[EXTERNAL QUALITY ASSESSMENT FOR THE LABORATORY IDENTIFICATION OF THE PATHOGENS OF PARASITIC DISEASES AS AN ELEMENT FOR IMPROVING THE POSTGRADUATE TRAINING OF SPECIALISTS].

Within the framework of the Federal External Quality Assessment (EQA) System and in the context of postgraduate training improvement for health workers in 2010-2014, specialists from the laboratories of the therapeutic-prophylactic organizations and institutions of the Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare were examined for their professional competence in microscopically identifying the pathogens of parasitic diseases in feces. The virtual remote educational computer technology tools that included different combinations of 16 helminthic species, 5 intestinal protozoan species, and a number of artefacts, were used. The specialists from 984 laboratories of multidisciplinary therapeutic-prophylactic organizations and hygiene and epidemiology centers in all Federal Districts of the Russian Federation were covered. A total of 8245 replies were analyzed. The detection rate for helminths was 64.0%, including those by a taxonomic group (nematodes, 65.0%; cestodes, 72.0%; trematodes, 55.1%). There was a dynamic decrease in the above indicators. There were low detection rates for trematodes parasitizing the small intestine (Metagonimus, 10.2%; Nanophyetus, 26.2%) and hepatobiliary organs (Fasciola, 59.6%; Clonorchis, 34.9%). The similar trend was seen in the detection rates for the pathogens of geohelminthisms (ascariasis, trichocephaliasis, etc.) and contagious helminthisms (enterobiasis, hymenolepiasis). The level of competence in detecting and identifying intestinal protozoa was much lower than the similar rates for helminthism pathogens. EQA for the laboratory diagnosis of the pathogens of parasitic diseases, by using the virtual tools is a leading element of the postgraduate training system for laboratory specialists. The results of EQA for the laboratory diagnosis of the pathogens of parasitic diseases are a basic material for the development, and improvement of training modernization programs, by applying a modular approach.

[Morphological identification of blastocystis].

The authors have attempted to systematize the currently known specific morphological features of the composition of Blastocystis spp. existing in different forms and to present this material as a reference table, by understanding the need for further data clarification. In addition, the paper describes observations of variations in the forms of human blastocysts. In particular, it depicts the species of multinucleated cysts, the identification of which may cause difficulties in diagnosing and differentiating these forms with some representative species of the genus Entamoeba.

[Extraenteric infection caused by Blastocystis spp. in a female patient with liver abscess].

The cases associated with the development of liver abscesses in a 64-year-old female patient after elective surgery for colon polyposis could form an opinion that extraenteric infection caused by Blastocystis spp. might develop in the immunocompromised host. The development of Blastocystis spp. in the presence of disintegrated liver tissue and inflammatory cells was verified by microscopic examination of liver abscess aspirates. The Romanovsky-Giemsa stained specimens exhibited typical amoeboid, vacuolar and, what is particularly important, dividing forms of Blastocystis spp. The patients full recovery after timely combination therapy with broad-spectrum antibiotics and imidazole group preparations also indirectly argues for the etiological role of Blastocystis spp. in the development of liver abscess with the signs of changes in both lungs (the signs of right lung compression and bilateral hydrothorax). Physicians' awareness of the potential clinical significance of Blastocystis spp. in immunodeficient patients is sure to expand the range of differential diagnostic studies of patients infected with Blastocystis spp.. particularly in case of gastrointestinal tract diseases of unknown etiology.

[Blastocystis spp. culturing as a method for diagnosing the parasite].

The technique for isolating blastocysts in the culture was assessed, by examining the fresh specimens from 196 patients with gastrointestinal tract (GIT) disorders and from 56 persons with an uncertain protozoological diagnosis. A set of techniques, such as triple examination of native smears, parallel inoculation of the Pavlova medium, and microscopy of obtained permanent specimens as may be required, contributes to the timely identification of protozoa, including blastocysts, in persons with GIT disorder. The efficiency of the technique for isolating blastocysts on Pavlova's medium and the native smear test averaged 34.8% and 49.4%, respectively. Among those known to be infected, the rate of parasite development in vitro was not greater than 52.9%. The culture showed amoeboids generally with the clinical manifestation of infection. The culture-based diagnostic method cannot be changed for routine microscopy techniques in detecting blastocysts, although it is essential to investigate the morphofunctional and phylogenetic properties of the parasite. The pleomorphism of cultured blastocysts with variability of growth properties was shown as a manifestation of phenotypic characteristics when isolating the parasite.

[Blastocystis hominis infection in a baby with food allergy].

The paper describes a rare manifestation of Blastocystis hominis infection in a 3-month-old baby with food allergy that appeared as atopic dermatitis and coloproctitis induced by food proteins (cow's milk, hen's egg). The fact that food allergy may be one of the predisposing factors in the development of clinical manifestations of B. hominis infection is discussed. The assumption that the amoeboid form of blastocysts accompanies the clinical manifestation of the infection is confirmed.

[Intestinal protozoa in children of child day care centers and orphanages of Moscow].

On the basis of an analysis of the contamination with intestinal protozoa in 373 Moscow children and comparison of the data of a randomized protozoological study of matched groups of 543 children from three towns of the Russian Federation in the past 15 years, the authors revealed profound changes in the pattern of intestinal parasitocenosis in the examinees: preponderance of B. hominis recently reclassified as a protozoan in all groups of examinees; a reduction in the detectable protozoan types up to a single type both among parasitic amoebas (E. coli) and flagellates (L. intestinalis). The incidence of giardiasis among the children's collective bodies averaged 3.5% and that in the kindergartens was 0.5%.

[Chromosome-like bodies of dysentery ameba Entamoeba histolytica]. / Khromosomopodobnye tela dizenteriinoi ameby Entamoeba histolytica.

Intact and surface stretched amembraneous nuclei of Entamoeba histolytica (Rhizopoda, Lobosea, Entamoebidae) trophozoites were studied by light and electron microscopy. A moderately dense karyosome about 1.5 microns in diameter, localized in the central part of the interphase nucleus, contains the bulk of nuclear DNA. Within the karyosome, beaded and ribbon-like chromatin bodies surrounding a loose fibrillar core are commonly recognized. The peripheral domain of both interphase and several mitotic nuclei is filled with a heterogeneous material similar in its ultrastructure to the nucleolar substance. A wide fibrogranular domain lies between this unusual nucleolus and the karyosome. Rosette-like intranuclear inclusions 0.2-0.4 micron in diameter are often seen in both the fibrogranular and nucleolar domains. At the prophase-metaphase, nearly 50 linear chromosome-like bodies are detected as being in close association with several large beaded and ribbon-like chromatin bodies. At the anaphase-telophase, the chromatin bodies per surface-stretched daughter nucleus of live entamoebae, and in each amembraneous daughter nuclear preparation number nearly 14 and 6, respectively. Besides, in each amembraneous DAPI-stained nucleus a set of 50 or so linear chromosome-like bodies are clearly identified. We infer that the nucleus of E. histolytica contains more than 50 linear chromosomes which at different stages of the cell cycle can unite into several beaded and ribbon-like associations. These form a single moderately dense chromatin karyosome in the central part of the interphase nucleus.

[Possible entry of fragments of a bacterial genome into the trophozoite nucleus of the dysentery amoeba]. / Vozmozhnoe postuplenie fragmentov bakterial'nogo genoma v iadro trofozoita dizenteriinoi ameby.

The use of Fölgen-like electron microscopy reaction has revealed particles in the cytoplasm and nucleus of the dysentery amoeba trophozoites which in their size and resistance to acidic hydrolysis and in their affinity for uranilacetate are similar to tightly packed elements of the bacterial genome. On this basis a conclusion was drawn that some fragments of genomes of phagocytic bacteria can be preserved in the amoebal cell. The community of microorganisms consisting of trophozoites of the dysentery amoeba and bacteria of the intestinal flora is supposed to be a suitable model for studying the possibility of penetration of transgenetic elements from procaryote to eucaryote.

[Morphology of the intranuclear inclusions in Entamoeba histolytica trophozoites]. / Morfologiia vnutriiadernykh vkliuchenii trofozoitov Entamoeba histolytica.

Electron microscope studies of spherical intranuclear inclusions (II) of Entamoeba histolytica trophozoites of two strains, which were maintained in polyxenous culture for different periods of time, were carried out. Data on the number of II in different individuals and in different strains are given. The structure of II whose external layer consists of electron dense material and resembles morphologically peripheral chromatin of the ameba's nucleus, an analogy of nucleolus chromatin of cells of other eucariots, is considered. Inside this layer some II have annular filaments about 9 nm thick rolled up spherically around the central zone of II. Comparison of results obtained and literary data suggests that the dynamic structure of II in question reflects a number of biosynthetic processes on the basis of annular extrachromosomal DNA of exogenic origin.