Infectious Bronchitis Virus In Chickens Research Articles

Pathological and molecular findings of visceral gout caused by Israel variant 2 (IS/1494/06) genotype of infectious bronchitis virus in chickens

The aim of this study was to investigate pathological lesions and the presence of of Israel variant 2 (IS /1494/06) genotype of infectious bronchitis virus (IBV) in chickens with visceral gout. Sudden deaths were observed in broiler breeders and layer hens belonging to two different flocks located in eastern Türkiye. Broiler chickens were previously vaccinated with a vaccine containing strains of IBV Massachusetts serotype, but no information was available about the vaccination history of laying hens. At necropsy, there was accumulation of white chalk-like material on the serosal surface of the heart, liver, spleen and air sacs. The kidneys were unilaterally or bilaterally enlarged and pale in color and, ureters were also enlarged. Pooled organ samples from diseased chickens and kidneys alone were examined by virus isolation, real-time reverse transcription polymerase chain reaction (rRT-PCR), nucleotide sequencing analysis and histological methods. Israel variant 2 genotype of IBV was detected in the samples of both flocks as a result of virus isolation, rRT-PCR and DNA sequencing analysis. Histological examination revealed multifocal and randomly distributed crystal deposits in the renal tubulus and adjacent interstitium. Mild to moderate crystalline deposits surrounded by heterophils and macrophages were detected in the serosal layers of the heart, spleen, liver, and air sacs. The findings of this study indicated that IBV should be taken into consideration in visceral gout cases of chickens, and detection of IBV genotypes in the field will enable us to use vaccines compatible with these genotypes in order to control the disease more efficiently.

Serological Survey of Infectious Bronchitis Virus in Chickens in Sokoto State Nigeria

In the present study, blood samples were collected from 400 chickens and sera harvested for serology using an IgG based indirect enzyme linked immunosorbent assay (ELISA). This research aimed at determining the prevalence of antibodies to infectious bronchitis virus in chickens in sokoto state Nigeria. The samples were collected from selected areas in each of the four Agricultural zones of Sokoto State. The overall sero-prevalence obtained was 346 (86.50%). The sero-prevalence of infectious bronchitis viral antibodies in indigenous and exotic chickens was 88.72% and 84.39% respectively, chi square showed no significant relationship between the two groups, the chi value was 1.603 and P value was 0.205 (>0.05%). In young and adult chickens sampled, the sero-prevalence was 89.50% and 82.87% respectively, chi square showed significant relationship between the two age groups with chi value 3.179 and P value 0.038 (<0.05), binary logistic regression for the two age groups showed no significant association with P= 0.09 (>0.05). The result in male and female chickens tested was 86.88% and 86.17% positives respectively showing slightly higher positives in males than in females with no significant statistical relationship using chi square, chi value was 0,043 and P value 0.836 (>0.05%). This study has provided an update on sero-prevalence of IBV in Sokoto State. It was concluded that there was high sero-prevalence of IBV in the chickens sampled in the State. General survey of the virus in the entire region where Sokoto belongs (Northwestern Nigeria) or the country as a whole is recommended, so as to have a clearer picture of IB and Veterinarians probably consider vaccination as a mean of prevention of the disease, and vaccine be produced using local strains

A DNA Prime and MVA Boost Strategy Provides a Robust Immunity against Infectious Bronchitis Virus in Chickens.

Infectious bronchitis (IB) is an acute respiratory disease of chickens caused by the avian coronavirus Infectious Bronchitis Virus (IBV). Modified Live Virus (MLV) vaccines used commercially can revert to virulence in the field, recombine with circulating serotypes, and cause tissue damage in vaccinated birds. Previously, we showed that a mucosal adjuvant system, QuilA-loaded Chitosan (QAC) nanoparticles encapsulating plasmid vaccine encoding for IBV nucleocapsid (N), is protective against IBV. Herein, we report a heterologous vaccination strategy against IBV, where QAC-encapsulated plasmid immunization is followed by Modified Vaccinia Ankara (MVA) immunization, both expressing the same IBV-N antigen. This strategy led to the initiation of robust T-cell responses. Birds immunized with the heterologous vaccine strategy had reduced clinical severity and >two-fold reduction in viral burden in lachrymal fluid and tracheal swabs post-challenge compared to priming and boosting with the MVA-vectored vaccine alone. The outcomes of this study indicate that the heterologous vaccine platform is more immunogenic and protective than a homologous MVA prime/boost vaccination strategy.

Diagnosis of avian metapneumovirus infection using multiplex PCR

Avian metapneumovirus infection causes significant economic damage to poultry farming, which consists of losses from a decrease in safety and productivity, as well as the cost of health and preventive measures.The causative agent of the disease is avian metapneumovirus family Paramyxoviridae subfamily Pneumovirinae genus Metapneumovirus. The viral genome consists of 8 genes encoding 9 proteins: N-nucleoprotein, P-phosphoprotein, Mmatrix protein, F-fusion protein, M2 (M2-1,M2-2) - elongation/transcription factor, SH-(small) hydrophobic protein, Gglycoprotein, L-(large) polymerase. The virus lacks non-structural NS1 and NS2 proteins that counteract interferon.Based on the nucleotide seguence of the variable glycoprotein G gene, avian metapneumovirus was classified into four 4 subtypes of MPV are officially known, although recent publications have reported of two new pneumoviruses, GuMPV and AMPV PAR-05 isolated from the seagull and parrot in North America.The diversity of pathogen subtypes and differences in virulence properties of metapneumovirus create difficulties both in the prevention of this disease and in its diagnosis.The complexity of isolating the metapneumovirus from the test material is due to the short period of persistence of the virus in the organs of birds. It is possible to isolate the RNA of the causative agent of MPVI by the molecular biological method within 17-19 days after infection. The aim of our work was development and testing of primers and probes for the simultaneous detection and differentiation of avian metapneumovirus subtypes A and B by PCR with real-time fluorescence detection, with high specificity.Using vaccine strains 8544 and VC-03, the conditions for PCR were selected according to the composition of the PCR mixture and the annealing temperature of primers and probes. During PCR, we recorded the fluorescence signal through the FAM channel for cDNA obtained from the 8544 vaccine strain, and through the HEX channel for the VC-03 vaccine strain. The specificity of the developed primers and probes was also tested in studies with heterogeneous viruses such as Newcastle disease, classical and variant strains of chicken infectious bronchitis virus, and with bird DNA.The studies conducted to determine the specificity of the primers selected by us for multiplex PCR diagnostics make it possible to simultaneously specifically detect subtypes A and B of the causative agent of MPVI in birds in real time using different fluorescence channels, while other non-target respiratory pathogens were not observed.

Targeted detection and molecular epidemiology of turkey coronavirus spike gene variants in turkeys and chickens.

Turkey coronavirus (TCoV) is a member of the Avian coronavirus species with infectious bronchitis virus (IBV), which is considered to be the source of TCoV. These 2 viruses are highly similar in all regions of their genomes, except for the spike gene, which is necessary for virus attachment. Although TCoV causes severe enteric disease in turkey poults, it does not cause clinical disease in chickens. However, considering that TCoV can infect chickens, it is important to distinguish TCoV from IBV in chickens. This is particularly true for chickens that are housed near turkeys and thus might be infected with TCoV and serve as a silent source of TCoV for turkeys. We developed and validated a real-time PCR assay to detect the spike gene of TCoV and sequenced a portion of this gene to evaluate the molecular epidemiology of TCoV infections associated with a commercial turkey premises in the United States in 2020-2021. We identified natural infections of TCoV in chickens, and based on the molecular epidemiology of the viruses detected, these chickens may have served as a source of infection for the commercial turkey premises located nearby.

The Advances of Broad-Spectrum and Hot Anti-Coronavirus Drugs.

Coronaviruses, mainly including severe acute respiratory syndrome virus, severe acute respiratory syndrome coronavirus 2, Middle East respiratory syndrome virus, human coronavirus OC43, chicken infectious bronchitis virus, porcine infectious gastroenteritis virus, porcine epidemic diarrhea virus, and murine hepatitis virus, can cause severe diseases in humans and livestock. The severe acute respiratory syndrome coronavirus 2 is infecting millions of human beings with high morbidity and mortality worldwide, and the multiplicity of swine epidemic diarrhea coronavirus in swine suggests that coronaviruses seriously jeopardize the safety of public health and that therapeutic intervention is urgently needed. Currently, the most effective methods of prevention and control for coronaviruses are vaccine immunization and pharmacotherapy. However, the emergence of mutated viruses reduces the effectiveness of vaccines. In addition, vaccine developments often lag behind, making it difficult to put them into use early in the outbreak. Therefore, it is meaningful to screen safe, cheap, and broad-spectrum antiviral agents for coronaviruses. This review systematically summarizes the mechanisms and state of anti-human and porcine coronavirus drugs, in order to provide theoretical support for the development of anti-coronavirus drugs and other antivirals.

Immune Responses and B Complex Associated Resistance to Infectious Bronchitis Virus in Chickens.

Infectious bronchitis (IB) continues to be a global threat to poultry producers. The chicken major histocompatibility complex (MHC) or chicken B complex is compact, restricted to a single chromosome, and approximately 20-fold smaller than the mammalian MHC. Abundant evidence indicates that the B complex is strongly associated with resistance to various infectious agents in chickens. While an association between different B haplotypes and resistance against several bacterial and viral diseases has been established, additional work needs to be performed on the association between the B complex and resistance to IB viruses (IBV). Here, some of the available knowledge on genetic resistance to viral poultry diseases conferred by the chicken B locus is reviewed. IBV immune responses and resistance associated with differing B haplotype chicken lines are reviewed and discussed herein.

Anti-inflammatory therapy of viral pneumonia on the model of chicken infectious bronchitis

The effect of the drug Lumantse on the infectious bronchitis virus of chickens was evaluated. Infectious bronchitis of chickens is a highly contagious disease characterized by damage to the respiratory system and reproductive organs in young animals caused by a virus of the genus Gamma-coronavirus. The condition of the respiratory system caused by the infectious bronchitis virus (IBD) in chickens has much in common with the pathology of the respiratory system caused by SARS-CoV-2 in humans. For broilers, the course of IBD is characterized more often with damage to the respiratory system, manifested by bronchitis, pneumonia, tracheitis, as well as with kidney damage in the case of circulation of nephropathogenic strains. The effectiveness of the virocidal drug Lumantse was tested on 14-day-old cross shawer chickens infected with a ten-fold dose of the Nobilis IB Ma5 vaccine strain against infectious chicken bronchitis. The results of the studies showed that when the immune system is actively stimulated, the inflammatory response increases, with a simultaneous drop in the viral load, which is why a significant percentage of lung inflammation (60%) was observed in the experimental group. Compared with the control group, when using the drug Lumantse, there is a lower number of inflammatory reactions of the lungs, thymus by 40%, as well as the lowest concentration of viral particles in the lungs and intestines.

The Infectious Bronchitis Coronavirus Pneumonia Model Presenting a Novel Insight for the SARS-CoV-2 Dissemination Route.

Infectious bronchitis (IB) of chickens is a highly contagious disease characterized by damage of the respiratory system and reproductive organs in young animals caused by a virus of the genus Gamma coronavirus. The condition of the respiratory system caused by the IB virus in chickens has many similarities with the pathology of the respiratory system caused by SARS-CoV-2 in humans. The effectiveness of virucidal drugs (Argovit, Triviron, Ecocid, and lauric acid monoglyceride) was tested on chickens inoculated with a tenfold dose of a vaccine strain based on the attenuated virus H120 against IB of chickens. On the 6th day after inoculation, inflammatory changes in the intestines, lungs, and thymus were observed in the control group. The experimental groups were characterized by less pronounced inflammatory reactions and a lower proportion of thymus and lung probes containing genomic IB virus RNA. Since the virucidal activity of four orally administrated formulations was possible only in the intestine, the experimental data indirectly confirmed the hypothesis of the possibility of the predominant accumulation of coronaviruses in the intestine and subsequent lung damage due to the hematogenous redistribution of viral particles and IBV antigens. It was suggested that other coronaviruses including SARS-CoV-2 can implement a similar mechanism.

Circulation of three genotypes and identification of unique mutations in neutralizing epitopes of infectious bronchitis virus in chickens in Bangladesh.

Infectious bronchitis (IB) is a highly contagious respiratory disease caused by a gammacoronavirus that has been circulating for many years in chickens in Bangladesh, resulting in significant economic losses. The aim of this study was to detect and characterize infectious bronchitis virus (IBV) from clinical outbreaks and surveillance samples. Real-time RT-PCR was used to detect IBV in pooled lung and tracheal tissue samples (n = 78), oropharyngeal swabs (n = 19), and pooled fecal samples (n = 13) from live-bird markets. Both respiratory and nephropathogenic forms of IB were suspected at necropsy (n = 7) from clinical outbreaks. Sequencing of hypervariable regions (HVR1-2 and HVR3) of the region of the spike gene (S) encoding the S1 subunit of five isolates revealed circulation of the Mass-like, QX-like, and 4/91-like genotypes of IBV in Bangladesh. Each genotype was extremely variable, as shown by separate clustering of the viruses in a phylogenetic tree and high nucleotide (nt) sequence divergence (38.8–41.2% and 25.7–37.4% in the HVR1-2 and HVR3 sequence, respectively). The unique mutation G65E was observed in each Mass-like isolate, and Y328S was observed in each 4/91-like Bangladeshi isolate. Three neutralizing epitope sites were predicted within the HVRs that differed significantly among the three genotypes. In addition, one Bangladeshi isolate carried fixed mutations at 294F and 306Y, like other pathogenic QX-like IBVs, which could affect epitopes involved in neutralization, facilitating virus circulation among vaccinated flocks. Therefore, continuous screening and genotype characterization will be necessary to track the epidemiology of IBV and control IB infection in Bangladesh.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00705-021-05227-3.

In-silico evidence for enhancement of avian influenza virus H9N2 virulence by modulation of its hemagglutinin (HA) antigen function and stability during co-infection with infectious bronchitis virus in chickens.

The online version contains supplementary material available at 10.1007/s13337-021-00688-1.

Aspects of “antigen–antibody” interaction of chicken infectious bronchitis virus determined by surface plasmon resonance

Authors performed investigation on “antigen–antibody” interaction of chicken infectious bronchitis coronavirus (IBV) by a method based on the surface plasmon resonance (SPR). Presence of space-size effect related to a difference between antigen and antibody particle sizes has been theoretically grounded and experimentally proven. Herewith, the difference between responses of the SPR-sensor to specific and non-specific interactions is considerably less (up to 6.3 times) than the expected one (8 – 11 times). An impact of functionalization of sensor’s sensitive element surface, as well as acidity of buffer solution on the activity of antigen–antibody interaction was studied here. The difference between sensor’s responses to specific and non-specific interactions increased two-fold from 200 to 432ang sec due to this treatment. When changing the acidity of analyzed solution from pH7.3 to pH6.8, the corresponding difference between sensor’s responses increased by 6.3 times from 194 up to 1235ang.sec. Thus, an impact of space-size effect on interaction between IBV antigen and specific antibody can be considerably (almost in 3 times) decreased by reducing the acidity of used buffer solution. The results of our investigation can be successfully applied to develop new methods for detection of pathogens and specific antibodies using SPR.

SURFACE PLASMON RESONANCE METHOD FOR DETECTION CHICKEN INFECTIOUS BRONCHITIS CORONAVIRUS

The article presents a new developed method, which is able to detect the chicken infectious bronchitis virus (IBV) antigen in real time in various buffer solutions, using the surface plasmon resonance (PPR) nanobiosensor of the Plasmon-6 device. The PPR method is hypersensitive to changes in external factors, including the interaction of antigen (coronavirus) and specific antibodies. If the interaction does not happen, the resonance occurs at other angular parameters of the position of the sensitive PPR element relative to the laser radiation. Therefore, the PPR method is becoming a new effective rapid technique of viral pathogen detection, which is important for effective control over infectious diseases spreading. The possibility of IBK virus detection by the PPR sensor response, with preliminary immobilization of antigen or antibodies, is shown, involving the device "Plasmon- 6". The duration of the experiment is about 2 hours, which significantly saves research time compared to other methods (6-48 hours). The changes in the resonance angle in the range of 360-500 angle. sec when the IBC virus antigen binds to serum antibodies in water (distilled) were detected. The angular shift of the nanosensor resonance was determined when the IBC virus antigen bound to the serum antibodies in the PBS, which averaged 354 angular seconds. The possibilities of using the PPR method for express detection of the coronavirus infections pathogen in animal fluids in real time are demonstrated in article. Taking into account the significant social and economic negative consequences of the Coronaviridae virus family members and considering the current situation with the worldwide spread of COVID-19, the representative of the coronavirus family – the Infectious Bronchitis virus has been selected as a model.

A bio-safe multiple antigenic peptide (MAP) enzyme-linked immunoassay for the detection of antibodies to infectious bronchitis virus in chickens.

The objective of the study was to develop a bio-safe synthetic peptide ELISA for the detection of antibodies against the infectious bronchitis virus (IBV) using a novel multiple antigenic peptide approach (MAP). After initial ELISA optimization, diagnostic sensitivity (DSn) and specificity (DSp) for the linear peptides were determined using receiver operator curve (ROC) analysis. The peptide IBVP1 showed 90.44% DSn and 88.64% DSp at ROC cut off 22.8% while IBVP2 showed 88.24% DSn and 85.23% DSp at ROC cut off 23.05%. The multimerization of linear peptides to MAP design resulted in the improvement of the diagnostic efficiency up to 94.85% DSn and 92.05% DSp for IBVM1 with 19.95% cut off. A similar improvement in the performance was also observed with 92.65% DSn and 90.91% DSp for IBVM2 at 20.72% cut off. All the peptides were tested for diagnostic specificity and did not show the cross-reactivity with Newcastle disease virus and infectious bursal disease virus positive serum samples. In addition, repeatability testing for all linear and multimeric peptide showed that the coefficient of variation for intra-assay was within the expected limits, ranging from 2.4 to 10.4% and inter-assay coefficient of variation was ranging from 5.56 to 14.3%. In a nutshell, the present study used predicted B cell epitope, the synthetic peptide in linear and multimeric design for IBV antibody detection. The study also highlights peptide antigen with modified scaffold design could be a safe alternative to whole virion-based ELISA for IBV antibody detection.

Viral Metagenomic Analysis of Japanese Quail (Coturnix japonica) with Enteritis in the Republic of Korea.

We performed viral metagenomics analysis of Japanese quail affected with enteritis to elucidate the viral etiology. Metagenomics generated 21,066,442 sequence reads via high-throughput sequencing, with a mean length of 136 nt. Enrichment in viral sequences suggested that at least three viruses were present in quail samples. Coronavirus and picornavirus were identified and are known as pathogens causing quail enteritis that match the observed morphology. Abundant reads of coronavirus from quail samples yielded four fragment sequences exhibiting six genomes of avian coronavirus. Sequence analysis showed that this quail coronavirus was related to turkey coronavirus and chicken infectious bronchitis virus. Quail picornavirus 8177 bp in size was identified and was similar to the QPV1/HUN/01 virus detected in quails without clinical symptoms in Hungary with 84.6% nucleotide and 94.6% amino acid identity. Our results are useful for understanding the genetic diversity of quail viruses. Further studies must be performed to determine whether quail coronavirus and quail picornavirus are pathogens of the digestive tract of quails.

Comparative Protective Efficacies of Novel Avian Paramyxovirus-Vectored Vaccines against Virulent Infectious Bronchitis Virus in Chickens.

Viral vectored vaccines are desirable alternatives for conventional infectious bronchitis virus (IBV) vaccines. We have recently shown that a recombinant Newcastle disease virus (rNDV) strain LaSota expressing the spike (S) protein of IBV strain Mass-41 (rLaSota/IBV-S) was a promising vaccine candidate for IBV. Here we evaluated a novel chimeric rNDV/avian paramyxovirus serotype 2 (rNDV/APMV-2) as a vaccine vector against IBV. The rNDV/APMV-2 vector was chosen because it is much safer than the rNDV strain LaSota vector, particularly for young chicks and chicken embryos. In order to determine the effectiveness of this vector, a recombinant rNDV/APMV-2 expressing the S protein of IBV strain Mass-41 (rNDV/APMV-2/IBV-S) was constructed. The protective efficacy of this vector vaccine was compared to that of the rNDV vector vaccine. In one study, groups of one-day-old specific-pathogenic-free (SPF) chickens were immunized with rLaSota/IBV-S and rNDV/APMV-2/IBV-S and challenged four weeks later with the homologous highly virulent IBV strain Mass-41. In another study, groups of broiler chickens were single (at day one or three weeks of age) or prime-boost (prime at day one and boost at three weeks of age) immunized with rLaSota/IBV-S and/or rNDV-APMV-2/IBV-S. At weeks six of age, chickens were challenged with a highly virulent IBV strain Mass-41. Our challenge study showed that novel rNDV/APMV-2/IBV-S provided similar protection as rLaSota/IBV-S in SPF chickens. However, compared to prime-boost immunization of chickens with chimeric rNDV/APMV-2, rLaSota/IBV-S and/or a live IBV vaccine, single immunization of chickens with rLaSota/IBV-S, or live IBV vaccine provided better protection against IBV. In conclusion, we have developed the novel rNDV/APMV-2 vector expressing S protein of IBV that can be a safer vaccine against IB in chickens. Our results also suggest a single immunization with a LaSota vectored IBV vaccine candidate provides better protection than prime-boost immunization regimens.

Genetic characterization of infectious bronchitis viruses in Thailand, 2014–2016: identification of a novel recombinant variant

Infectious bronchitis (IB) causes severe economic losses to the poultry industry worldwide owing to frequent emergence of novel infectious bronchitis virus (IBV) variants, which potentially affect the effectiveness of the currently used IBV vaccine. Therefore, continuous monitoring of IBV genotypes and lineages recently circulating in chickens worldwide is essential. In this study, we characterized the complete S1 gene from 120 IBVs circulating in chickens in Thailand from 2014 to 2016. Phylogenetic analysis of the complete S1 gene of 120 Thai IBVs revealed that the 2014–2016 Thai IBVs were divided into 3 lineages (GI-1, GI-13, and GI-19) and a novel IBV variant. Our results also showed that GI-19 lineage has become the predominant lineage of IBV circulating in chicken flocks in Thailand from 2014 to 2016. It is interesting to note that a novel IBV variant, which was genetically different from the established IBV lineages, was identified in this study. The recombination analysis demonstrated that this novel IBV variant was a recombinant virus, which was originated from the GI-19 and GI-13 lineage viruses. In conclusion, our data demonstrate the circulation of different lineages of IBV and the presence of a novel recombinant IBV variant in chicken flocks in Thailand. This study highlights the high genetic diversity and continued evolution of IBVs in chickens in Thailand, and the importance of continued IBV surveillance for effective control and prevention of IB.

Peptides with 16R in S2 protein showed broad reactions with sera against different types of infectious bronchitis viruses

Vaccination plays a vital role in controlling diseases caused by chicken infectious bronchitis virus (IBV). The continuously variant antigenicity of IBV limits the application of current vaccine strategies and serological diagnostic systems. S2 protein is an invariant that harbors broad neutralizing epitopes. However, little is known about the key amino acids that contribute to the broad-spectrum S2 epitopes. In this study, we aimed to elucidate the specific amino acids contributing to S2 epitopes. Site mutagenesis and peptide-based enzyme-linked immunosorbent assays (ELISAs) showed that 16R in S2 protein was a key amino acid mediating the antigenicity of S2 protein. S2-derived peptides with 16R, but not those with 16 K, could react with sera against different types of IBVs. Notably, a commercial ELISA kit for detection of antibodies against IBV did not react with sera against all types of IBVs. Taken together, these data demonstrated that S2-derived peptides with 16R could be used as novel marker-based antigens for developing both broad-spectrum vaccines and serological diagnostic kits to control IBV.

Combined adjuvant effect of ginseng stem-leaf saponins and selenium on immune responses to a live bivalent vaccine of Newcastle disease virus and infectious bronchitis virus in chickens.

ABSTRACTVaccination with a live bivalent vaccine of Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) is a routine practice in poultry industry in China. This study was designed to evaluate ginseng stem-leaf saponins (GSLS) in combination with selenium (Se) for their adjuvant effect on the immune response to vaccination against NDV and IBV in chickens. A live bivalent vaccine of NDV and IBV was diluted in saline solution containing GSLS or Se or both and used to immunize chickens via a intraocular-and-intranasal route. Results showed that GSLS promoted significantly higher NDV- and IBV-specific antibody responses with the highest antibody response detected in GSLS-Se group. The increased antibody was capable of neutralizing NDV and IBV. In addition, GSLS-Se enhanced lymphocyte proliferation and production of IFN-γ and IL-4. More importantly GSLS-Se was found to promote early production and prolong the duration of the antibody responses. In order to improve the efficacy of vaccination in chicken flocks, the diluent containing GSLS-Se deserves further studies to evaluate its effect on other chicken vaccines.

Determination of antimicrobial activity of some 1,2,4-triazole derivatives

We carried out MIC of the derivatives of 1,2,4-triazole II (4-((5-nitrofuran-2-yl)methyleneamino)-1-propyl-4H-1,2,4-triazolium bromide) and I (N-((5-nitrofuran-2-yl)methylene)-4H-4-amino-1,2,4-triazolidium chloride) against Escherichia coli ATCC 3912/4 and E. coli k88ad, Staphylococcus aureus ATCC 25923 and S. aureus k99, Klebsiella pneumonia k56 and Salmonella typhimurium 144, S. enteritidis. All test cultures were sensitive to compound II at concentrations of 1,25–0,039 μg/ml. Similar MIC (0,039 μg/ml) of compounds II and I were set for E. coli k88a and S. aureus k99 test cultures – 0,156 μg/ml. Only S. aureus ATCC 25923 and K. pneumonia k56 had sensitivity to ceftriaxone (MIC = 0,097 μg/ml). Antiviral activity of Trifuzol (piperidine 2-[5-(furan-2-il)-4-phenil-1,2,4-triazol-3-ilthio]acetate) and avistim (morpholines 3-(4-pyridyl)-1,2,4-triazolil-5-thioacetate) against the chicken infectious bronchitis virus (VIB) strain 4/91 was characterized by a decrease in mortality and pathological changes of chicken embryos (CE) which were induced by the virus. Death of infected CE provoked by the strain 4/91 of VIB in dilution 10–3 occurred at 57.1%. The reduction in the percentage of deaths of CE infected by the virus in dilution 10–3 in the presence of Avistim was 28.6%, and with Trifuzol 14.3%. The use of avistim and Trifuzol compounds reduced VIB infectious activity when it was cultivated in CE, reducing the titre of the virus (strain 4/91) by 3 lg EID 50 cm–3.