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Avian reticuloendotheliosis in chickens – an update on disease occurrence and clinical course Full text
2018
Woźniakowski, Grzegorz | Frant, Maciej | Mamczur, Andrzej
Avian reticuloendotheliosis in chickens – an update on disease occurrence and clinical course Full text
2018
Woźniakowski, Grzegorz | Frant, Maciej | Mamczur, Andrzej
Avian reticuloendotheliosis (RE) represents an important immunosuppressive disease of poultry. The occurrence of RE in both chickens and turkeys has an immunosuppressive effect and may lead to vaccination failures. Avian reticuloendotheliosis virus (REV) is widely distributed in different kinds of birds, causing subclinical infections. Another important issue adhering to this disease is contamination of vaccines against fowl pox (FP) and Marek’s disease (MD) with REV. The capability of REV to integrate into the genome of other larger DNA viruses complicates its diagnosis and prevention. There are no efficient vaccines against RE nor treatment, which also complicates how to limit its impact on poultry farming. This paper reviews the current state of knowledge of this important immunosuppressive agent of poultry emphasising the importance of this problem in terms of diagnosis of RE.
Show more [+] Less [-]Avian reticuloendotheliosis in chickens – an update on disease occurrence and clinical course Full text
2018
Woźniakowski Grzegorz | Frant Maciej | Mamczur Andrzej
Avian reticuloendotheliosis (RE) represents an important immunosuppressive disease of poultry. The occurrence of RE in both chickens and turkeys has an immunosuppressive effect and may lead to vaccination failures. Avian reticuloendotheliosis virus (REV) is widely distributed in different kinds of birds, causing subclinical infections. Another important issue adhering to this disease is contamination of vaccines against fowl pox (FP) and Marek’s disease (MD) with REV. The capability of REV to integrate into the genome of other larger DNA viruses complicates its diagnosis and prevention. There are no efficient vaccines against RE nor treatment, which also complicates how to limit its impact on poultry farming. This paper reviews the current state of knowledge of this important immunosuppressive agent of poultry emphasising the importance of this problem in terms of diagnosis of RE.
Show more [+] Less [-]The main DNA viruses significantly affecting pig livestock Full text
2020
Díaz Carlos | Celer Vladimír | Frébort Ivo
The main DNA viruses significantly affecting pig livestock Full text
2020
Díaz Carlos | Celer Vladimír | Frébort Ivo
Swine DNA viruses have developed unique mechanisms for evasion of the host immune system, infection and DNA replication, and finally, construction and release of new viral particles. This article reviews four classes of DNA viruses affecting swine: porcine circoviruses, African swine fever virus, porcine parvoviruses, and pseudorabies virus. Porcine circoviruses belonging to the Circoviridae family are small single-stranded DNA viruses causing different diseases in swine including poly-weaning multisystemic wasting syndrome, porcine dermatitis and nephropathy syndrome, and porcine respiratory disease complex. African swine fever virus, the only member of the Asfivirus genus in the Asfarviridae family, is a large double-stranded DNA virus and for its propensity to cause high mortality, it is currently considered the most dangerous virus in the pig industry. Porcine parvoviruses are small single-stranded DNA viruses belonging to the Parvoviridae family that cause reproductive failure in pregnant gilts. Pseudorabies virus, or suid herpesvirus 1, is a large double-stranded DNA virus belonging to the Herpesviridae family and Alphaherpesvirinae subfamily. Recent findings including general as well as genetic classification, virus structure, clinical syndromes and the host immune system responses and vaccine protection are described for all four swine DNA virus classes.
Show more [+] Less [-]The main DNA viruses significantly affecting pig livestock Full text
2020
Swine DNA viruses have developed unique mechanisms for evasion of the host immune system, infection and DNA replication, and finally, construction and release of new viral particles. This article reviews four classes of DNA viruses affecting swine: porcine circoviruses, African swine fever virus, porcine parvoviruses, and pseudorabies virus. Porcine circoviruses belonging to the Circoviridae family are small single-stranded DNA viruses causing different diseases in swine including poly-weaning multisystemic wasting syndrome, porcine dermatitis and nephropathy syndrome, and porcine respiratory disease complex. African swine fever virus, the only member of the Asfivirus genus in the Asfarviridae family, is a large double-stranded DNA virus and for its propensity to cause high mortality, it is currently considered the most dangerous virus in the pig industry. Porcine parvoviruses are small single-stranded DNA viruses belonging to the Parvoviridae family that cause reproductive failure in pregnant gilts. Pseudorabies virus, or suid herpesvirus 1, is a large double-stranded DNA virus belonging to the Herpesviridae family and Alphaherpesvirinae subfamily. Recent findings including general as well as genetic classification, virus structure, clinical syndromes and the host immune system responses and vaccine protection are described for all four swine DNA virus classes.
Show more [+] Less [-]Genetic Phylocomparative Analysis of B2L, F1L Genes in Orf Virus Isolated from Felid Infected Sheep Full text
2023
Khetam Mayea | Hazim Thwiny | Hayder Ayyez
Contagious ecthyma virus Large, oval, double-stranded DNA viruses from the family Poxviridae they are distinct from other poxviruses due to their unusual spiral coat. Orf virus encoded highly conserved F1L gene, B2L gene, which codes for highly immunogenic envelope protein. Orf lesions were observed on the upper and lower lips, upper and/or lower eyelids, and around the mouth and nose of sheep. This study evaluated the histology and genetics of Orf virus in AL-Qadisyah sheep infected with infectious ecthyma. Positive histology is defined by the presence of subcorneal pustules, hydropic degeneration of necrotic keratinocytes, and epidermal hyperplasia with pronounced rete ridges. Samples were fixed in paraffin and sectioned into 5m slices. PCR on DNA-extracted samples was positive for both the B2L and F1L genes. Four positive samples were sequenced and recorded in GeneBank, and phylogenetic analysis was performed. Histopathology and clinical symptoms can aid in the diagnosis of infectious ecthyma rapidly and affordably, whereas PCR distinguishes between identical diseases in endemic regions. Analyzing the divergence between the inferred amino acid sequences of the incomplete B2L gene in different strains from Iraq OK336711.1, OK336710.1, and other Indians, we found that two locations contain different amino acid changes, resulting in a nucleotide and amino acid identity of 97.8% and 97.6%, respectively. The F1L envelope protein of the Iraqi strain OK330734.1 was comparable to those of China and India, while the envelope protein of the Italian strain OK330733.1 was identical to that of Italy.
Show more [+] Less [-]Hemagglutination by psittacine beak and feather disease virus and use of hemagglutination inhibition for detection of antibodies against the virus
1991
Ritchie, B.W. | Niagro, F.D. | Latimer, K.S. | Steffens, W.L. | Pesti, D. | Lukert, P.D.
Conditions for psittacine beak and feather disease (PBFD) virus hemagglutination and hemagglutination-inhibition (HI) test reactions are defined. The PBFD virus was found to hemagglutinate cockatoo and some guinea pig erythrocytes. The HI test was used to assay serum antibody titer in birds with active PBFD virus infections and in others that had been exposed to diseased birds. On the basis of HI antibody titers in psittacine birds that had been exposed to PBFD virus, but remained clinically normal, we suggest that some birds exposed to the virus are able to mount an effective immune response. Birds with active PBFD virus infections had lower antibody values than did birds that had been exposed to the virus, but remained clinically normal. On the basis of these findings, the ability to develop a suitable HI antibody response may be crucial in determining the disease status of susceptible birds exposed to the PBFD virus. If HI antibodies are found to have neutralizing activity, then the fact that a high HI titer was induced in birds inoculated with purified PBFD virus might suggest that an immunization program would be effective in preventing PBFD virus infections.
Show more [+] Less [-]Routes and prevalence of shedding of psittacine beak and feather disease virus
1991
Ritchie, B.W. | Niagro, F.D. | Latimer, K.S. | Steffens, W.L. | Pesti, D. | Ancona, J. | Lukert, P.D.
Psittacine beak and feather disease (PBFD) virus was recovered from the feces and crop washings from various species of psittacine birds diagnosed with PBFD. High concentrations of the virus also could be demonstrated in feather dust collection from a room where 22 birds with active cases of PBFD were being housed. The virions recovered from the feces, crop, and feather dust were confirmed to be PBFD virus by ultrastructural, physical, or antigenic characteristics. Virus recovered from the feather dust and feces hemagglutinated cockatoo erythrocytes. The specificity of the agglutination was confirmed by hemagglutination inhibition, using rabbit antibodies against PBFD virus. During the test period, 26% (8 of 31) of the birds screened were found to be excreting PBFD virus in their feces, and 21% (3 of 14) of crop washings were positive for PBFD virus. Some birds in the sample group had active cases of diarrhea, whereas others had normal-appearing feces. Diarrhea was found to be the only significant indicator of whether a bird was likely to be excreting virus from the digestive tract. These findings suggest that exposure of susceptible birds to PBFD virus may occur from contact with contaminated feather dust, feces, or crop secretions. Viral particles that were morphologically similar to parvovirus (2- to 24 nm-icosahedral nonenveloped virions) also were recovered from feces of some of the birds.
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