scholarly journals Detection of Newcastle Disease Virus Minor Genetic Variants by Modified Single-Stranded Conformational Polymorphism Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lukasz Rabalski ◽  
Krzysztof Smietanka ◽  
Zenon Minta ◽  
Boguslaw Szewczyk
Keyword(s):  
Newcastle Disease ◽  
Diagnostic Method ◽  
Rna Virus ◽  
Economic Losses ◽  
Polymorphism Analysis ◽  
Gene Encoding ◽  
Conformational Polymorphism ◽  
Live Vaccines ◽  
Single Stranded Conformational Polymorphism ◽  
Pathogenic Virus

Newcastle disease and Avian Influenza are considered to be the most dangerous fowl diseases which may cause huge economic losses. Newcastle disease is caused by the enveloped, and single-stranded RNA virus (NDV, APMV-1; belonging to Paramyxoviridae family), which can be further divided into sixteen different genotypes grouped into five pathotypes according to their pathogenicity. It has been reported that low pathogenic virus can greatly increase its pathogenicity even during a single passage. Additionally, due to the widespread use of live vaccines, a mixture of two or more different viruses in one sample can be detected. Hence, there is a great need for establishment of fast, inexpensive, sensitive, and relatively simple diagnostic method for multistrain and quasispecies detection of NDV infection. In this paper we describe a diagnostic method based on RT-PCR followed by a modified version of single-stranded conformational polymorphism analysis using short DNA fragments of gene encoding viral F protein. The method allows for rapid diagnosis of genetic variant emerging from previously stable population which may prevent the spread of the pathogenic viral variant.

scholarly journals Porcine Reproductive and Respiratory Syndrome Virus: Immune Escape and Application of Reverse Genetics in Attenuated Live Vaccine Development

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 480
Author(s):  
Honglei Wang ◽  
Yangyang Xu ◽  
Wenhai Feng
Keyword(s):  
Immune Responses ◽  
Reverse Genetics ◽  
Vaccine Development ◽  
Immune Escape ◽  
Rna Virus ◽  
Economic Losses ◽  
Respiratory Syndrome Virus ◽  
Live Vaccines ◽  
Host Immune Responses ◽  
Inactivated Vaccines

Porcine reproductive and respiratory syndrome virus (PRRSV), an RNA virus widely prevalent in pigs, results in significant economic losses worldwide. PRRSV can escape from the host immune response in several processes. Vaccines, including modified live vaccines and inactivated vaccines, are the best available countermeasures against PRRSV infection. However, challenges still exist as the vaccines are not able to induce broad protection. The reason lies in several facts, mainly the variability of PRRSV and the complexity of the interaction between PRRSV and host immune responses, and overcoming these obstacles will require more exploration. Many novel strategies have been proposed to construct more effective vaccines against this evolving and smart virus. In this review, we will describe the mechanisms of how PRRSV induces weak and delayed immune responses, the current vaccines of PRRSV, and the strategies to develop modified live vaccines using reverse genetics systems.

scholarly journals INFECTIOUS BURSAL DISEASE (GUMBORO DISEASE)

2008 ◽  
Vol 1 (1) ◽  
pp. 5-17
Author(s):  
Maja Velhner
Keyword(s):  
Rna Virus ◽  
Genetically Engineered ◽  
Bursa Of Fabricius ◽  
Infectious Bursal Disease ◽  
Antigenic Structure ◽  
Economic Losses ◽  
Oil Emulsion ◽  
Live Vaccines ◽  
Bursal Disease ◽  
Serotype 1

Infectious bursal disease (IBD) is widespread in many countries with intensive poultry industry. The causative agent is an RNA virus that belongs to Birnaviridae family. Two serotypes of IBDV exist. Serotype 1 strains originate from chickens, while serotypes 2 viruses are isolated from turkeys. Serotype 1 strains are further divided as classical, variant and very virulent. All the categories of young chickens are prone to the disease. Due to resultant immunosuppression the birds are exposed to secondary bacterial and viral infection that causes additional economic losses. The virus multiplies in the bursa of Fabricius inducing lymphocyte depletion (all strains) and inflammation (classical and very virulent strains). Approximately four days post infection, atrophy of bursa occurs followed by recovery process. Spleen, thymus and bone marrow are also damaged and the intensity of damage depends on the virus involved. Damages of these organs could be detected by pathohistological examination. The inflammatory response in bursa coincides with strong influx of CD3+ cells that take part in virus clearance and recovery. The disease can be controlled by the application of vaccination. Parent flocks are vaccinated with oil emulsion vaccines providing transfer of maternally derived antibodies to the progeny. In this way chickens are protected at an early age, while live vaccines provide protection during rearing. Live vaccines are classified as mild, intermediate and “hot”. Stronger vaccines can overcome high levels of maternal antibodies more efficiently and are recommended in questionable filed situation. Such vaccines may cause destruction of the bursa followed by a quick and full recovery. The knowledge about the antigenic structure of the virus leads to the production of genetically engineered vaccines that could be used in the future.

Variation in ovine KRTAP8-1 is associated with variation in wool fibre staple strength and curvature

2019 ◽  
Vol 157 (6) ◽  
pp. 550-554 ◽  
Author(s):  
H. Gong ◽  
H. Zhou ◽  
W. Li ◽  
J. Wang ◽  
S. Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Genetic Marker ◽  
Protein Gene ◽  
Wool Fibre ◽  
Polymorphism Analysis ◽  
Chain Reaction ◽  
Conformational Polymorphism ◽  
Single Stranded Conformational Polymorphism ◽  
Polymerase Chain ◽  
Staple Strength

AbstractKRTAP8-1 was the initial high-glycine-tyrosine keratin-associated protein gene recognized in sheep, but little is known about the functional influence of this gene. The current study used polymerase chain reaction-single stranded conformational polymorphism analysis to genotype KRTAP8-1 in 391 Southdown × Merino-cross sheep from six sire-lines. Five previously described variants (named A to E) of KRTAP8-1 were identified with frequencies of 67.0, 14.2, 7.0, 10.7 and 1.0%, respectively. Of the four variants (A, B, C and D) that occurred at a frequency greater than 5%, the presence of C was found to be associated with a reduction in mean fibre curvature (MFC) and the presence of D was associated with an increase in mean staple strength (MSS), whereas the presence of A had a trend of association with reduced MSS. Associations were not identified with other wool traits. These results suggest that variation in KRTAP8-1 affects MSS and MFC, and that KRTAP8-1 has the potential to be used as a genetic marker for improving these traits.

scholarly journals Effect of infectious bronchitis and Newcastle disease vaccines on experimental avian influenza infection (H9N2) in broiler chickens

2021 ◽  
Vol 24 (4) ◽  
pp. 574-585
Author(s):  
R. Amanollahi ◽  
K. Asasi ◽  
B. Abdi-Hachesoo ◽  
N. Ahmadi ◽  
A. Mohammadi
Keyword(s):  
Avian Influenza ◽  
Newcastle Disease ◽  
Broiler Chickens ◽  
Clinical Signs ◽  
Respiratory Pathogen ◽  
Economic Losses ◽  
Control Group ◽  
Virus Shedding ◽  
Live Vaccines ◽  
Infectious Bronchitis

Despite the fact that H9N2 avian influenza virus (AIV) is considered a low-pathogenic agent, frequent outbreaks of this subtype have caused high mortality and economic losses in poultry farms around the world including Iran. Coinfection with a respiratory pathogen or environmental factors may explain the exacerbation of H9N2 AIV infection. In this study, the role of infectious bronchitis (IB) vaccines (H120 and 4/91) and Newcastle disease (ND) vaccines (B1 and LaSota) on experimental H9N2 AIV infection was investigated in 180 broiler chickens allotted into 6 groups (n=30). At the age of 18 days, groups 3 and 4 received H120 and 4/91 infectious bronchitis live vaccines (IBLVs) and groups 5 and 6 received B1 and LaSota Newcastle disease live vaccines (NDLVs), respectively. At the age of 20 days, all birds in the experimental groups except the negative control group (group 1), were inoculated intra-nasally with H9N2 AIV. After the inoculation, clinical signs, gross and microscopic lesions, and viral detection were examined. The results of this study revealed that clinical signs, gross and microscopic lesions were more severe in the AIV challenged groups which had been previously vaccinated with IB vaccines. In addition, AI viral RNA from tracheal and faecal samples in IB vaccinated birds were recovered at a higher rate. Moreover, in the 4/91 IB vaccinated group, the AI virus shedding period was longer than the other challenged groups. In conclusion, infectious bronchitis live vaccines (IBLVs) exacerbated the H9N2 AIV infection; also, 4/91 IBLV extended AI virus shedding period and increased the recovery rate of AI virus from feaces. However, the coinfection of Newcastle disease live vaccines (NDLVs) had no considerable adverse effects on AIV infection in broiler chickens.

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