentina (Antofagasta de la Sierra, Catamarca)

South American camelids (SAC) have occupied a central role in the development of Andean societies. They are widely distributed in South America and since ancient times are an important factor in Andean economies and social and ritual life. The archaeological site Punta de Peña 4 (PP4) is located in Antofagasta de la Sierra Basin (Southern Puna of Argentina). PP4 is a rock overhang and presents a large occupational sequence (early Holocene until historic times). The aim of this contribution is to study parasite diversity and the relationship among parasites and SAC through holocenic times in the Southern Puna of Argentina. Besides, differences in parasite egg preservation in the site were discussed. A total of 65 coprolites assigned to SAC were rehydratated, homogenized, filtered, allowed to spontaneous sedimentation and examined for parasite remains. Given the morphology of the coprolites, the biogeographic origin and the presence of coccidian oocysts of Eimeria macusaniensis in some of them, a camelid origin of the coprolites is suggested. This is the first paleoparasitological study from PP4, an archaeological site of Antofagasta de la Sierra, a key region in northwestern Argentina and Central Andes. Eleven taxa of parasites were found belonging to Apicomplexa, Platyhelminthes, and Nematoda. Specific parasite species of SAC were found, such as E. macusaniensis and Lamanema chavezi/Nematodirus lamae. A remarkable finding was the presence of Moniezia sp. and Strongyloides sp. in coprolites from different levels of PP4, pointing out the presence of these genera in native artiodactyls of the region previous to the arrival of Hispanic societies. Results displayed a change in the number of parasite taxa present in SAC through time. The parasite-SAC relation through time and differences in parasite egg preservation between levels and sectors (covered and uncovered) of the site are discussed.

Host preferences of coexisting Perkinsea parasitoids during coastal dinoflagellate blooms

ABSTRACTParasites in aquatic systems are highly diverse and ubiquitous. In marine environments, parasite-host interactions contribute substantially to shaping microbial communities, but their nature and complexity remain poorly understood. In this study, we examined the relationship between Perkinsea parasitoids and bloom-forming dinoflagellate species. Our aim was to determine whether parasite-host species interactions are specific and whether the diversity and distribution of parasitoids are shaped by their dinoflagellate hosts. Several locations along the Catalan coast (NW Mediterranean Sea) were sampled during the blooms of five dinoflagellate species and the diversity of Perkinsea was determined by combining cultivation-based methods with metabarcoding of the V4 region of 18S rDNA. Most known species of Parviluciferaceae, and others not yet described, were detected, some of them coexisting in the same coastal location, and with a wide distribution. The specific parasite-host interactions determined for each of the studied blooms demonstrated the host preferences exhibited by parasitoids in nature. The dominance of a species within the parasitoid community is driven by the presence and abundances of its preferred host(s).The absence of parasitoid species, often associated with a low abundance of their preferred hosts, suggested that high infection rates are reached only under conditions that favour parasitoid propagation, especially dinoflagellate blooms.

Molecular data on Phyllodistomum macrocotyle (Digenea: Gorgoderidae) from an intermediate host Dreissena polymorpha (Bivalvia: Dreissenidae) in the Northern Dvina River Basin, Northwest Russia

We report the first molecular identification of Phyllodistomum macrocotyle (Digenea: Gorgoderidae) from the Northern Dvina River Basin, Northwest Russia. Comparative analysis of our sequence was 100% identical to the 28S and ITS2 rDNA sequences of the species P. macrocotyle in zebra mussels discovered in Poland (Wigry Lake), Lithuania (Elektrenai Reservoir and Sirvinta River), Russia, Belarus (Lepelskoe Lake and Lukomskoe Lake), and in fish Leuciscus idus, Scardinius erythrophthalmus in Russia (Rybinsk Reservoir on the Volga River). At the same time, some sequences of the 28S rDNA of P. macrocotyle in zebra mussel detected in Lithuania, and Belarus were different from our sequence on 0.2-0.6%. The ITS2 sequences which have 100% similarity with our specimens of P. macrocotyle were discovered in sporocyst of phyllodistomes from its intermediate host D. polymorpha in Poland, Lithuania, Russia, and Belarus. Our observation in the Yuras and Isakogorka rivers represents the northernmost record of this host-specific parasite, to the best of our knowledge.

DNA Footprints: Using Parasites to Detect Elusive Animals, Proof of Principle in Hedgehogs

The Western European Hedgehog (Erinaceous europaeus) is a nocturnal animal that is in decline in much of Europe, but the monitoring of this species is subjective, prone to error, and an inadequate basis for estimating population trends. Here, we report the use of Crenosoma striatum, a parasitic nematode specific to hedgehogs as definitive hosts, to detect hedgehog presence in the natural environment. This is achieved through collecting and sampling the parasites within their intermediate hosts, gastropoda, a group much simpler to locate and sample in both urban and rural habitats. C. striatum and Crenosoma vulpis were collected post-mortem from the lungs of hedgehogs and foxes, respectively. Slugs were collected in two sessions, during spring and autumn, from Skomer Island (n = 21), which is known to be free of hedgehogs (and foxes); and Pennard, Swansea (n = 42), known to have a healthy hedgehog population. The second internal transcribed spacer of parasite ribosomal DNA was used to develop a highly specific, novel, PCR based multiplex assay. Crenosoma striatum was found only at the site known to be inhabited by hedgehogs, at an average prevalence in gastropods of 10% in spring and autumn. The molecular test was highly specific: One mollusc was positive for both C. striatum and C. vulpis, and differentiation between the two nematode species was clear. This study demonstrates proof of principle for using detection of specific parasite DNA in easily sampled intermediate hosts to confirm the presence of an elusive nocturnal definitive host species. The approach has great potential as an adaptable, objective tool to supplement and support existing ecological survey methods.

Identification of Inhibitors to Trypanosoma cruzi Sirtuins Based on Compounds Developed to Human Enzymes

Chagas disease is an illness caused by the protozoan parasite Trypanosoma cruzi, affecting more than 7 million people in the world. Benznidazole and nifurtimox are the only drugs available for treatment and in addition to causing several side effects, are only satisfactory in the acute phase of the disease. Sirtuins are NAD+-dependent deacetylases involved in several biological processes, which have become drug target candidates in various disease settings. T. cruzi presents two sirtuins, one cytosolic (TcSir2rp1) and the latter mitochondrial (TcSir2rp3). Here, we characterized the effects of human sirtuin inhibitors against T. cruzi sirtuins as an initial approach to develop specific parasite inhibitors. We found that, of 33 compounds tested, two inhibited TcSir2rp1 (15 and 17), while other five inhibited TcSir2rp3 (8, 12, 13, 30, and 32), indicating that specific inhibitors can be devised for each one of the enzymes. Furthermore, all inhibiting compounds prevented parasite proliferation in cultured mammalian cells. When combining the most effective inhibitors with benznidazole at least two compounds, 17 and 32, demonstrated synergistic effects. Altogether, these results support the importance of exploring T. cruzi sirtuins as drug targets and provide key elements to develop specific inhibitors for these enzymes as potential targets for Chagas disease treatment.

Global Spread of Mutant PfCRT and Its Pleiotropic Impact on Plasmodium falciparum Multidrug Resistance and Fitness

Our study defines the allelic distribution of pfcrt, an important mediator of multidrug resistance in Plasmodium falciparum, in Africa and Asia. We leveraged whole-genome sequence analysis and gene editing to demonstrate how current drug combinations can select different allelic variants of this gene and shape region-specific parasite population structures. We document the ability of PfCRT mutations to modulate parasite susceptibility to current antimalarials in dissimilar, pfcrt allele-specific ways. This study underscores the importance of actively monitoring pfcrt genotypes to identify emerging patterns of multidrug resistance and help guide region-specific treatment options.