Characterization of three infectious bursal disease virus isolates obtained from layer chickens in Iran.

Three infectious bursal disease viruses (IBDVs) were isolated from field outbreaks in IBDV-vaccinated and non-vaccinated layer chicken flocks. Agar gel precipitation test (AGPT), immunoperoxidase staining, transmission electron microscopy (TEM), inoculation into embryonated eggs, and chicken embryo fibroblasts (CEFs) confirmed that the isolates were IBDVs. RT-PCR, restriction fragment length polymorphism (RFLP), and phylogenetic analysis demonstrated that the isolates were very virulent IBDV (vvIBDV) and showed a nucleotide sequence similarity of 96.3 to 99.8% in comparison with other vvIBDV strains. It was concluded that the Iranian isolates represented vvIBDV of serotype 1 originating from Europe, Japan, and China

Assessing the Combined Public Health Impact of Pharmaceutical Interventions on Pandemic Transmission and Mortality: An Example in SARS CoV-2

To assess the combined role of anti-viral monoclonal antibodies (mAbs) and vaccines in reducing severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) transmission and mortality in the United States, an agent-based model was developed that accounted for social contacts, movement/travel, disease progression, and viral shedding. The model was calibrated to coronavirus disease 2019 (COVID-19) mortality between October 2020 and April 2021 (aggressive pandemic phase), and projected an extended outlook to estimate mortality during a less aggressive phase (April–August 2021). Simulated scenarios evaluated mAbs for averting infections and deaths in addition to vaccines and aggregated non-pharmaceutical interventions. Scenarios included mAbs as a treatment of COVID-19 and for passive immunity for postexposure prophylaxis (PEP) during a period when variants were susceptible to the mAbs. Rapid diagnostic testing paired with mAbs was evaluated as an early treatment-as-prevention strategy. Sensitivity analyses included increasing mAb supply and vaccine rollout. Allocation of mAbs for use only as PEP averted up to 14% more infections than vaccine alone, and targeting individuals ≥ 65 years averted up to 37% more deaths. Rapid testing for earlier diagnosis and mAb use amplified these benefits. Doubling the mAb supply further reduced infections and mortality. mAbs provided benefits even as proportion of the immunized population increased. Model projections estimated that ~ 42% of expected deaths between April and August 2021 could be averted. Assuming sensitivity to mAbs, their use as early treatment and PEP in addition to vaccines would substantially reduce SARS-CoV-2 transmission and mortality even as vaccination increases and mortality decreases. These results provide a template for informing public health policy for future pandemic preparedness

An Experimental Study on the Effect of Premixed and Equivalence Ratios on CO and HC Emissions of Dual Fuel HCCI Engine

In this study, effects of premixed and equivalence ratios on CO and HC emissions of a dual fuel HCCI engine are investigated. Tests were conducted on a single-cylinder engine with compression ratio of 17.5. Premixed gasoline is provided by a carburetor connected to intake manifold and equipped with a screw to adjust premixed air-fuel ratio, and diesel fuel is injected directly into the cylinder through an injector at pressure of 250 bars. A heater placed at inlet manifold is used to control the intake charge temperature. Optimal intake charge temperature results in better HCCI combustion due to formation of a homogeneous mixture, therefore, all tests were carried out over the optimum intake temperature of 110-115 ºC. Timing of diesel fuel injection has a great effect on stratification of in-cylinder charge and plays an important role in HCCI combustion phasing. Experiments indicated 35 BTDC as the optimum injection timing. Varying the coolant temperature in a range of 40 to 70 ºC, better HCCI combustion was achieved at 50 ºC. Therefore, coolant temperature was maintained 50 ºC during all tests. Simultaneous investigation of effective parameters on HCCI combustion was conducted to determine optimum parameters resulting in fast transition to HCCI combustion. One of the advantages of the method studied in this study is feasibility of easy and fast transition of typical diesel engine to a dual fuel HCCI engine. Results show that increasing premixed ratio, while keeping EGR rate constant, increases unburned hydrocarbon (UHC) emissions due to quenching phenomena and trapping of premixed fuel in crevices, but CO emission decreases due to increase in CO to CO2 reactions

Experimental studies of pathogenecity of Chicken Infectious

To evaluate pathogenicity of 3 Chicken Anemia Virus isolates-CV1, CV2 and CV3 respectively - the current experiment carried out. After tittering of the viruses, 30 one day old SPF chicks were grouped and intramuscularly inoculated with each isolate in a separate group. Two other groups as positive and control groups were inoculate with a live vaccine virus and normal saline respectively. During the study the birds in first three groups clinically showed raffling feathers, depression and body weight reduction. After 18 days they were weighed, bled and euthanized. Three birds were found dead during the experiment (one in each tested group). Antibodies against CAV in the serum of all 3 groups were detected while no antibody found in negative control group. Hematocrit Values of the three tested groups were under the normal. Grossly the thymus and bursa tissues were severely atrophied. Bone marrow became yellowish and pale. In histopathological study we found aplasia and devoid of erythroid and myeloid cells replacing by fat cells in bone marrow. Severe atrophy and depletion in thymus ,bursa of Fabricius and bone marrow tissues statistically were analyzed and showed that the significance difference in comparing with control groups ( p<0.05 ). By using a type specific Polymerase Chain Reaction (PCR) assay the occurrence of virus was confirmed in thymus and liver tissues. In conclusion the authors interpreted that the 3 strains of CAV were able to infect and induce a wide range of damages in one day old SPF chicken

Neuraminidase gene sequence analysis of avian influenza H9N2 viruses isolated from Iran (19982001) Arch. Razi Institute

ABSTRACT Influenza A viruses possesses two virion surface glycoproteins including haemagglutinin (HA) and neuraminidase (NA). The NA plays an important role in viral replication and promotes virus release from infected cells and facilitates virus spread throughout the body. To find out any genomic changes that might be occurred on NA gene of avian influenza circulating viruses, we have genetically analyzed the neuraminidase gene of six Avian Influenza (AI) viruses H9N2 subtype isolated from different parts of Iran. A comparison of deduced amino acid sequences, showed some amino acid substitutions among the local AI isolates. However no insertions/deletions or shortening in the stalk region of the genes were observed. Mutation in Glu 119 as a marker for enzyme sensitivity to the antiviral drugs was not observed. Phylogenitic analysis revealed three distinct groups among the isolates of Iran, Hong Kong, and Pakistan/Japan/Saudi Arabia respectively. Based on the results, no significant mutations in NA genes of the viruses isolated during the period of the study occurred and our findings are in agreement with results of previous study of the viruses indicated a low pathogen character for the isolates on the basis of amino acid sequence of HA cleavage site and experimental infection

Immunogenicity of commercial, formaldehyde and binary ethylenimine inactivated Newcastle disease virus vaccines in specific pathogen free chickens

Newcastle disease (ND) is one of the most important diseases that affect birds; the epizootic nature of the disease has caused severe economic losses in the poultry industry worldwide. In this experiment ND virus (NDV) was inactivated by two different chemicals binary ethylenimine (BEI) and formaldehyde. Formaldehyde was used at 0.1%, while BEI was used at concentrations of 1 to 4 mM. NDV inactivation with BEI was done in various incubation temperatures and periods and the best result (30 °C, 4 mM BEI and 21 hrs treatment) used as an experimental vaccine. Prepared inactivated NDV vaccines and a commercial vaccine were tested for their efficiency in generating humoral immune response in different groups of specific pathogen free (SPF) chicks. Test groups received 0.2 ml formaldehyde inactivated NDV (NDVF), BEI inactivated NDV (NDVEI) and Razi institute produced NDV vaccine (NDVR) subcutaneously respectively. HI Log 2 total mean titer of NDVEI group (8.42 ± 0.12) were significantly higher than NDVF (7.64 ± 0.16) and NDVR (7.86 ± 0.11) groups (p<0.05). BEI-inactivated vaccine gave higher antibody titers than formaldehyde-inactivated vaccine and preserves both structural integrity and antigenicity of the virus. Thus, it might be possible to use these compounds as an inactivator agent for commercial NDV inactivated vaccines in future

Comparison Of Hormonal And Non-Hormonal Contraceptive Method Effects On The Mothers Milk And Infants Growth Among Lactating Women

Background: This research was conducted for the purpose of determining the effect of hormonal and non-hormonal contraception on the mother milk and infants growth among lactating women received by south Tehran’s Health Centers. In this regard a broad spectrum study from December 2000 until February 2001 was done by Tehran university. Materials and Methods: By sampling method, 200 lactating women were chosen randomly. They were divided into two groups according to their preferred method of contraception: 67 women chose hormonal method and 133 women chose non –hormonal method. Results&amp;Conclusion: During the time of the study on infants growth (increase in head circumstances, increase in height, increase in weight), There was no significant difference between the two groups. If we take the effect of contraceptive methods into consideration, the Triglyceride levels in non-hormonal group were increased considerably compared to the other group. Other ingredients were almost the same