VIOLIN: Vaccine Investigation and Online Information Network

Chicken Anemia Virus

Table of Contents

General Information
Vaccine Related Pathogen Genes
1. VP1 (Protective antigen)
2. VP2 (Protective antigen)
Vaccine Information
References

I. General Information

1. NCBI Taxonomy ID:

12618

2. Disease:

Chicken infectious anemia, Blue wing disease, Anemia dermatitis syndrome, Hemorrhagic aplastic anemi

3. Introduction

Chicken anemia virus (CAV), a 25 nm, nonenveloped, icosahedral virus with a single-stranded, circular DNA genome, is the only member of the genus Gyrovirus of the Circoviridae family. The genome codes for 3 viral proteins (VP). VP1 is the capsid protein, but VP2 may be needed as a scaffold protein to allow proper folding of VP1. VP3, or apoptin, is a nonstructural protein that induces apoptosis in infected cells. CAV infects only chickens, although antibodies have been detected in Japanese quail. The virus is present worldwide based on serology and virus isolation. The disease, chicken infectious anemia, has been described in most countries where chickens are raised commercially.
Horizontal transmission of CAV is by the fecal-oral route and perhaps by the respiratory route. Vertical transmission occurs when seronegative hens become infected and continues until neutralizing antibodies develop. Chicks hatched from these eggs are viremic, and CAV can rapidly spread horizontally from these chicks to susceptible, maternal antibody-negative hatchmates. Roosters shedding CAV in the semen are another source of vertical transmission. Vaccination of seronegative flocks prior to the onset of egg production is recommended to prevent vertical transmission (Merck Vet Manual: Chicken Anemia Virus Infection).

4. Microbial Pathogenesis

The principal sites of CAV replication are hemocytoblasts in the bone marrow, precursor T cells in the cortex of the thymus, and CD8 cells in the spleen. Replication in the first leads to anemia, while replication in the latter two causes immunosuppression. Neutralizing antibodies are detectable 21 days after infection and clinical, hematologic, and pathologic parameters return to normal ~35 days after infection. CAV infection has adverse effects on proliferative responses of spleen lymphocytes and on the production of interleukin-2 and interferons by splenocytes. Infection can cause a marked decrease in generation of antigen-specific cytotoxic T cells directed against other pathogens. In addition to T-cell defects, macrophage functions such as Fc-receptor expression, phagocytosis, and antimicrobial activity may be impaired. Subclinical, horizontally acquired infection with CAV in broiler progeny of seropositive parent flocks may be associated with impaired economic performance (Merck Vet Manual: Chicken Anemia Virus Infection).

5. Host Ranges and Animal Models

Chickens

II. Vaccine Related Pathogen Genes

1. VP1

Gene Name : VP1
Sequence Strain (Species/Organism) : Chicken Anemia Virus
NCBI Protein GI : ABJ90436
Other Database IDs : CDD:282072
Taxonomy ID : 12618
Protein Name : VP1
Protein pI : 11.12
Protein Weight : 50262.7
Protein Length : 496
Protein Note : Gyrovirus capsid protein (VP1); pfam04162

Protein Sequence : Show Sequence

>ABJ90436.1 VP1 [Chicken anemia virus]
MARRARRPRGRFYAFRRGRWHHLKRLRRRYKFRHRRRQRYRRRAFRKAFHNPRPGTYSVRLPNPQSTMTI
RFQGVIFLTEGLILPKNSTAGGYADHMYGARVAKISVNLKEFLLASMNLTYVSKIGGPIAGELIADGSKS
QAAENWPNCWLPLDNNVPSATPSAWWRWALMMMQPTDSCRFFNHPKQMTLQDMGRMFGGWHLFRHIETRF
QLLATKNEGSFSPVASLLSQGEYLTRRDDVKYSSDHQNRWRKGEQPMTGGIAYATGKMRPDEQQYPAMPP
DPPIITSTTAQGTQVRCMNSTQAWWSWDTYMSFATLTALGAQWSFPPGQRSVSRRSFNHHKARGAGDPKG
QRWHTLVPLGTETITDSYMGAPASELDTNFFTLYVAQGTNKSQQYKFGTATYALKEPVMKSDSWAVVRVQ
SVWQLGNRQRPYPWDVNWANSTMYWGGQP

Molecule Role : Protective antigen
Molecule Role Annotation : (Sawant et al., 2015)

2. VP2

Gene Name : VP2
Sequence Strain (Species/Organism) : Chicken Anemia Virus
NCBI Protein GI : AIU44252
Other Database IDs : CDD:251643
Taxonomy ID : 12618
Protein Name : VP2
Protein pI : 7.89
Protein Weight : 23530.11
Protein Length : 260
Protein Note : TT viral ORF2; pfam02957

Protein Sequence : Show Sequence

>AIU44252.1 VP2 [Chicken anemia virus]
MHGNGGQPAAGGSESALSREGQPGPSGAAQGQVISNERSPRRYSTRTINGVQATNKFTAVGNPSLQRDPD
WYRWNYNHSIAVWLRECSRSHAKICNCGQFRKHWFQECAGLEDRSTQASLEEAILRPLRVQGKRAKRKLD
YHYSQPTPNRKKVYKTVRWQDELADREADFTPSEEDGGTTSSDFDEDINFDIGGDSGIVDELLGRPFTTP
APVRIV

Molecule Role : Protective antigen
Molecule Role Annotation : (Sawant et al., 2015)

III. Vaccine Information

1. Chicken Anemia Virus GD-G-12 Vaccine

a. Type:

Live, attenuated vaccine

b. Status:

Research

c. Host Species for Licensed Use:

None

d. Antigen

GD-G-12 strain (Zhang et al., 2015)

e. Preparation

Two CAV strains GD-G-12 (GenBank accession number: KF224931) and GD-E-12 (KF224929) were isolated from a commercial farm in southern China and have been previously described. The viruses were propagated in MDCC-MSB1 cells in RPMI-1640 medium supplemented with 10% fetal calf serum plus, 100 μg/mL kanamycin sulfate, and 1 μg/mL Fungizone. The cells were cultured in bottles in an incubator at 37 °C. (Zhang et al., 2015)

f. Immunization Route

Intramuscular injection (i.m.)

g. Description

CAV GD-G-12 inactivated vaccine induces high titers of CAV specific antibodies and resistance to CAV challenge in hens. (Zhang et al., 2015)

h. Chicken Response

Vaccination Protocol: The levels of maternal CAV antibodies passed from vaccinated hens to their chicks were measured. Ninety SPF hens at one day old confirmed free of CAV antibodies were purchased and divided into two groups (n = 30/group). Hens in the experimental group were vaccinated intramuscularly with 1 mL of the inactivated vaccine (7.9 × 10^17 copy/μL). The control group was inoculated with 1 mL of PBS. Fourteen days post-vaccination, the vaccinated hens received a second immunization with 1 mL of the inactivated vaccine (7.9 × 10^17 copy/μL). Forty-two days post-vaccination, fertilized eggs were collected from each group, incubated, and hatched in an automatic incubator. After the chicks had successfully hatched (approximately 21 days), chicks (n = 80) from vaccinated hens and control hens were divided into two sub-groups and placed into separate negative pressure chicken disconnectors. (Zhang et al., 2015)
Immune Response: Following vaccination with inactivated GD-G-12, the level of CAV specific antibodies increased, and peaked 8861 at 14 days after the second immunization. The antibody level remained elevated until 42 days after the second immunization. We next assessed whether the maternal antibodies were effectively transmitted to chicks. The antibody levels in chicks from the vaccinated and unvaccinated hens were assessed when the chicks were one day old. No CAV specific maternal antibodies were detected in chicks from the unvaccinated hens. In the chicks from vaccinated hens, the titer of CAV specific was 8518 on day 1. The levels remained detectable but started to decline on day 7 (8398), 14 (7780), and 21 (3500) after hatching. (Zhang et al., 2015)
Challenge Protocol: One sub-group of chicks from each group was challenged intramuscularly with 1 mL of GD-E-12 (5.6 × 10^16 copy/μL) at one day old.
Efficacy: Chicks from the vaccinated hens had a significantly greater mean body weight than chicks from the unvaccinated hens on days 7, 14, and 21 post challenge (P < 0.01). The mean thymus to body weight ratios were significantly increased in the chicks from the vaccinated hens compared to the chicks from the unvaccinated hens on days 7, 14, and 21 (P < 0.01). At day 7 post challenge the chicks from unvaccinated hens showed severe bleeding in the thymus, and at day 14 post challenge, these chicks had thymic atrophy and the thymus was yellow. Finally, by day 21 post challenge, the unvaccinated chicks had clear bloody spots in the thymus. There were no apparent signs of CAV pathology in the chicks from vaccinated hens on day 7, 14, or 21 post challenge. Similar results were observed in the histopathology studies. (Zhang et al., 2015)

2. Chicken Anemia Virus Live Virus Vaccine (USDA: 10A1.00)

a. Manufacturer:

Biomune Company

b. Vaccine Ontology ID:

VO_0001660

c. Type:

Live vaccine

d. Status:

Licensed

e. Location Licensed:

USA

f. Host Species for Licensed Use:

Chicken

3. Chicken Anemia Virus Live Virus Vaccine (USDA: 10A1.01)

a. Manufacturer:

Biomune Company

b. Vaccine Ontology ID:

VO_0001661

c. Type:

Live vaccine

d. Status:

Licensed

e. Location Licensed:

USA

f. Host Species for Licensed Use:

Chicken

4. Chicken Anemia Virus Modified Live Virus Vaccine (USDA: 10A1.10)

a. Manufacturer:

Intervet Inc.

b. Vaccine Ontology ID:

VO_0001662

c. Type:

Live, attenuated vaccine

d. Status:

Licensed

e. Location Licensed:

USA

f. Host Species for Licensed Use:

Chicken

IV. References

1. Merck Vet Manual: Chicken Anemia Virus Infection: Merck Vet Manual: Chicken Anemia Virus Infection [http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/200200.htm]

2. Sawant et al., 2015: Sawant PM, Dhama K, Rawool DB, Wani MY, Tiwari R, Singh SD, Singh RK. Development of a DNA vaccine for chicken infectious anemia and its immunogenicity studies using high mobility group box 1 protein as a novel immunoadjuvant indicated induction of promising protective immune responses. Vaccine. 2015; 33(2); 333-340. [PubMed: 25448094].