First detection and genetic characterization of chicken infectious anemia virus in the Mekong Delta, Vietnam

Background

Chicken infectious anemia (CIA) caused by the CIA virus (CIAV) is considered one of the most important immunosuppressive diseases affecting chickens and recently poses a great economic burden to the poultry industry worldwide.

Aim

This study aims to identify the presence of CIAV in the Mekong Delta (MD), Vietnam, and to determine genotypes of CIAVs that are currently circulating in this area.

Methods

Organ samples (spleen, liver, and thymus) of 144 chickens suspected with CIA from 47 poultry farms were collected. A total of 47 pooled samples, each containing 2-4 chickens from each farm, were tested for the presence of CIAV.

Results

Twenty out of 47 pooled organ samples (pool of 2-4 chickens per farm) were positive for CIAV using polymerase chain reaction targeting the viral VP1 gene. The VP1 amplicons of eight representative CIAVs were subjected to sequencing and genetic characterization. Phylogenetic analysis based on partial VP1 gene sequence revealed that the CIAVs detected in the MD grouped into different genotypes of II, IIIa, and IIIc together with CIAVs previously detected in the northern Vietnam and other Asian countries. The phylogenetic analysis also confirmed that detected CIAVs genetically differed from vaccine strains. In addition, deduced amino acids of the VP1 identified several critical amino acid substitutions in the VP1 protein that are likely associated with the virulence of CIAV.

Conclusion

This is the first report to detect and determine the genetic characterization of the circulating CIAVs in the MD. Therefore, this study provides an important understanding of the evolution of CIAVs and highlights the importance of implementing prompt control measures against CIAVs in the MD and Vietnam.

Whole genome analysis and molecular characterization of chicken infectious anemia virus from an outbreak in a layer flock reveals circulation of genogroup IIIb in South India

The complete genome (2298 nucleotides) of the economically important and immunosuppressive, chicken infectious anemia virus (CAV), from a disease outbreak in a layer flock is discussed. This is the first report of a complete genome sequence of CAV from India. The phylogenetic analyses grouped this isolate with CAV genogroup IIIb based on both complete genome and capsid protein (VP1) sequences. The analyses further revealed the presence of CAV genogroups II, IIIa and IIIb in India. The VP1 sequence identity ranged between 84.4 to 99.3% with that of the Indian isolates and carried a unique substitution at position 447 (serine instead of threonine). Two novel amino acid substitutions were observed at position 52 of VP1 (serine instead of proline) and at position 26 of VP2 (asparagine instead of serine). Sequence analyses of VP1, VP2 and VP3 suggested that the isolate could be attenuated. Comparison with CAV variants, isolated from mammalian species, showed similarities in the numbers of certain transcription factor binding sites in the non-coding regions. Recombination analysis detected no recombination events in this isolate. Further investigations are needed to understand the implications of the unique features of this isolate on viral virulence.

Molecular characterization and the first full sequencing genome of chicken infectious anemia virus (CIAV) in Iran

BACKGROUND

The chicken infectious anemia virus (CIAV) is an important pathogen that causes severe immunosuppression in young chickens.

AIMS

The study aims to characterize the genotype and full-length sequencing of CIAV strains in Iran.

METHODS

First, the collected thymus samples were investigated by conventional PCR for CIAV detection. Second, one of the CIAV positive samples (UT-Zahraee) was chosen for full genome sequencing.

RESULTS

Throughout 2017, we detected 13 CIAVs isolated from 40 broiler flocks of different provinces of Iran. A comparison of the complete sequences of the genome and homologies of the nucleotides revealed that UT-Zahraee had a high similarity with American and Egyptian CIAV isolates. Moreover, VP1 sequence analysis showed that UT-Zahraee shared high homology with previously reported Iranian CIAV strains, Chinese, and Egyptian isolates.

CONCLUSION

This study is the first report of full genome sequencing of CIAV strain from Iran. It will be beneficial to understand better the epidemiology and molecular characteristics of CIAV circulating in Iran.

Newcastle disease virus-attenuated vaccine co-contaminated with fowl adenovirus and chicken infectious anemia virus results in inclusion body hepatitis-hydropericardium syndrome in poultry

Inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) induced by fowl adenovirus type 4 (FAdV-4) has caused huge economic losses to the poultry industry of China, but the source of infection for different flocks, especially flocks with high biological safety conditions, has remained unclear. This study tested the pathogenicity of Newcastle disease virus (NDV)-attenuated vaccine from a large-scale poultry farm in China where IBH-HPS had appeared with high mortality. Analysis revealed that the NDV-attenuated vaccine in use from the abovementioned poultry farm was simultaneously contaminated with FAdV-4 and chicken infectious anemia virus (CIAV). The FAdV and CIAV isolated from the vaccine were purified for the artificial preparation of an NDV-attenuated vaccine singly contaminated with FAdV or CIAV, or simultaneously contaminated with both of them. Seven-day-old specific pathogen-free chicks were inoculated with the artificially prepared contaminated vaccines and tested for corresponding indices. The experiments showed that no hydropericardium syndrome (HPS) and corresponding death occurred after administering the NDV-attenuated vaccine singly contaminated with FAdV or CIAV, but a mortality of 75% with IBH-HPS was commonly found in birds after administering the NDV-attenuated vaccine co-contaminated with FAdV and CIAV. In conclusion, this study found the co-contamination of FAdV-4 and CIAV in the same attenuated vaccine and confirmed that such a contaminated attenuated vaccine was a significant source of infection for outbreaks of IBH-HPS in some flocks.

Combined administration of the apoptin gene and poly (I:C) induces potent anti-tumor immune response and inhibits growth of mouse mammary tumors

BACKGROUND

Many viral proteins exhibit selective cytotoxicity for tumor cells without affecting the normal diploid cells. The apoptin protein of chicken infectious anemia virus is one of such proteins, which has been shown to kill tumor cells specifically. However, an effective cancer treatment strategy also requires assistance from the immune system. Recently, poly (I:C) has been shown to be an effective cancer vaccine adjuvant.

AIM

In this study, we assessed the anti-tumor potential of apoptin gene transfer alone and in combination with poly (I:C) in a 4T1 mouse mammary tumor model.

METHODS

4T1 cells were used to induce mammary tumor in Balb/c mice. Mice bearing tumors were divided into 6 groups, and each group received six intratumoral injections during a period of one month. After the last immunization, the animals were sacrificed, and peripheral blood, spleen, lungs, liver, heart, kidney and tumor tissues were collected for immunological, molecular and pathological analysis.

RESULTS

We report that intratumoral administration of apoptin plasmid along with poly (I:C) not only significantly inhibited the growth of mammary tumor, but also induced a potent anti-tumor immune response as indicated by the increase in blood CD4+, CD8+ cells and infiltration of immune cells in the tumor tissue. Further, blood serum analysis of the cytokines revealed increased secretion of Th1 cytokines (IFN-γ and IL-2).

CONCLUSIONS

The results of our study demonstrate that the inclusion of poly (I:C) significantly enhanced the anti-tumor activity of apoptin mainly by inducing a potent anti-tumor immune response. Therefore, we report the use of apoptin and poly (I:C) combination as a novel and powerful strategy for cancer immunotherapy.