Complex method for epizootiological and epidemiological surveillance

A complex method for the epizootological and epidemiological surveillance of a number of bacterial and viral infections on the territories inside and outside their natural foci has been developed. The investigation techniques are described and the data on the isolation rate of each causative agent in different geographical zones are presented. In the natural foci of plague and tularemia, as well as on the territories outside such foci, the causative agents of intestinal yersiniosis, pseudotuberculosis, salmonellosis, erysipeloid, staphylococci and streptococci, arena- and arboviruses have been isolated from the rodents and ectoparasites under study. The results of this investigation suggest that the method may be recommended for use in medical institutions dealing with the problems of infections originating from natural foci.     

Yersinia lipopolysaccharide and its biological activity

The data on the structure and biological activity of the lipopolysaccharide (LPS) of Yersinia as an important virulence factor are analyzed. The biological effects of LPS are characterized by dose dependence: small doses stimulate the intensity of phagocytosis, while large doses decrease phagocytic activity and produce cytotoxic effect. Yersinia LPS plays an important role in the development of such consequences of yersiniosis as reactive arthritis, erythema nodosum, Reiter's syndrome. Yersinia LPS is a widespread component for the diagnostics of yersiniosis and pseudotuberculosis.     

Shotgun genome sequence of a Yersinia enterocolitica isolate from the Philippines

The first shotgun genome sequence of a microbial pathogen from the Philippines is reported. Yersinia enterocolitica subsp. palearctica strain PhRBD_Ye1 is the first Y. enterocolitica strain sequenced from an animal source, swine, which is a natural source of yersiniosis. The closest phylogenetic match is a human clinical isolate from Germany.     

Yersiniosis in Czechoslovakia. Results of a long-term study involving microbiological laboratories of the hygienic service

The paper reports on 17 years' experience of yersiniosis surveillance. Despite the fact that the microbiological identification of Y. enterocolitica 03 was successfully carried out by virtually all the microbiological laboratories of the Hygienic Service, reported cases of yersiniosis account for only one sixtieth part of alimentary infections. Enteric disease is the prevailing form of yersiniosis, extraintestinal ones being very rare. Most of the implicated patients were children, namely boys. An analysis of symptoms was performed based on the results of two epidemiological studies focussed around 215 and 37 cases of yersiniosis, indicating the involvement of the upper respiratory tract at the very beginning of the disease. The role of not sufficiently cooked pork as a vehicle of infection was proved only once (presswurst), however interhuman transmission of yersiniosis was confirmed in 4 cases with an incubation period of approximately 7 days. There appear to be many obscure areas in the epidemiology of yersiniosis, which may be illuminated using cultivation procedures to detect even small amounts of yersinia.     

Ecological regularities of the existence of pathogenic Yersinia in soil ecosystems

In this review the data on the ecology of pathogenic Yersinia in soil ecosystems, based on prolonged observations, were analyzed and summarized. In contrast to saprophytic species, ubiquitously spread in nature, pathogenic representatives of the genus Yersinia occurred only in the soil of natural foci and of these, Y. pestis were found only in the soil of burrows of the main carriers. The complex of abiotic and biotic factors (temperature, humidity, chemical composition, interactions in biocenosis) which determined the possibility of the existence of Yersinia in the soil environment and the preservation of their pathogenic properties was considered. Special attention was paid to their geno-phenotypic variability as the main factor of the adaptation of the causative agents of plague, pseudotuberculosis and intestinal yersiniosis in the environment.     

Use of an in vitro allergy test for the differential diagnosis of human brucellosis and yersiniosis

The degree of the allergic reorganization in the body of brucellosis and yersiniosis patients was determined by the study of their blood and serum samples in the in vitro allergy test (the direct and indirect leukocytolysis test). The allergy test is highly specific and recommended as a differential diagnostic method in brucellosis and yersiniosis infections.     

Development of immunoreagents for the diagnostics of intestinal yersiniosis by antigen-binding lymphocytes

To diagnose intestinal yersiniosis, the detection of antigen-binding lymphocytes (ABL) with respect to Y. enterocolitica O3, O5 and O9 is proposed. Experiments on the immunization of rabbits with Y. enterocolitica LPS of these serovars revealed that immunoreagents, according to the data of cross antigen-dependent rosette formation and its inhibition, had species specificity (ABL of rabbits immunized with Y. enterocolitica did not interact with Salmonella, Shigella and Y. pseudotuberculosis antigens) and serovar specificity. Cross reactions in the detection of ABL by means of specific Y. enterocolitica O9 and Brucella melitensis immunoreagents in rabbits immunized with Y. enterocolitica were absent during the first days and could be detected only of day 25 after the injection of the immunogen. The method for the detection of ABL with the use of newly developed reagents could be used in clinics for the diagnostics of intestinal yersiniosis.     

Possibility of the serological differential diagnosis of human brucellosis and yersiniasis

The results of the examination of patients with brucellosis and yersiniosis (serotype 0-9) are presented. The possibility of making, in principle, the differential serological diagnosis of brucellosis and yersiniosis in the agglutination test with the use of Yersinia OH-antigen has been established.     

The intensity of cell receptor catabolism in intestinal yersiniosis and pseudotuberculosis

The intensity of the catabolism of cell receptors in yersiniosis was evaluated by the level of R-proteins in the blood sera of 95 patients. The study revealed that the degree of an increase in the level of R-protein depended on the severity and the course of the pathological process was the same in both nosological forms of the disease. The high and stable level of R-proteins was indicative of the possibility of the prolonged and relapsing course of yersiniosis.     

Utilization of released proteins (RPs) of Yersinia enterocolitica for serologic diagnosis of yersiniosis. III. Western-blot

The usefulness of the immunoblotting using released proteins (Yersinia outer proteins-Yop) as the antigen for the serological diagnosis of yersiniosis was estimated. The IgA, IgG, and IgM antibody responses of patients with yersiniosis and healthy blood donors were studied by western-blot prepared in our laboratory, and two commercial assays. The results indicate that antibodies of all three classes are most consistently directed against the proteins of YopD, YopM and YopE. Good correlations between the three western-blots were obtained for all proteins except the protein V-AG. Patients with yersinia-triggered reactive arthritis have IgA class antibodies against the YopD more often and for longer period than the non-arthritic patients with yersiniosis.     

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.     

Enteropathogenic Yersinia and host cytokine system

Data about interaction of virulence factors of Yersinia enterocolitica and Yersinia pseudotuberculosis with host immune system cells are presented in the review. Response of innate and adaptive immunity cytokine system in cultures in vitro and during experiment was characterized; scarce data on production of cytokines in patients with yersiniosis are presented.     

Effects of dietary probiotic supplementations on prevention/treatment of yersiniosis disease

Aims:  To evaluate Enterobacter cloacae and Bacillus mojavensis , isolated from rainbow trout gut in the present study, as a probiotic to control yersiniosis disease.
Methods and Results:  A strain of Ent. cloacae and B. mojavensis , isolated from the digestive tract of rainbow trout had an antagonistic effect to Yersinia ruckeri , which causes yersiniosis. After feeding fish with 1 × 10⁸ cells g⁻¹ probiotic containing feed for 60 days, the fish survival rate increased to 99·2% following challenge with Y. ruckeri compared with controls that had 35% survival rate. Effects of Ent. cloacae and B. mojavensis on weight gains and stimulation of red blood cells, white blood cells, platelets and hemoglobin were also evaluated in separate groups of fish fed probiotic containing feed for 2 months. Probiotic significantly affected white blood cells, hemoglobin and weight gains of the experimental fish.
Conclusions:  Enterobacter cloacae and B. mojavensis , can be used to prevent and control yersiniosis disease.
Significance and Impact of the Study:  In conclusion, concomitant use of Ent. cloacae and B. mojavensis as a feed supplement is beneficial to rainbow trout. Use of these organisms can protect fish from yersiniosis and enhance digestibility and utilization of feed. Use of such probiotics may also limit the use of antibiotics and other chemicals in control and treatment of diseases, and thus contribute to the effort to reduce environmental contamination by residual antibiotics and chemicals .     

Clinicoimmunological monitoring of therapy in patients with associated forms of yersiniosis

Characteristics of the clinical process and immunological profile in children with yersiniosis as a monoinfection or in association with acute intenstinal infections and virus hepatitis A are presented. The efficacy of the immunotropic therapy with cycloferon, an interferon inductor, and recombinant interferon in the patients with the viral and bacterial association of the disease (yersiniosis + hepatitis A) and initial disbalance of the serum cytokines was estimated. Dependence of the interferon clinicolaboratory efficacy on the initial levels of serum y-interferon, IL2 and IIA, promoting shorter terms of hyperthermia, diarrhea syndrome and cytolysis syndrome was shown. It allowed to optimize the scheme of the pathogenetic therapy of Yersinia mixed infection.     

Long-term yersiniosis surveillance project in Czechoslovakia

The paper presents an epidemiological analysis of 8,232 cases of yersiniosis caused by Y. enterocolitica 03 over 1972-1988 as reported by Hygienic Stations. The steady epidemiological characteristics of yersiniosis were the prevalence of children and boys and a typical seasonal pattern with differences between the Czech and Slovak Republics. In the Czech Republic, there were several incidence peaks following, when summarized, the incidence curve of other alimentary infections, whereas in the Slovak Republic morbidity reached its peak during winter months. The numbers of isolated strains oscillated significantly between districts and by years. It appears that the number of positive findings in different districts is not only an objective value reflecting a mosaic-like pattern of incidence but also depends on the quality of microbiological diagnostics.     

Humoral response to selected antigens of Yersinia enterocolitica and Yersinia pseudotuberculosis in the course of yersiniosis in humans. I. Occurrence of antibodies to enterobacterial common antigen (ECA)

The antibodies against the Enterobacterial Common Antigen (ECA) were detected using the ELISA in 293 serum samples collected from 185 persons suspected for yersiniosis, as well as 115 serum samples from healthy individuals (blood donors). The presence of IgA antibody in diagnostically significant titres for ECA were detected by ELISA in 3.5%, IgG in 13.0%, and IgM in 5.2% of blood donors. Statistical analysis showed that the frequency of detecting antibodies for ECA among the patients with yersiniosis was significantly higher (p < 0.05) in relation to the blood donors. Most frequently the elevated antibody levels were detected among patients with reactive arthritis (IgA 29.2%, IgG 35.4%, IgM 16.7%) while the most infrequent among patients with abdominal pain in acute phase of yersiniosis (IgA 14.9%, IgG 25.3%, IgM 19.5%). The level of antibodies for ECA, together with age increased reaching its peak, on the average, among individuals aged 41 - 60 years. In majority of the individuals studied antibodies of the IgG class reached the level much higher in relation to those of the IgA and IgM classes. The obtained results showed that the detection of antibodies to ECA may be useful in serodiagnosis of Yersinia infections.     

Yersiniosis in free-ranging muskoxen on Banks Island, Northwest Territories, Canada.

Sixty-seven muskox (Ovibos moschatus) carcasses, 53 skeletal remains and two sick muskoxen were seen during an aerial survey of the Thomsen River region, northern Banks Island, Northwest Territories, Canada in late July 1986. Complete necropsies were performed on 29 muskoxen estimated to have died within the previous 3 to 5 days. Twenty were diagnosed with acute yersiniosis due to Yersinia pseudotuberculosis serotype 1B and were in excellent body condition. A diagnosis could not be made on seven animals due to marked autolysis; however, these muskoxen also were in excellent body condition. The remaining two were aged, emaciated muskoxen. This report describes the first occurrence of yersiniosis in free-ranging muskoxen and the first documentation of large scale mortality due to this disease in a free-ranging population of wild ungulates.     

Molecular epidemiology of Yersinia enterocolitica infections

Yersinia enterocolitica is an important food-borne pathogen that can cause yersiniosis in humans and animals. The epidemiology of Y. enterocolitica infections is complex and remains poorly understood. Most cases of yersiniosis occur sporadically without an apparent source. The main sources of human infection are assumed to be pork and pork products, as pigs are a major reservoir of pathogenic Y. enterocolitica. However, no clear evidence shows that such a transmission route exists. Using PCR, the detection rate of pathogenic Y. enterocolitica in raw pork products is high, which reinforces the assumption that these products are a transmission link between pigs and humans. Several different DNA-based methods have been used to characterize Y. enterocolitica strains. However, the high genetic similarity between strains and the predominating genotypes within the bio- and serotype have limited the benefit of these methods in epidemiological studies. Similar DNA patterns have been obtained among human and pig strains of pathogenic Y. enterocolitica, corroborating the view that pigs are an important source of human yersiniosis. Indistinguishable genotypes have also been found between human strains and dog, cat, sheep and wild rodent strains, indicating that these animals are other possible infection sources for humans.     

Application of released proteins (RPs) of Yersinia enterocolitica for serological diagnosis of yersiniosis. II. Gene recombination for production of the YopD protein

The aim of this study was to evaluate the usefulness of gene recombination technique using the pET-30 Ek/LIC expression vector for production a 36 kDa released protein called YopD and evaluate of this purified protein as antigen in serodiagnosis of yersiniosis. Protein YopD of Y. enterocolitica was expressing in Escherichia coli BL21 (DE3) using the pET-30 Ek/LIC expression vector. Purification of the expressed enzyme from suspensions of E. coli cells treated with Bug Buster Protein/Extraction Reagent was accomplished by immobilised metal (Ni2+) affinity column chromatography (His-trap). The IgM, IgG and IgA class antibodies to YopD were measured in 100 serum samples collected from patients suspected for yersiniosis and 100 blood donors. The obtained results were compared to the results of ELISA with released proteins isolated from the culture of Y. enterocolitica supernatant under calcium deficient conditions and commercial ELISA with recombinant released proteins. A very high (94.0-100.0%) specificity and good sensitivity (55.2-80.4%) were displayed by the ELISA with YopD in relation to other two ELISA. The results of our study showed that recombinant YopD protein purified by chromatography of bio-affinity may be used in serodiagnosis of yersiniosis as a high specific antigen free of Yersinia lipopolysaccharides.