[The characteristics of cryptosporidiosis epidemiology in the European part of Russia]. / Osobennosti épidemiologii kriptosporidioza v Evropeiskoi chasti Rossii.

Large-scale surveys of representative population groups (n = 2243) in 7 cities and 3 provinces of the central, Povolzh'e, and northwestern regions of the Russian Federation provided the basic epidemiological features of cryptosporidiosis in the European part of the country. Its mean incidence of the population was 3.34%, much higher in children (3.69%) than in adults (0.41%). The boys were more frequently afflicted than the girls (4.69% versus 1.92%). There were no differences in the infection rates between rural and urban children. Young children (aged 1-3 years) with diarrhea and children in closed collective bodies are infection risk groups. The detection rate of persons infected with Cryptosporidium was much greater by the formalin-ether precipitation technique than that by the routine smear test. The correlation coefficient as to the infection rates detected by the routine smear tests was 1.75.

[The host-opportunistic protozoa system. The incidence of mixed infections (Pneumocystis and cytomegalovirus) in children living in radionuclide-contaminated areas]. / Sistema "khoziain-uslovno-patogennye prosteishie". Chastota smeshannykh infektsii (pneumotsistnoi i tsitomegalovirusnoi) u detei, prozhivaiushchikh na zagriaznennykh radionuklidami territoriiakh.

The purpose of our study was to determine the influence of ionized radiation onto the frequency of mixed infections (P. carinii and Cytomegalovirus) in children inhabitants of the settlements affected with radionuclide after Chernobyl accident. Two groups of children were under survey. 1) 103 inhabitants of Novozybkov (Bryansk Province, Russia) and 38 patients under observation in Moscow paediatric hospital from another affected villages (5-15 Ci/km2) were examined serologically by the diagnostic system "Pneumo-test" and "Cytomegatest" (Nyarmedic, Moscow, Russia). Cut-off titers for P. carinii were IgM-1: 200, IgG-1: 20, for CMV IgG-1: 200, 2) Retrospective study of 563 patients with respiratory pathology and 1809 died children after acute pneumonia during 14 years period. Sputum and mucus of the patients taken by laryngoscopy and bronchoscopy were studied for P. carinii by microscopy, the section of lungs--histologically. The sediments of urine and saliva were examined for CMV by microscopy and section of different organs_-histologically. Examinations were performed by one and the same highly qualified pathologist. The results of the study were as follows. 1. Of 563 children examined for both P. carinii and CMV 186 (33%) were positive for P. carinii and 189 (33.7%) for CMV. Both pathogens were found in 46 children (8.2%), mainly among 1-2 and 6-12 month age (8.5 and 14.5%, respectively). Retrospective analysis of 1809 autopsy results shows, that in 73 cases (4%) were found only P. carinii, in 200 (11.1%) only CMV and in 24 (1.3%) two pathogens simultaneously. 2. Of 103 children surveyed serologically P. carinii monoinfection was found in 7 (8.8%), CMV-in 25 (24.3%) and coinfection in 55 (53.4%). Estimated frequency for coinfection (if combination of two infections were to be accidental) should equal 46.8%. In control group consisted of 30 children from clean Moscow region the rate of coinfection was 16.7% and estimated rate 15% (the difference between empiric and estimated rates are statistically significant, t > 4). Thus it is clear that the rate of coinfection of P. carinii and CMV is always high either in clean or in affected by ionized radiation regions. This rate determined by microscopy was higher in patients (8.2%) than in autopsy cases (1.3%) and much higher in children from affected region (53.3%) than in control (16.7%), being determined serologically. Separate interest present geometric mean titers found in the cases of coinfection. The titer for anti-CMV IgG in children from affected regions was rather high (5884 vs. 1246 in control) and on the contrary titers for anti-P. carinii IgM and IgG were lower than in control (512 vs. 1245 and 58 vs. 159 respectively). We are incline to interpret the results of our study as evidence of increased susceptibility to P. carinii and CMV in those children whose immune system was suppressed by premorbid factors or ionized radiation and peculiar symbiotic relationships of P. carinii and CMV resulting in enhancement of their infectiousness.

[The host-opportunistic protozoa system. The effect of ionizing radiation on the prevalence of cryptosporidiosis and pneumocystosis]. / Sistema "khoziain-uslovno-patogennye prosteishie". Vliianie ioniziruiushchei radiatsii na rasprostranenie kriptosporidioza i pnevmotsistoza.

The aim of this study was to determine an influence of ionized radiation on the prevalence of Cryptosporidium and Pneumocystis carinii (P. c.) infections in children inhabitants of settlements affected by radionuclides after Chernobyl accident. Survey of children from day-care centers for prevalence of Cryptosporidium was carried out in Bryansk region, Russia, and Gomel and Mogilev regions, Belarus; children from cities Mogilev and Gomel as well as small town Pochep, Bryansk region, serve as control clean zones. Survey for P. c. seroprevalence was carried out in town Novozybkov, Bryansk region, Specific Ab to P. c. determined by "Pneumo-test" system (Nyarmedic. Moscow. Russia), an evaluation of immune status included assessment of Ig in serum and saliva by Manchini method. Results of the study were as follows: 1) of 432 healthy children surveyed for Cryptosporidium oocysts 352 were from affected regions: the prevalence in Bryansk region was 8% vs. 2.8% in control, in Gomel and Mogilev 4.1% vs. 2.8%. 2) Prevalence anti-P.c. Ab accounts 56.3% in children and 78.2% in adult inhabitants of Novozybkov vs. 30% in children of control group. Special interest presents an relationship of seroprevalence P.c. and secretory immunity examined twice with 2 month interval. At the first survey IgG in seropositive for P. c. children was found in 36.8% (vs. 23.1% in control) and secretary IgA in 13.2% vs. 5.8% in control. At the second survey IgG was found in 53.4% vs. 21.8% and IgA in 2.7% vs. 1.8% in control. Taking into consideration the known fact that IgG and IgA in saliva are result of their transudation from blood through the inflammatory mucosa we consider that long ionized radiation impairs the barrier function of mucosae.

[The host-opportunistic protozoa system. The outcome of a Leishmania infantum infection in white rat pups naturally resistant to Leishmania infection]. / Sistema "khoziain-uslovnopatogennye prosteishie". Iskhod zarazheniia Leishmania infantum molodniaka belykh krys, estestvenno ustoichivykh k leishmaniinoi infektsii.

It was found out, that non-lineal young white rats have a natural resistance to the leishmania infection, but it could be overcome with the mean of immunosuppression caused by the corticosteroid of prolonged action Tricort-40. The leishmania infection caused by immunosuppression is successfully eliminated by the animal organism soon after the stopping of immunosuppressant action, that could be considered as the restitution of the natural resistance.

[Immune status of adult population of the Bryansk region living in territory polluted by radionuclides]. / Immunnyi status vzroslogo naseleniia Brianskoi oblasti, prozhivaiushchego na territoriiakh, zagriaznennykh radionuklidami.

Clinical and immunological investigation with immune status evaluation of three groups of adult population of Bryansk Region was performed. The first group included 165 persons living in Vyshkov (settlement of town type in Bryansk Region) contaminated with radionuclides as a result of Chernobyl accident. The second group included 68 persons living in Vyshkov, immunological monitoring of those was performed. The third group consisted of 114 persons living on the "clean" area of Pochep (Bryansk Region). On both areas (contaminated Vyshkov and "clean" Pochep) the large percent of persons (three quarters of all investigated ones) had clinical manifestations of immune deficiency. The immune status of Vyshkov inhabitants was characterized by T-helper/inductor activation. That was expressed in significant increase of CD4+, CD4+/CD8+ in comparison of control group of primary donors and to "clean" Pochep inhabitants and in stable decrease of average values of serum IgG in comparison to control group, IgG and IgM in comparison to Pochep group. Maximum high values of T-helpers under lowest T-suppressor/killer values were observed at clinical symptoms which may be stipulated by radiation factor (loss of hair and teeth, surplus weight, predisposition to bleedings) and in persons working in cattle-breeding.

[The host-opportunistic protozoon system. The manifestation of Leishmania infantum infection in naturally resistant adult white rats subjected to drug immunosuppression]. / Sistema "khoziain--uslovno-patogennye prosteishie". Manifestatsiia infektsii Leishmania infantum u estestvenno ustoichivykh vzroslykh belykh krys, podvergnutykh medikamentoznoi immunosupressii.

The attempt to overcome the natural resistance of white rats Wistar to Leishmania infantum infection was made by the mean of the immunodepressant Tricort-40, the corticosteroid of prolonged activity. In the series of experiments with the mercy scheme of immunosuppression the inoculation of the amastigotes L. infantum taken out of the donors, the golden hamsters Mesocricetus auratus, caused the progressive infection with intensive affection on target organs (the spleen, liver, bone marrow). The stem of L. infantum been passed through the immunosuppressed rats has preserved its pathogenicity to the golden hamsters.

[The host-opportunistic protozoa system. The dissemination of Leishmania infantum infection in naturally susceptible laboratory animals subjected to drug-induced immunosuppression]. / Sistema "khoziain--uslovno-patogennye prosteishie". Disseminatsiia infektsii Leishmania infantum u estestvenno vospriimchivykh laboratornykh zhivotnykh, podvergnutykh medikamentoznoi immunosupressii.

The possibility to awake the disseminated infection of Leishmania infantum in golden hamsters Mesocricetus auratus, hispid cotton rats Sigmodon hispidus, soft furred rats Mastomys natalensis by means of different immunodepressants has been examined. On the background of the immunosuppression caused by corticosteroids of short time activity (metipred, hydrocortison) leishmaniae were revealed both in the target organs (spleen, liver, marrow) and in lungs, in cases of using the corticosteroid of prolonged activity (tricort-40) leishmaniae were observed also in lungs, kidneys, testis.

[The host-opportunistic protozoa system. The dissemination of Pneumocystis infection in white rats under the influence of drug-induced and biological immunosuppression]. / Sistema "khoziain--uslovno-patogennye prosteishie". Disseminatsiia pnevmotsistnoi infektsii u belykh krys pod vliianiem medikamentoznoi i biologicheskoi immunosupressii.

The main purpose of the present study is the investigation of relationships of Pneumocystis carinii with the organism of white rat Wistar, which is natural carrier of this parasite. The series of experiments has shown that the immunosuppressor Tricort-40 (corticosteroid of prolonged activity) in a short time reactivates the Pneumocystis infection. The parasites have been observed in a great number in the lungs and rarely in the liver. The reactivation and dissemination of the Pneumocystis infection have been achieved constantly and with great expression by the combined immunosuppression of rats, by the medicamentous immunosuppression (injection of T-40) and biological one (infection with amastigotes Leishmania infantum). The developing mixed-infection (with pneumocysts and leishmania) could be the basis for the parasitocenological relationships.

[The development of a new experimental model of pneumocystosis]. / Razrabotka novoi éksperimental'noi modeli pnevmotsistoza.

The corticosteroid tricort-40 (triamcinolone acetonide) was found to induce the reactivation of endogenous pneumocystic injection caused by P. carinii in Wistar rats given 5-9 infections subcutaneously in median doses of 0.5-4.0 mg/kg at 6-22 days intervals each. Manifest P. carinii infection in the animals was characterized by early detection of its agent (starting from week 2 of immunosuppression), a progression of the infection and its transition to the generalized stage. The combined use of tricort-40 and infection of the animals with Leishmania infantum as an immunosuppressive cofactor ensured an increase in reproducibility of a manifest pneumocystosis model and its more rapid transition to the generalized stage. The experimental model of mixed infection of two AIDS-associated parasite infections--generalized pneumocystosis and visceral leishmaniasis--was first reproduced in inbred rats, which may be suitable for simultaneous screening of new antipneumocystic and antileishmanial drugs.

[The prevalence of cryptosporidiosis among the city population of Russia and Belarus]. / Rasprostranenie kriptosporidioza sredi naseleniia nekotorykh gorodov Rossii i Belarusi.

A total of 248 adults (170 with somatic diseases and 78 with the diarrheal syndrome) and 1206 children (323 attending kindergartens, 231 with somatic diseases, and 652 with the diarrheal syndrome), residents of seven towns of Russia and Belarus, were examined for cryptosporidiosis in 1989-1992. The mean infection rate of children and adults with the diarrheal syndrome was 4.8 and 2.7%, respectively, of those with somatic diseases 2.6 and 0% respectively, and of healthy children 1.9%. Children living in the towns of Belarus, localized in the radiation contamination zone, were more frequently infected than children living in other towns. The towns of the European Russia and Belarus should be regarded as stable foci of cryptosporidiosis infection.