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Introduction: The association between schizophrenia and toxoplasmosis has been demonstrated in a number of studies: the prevalence of schizophrenia is significantly higher in toxoplasmosis positive subjects than in those with T. gondii negative status. However, the clinical significance of this association remains poorly understood., Objectives: To identify clinical phenomena that are typical for toxoplasmosis-associated ( T. gondii seropositive) schizophrenia compared to Toxoplasma-seronegative schizophrenia., Methods: A retrospective database analysis of serum samples from 105 inpatients with schizophrenia (ICD-10code: F20; including 55 male patients; mean age of 27.4 6.4 years) was carried out. The clinical examination involved a structured interview including ICD-10 and E. Bleulers criteria for schizophrenia and psychometric tests(Positive and Negative Scales of PANSS). Serum antibodies (IgG) to T. gondii were identified using ELISA. The statistical significance of any differences were evaluated using the non-parametric Mann-Whitney (U) and X 2 tests., Results: The proportion of seropositive patients in the sample was 16.2%. Comparing schizophrenia patients, who were seropositive or seronegative for toxoplasmosis, there were no statistically significant differences for the mean total PANSS score, mean PANSS-P, PANSS-N or PANSS-G scores. For the majority of PANSS items, differences were also statistically insignificant, except for G5 and G6mannerism and posturing. Seropositive patients had a higher score for this item than seronegative patients: 3.5 versus 2.1 points (U=389.5; р=0.001). Depression, on the contrary,was less pronounced in seropositive than seronegative patients: 1.4 versus 2.4 points (U=509.5; р=0.023). In addition,in seropositive patients, the frequency of symptoms such as mutism according to ICD-10 criteria for schizophrenia was significantly higher (23.5% versus 3.4%, X 2 =9.27, р=0.013), and the whole group of catatonic symptoms according to the E. Bleulers criteria for schizophrenia was higher (52.9% versus 28.4%, X 2 =3.916, p = 0.048)., Conclusion: The association between a positive toxoplasmosis status in patients with schizophrenia and catatonic symptoms has been revealed for the first time and should be verified in larger studies., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020, Romanov D.V., Brazhnikov A.I., Andreyuk D.S., Zakharova N.V., Bravve L.V., Kovaleva V.A., Abbazova E.V., Goncharov D.B., Titova I.V., Domonova E.A., Kostyuk G.P.)

The article presents the results of clinical laboratory examination of women (n=104) with gynecological diseases for detection of Toxoplasma gondii. The antibodies to T. gondii were detected in 39.42% of women using enzyme-linked immunosorbent assay and indirect immuno-fluorescence test. In women with various gynecological diseases the toxoplasmosis is detected against the background of concomitant extra-genital pathology. This disease takes its course mostly latent together with urogenital infections being accompanied by hemostasis changes. The detection of antibodies to T. gondii in most cases of inflammation process in oviducts, uterus, ovaries can indicate the role of toxoplasma in development of inflammation diseases of female genitals., Competing Interests: The authors declare no conflict of interest.

The incidence of cerebral toxoplasmosis (CT) among all brain involvements was determined in patients with Stage 4B HIV infection (AIDS) in 2003-2009. Clinical and laboratory parameters were estimated in 156 patients to reveal diagnostic criteria. As a result, CT was shown to be a leading cause of neurologic diseases in patients with late-stage HIV infection (34.7% of cases of brain involvement). In 11.5%, it took place as a generalized process. CT concurrent with cytomegalovirus infection, tuberculosis, or other secondary lesions was frequently diagnosed. Of importance in the diagnosis of CT are magnetic resonance imaging results in addition to basic, clinical data that can assume this diagnosis. The high and moderate serum concentrations of T.gondii IgG are of diagnostic value, which may be used as an auxiliary method to verify the diagnosis.

Cerebral toxoplasmosis is one of the leading causes of neurologic diseases with high mortality rates in patients with HIV infection. Invasion was difficult to diagnose for a number of objective reasons. The objective of the investigation was to determine the clinical sensitivity of different laboratory techniques as both a single study and their various combinations to verify the diagnosis of cerebral toxoplasmosis in HIV-infected patients. Blood and cerebrospinal fluid were tested in 51 patients with Stage 4B HIV infection (AIDS) with the verified diagnosis of cerebral toxoplasmosis. Separate determination of specific antibodies of IgG, IgM, IgA and toxoplasma DNA in the blood and cerebrospinal fluid was shown to have an insufficient clinical sensitivity (37.3-68.6%). The benefits of various combinations of immunological and molecular biological assays enhancing the diagnostic efficiency up to 76.5-96.1% are demonstrated.

Contemporary representation of toxoplasmosis reactivation criteria in HIV infection is generalized. Significance of the issue is justified: toxoplasmosis is a leading neurological pathology in AIDS with a high lethality percentage due to complexity of clinical confirmation and difficulties of laboratory confirmation of the start of reactivation. Clinical, instrumental, immunologic, molecular genetic invasion reactivation criteria are discussed in the article and analysis of their effectiveness is performed; their most feasible combinations are justified. Further system analysis of the cerebral toxoplasmosis reactivation criteria specified in the article in combination with search of new pathogen dissemination markers will allow to obtain important information that has both fundamental interest and important practical significance.

Aim: Comparative assessment of effectiveness of serologic methods for toxoplasmosis diagnostics in patients with HIV-infection., Materials and Methods: Sera and CSF samples from 166 patients with AIDS stage IIIB were tested for antibodies to Toxoplasma gondii by indirect immunofluorescence, ELISA and immunoblotting. Results of serological tests were compared with clinical, pathological data as well as with results of MRI and PCR., Results: Clinical value of IgG detection in blood and CSF by ELISA was shown--high level of antibodies marked reactivation of the invasion. IgG antibodies in CSF were detected only if high levels of IgG were present in the blood. Detection of antigenic determinants with molecular mass 18 - 20 and 65 - 70 kDa in immunoblotting was proposed as a criterion of cerebral toxoplasmosis reactivation., Conclusion: Complex laboratory serologic tests along with data obtained by MRI, PCR and microscopy of T. gondii cysts enhances the effectiveness of toxoplasmosis diagnostics. Knowledge of toxoplasmosis reactivation criteria in patients with AIDS will allow to develop the optimal protocol of toxoplasmosis diagnostics and substantiate measures for its prevention.

Aim: To define the incidence and features of brain lesion (BL) in HIV-infected inpatients., Subjects and Methods: Four hundred and fifty-eight patients with Stage 4B HIV infection (AIDS) and central nervous system (CNS) lesion admitted to Infectious Diseases Hospital Two, Moscow, were followed up in 2003-2009. The authors used cerebrospinal fluid (CSF) microscopic and bacteriological assays for DNA of T. gondii, M. tuberculosis, herpes simplex virus (HSV) types 1 and 2, cytomegalovirus (CMV), HSV type 6, and varicella-zoster virus, Cr. neoformans, C. albicans, C. glabrata, and C. krusei. Blood and CSF were tested for IgM and IgG T. gondii antibodies; brain magnetic resonance imaging was carried out., Results: In patients with late-stage HIV infection, the principal cause of neurological diseases was cerebral toxoplasmosis (34.7% of BL cases) and a generalized process involving the brain, lung, heart, liver, and eyes in 11.5%. There was commonly cerebral toxoplasmosis concurrent with CMV infection with clinical manifestations. 16-32% of the inpatients developed tuberculosis meningoencephalitis that was a manifestation of hematogenous disseminated tuberculosis involving the lung. There was a rise in the incidence of cancers (brain lymphomas, astrocytomas) running with CNS lesion. Mental disorders progressing to dementia were a distinctive property of CMV ventriculoencephalitis, one of the leading factors in the development of AIDS dementia complex. Molecular diagnostic techniques are needed to ascertain the etiology of BL in HIV infection., Conclusion: The CSF test for DNA of causative agents is a specific and most sensitive method for diagnosing a relevant CNS lesion.

Aim: To study virulence of Toxoplasma gondii strain isolated from pathologicoanatomic brain tissue of HIV-infected patients on in vivo model as well as immune response to the pathogen in immunocompetent animals and in animals with cyclophosphamide-induced areactivity., Materials and Methods: Groups of immunocompetent and immunodeficient mice were inoculated with cysts of T. gondii obtained from brain tissues of deceased HIV-infected patients. Parasites were detected in different organs and tissues by PCR as well as by parasitological and histological methods. Antibodies to T. gondii belonging to isotypes IgG, IgG1, IgG2, IgA were detected by immunofluorescence assay., Results: Cysts of the pathogen located predominantly in animals' brain, and more rarely - in spleen and liver. Using detection of antibodies of different isotypes, which marked stage of invasion, dynamics of humoral response during persistence of toxoplasms in organism was determined. Analysis of disease pathogenesis as well as peculiarities of immune response to the pathogen in immunocompetent animals and in animals with cyclophosphamide-induced areactivity was performed., Conclusion: Characteristics of strains of toxoplasms isolated from material of brain section of patients with HIV infection were studied. Their low virulence and ability to prolonged persistence in organism of mice were demonstrated on in vivo model. Possible association of T. gondii strains' virulence and clinical symptoms with pathogen's genetic polymorphism and its clonal population structure was discussed.

Aim: To detect clinical characteristics of cerebral toxoplasmosis in HIV-infected patients, to clarify diagnostic role of detection of DNA and antibodies to Toxoplasma gondii in the cerebrospinal fluid (CSF) and blood., Material and Methods: Diagnostic procedures were performed in 156 patients with HIV infection at the stage IVB (AIDS) in 2003-2006. All the patients suffered from diseases of the central nervous system (CNS). Toxoplasmosis was diagnosed in 57 (36%) cases. Lumbar puncture, MR imaging of the brain, reaction of indirect immunofluorescence, polymerase chain reaction and enzyme immunoassay were made to identify IgM and IgG to T. gondii., Results: Typical for HIV-infected patients with cerebral toxoplasmosis were focal symptoms of CNS affection, hemipareses, adynamia, mental disorders, intoxication symptoms., Conclusion: MR imaging data are very important. Toxoplastosis is characterized by multiple destructive foci in the hemispheres and cerebellum with great amount of the parasites along the periphery of brain tissue necrosis. Detection of the infective agent DNA and specific IgG antibodies in cerebrospinal fluid confirms the presence of toxoplasmosis but sensitivity of the markers is low. IgG antibodies to T. gondii have diagnostic implications if they occur in high and moderate titers.

Cryptosporidiosis is a socially dangerous opportunistic infection that is intractable and, according to recent data, caused by a diversity of species of the genus Cryptosporidium, which are still recently considered to be nonpathogenic to a human being. The transmission of this infection is by the water route and the technology of water purification cannot be saved from the oocysts of Cryptosporidium. Therefore, the important line of investigations is to study the immunological aspects of the interaction of Cryptosporidia with the cells of a microorganism, the development of a pathological process, and the persistence of the pathogen. The review analyzes the factors providing the mobility of the pathogen, its attachment to and penetration into the cell. The inhibitory effect of a number of substances preventing the binding of sporozoites to the cell is described. It has been established that Cryptosporidia can control the apoptosis of the host's cells and affect different other parameters of cell functional activity. It is shown that infection resistance depends on many factors and it is studied on models with genome or immunity or artificially induced defects. Nitric oxide should be emphasized among the determinants of natural resistance to Cryptosporidia. gamma-IFN has a dominant role in infection control and the good response to infection is associated with the production of a number of cytokines mainly of the Th1 type. There is evidence that there is a relationship of the local immune response to the systemic one in cryptosporidiosis. It is noted that the loss of local immune reactions may cause severe sequels in patients with immunodeficiencies. The importance of nonspecific T-cell defense and antiparasitic antibodies in the control of the infection is demonstrated. It is concluded that the studies that give a better insight into the systemic mechanisms of infection protection should be conducted. In this direction, it is promising to construct models of cryptosporidiosis in the immunocompetent host and those of generalized infection, which will assist in studying the mechanisms that are responsible for the control of cryptosporidial dissemination in immunodeficiencies.

The results of studies of visceral leishmaniasis (VL) made in the 20th century in the Commonwealth of Independent States that are VL-endemic, such as Azerbaijan, Armenia, Georgia, Kazakhstan, Kyrghyzstan, Tadjikistan, Turkmenistan, and Uzbekistan are summed up. The magnitude of studies of VL in different regions is different. The authors analyze the epidemiological and epizootological situation and define the basic lines of further studies of VL, which include the present view of the prevalence of VL in Central Asia and Transcaucasia; identification of strains of the pathogen by molecular genetic methods; study of its vectors; detection of natural reservoirs of the pathogen, improvement of methods for VL diagnosis; and their introduction into laboratories' work.

The publications, including those of the author, on persistence phenomenon of the obligatory intracellular parasite, Toxoplasma gondii, are updated. The latent form of toxoplasmosis was shown to be prevailing. The role of congenital and acquired toxoplasmosis in kids' and adults' pathology, the opportunistic nature of this infection, the reactivating factors of latent and chronic infection as well as the mechanism of pathogen persistence are under discussion.

Changes in expression of lectin-binding sites, which are complex carbohydrate structures of Leishmania gymnoductyli reptulii, were studied by the classical lectin agglutination test. The results evidence that this test may be used to assess the level of ontogenesis of Leishmania strains, as well as for the detection and isolation of metacyclic (invasion) stage from Leishmania cell culture by lectins.

It was demonstrated that soybean agglutinin and peanut agglutinin aggregated all the investigated species of Leishmania, including virulent and avirulent members of L. major in agglutination tests. Concanavalin A and Pisum sativum agglutinin were shown to aggregate L. species ZMA and L. major but showed no effect on L. gymnodactyli and L. mexicana amazonensis which were aggregated by wheat germ agglutinin, an extract from Ulex europaeus and Ricinus communis. There was no correlation between the results of ELLBA studied in agglutination tests. The results indicate that the surfaces of Leishmania strains and species are heterogeneous with respect to lectin binding. There are possibly two subsets of lectin receptors on the surface structures of Leishmania cells.

The authors analyze the results of C-ELISA, used in screening of the population in combined foci of zoonotic cutaneous leishmaniasis and visceral leishmaniasis in two types of landscapes in Turkmenistan. In the deltas, on the plains [correction of planes] and oases, where the incidence of zoonotic cutaneous leishmaniasis is very high, 1.6% of the examinees were found to have antibody to L. major. The antibodies in this condition are detectable only during the acute stage of the disease and persist for just a few months after convalescence. The share of the positive sera with antibody to L. donovani sensu lato was the minimal (0.48%) in the population of the alluvial plain [correction of plane] at the Kopet-Dag hills, the highest share (4%) of the population with such antibodies lived in the sandy deserts in the interfluvial areas of southern-eastern Turkmenistan. The authors have validated the criteria for the assessment of the endemicity level of leishmaniasis foci with due consideration for various incidence rates of visceral and zoonotic cutaneous leishmaniases and the specific features of the immune response in these nosologic forms. They suggest that a positive serologic response be considered as the basic criterion of a visceral leishmaniasis focus, and the disease incidence and the number of subjects who had had this disease in the focus--the basic criterion for the assessment of a zoonotic cutaneous leishmaniasis focus endemicity.

189 sera from patients with ZCL of different stages were studied by means of RNIF and C-ELISA. A high significant correlation between RNIF and C-ELISA indices was shown, but the latter test was proved to be more sensitive and therefore more effective. In patients with ZCL, a significant direct correlation between the duration of the process and the antibody titer was established by means of C-ELISA. In patients with ZCL at the third (final) stage (reduction and granulation of lesions), the C-ELISA liter of specific antibodies was higher than at the second stage (rapidly progressing ulceration of lesions). The findings indicate the presence of clinical and serological parallels in ZCL and show it expedient to compare the dynamics of antibody genesis and cell immunity indices in further studies.

A serological study on leishmaniasis in human population of Guinea revealed the percentage of seropositive persons varying in different parts of the country from 0.84 to 4.76 (according to C-ELISA) and from 1.0 to 5.1 (according to IFAT). The majority of sera positively reacting in C-ELISA with the antigen of Leishmania major in dilutions of 1:800 and higher were received from Kundara District (northwestern part of the country), and with the antigen of L. donovani sensu lato from Sigiri and Kankan districts (northeastern part of the country). All the districts were situated in the savanna zone. The amastigotes of Leishmania were found in the liver and spleen of Tatera gambiana caught near Kindia. These data suggest the circulation of Leishmania over the territory of Guinea.

Species-specificity of two serological tests has been compared: Indirect immunofluorescence test and C-ELISA using antigens prepared of 7 Leishmania species of various groups of human sera, including sera from healthy donors; sera of patients with various tropical parasitoses; sera containing rheumatoid factor and antinuclear antibodies; sera of patients with visceral leishmaniasis (VL); sera of normal subjects arrived from regions endemic for VL; sera of students arrived in Czechoslovakia from various tropical countries endemic for leishmaniasis. It has been shown that C-ELISA (and EIA with corpuscular antigen), being highly sensitive techniques, are very promising for the identification of species-specific Leishmania antibodies. C-ELISA titres beginning from 1:800 and above may be considered as species-specific. With the titre 1:400, cross-reactions with antigens of various Leishmania species are observed.

Using immunoblotting, the antigenic structure of 6 Leishmania strains has been studied: 1) MHOM/IN/80/DDS--Leishmania (Leishmania) donovani; 2) MHOM/SU/63/VL--L. sp. ZMA; 3) MHOM/SU/73/K-27--L. tropica; 4) MHOM/SU/73/5Ash--L. major; 5) MHOM/GE/84/H-132--L. mexicana amazonensis; 6) REPT/SU/83/3960-GC--L. (Sauroleishmania) gymnodactyli. Antigens of Leishmania surface membranes and rabbit antisera against them have been used. Among the agents of leishmaniasis in the Old World (1-4), the most intensive antigenic lines were found in the medium and high-molecular mass area (43-200 kD). In L. (L) mexican a amazonensis (5) species-specific lines have been identified in 10-22 kD area, which is indicative of considerable antigenic differences in Leishmania of the Old and New Worlds. The most marked antigenic differences from other types were noted in L. (S) gymnodactyli (6). It was characterized by the absence of antigenic bands in the medium and high molecular mass areas, the lines associated with species-specific determinants located in the low molecular mass area (18 and 25 kD). The results of cross-reacting c-ELISA using the same antigens and antisera correlated well with the above data of immunoblotting. Immunoblotting may be used for identification of species-specific antigenic structures which may be helpful in serological tests for more accurate leishmania identification and leishmaniasis diagnosis.

The authors propose polystyrol carrier enzyme-linked immunoassay using corpuscular Leishmania antigens (intact cells of Leishmania promastigotes)--C-ELISA. The standard lyophilic Leishmania antigen for ELISA may be used as an antigen in indirect immunofluorescence reaction. C-ELISA allowed the authors to determine clear antigenic differences between the mammalian leishmaniasis causative agents (subgen. Leishmania) and the reptilian ones (L. gymnodactyli--subgen. Sauroleishmania). Different levels of the antigenic relationship were demonstrated between separate species within the mammalian Leishmania serogroup. The method shows promise for elaboration of the specific test systems in order to differentially diagnose various nosologic entities of leishmaniasis, including ones in the mixed natural foci.

The present state of leishmaniasis serological studies' problem is elucidated by analysing the data obtained for the last decade. The Data presented in the review demonstrate the possibility of studying quite different leishmaniasis problems by serological methods. The modified Adler test seems most suitable as serological method for Leishmania identification, while monoclonal antibody method looks most promising. Enzyme immunoassay is the most effective test used for serodiagnosis and leishmaniasis seroepidemiological studies, though it doesn't exclude other methods and, first of all, indirect immunofluorescence.

Comparative study of sera from patients suffering from zoonotic cutaneous leishmaniasis by indirect immunofluorescence (IIF) and by enzyme immunoassay (ELISA) gave 72.4 and 89.6% positive results, correspondingly, with homologous antigen L. major. Good correlation of these methods was revealed--coincidence in 83% cases. Authors used ELISA with corpuscular Leishmania antigen. The test was superior to IIF in sensitivity and specificity. Creation of type-specific Leishmania test systems for ELISA opens new vistas in studies of the population immune structure in combined zoonotic cutaneous leishmaniasis and visceral leishmaniasis foci.