Indirect Hemagglutination Reaction Research Articles

Immunological and epidemiological effectiveness of tularemia vaccination in the Donbass region

Objective: to evaluate the epidemiological and immunological efficacy of tularemia vaccination in the Donbass region from 1991 to the present.Materials and methods: data on the incidence of tularemia, immunization coverage of the population, results of intradermal tests with tularin, agglutination reaction and indirect hemagglutination reaction with tularemia antigen were analyzed.Results: since 2012, immunization against tularemia has not been carried out on the territory of the republic. Since 2015, this approach has resulted in the emergence of foci with multiple cases of human tularemia. Cases were registered on the territory of natural foci of Novoazovsky and Yasinovatsky districts. Since 2017, immunization of the population in enzootic territories has been resumed, planning and selection of contingents to be vaccinated was carried out in a differentiated manner. According to epidemic indications, 400 people were vaccinated from among those at risk of contracting tularemia. In 2020– 2022 vaccination was not carried out. In the five months of 2023, 520 people were vaccinated against tularemia, 80 people were revaccinated.Conclusions: the use of tularemia vaccine in the Donetsk region for 70 years led to the containment of tularemia, demonstrating the epidemiological and immunological effectiveness of specific immunoprophylaxis. The armed conflict and the cessation of vaccination led to an increase in the activity of the epidemic process in natural foci among animals and a significant increase in the incidence of tularemia in humans.

New brucellosis erythrocyte diagnosticum for IHT in comparison with other serological methods (SAT, CFT, RBT and IDT)

Relevance. Brucellosis is registered in many countries of the world, including Russia. The most unfavorable situation in the Russian Federation has developed in the Southern and North Caucasus Federal Districts. In the first place among the number of identified sick animals is the Dagestan Republic, where, despite the efforts of veterinary specialists, it is not possible to reduce the number of oci of brucellosis. With the help of classical methods (SAT, CFT), only 70% of animals infected with brucellosis can be detected. In this regard, domestic and foreign researchers have done a lot of work to improve existing and develop new diagnostic tools and methods.Methods. One of the most sensitive methods for the diagnosis of brucellosis is the indirect hemagglutination reaction (IHT). In comparative tests in IHT, with an improved antigen, good results were obtained.Results. The possibility of obtaining a highly active erythrocyte diagnosticum has been established with the combined use of two new surfactants: Progress products manufactured by AMC Media LLC (LosinoPetrovsk, Moscow region) and sodium dodecyl sulfate. The most rational parameters of the use of detergents for the treatment of brucella suspension and their optimal concentrations have been determined. It was found that IHT with a new antigen is specific and highly sensitive, compared with other serological reactions.

Dynamics of the immune response in laboratory animals to the introduction of a protective protein of the cause of respiratory syncytial infection in cattle

The authors in the article presented the results of assessing the immune response of guinea pigs using the protective protein of the bovine respiratory syncytial infection virus (RSI), obtained using recombinant E. coli BRSV-F1. The research was carried out in the branch laboratory of veterinary biotechnology and infectious animal diseases of the Vitebsk Order of the Badge of Honor of the State Academy of Veterinary Medicine. The average titer of specific antibodies of guinea pigs to the use of the protective protein of the bovine RSI virus was studied in 9 experimental groups and one control group. Blood sampling was carried out at the beginning of the experiment, before the second immunisation and 14 days after the second immunisation. The average titer of specific antibodies to the use of the protective protein of the bovine RSI virus was determined using an indirect hemagglutination reaction with an erythrocyte diagnosticum containing the bovine respiratory syncytial virus (RSV). With the introduction of samples of the prototype vaccine containing the gene encoding the production of the bovine RSI virus protein: group 1 - whole bacteria E. coli BRSV-F1 with an inducer of protein synthesis IPTG; 2nd, whole bacteria E. coli BRSV-F1 with protein synthesis inducer IPTG + 15% adjuvant IZA-15; 3rd, bacterial lysate E. coli BRSV-F1 with an inducer of protein synthesis IPTG; 4th – E. coli bacterial lysate BRSV-F1 with protein synthesis inducer IPTG + 15% adjuvant IZA-15; 5th - protective protein F1 + 15% adjuvant IZA-15; 6th - protective protein F1 + 2% cellulose, 7th - inactivated bovine RSV (JSC «Belvitunipharm») + 15% adjuvant IZA15; 8th - Hiprabovis 4 vaccines (HIPRA, Spain) and 9th - Bovi-shield Gold FP 5 L5 vaccines (Zoetis, USA) - in the experimental groups, an increase in antibody titer in paired blood sera was noted compared to the control group. From the data obtained, it was concluded that the studied samples of the vaccine prototype containing the gene encoding the production of the bovine RSV protein are not inferior in immunogenic activity to the vaccines Bovishield Gold FP 5 L5 and Hiprabovis 4. Therefore, the protective protein of the bovine RSI virus can be included in the composition of vaccines against this pathology to replace the cultural virus.

Generalized form of tularemia in pediatric surgeon practice: Difficulties of diagnosis and treatment

Tularemia in the practice of a pediatric surgeon is a rare disease, and abdominal and generalized forms of it are not detected without specific laboratory diagnostics. The long-term serious condition of patients, intoxication, abdominal pain with excluded acute surgical pathology in children force differential diagnosis with rare infectious diseases, including tularemia. In the Russian Federation, up to 30 children a year are diagnosed with tularemia, with the exception of outbreaks of the disease in some years. At the same time, the generalized form is detected in no more than 10% of patients. The authors presented a clinical case of a generalized form of tularemia in a 17-year-old patient. The disease started with abdominal pain, diarrhea and vomiting. At the beginning of the disease, a diagnostic error was made — suspicion of ovarian inversion and laparotomy according to Pfannenstiel. In the further development of the disease, pronounced ascites were detected with the production of up to 5 liters of effusion per day, damage to the kidneys, liver, heart, gastrointestinal tract. Laboratory data revealed leukocytosis up to 89×109, accelerated erythrocyte sedimentation rate, increased levels of creatinine, urea, transaminases, C-reactive protein, proteinuria persisted for a long time. Indirect hemagglutination reaction with tularemia diagnosticum made it possible to establish the diagnosis of tularemia, generalized form. During two weeks of the disease, an 8-fold increase in the titer of antibodies was noted. Syndrome therapy and specific antibacterial therapy made it possible to stop the infectious process and discharge the patient home on the 44th day of the illness with recovery.

The structure of intestinal infections in the infectious department

Background. Every year in Russia, the number of patients with acute intestinal infections of unknown etiology remains at a significant level.
 Aim. To determine the current etiological structure and features of the clinical course of acute intestinal infections in the infectious diseases department of a city hospital.
 Material and methods. For the period from 2017 to 2019, 181 patients with manifestations of acute intestinal infections, who were in the infectious departments of the City Hospital No. 5, Barnaul, were examined. The age of the patients ranged from 18 to 76 years (mean age 35.414.8 years), including 55.6% females and 44.4% males. The study of biological material from patients (feces) was performed using polymerase chain reaction with hybridization-fluorescence detection, bacteriological examination and serological method (indirect hemagglutination reaction) for the presence of antibodies to pathogens of acute intestinal infections (in blood serum). The statistical significance of differences was assessed by the 2 test.
 Results. Out of 181 patients with acute intestinal infections, 108 (59.7%) had the etiology of the disease, of which 54 (50%) patients had an infection of viral etiology, including in the form of monoinfection in 45 cases, and caused by a combination of two viruses in 9 cases. In 41 (38%) patients, acute intestinal infections of bacterial etiology were diagnosed, including a combination of two pathogens in 4 cases, and three pathogens in 1 case. 13 patients had viral-bacterial intestinal infections. As a result of the survey, on the existing list of laboratory tests, the etiology of intestinal infection was not established in 73 (40.3%) patients. In patients with acute intestinal infection of bacterial etiology, the disease proceeded more severely, with higher body temperature and colitis, in patients with intestinal infection of viral etiology with gastroenteritis.
 Conclusion. A high proportion of intestinal infections of viral etiology (up to 50%) with etiological dominance of noroviruses has been established. Among the causative agents of bacterial acute intestinal infections, Campylobacter and Salmonella prevailed.

Polimeric Immunoglobulin Diagnosticum for Detection of Cholera Toxin and Assessing the Level of Its Production by Vibrios

A marker of the epidemic significance of Vibrio cholerae is their toxigenicity. Therefore, much attention is currently paid to the creation of diagnostic preparations for the detection of cholera toxin and assessment of the level of its production. The volumetric immunosuspension agglomeration reaction, carried out with the help of latex diagnosticums, is an analogue of the indirect hemagglutination reaction, an affordable and technically simple method, since it does not require special equipment and can be used when conducting research in the field. The aim of the study was to design a polymeric immunoglobulin diagnosticum for determining cholera toxin and the level of its production by vibrio strains. Materials and methods. Cholera toxin was obtained from the producer strain Vibrio cholerae Classical 569 B. Rabbit serum to the toxin was obtained according to the method selected by the authors. A polymeric diagnostic immunoglobulin antitoxic drug was obtained through sensitizing immunoglobulins from cholera antitoxic rabbit serum on the surface of polyacrolein microspheres with a size of (1±0.1) μm. Results and discussion. The analytical sensitivity of the developed diagnostic preparation with control cholera toxin is 100 ng/ml. It detects cholera toxin in toxigenic strains of Vibrio cholerae in a titer of 1:16 – 1:512, gives negative results with non-toxigenic strains of V. cholerae O1, V. Cholerae nonO1/nonO139, with samples of heterologous cultures, LPS preparations, liquid nutrient medium used for the cultivation of V. cholerae. Thus, a polymeric immunoglobulin diagnosticum has been constructed to detect and quantify the production of cholera toxin by vibrio strains, and its analytical sensitivity and specificity have been established.

Использование перевиваемых культур клеток ПТ-80 и КСТ для постановки реакции нейтрализации на обнаружение антител к вирусу вирусной диареи крупного рогатого скота

The flavivirus family (from Lat. flavus – yellow) represents a significant group of viruses circulating among vertebrates and insects, consists of three genera, one of which is the genus Pestivirus (classical swine fever virus, viral diarrhea (BVD) of cattle, borderline sheep disease, etc.). Viral diarrhea of cattle is a widespread infection in the world, and It is one of the most difficult economic problems in animal husbandry. The clinical picture of BVD is diverse: respiratory organ damage, fever, leukopenia, thrombocytopenia, enteritis, immunosuppression, the virus passes through the placenta, which leads to the birth of persistently infected calves, abortions in cows at all stages of pregnancy are noted, fetal mummification, producing bulls can be virus carriers and secrete the virus with sperm. For serodiagnostics of viral diarrhea of cattle in laboratory practice, ELISA (enzyme immunoassay), RNGA (indirect hemagglutination reaction), PH (neutralization reaction) are used - the gold standard of diagnostics. The PH method is universal and makes it possible to detect the level of virus neutralizing antibodies for making a retrospective diagnosis, evaluating animals for virus transmission and confirming well-being. The PH method is unique and is the only correct one in assessing the effectiveness of vaccines, since only when it is used, the level of virus neutralizing (protective) antibodies protecting animals from direct infection is revealed. The aim of our research was to formulate a neutralization reaction to the detection of antibodies to the bovine viral diarrhea virus using transplanted cultures of PT-80 and KST cells.

Indirect hemagglutination reaction in the differential diagnosis of bovine tuberculosis

The main problem of improving the health of farms from tuberculosis is diagnosis, in particular, differential diagnosis. Despite the comprehensive study and a fairly impressive number of proposed diagnostic methods, including on the molecular genetic level, the problem of differentiation of non-specific reactions remains topical today. About effectiveness of serological methods of research, in particular, indirect hemagglutination reactions, in the literature there are scattered and polar data. In the methods of setting up reactions, in the variety of antigens, methods of adsorption of agglutinins, stabilization of red blood cells, etc., the researchers ' opinions differ. Four methods of stabilization of sheep erythrocytes sensitized with polysaccharide antigen (Feeli, Weinbach, Ling, RES) have been comparatively studied. The maximum antibody titer was established for the stabilization of red blood cells by Feeli. A total of 1911 blood samples from four farms with different relationships to tuberculosis were studied in the reaction of indirect hemagglutination with diagnostics from Mycobacterium bovis and Mycobacterium fortuitum. Relatively high positive indicators of the reaction of indirect hemagglutination were revealed in animals in farms with tuberculosis problems, in which the diagnosis was confirmed by pathoanatomic method in 87.5% of cases. The results of the tuberculin test coincided with the results of indirect hemagglutination reactions in 37.07% of cases. Diagnostic antibody titers were detected in 201 anergic animals of the treated herd and in 5 from the isolation unit. During the slaughter of 20 heads from a dysfunctional farm and 5 from the overexposure group, tuberculosis was established in 15 and 5, respectively. The practical significance of the reaction of indirect hemagglutination with different diagnostics in the detection of homologously infected animals is shown.

Метапневмовірусна інфекція птиці: розробка вітчизняного методу діагностики та епізоотологічний моніторинг у птахівничих господарствах України

The main biological (cultural) properties of field isolates of metapneumovirus (MPV) were studied, normal and hyperimmune sera to metapneumovirus for IHR-diagnosticum (erythrocyte diagnosticum based on indirect hemagglutination reaction) were obtained, and a set of M-component components was developed. A diagnostic system of IHR (indirect hemagglutination reaction) was developed, with the help of which epizootological monitoring was carried out in poultry farms and the spread of a new infectious disease of poultry (metapneumovirus infection) among turkeys and chickens in poultry farms of Ukraine was studied. The purpose of the research is to develop a domestic diagnostic test system (erythrocyte diagnosticum for IHR) for metapneumovirus infection (MPVI) or infectious avian rhinotracheitis (IRT). As a result of the conducted researches metapneumovirus infection or infectious rhinotracheitis was established in poultry farms of 4 regions of Ukraine. The pathogen was isolated, its molecular-biological properties were studied by PCR (polymerase chain reaction), and it was established that it belongs to the genus Metapneumovirus (MPV), subtype B. The results of the epidemiological monitoring indicate that the developed erythrocyte MPV (IRT) antigen based on IHR is sensitive and specific and can be used to control the spread of metapneumovirus infection and the intensity of immunity in birds vaccinated against this disease. The production inspection in poultry farms in the western regions of Ukraine established the possibility of using IHR-diagnosticum for control of MPVI. As a result of the performed work the new domestic method of diagnostics, forecasting and protection of poultry against a metapneumovirus infection is offered. Prospects for further research are to use this erythrocyte diagnosticum based on the indirect hemagglutination reaction to monitor metapneumovirus infection of birds in poultry farms in Ukraine and determine the epizootic situation for this disease.

Selection the optimal dose of application associated vaccine against rota-, coronavirus infection and colibacillosis in calves

The main rules for choosing the means of specific prophylactic against colibacillosis (escherichiosis) in cattle is the need to match the antigenic spectrum of the vaccine strains with epizootic strains isolated by diagnostic veteri-nary institutions from pathological material taken from dead calves. Only in this case one should expect high results of the preventive efficacy of the applied vac-cines. The design of vaccines based on pathogenicity factors of bacterias is the most promising direction in the development of new bioproducts of specific pre-vention of infectious diseases of farm animals. Researchs in the areas to choice the optimal doses and ratios of monocompo-nents, determining the optimal immunizing dose, and choosing a adjuvant is an im-portant part of research work on the creation of vaccines. We completed work to establish the optimal dose when using the associated vaccine against rota-, coronavirus infection and colibacillosis of cattle by vaccinat-ing cows in different doses of the test vaccine. Subsequently, serological studies of the blood of animals were carried out, according to the results of which the indica-tors of the best immune response were determined by comparing the established levels of biosynthesis of specific antibodies from animals of the experimental and control groups. A number of indicators of possible reactogenicity of the tested vac-cine were also studied. When conducting studies of blood serum of cows, the indi-rect hemagglutination reaction and agglutination reaction were performed. Serolog-ical blood tests carried out were accompanied by the necessary controls to ensure the reliability of the results. According to the results of studies of blood serum of cows in the experimental groups, immunization of cows with an associated vaccine against rota-, coronavirus infection and colibacillosis of cattle in different volumes led to a significant level of antiviral and antibacterial antibodies. The optimum dose for virus antigens with infectious titres from 7,0 lg and 5,5-TCI50/sm3 for vaccinated cows forms 1,5 sm3 for each viral monocomponents. The optimum dose for each vaccine strains E.coli F4, F5, Аtt25, F41 and 987P forms from 1,5-2,5 milliard bacterial cells for each bacterial monocomponents.

A retrospective analysis of Shigellosis in hospitalized patients

The relevance of the study of Shigellosis is due to the fact that the pathogen is capable of invasion and the production of cyto- and neurotoxins, which leads to the development of severe inflammation and toxicosis, and with massive infection — and neurotoxicosis. Purpose: to study the clinical and laboratory features of the course of Shigellosis in hospitalized patients at the present stage. Materials and Methods: a retrospective study of 17 case histories of children aged 9 month to 17 years old, hospitalized in the infectious diseases department of a Moscow hospital in 2019 with a confirmed diagnosis of Shigellosis, was carried out. Results: depending on the season, the frequency of hospitalizations of children with Shigellosis was practically the same in autumn, winter and spring, excluding summer (35%, 35%, 30% and 0%, respectively). Children with Shigellosis under the age of 1 year were 2, 1—3 years old — 4, 3—7 years old — 5, 7—14 years old — 3, over 14 years old — 3. The diagnosis of Shigellosis was confirmed in 13 patients according to the results of bacteriological research , in 4 — according to IHR (indirect hemagglutination reaction) data (without seeding). Shigella flexneri 2a was detected in 14 children, Shigella sonnei in 2, Shigella flexneri 2a together with Shigella sonnei in 1. Most of the patients 82.4% (14/17) were admitted to the hospital in the first three days of illness (by 2.8 ± 0.05 days). Intoxication symptoms were expressed in all patients, vomiting — in 76.5% of cases (13/17), fever — in 94% (16/17), abdominal pain — in 82.4% (14/17), inflammatory impurities in feces (cloudy mucus) — in all patients, hemocolitis (streaks of blood in feces) — in all but one — 94% (16/17). In one third of patients, Shigellosis was severe — in 35% (6/17). Conclusions. Shigellosis remains relevant due to the incidence of hemocolitis, severe forms, which requires hospitalization.

Indirect hemagglutination reaction in ram infectious epididymitis for indication of Brucella ovis antigen in biomaterial

The reaction of indirect hemagglutination with an antibody erythrocyte diagnosticum is one of the promising methods for identifying the causative agent of infectious diseases or antigen. This preparation has not yet been developed for the diagnosis of infectious epididymitis of rams. The results of the preparation of an antibody erythrocyte diagnosticum in the reaction of indirect hemagglutination for the detection of the causative agent of infectious epididymitis in various biological material are presented in the article. As a result of scientific research, authors developed the method for obtaining an original Brucella ovis antibody diagnosticum for the reaction of indirect hemagglutination by sensitizing sheep erythrocytes with hyperimmune Brucella ovis serum using alizarin blue indicator of the epididymitic pathogen or antigen in biomaterial as the conjugate. Studies have shown the specificity and higher sensitivity of the indirect hemagglutination reaction with the antibody erythrocyte diagnosticum, compared with the antibody neutralization reaction and the bacteriological method, and its suitability for the indication of Brucella ovis antigen in biomaterial and environmental objects. It was also found that the reaction of indirect hemagglutination with antibody diagnosticum is much faster than the reaction of neutralization of antibodies and the bacteriological method. Research to improve the diagnosis of infectious ram epididymitis caused by Brucella ovis has been completed with the development of the antibody erythrocyte diagnosticum for the indirect hemagglutination reaction.The high specificity and activity of this preparationwas established by the authors. As a result of the studies carried out to test the diagnostic value of the antibody diagnosticum, a higher sensitivity of the indirect hemagglutination reaction using the new antibody diagnosticum, compared with the neutralization reaction of antibodies and the bacteriological method, and the suitability of using the diagnosticum for the indication of the Brucella ovis antigen in biomaterial, was established, which meets the requirements for express methods for detecting antigens in pathological material.

Значение комплексной лабораторной диагностики ОРВИ крупного рогатого скота для ветеринарной практики

Abstract. This article summarizes the results of laboratory studies of acute respiratory viral infections of cattle in agricultural enterprises of the Ural Federal district and the Udmurt Republic. The purpose of the research was to show the spread of respiratory viral infections in cattle in various regions and the significance of laboratory diagnostics in this pathology. According to research data 815 samples for the period 2018–2020 a variety of combinations of mixed respiratory viruses in animals was detected using biomaterials from different age patients and patients with respiratory diseases of cattle from agricultural enterprises of the Ural Federal district, the Volga Federal District and the Udmurt Republic using polymerase chain reaction, indirect hemagglutination reaction, hemagglutination inhibition reaction, Elisa , and enzyme immunoassay. Scientific novelty. The etiological structure of mixed acute respiratory viral infections in cattle in agricultural enterprises in four regions of the Ural Federal District, the Volga Federal District and the Udmurt Republic in 2018–2020 was studied using modern diagnostic technologies. Results. In the Ural Federal District, the Volga Federal district and the Udmurt Republic, 80 % of cases of acute respiratory diseases were caused by bovine viral infections, mainly representatives of 2 families of viruses whose genome is represented by an RNA molecule (paramixoviruses, togaviruses) and a family of viruses whose genome is represented by a DNA molecule (herpesviruses,). The leading place among acute respiratory infections was occupied by infectious rhinotracheitis of cattle.

Serological methods for detection of the causative agent of tularemia and their evaluation

Aim. A comparative study of serological methods for the detection of the causative agent of tularemia and their evaluation. Materials and methods. We used experimental diagnostic kits and test systems for the production of serological methods: indirect hemagglutination reaction (RGA); the reaction immunofluorescence (RIF); enzyme immunoassay (ELISA) using traditional microplate; IFA after selective concentration of the pathogen of tularemia in magnoimmunosorbents (MIS); microgravimetric analysis (MGA) based on piezoresistors (SP) and surface plasmon resonance (SPR). The experiments were carried out with homologous strains of tularemia microbe (test strains) and with strains of heterologous microorganisms in model experiments on tap water contaminated with different concentrations of the pathogen. Results. The parameters of each diagnostic method are determined and evaluated according to the following indicators: sensitivity (when working with pure cultures (test strains), contaminated samples of large volumes), specificity, time of setting and taking into account the results, informativeness, determining the modes of setting and accounting. Conclusion. The above diagnostic methods have their advantages and disadvantages. Therefore, when choosing a method, the researcher should be guided by the goals pursued. So, for screening studies it is advisable to carry out the formulation of ELISA, RIF, RGA, in identifying the pathogen in large volumes and contaminated samples, the effective use of selective concentration on MIS followed by the formulation of ELISA, to identify small amounts of samples and take into account the reaction in real time, it is possible to use MGA and SPR.

Human response to live plague vaccine EV, Almaty region, Kazakhstan, 2014-2015.

BackgroundIn Kazakhstan, a live plague vaccine EV 76 NIIEG has been used for plague prophylaxis since the mid-1930s. Vaccination is administered yearly among people living in plague-enzootic areas. Similar practices are used in other former Soviet Union countries. Yet, to this day, the effectiveness period of the vaccine is unknown. It is also not clear how different factors can affect the effectiveness of the vaccine over time.MethodsWe surveyed changes in antibody levels specific for F1 antigens of Yersinia pestis among vaccinated people 4, 8, and 12 months post- vaccination. Blood samples were taken from the participants of the study for producing sera, which was later analyzed using indirect hemagglutination reaction with antigenic erythrocyte assay (micromethod) for identifying antibodies to F1 Y.pestis.ResultsIn first-time-receivers of the plague vaccine, antibody titer reached the highest level of antibody that represents a conditionally protective titer after 4 months, dropped drastically after 8 months, and dropped again after 12 months. Similar results were obtained among those who have been vaccinated previously. However, in that group, the percentage of people with a level of antibody that represents a conditionally protective titer remained statistically significant even after 8 and 12 months.ConclusionBased on the results of this study, we recommend initiating vaccination campaigns for the medical and veterinary staff, as well as the general population four months prior to the springtime epizootics of plague among wild rodents.

THE STUDY OF SPECIFICITY OF THE DIAGNOSTIC PRODUCTS PREPARED FROM EXCRETORY-SECRETORY AND SOMATIC ANTIGENTS OF FASCIOLA HEPATICA AND PARAMPHISTOMUM ICHIKAWAI IN ELISA AND RIHA

We studied the specificity of excretory-secretory and somatic antigens of Fasciola hepatica and Paramphistomum ichikawai using enzyme-linked immunosorbent analysis and indirect hemagglutination reaction. Antigens of Echinococcus granulosus (ESAgE), Toxocara canis (ESAgT) and Strongyloides papillosus (ESAgS) were selected for the study of the specificity of fasciola and parafistomum immune reagents on account of the presence of their common antigenic epitopes. Material for the preparation of diagnostic kits (antigenes primarily processed, purified by centrifugation) Fasciola hepatica and Paramphistomum ichikawai were kept frozen in plastic containers «Ependorf» (5, 10 ml) at -6-8°C. At the same time reducing of antigen activity was not observed for 15-18 months. Erythrocyte diagnosticuma stored at +4°C showed equal sensitivity in the RIHA for 10 months since the moment they had been prepared. In 14-16 months their sensitivity (compared with the native and positive for fascioliasis and paramfistomatozy blood sera) was reduced by 25-50%. The results of experimental investigation (performed ELISA and RIHA with the above said controls in homologous and heterologous systems) show that immune sera to Fasciola hepatica (working titer 1:10240) and Paramphistomum ichikawai (1:5120) with the corresponding diagnosticuma (ESAgF and ESAgP) are positive in the maximum titers, when using somatic trematode antigens (SomAgF and SomAgP) in the homologous system we obtained the data confirming insufficient (scanty) specificity of these antigenic immunoreagents (1:1280 and 1:640 for ELISA, 1:640 and 1:320 in RIHA respectively).

The outer membrane porin from Yersinia enterocolitica in yersiniosis diagnostics

The diagnostic test system based on a species-specific antigen, pore-forming protein from the outer membrane of Yersinia enterocolitica, for yersiniosis verification by the method of ELISA has been developed and approved. The proposed ELISA test system is characterized by high sensitivity (95%) and specificity (89%) and provides a differential diagnostics of yersiniosis from other acute enteric infections with similar clinical manifestations. In comparison with the commercial diagnostics based on indirect hemagglutination reaction, which is conventionally used in clinical practice, the porin-based ELISA provides the high level (90–95%) of yersiniosis identification at early (1st week) and late (2nd–4th week) stages of infection process. It has been found that the ELISA test system reveals antibodies to the Y. enterocolitica porin in patient’s serum irrespective of the serological variant of causative agent.

Avaliação do impacto das ações de controle vetorial da doença de Chagas através do inquérito sorológico em Mambaí/Buritinópolis, Goiás

In 1999, we performed serological and entomological surveys to evaluate the impact of vectorial control measures against transmission of Chagas' disease in the endemic area of Mambaí and Buritinópolis (GO). A census was undertaken of the population, after which the entomological survey was performed regarding the dwelling units and serological evaluation of the human population. Blood samples were collected by digital puncture in filter paper. The first serologic test performed to detect antibodies against Trypanosoma cruzi was the indirect immunofluorescence test (IFI) with (1/2)0 positive dilution as cut-off point and, positive samples were further evaluated with indirect hemagglutination reaction (HAI). The prevalence of positive IFI reactions was 12.3% (95%CL: 11.5-13.2). Triatoma infestans was not found within the dwellings. The absence of infection among individuals younger than 14 years and, the absence of T. infestans during the last entomological survey demonstrates the success of the control program of Chagas' disease in the studied area where the vectorial transmission can be considered to have been interrupted.

Hidatidosis humana en Chile. Seroprevalencia y estimación del número de personas infectadas

Chile is located in the southwestern border of South America. The country is 4,329 km long and 96-342 wide. From north to south it is divided into five marked different biogeographical zones: deserts, steppes, bushes, forests (cattle raising) and austral (sheep raising). Population (June 1999) 15,017,760 (14.6% rural). Human hydatidosis is endemic in Chile. According to Ministry of Health information about 320 cases are registered each year. In order to find out the likely prevalence of human hydatidosis in Chile, a series of serosurveys was carried out in 1988-1997 throughout the total country. By using the indirect hemagglutination reaction and ELISA for hydatidosis (tests with good sensibility and specificity) 60,790 unselected apparently healthy persons: 41,399 from urban areas (16,428 blood donors, 13,894 delivering mothers and 11,077 middle grade schoolchildren) and 19,361 from rural areas--from randomly selected family groupings--were studied. A total individuals 82 (136/100,000) resulted positive: 36 (87/100,000) urban and 46 (241/100,000) rural, being the prevalence higher in rural areas, particularly in the southern austral zone (mean 1068/100,00). These figures agree with those observed in clinical epidemiological studies. In conformity with the present results, in the whole country 17,002 individuals should have hydatidosis: 10,318 urban and 6,784 rural. All these possible infected people, not necessarily should present pathology in the future, as it has been observed in autopsies from unselected individuals, performed at the Medico-Legal Service in Santiago, in whom 71.3% of diagnosed hydatosis with hydatid cysts in many different locations, was an autopsy finding.

IMMUNODIAGNOSIS OF HUMAN LISTERIOSIS IN PREGNANCY

The recent increase in the incidence of the facultative bacterium Listeria monocytogenes severe infections of human and animals, makes it of significant public health importance. A total of 26 isolates of L. monocytogenes (23 from 23 patient group and 3 from 20 controls) were obtained from pregnant or non- pregnant women with spontaneous abortion and were submitted to serotyping. Only 2 L. monocytogenes serovars (1/2 a and 4b) are isolated in 90% of cases of human listeriosis. Of pregnant women sera , 56% were L. monocytogenes O and H agglutinating antibodies - positive while 100% and 78% of the cerebrospinal fluid (CSF) were L. monocytogenes O and H agglutinating antibodies positive, respectively. In the post-abortive subgroup, 100% and 90% were sero - and CSF-O and H agglutinins - positive , respectively. The detection of anti-listeriolysin O ( Anti-LLO) antibodies were done by Indirect Haemagglutination Reaction (IHR) with purified LLO in sera and CSF supernatant of 23 married women with frequent abortion due to L. monocytogenes infection and 20 controls to diagnose human listeriosis. The 23 patients (100%) with listeriosis and 3 (15%) of controls (non healthy subgroup), produced specific Anti-LLO titres ranged from 800.