Fowl Pox Vaccine Research Articles

Enhanced Expression of the L1R Gene of Vaccinia Virus by the tPA Signal Sequence Inserted in a Fowlpox-Based Recombinant Vaccine.

The use of Vaccinia virus (VACV) as a preventive vaccine against variola, the etiological agent of smallpox, led to the eradication of smallpox as a human disease. The L1 protein, a myristylated transmembrane protein present on the surface of mature virions, plays a significant role in infection and morphogenesis, is well-conserved in all orthopoxviruses, and is the target of neutralizing antibodies. DNA recombinant vaccines expressing this protein were successfully used, but they showed lower efficacy in non-human and human primates when used alone, and viral-vectored fowlpox vaccines were already proved to increase immunogenicity when used as a boost. Here, we constructed a novel fowlpox-based recombinant (FPtPA-L1R), in which the tissue plasminogen activator signal sequence was linked to the 5' end of the L1R gene to drive the L1 protein into the cellular secretion pathway. FPtPA-L1R expresses a functional heterologous protein that can be immunoprecipitated by hyperimmune rabbit serum. The protein shows cytoplasmic and membrane subcellular localizations and long-lasting expression in CEF, non-human primate Vero and human MRC-5 cells. The tissue plasminogen activator signal sequence can thus contribute significantly to the expression of the L1 protein and may enhance the immunogenicity of a putative DNA/FP prime-boost vaccine.

Outbreak Of Fowlpox In Commercial Brown Pullets Previously Vaccinated With Fowlpox Vaccine In Zaria, Kaduna State, Nigeria

Fowlpox is a contagious viral disease of poultry, ranked as the third most important cause of mortality in Nigerian indigenous chickens. The present study confirms an outbreak of fowlpox in a flock of 500 Isa brown, 11-weeks-old pullets in Zaria, Kaduna State, Nigeria. The pullets were managed under deep litter system and previously vaccinated with live attenuated vaccine (ABIC biological laboratories Ltd. Israel) at 8-weeks old. They had gross lesions suggestive of cutaneous fowlpox on skin of the head region with 58% morbidity but persistent low mortality rate of 13.8%. Fowlpox virus was isolated from the cutaneous lesions using chorioallantoic membrane (CAM) inoculation in 9 to 11-day-old embryonated chicken eggs based on the presence of opaque-white pock lesions, then confirmed by Agar Gel Immuno Diffusion test using homologous known fowlpox virus (antigen) and antisera. Specific antibodies to fowlpox virus were quantified from the sera of the chickens using an indirect ELISA (Abbkine, Inc, China). The case was managed using; Intramuscular injection of oxytetracycline (TLA), topical applications of oxytetracycline spray as well as oral administrations of Doxygen® and vitamins. Apparently healthy chickens were revaccinated against fowlpox and the pen was thoroughly cleaned, washed, and disinfected. This report had shown an occurrence of vaccine failure, alongside a promising management option and highlighted the significance of vaccination with strict biosecurity measures in the control of fowlpox in Nigeria.

Fowlpox virus in chicken’s skin: Persistence and the local immune response at the site of inoculation

Background: Fowlpox virus (FPV) has been used as a vector for many years. To date, surprisingly, very little data exist on the persistence of fowlpox vaccines in chicken tissues, or what kind of immune cells respond to vaccination at the site of inoculation. Although both humoral and cellular- mediated immunity (CMI) play a part in overall immunity against FPV, little is known regarding the cell-mediated immune responses to FPV infection. Aim: The main aim of this paper was to measure persistence of fowlpox vaccine in skin tissues following vaccination. Methods: One-day-old chicks were vaccinated with Fowlpox virus FP9. Skin samples were collected from the site of inoculation for several days following vaccination to assess the presence of for FPV, as well as other immune cells including macrophages, CD4+ T cells, CD8+ T cells, and B cells. Results: Results showed that FPV does not persist for long, and is cleared by 6 days post-vaccination (dpv). The response of immune cells (macrophages, B cells, CD4+ and CD8+ T cells) that infiltrated the site of vaccination was assessed. Conclusion: The results in this paper reflected the response at the site of inoculation following single vaccination, therefore, further studies regarding viral persistence and infiltration of immune cells at the site of inoculation after booster vaccination should be done.

KADAKNATH POULTRY FARMING – UPLIFT YOUR ECONOMY

Poultry farming is a profit earning business with less expenses. Mainly the chickens are reared for meat and eggs. Kadaknath is a dual purpose breed used for meat and eggs. The kadaknath is resistant to many diseases and well adaptable to any environmental conditions. It is a black flesh fowl. The varieties of kadaknath are jet black, Pencilled and golden black kadaknath. The poultry shed for kadaknath can be established in minimum area of 2000 square feet. The poultry shed should be kept clean and disinfectant must be sprayed twice a month to prevent disease attack. Grinded rava, pre- starter, starter and vegetable wastes are fed to kadaknath chickens. After six months kadaknath hens starts laying eggs and lay 100-120 eggs per annum per hen. The eggs are incubated in automatic incubator upto 17 days and after the embryo developed eggs are then incubated in manual incubator. On 18 -19th day the eggs are hatched out. F1 OR B1, IBD, lazota and fowl pox vaccine are vaccinated to kadaknath chickens. Kadaknath meat and eggs contains vitamins, minerals, protein and amino acids and it has great importance in curing various medical problems like head ache, post-delivery problems, nervous disorder and asthma.

The co-administration of live fowlpox and Newcastle disease vaccines by non-invasive routes to chickens reared by smallholders in Tanzania and Nepal

The co-administration of commercial live fowlpox (FP) and Newcastle disease (ND) vaccines when given by non-invasive (needle-free) routes was demonstrated to be safe and to elicit immunity in two field studies, one in Tanzania the other in Nepal. Both studies were of a cluster-randomised controlled design in which birds were randomly assigned to one of five treatment groups: (i) administration with FP vaccine alone (feather follicle), (ii) administration with ND vaccine alone (eye-drop), (iii) concurrent administration of FP (feather follicle) and ND (eye-drop) vaccines, (iv) concurrent administration of FP (wing-web) and ND (eye-drop) vaccines, and (v) unvaccinated, acting as environmental sentinels. Data from a total of 1167 birds from seven villages in Hanang District of Tanzania together with 1037 birds from eleven villages in Dhading District of Nepal were collected over a period of 21 and 28 days, respectively. Immune responses to FP vaccination were evaluated by local take reactions, while those to ND vaccination were evaluated serologically by haemagglutination inhibition test. The two studies demonstrated that the concurrent vaccination of free-range, indigenous breeds of chicken with live FP and ND vaccines, both administered by non-invasive routes, was safe and induced immunity against FP and ND that were non-inferior to the administration of FP and ND vaccines alone. These findings are important to appropriately trained small-scale backyard poultry farmers as well as to paraprofessionals and community health workers helping to increase vaccine uptake and the control of both FP and ND in low- to middle-income countries.

Flow Cytometric Evaluation of CD4+ and CD8+ T-cell Immune Response in SPF Chickens Induced by Fowlpox Vaccine.

Fowlpox (FP) is a viral disease that is widely distributed throughout the world. The disease has an economic impact on the poultry industry, and its prevalence has even been reported in vaccinated flocks. The present study used flow cytometry to evaluate the CD4+ and CD8+ T-cell immune response of chicks induced by FP vaccine. 120 specific pathogen-free (SPF) 21-day-old chicks were randomly divided into three groups of 40. One group was used as negative control with PBS inoculation, the other two groups were inoculated with the local fowlpox vaccine produced by Razi Institute and commercial FP vaccines, and they were kept for five weeks. Peripheral blood mononuclear cells (PBMC) were isolated using Ficoll-Hypaque density gradients and the percentages of CD3+, CD3+, CD4+, and CD3+CD8+ T lymphocytes were analyzed with flow cytometry. Seven days post-immunization, a maximum (90-100%) swelling formation ("take") on the vaccination site was observed. The ratios of CD4+ to CD8+ T-lymphocytes in both vaccinated groups were significantly higher (p < 0.05) than the control group inoculated with PBS. The percentages of CD3+, CD3+CD4+, and CD3+CD8+ T-lymphocytes were increased in chickens vaccinated with commercial and local FP vaccines. There were no significant differences between the groups receiving commercial and local fowl pox vaccines. The present study showed that protective immunity could be associated with increased cellular immune responses, which has been interpreted as enhancing T-cell proliferation and increasing CD4+ to CD8+ ratios through vaccination with the FP vaccine. This study further suggests that the induction of enhanced immune responses is due mainly to the Th1-type response.

First report on molecular characterization and phylogenetic analysis of Reticuloendotheliosis virus in Sudan.

The reticuloendotheliosis virus (REV) group of retroviruses infects a wide range of avian species, including chickens, turkeys, ducks, geese, quail, and prairie chickens. The infection can result in immunosuppression, runting syndrome, high mortality, acute reticular cell neoplasia, or T- and/or B-cell lymphoma. One PCR positive chicken spleen sample obtained in a previous study in addition to one Marek's disease and three fowl pox (FP) vaccine samples were investigated in this study. A PCR assay was performed to detect the presence of REV provirus DNA in these samples. The results indicated the contamination of fowl pox virus and Marek's disease vaccines with REV. In addition, detection of integration of REV inside the genome of fowl pox vaccine was confirmed using primers corresponding to the FPV DNA regions flanking the REV integration site. Alignments of two sequences, one from the spleen tissue and the other from contaminated FP vaccine with REV, with other REV (env) gene sequences obtained from GenBank indicated their high similarity. Furthermore, phylogenetic analysis indicated that the partial part of (env) gene of our two isolates was closely related to variants from India, USA, Taiwan, and China. These results confirmed the contamination of commercial fowl pox and Marek's disease vaccines used in Sudan with REV. Phylogenetic analysis indicated that the partial part of (env) gene sequences from Sudan was closely related to variants from India, USA, Taiwan, and China.

Efficacy of novel recombinant fowlpox vaccine against recent Mexican H7N3 highly pathogenic avian influenza virus

Since 2012, H7N3 highly pathogenic avian influenza (HPAI) has produced negative economic and animal welfare impacts on poultry in central Mexico. In the present study, chickens were vaccinated with two different recombinant fowlpox virus vaccines (rFPV-H7/3002 with 2015 H7 hemagglutinin [HA] gene insert, and rFPV-H7/2155 with 2002 H7 HA gene insert), and were then challenged three weeks later with H7N3 HPAI virus (A/chicken/Jalisco/CPA-37905/2015). The rFPV-H7/3002 vaccine conferred 100% protection against mortality and morbidity, and significantly reduced virus shed titers from the respiratory and gastrointestinal tracts. In contrast, 100% of sham and rFPV-H7/2155 vaccinated birds shed virus at higher titers and died within 4 days. Pre- (15/20) and post- (20/20) challenge serum of birds vaccinated with rFPV-H7/3002 had antibodies detectable by hemagglutination inhibition (HI) assay using challenge virus antigen. However, only a few birds (3/20) in the rFPV-H7/2155 vaccinated group had antibodies that reacted against the challenge strain but all birds had antibodies that reacted against the homologous vaccine antigen (A/turkey/Virginia/SEP-66/2002) (20/20). One possible explanation for differences in vaccines efficacy is the antigenic drift between circulating viruses and vaccines. Molecular analysis demonstrated that the Mexican H7N3 strains have continued to rapidly evolve since 2012. In addition, we identified in silico three potential new N-glycosylation sites on the globular head of the H7 HA of A/chicken/Jalisco/CPA-37905/2015 challenge virus, which were absent in 2012 H7N3 outbreak virus. Our results suggested that mutations in the HA antigenic sites including increased glycosylation sites, accumulated in the new circulating Mexican H7 HPAIV strains, altered the recognition of neutralizing antibodies from the older vaccine strain rFPV-H7/2155. Therefore, the protective efficacy of novel rFPV-H7/3002 against recent outbreak Mexican H7N3 HPAIV confirms the importance of frequent updating of vaccines seed strains for long-term effective control of H7 HPAI virus.

Avian leukosis virus subgroup – J as a contaminant in live commercially available poultry vaccines distributed in Nigeria

Globally, vaccines are used to prevent and control the menace of infectious diseases in livestock with some reported to be inadvertently contaminated with extraneous agents (EAs). With the aim of screening and characterizing for some selected EAs, 44 live viral poultry vaccines were randomly selected based on availability. The vaccines comprised 14 manufacturers in 10 different countries including Nigeria were screened by Polymerase Chain Reaction. In 9% (4/44) of the vaccines, contamination with only avian leukosis virus (ALV) subgroup J (ALV-J) was recorded. Other exogenous ALV subgroups, chicken infectious anemia and infectious laryngotracheitis viruses were absent. The EAs was found in infectious bursal disease (n = 1), Fowlpox (n = 2) and Mareks disease (n = 1) vaccines. Phylogenetic analysis of the ALV-J env gene showed clustering with contemporary group I and II. The result underscores the importance of screening vaccines to avoid the introduction and spread of EAs that could pose a threat to poultry production.

English

An experimental study was conducted on day-old chicks to evaluate the safety and efficacy of combined Newcastle diseases (ND), fowl pox (FP) and fowl typhoid (FT) vaccine. The vaccine was prepared using the Lasota strain of Newcastle disease virus (NDV), the FP strain of fowl pox virus (FPV) and the 9R strain of FT. The vaccine was found safe, as no clinical signs or mortalities were observed. Post vaccination Haemaglutination Inhibition (HI) titre for ND was above the required protection level (≥1:16) and its geometric means (GM) were 0.0098, 0.0063 and 0.0059 for group one, two and three respectively, who received conventional and combined vaccine. The difference in GM between the three vaccinated groups were not significant (p=0.544). The trivalent combined vaccine did not show significant difference in the HI titre result among the groups that were given conventional vaccines and the other two experimental groups which received trivalent vaccine (p=0.257). From 75 samples, 73 (97.3%) were positive for FT through rapid slide agglutination test (RSAT). The chicks were challenged separately for the three diseases using the specific pathogens. Both combined and conventional vaccine conferred protection upon challenge. For ND challenge, 93.3% (n=14/15) of the control groups died. From FT and FP control groups 86.6% (n=13/15) and 20% (n=3/15) respectively died up on challenge. Both combined and conventional vaccine type conferred a similar and good level of protection. However, the use of combined vaccine has considerable advantage particularly in terms of convenience and cost effectiveness to control multiple diseases through simple immunization schedule. Further studies were recommended on the development of combined avian vaccines in Ethiopia. Key words: Newcastle disease, fowl pox, fowl typhoid, experimental study, combined vaccine.

Molecular characterization of chicken infectious anemia virus from contaminated live-virus vaccines

The aim of this study was to investigate possible causes of the pervasiveness of chicken infectious anemia virus (CIAV) infection in chickens in recent years in China. A total of 14 batches of live-virus vaccines were examined using PCR to detect CIAV contamination, of which only 2 samples (a Newcastle disease vaccine and a fowl pox vaccine) tested positive for CIAV. These Newcastle and fowl pox vaccines were then inoculated into 1-day-old specific-pathogen-free chickens. Serum samples were collected from chickens infected with the PCR-positive vaccines, and these tested positive for CIAV-specific antibodies as tested using ELISA. In addition, DNA samples isolated from the serum samples also tested positive by PCR. The results indicated that the samples were contaminated with CIAV and identified 2 exogenous CIAV strains, designated CIAV-N22 and CIAV-F10, in the respective samples. The full genome sequences of these novel CIAV strains were sequenced and analyzed. Phylogenetic tree analysis indicated that the CIAV-F10 strain might represent a recombinant viral strain arising from the parental CIAV strains JQ690762 and KJ728816. Overall, the results suggested that vaccination with CIAV-contaminated vaccines contributed to the prevalence and spread of CIAV infection in chickens. Furthermore, the CIAV contaminant was likely subsequently transmitted to commercial chickens through congenital transmission. Our findings therefore highlight the need for more extensive screening of live-virus vaccines for poultry in China to reduce the threat of contamination with exogenous viruses.

Baby Grivet Monkey Kidney (BGM) a new cell line for adaptation of fowl pox virus

The need to economic, sensitive and easily maintained cell cultures use for massive production of fowl pox vaccine wasnecessary. We adapted Fowl pox virus (FPV) Baudette strain on Primary chicken embryo fibroblast (CEF), Baby GrivetMonkey Kidney cell line (BGM) and African green monkey kidney (Vero) cell lines. The highest virus titers were 106.5after the 9th passage in CEF and 106.2 after the 12th passage on BGM while Vero cells were abortive to the virus. BGMcells were selected for study cytopathic effect (CPE) and growth kinetic as it easily maintained than primary CEF cells.The characteristic CPE were rounding till 6th passage with intracytoplasmic inclusion by the 7th passage and syncytiumformation appeared from the 9th passage till the 13th passage. The virus was highly cell associated for the first 84h postinoculation(PI) with a titer of 104.5 then a maximum titer was 106.2 in cell free portion after 120h PI. In conclusion, BGMwere considered a new susceptible cell for growth of FPV with best harvesting time 120h PI to obtain a maximum titerfor subsequent vaccine production

Relationship Between Values of Fowlpox ELISA and the Presence of "Takes" After Vaccination.

Values from an ELISA for evaluating the immune response induced by a commercial vaccine against fowlpox virus and the lesion at the site of inoculation (i.e., swelling of the skin or a pox where the vaccine was applied) were compared. The ELISA was carried out with an antigen prepared by precipitation of a cell culture-propagated virus suspension with ammonium sulfate and concentration by centrifugation. A 0.1 M acetate buffer (pH 5) was used as the sensitizing solution for maximum specific binding of the antigen to the microplate plastic well. Four experiments were conducted where the birds were bled once a week before and after vaccination and then were examined simultaneously for evidence of "takes." This study showed that there is a relationship between the ELISA values to the fowlpox vaccine that are considered positive and the presence of postvaccination lesions.

Trials for increasing the infectivity titer of fowl pox vaccines prepared on SPF embroynated chicken egg and tissue culture

The present work was designed to study the effect of DEAE-dextran and Magnesium Chloride (MgCl) on fowl pox virus vaccine (FPV) in order to obtain a maximum titer allowing the massive production of the vaccine. Fowl pox virus; used for vaccine production; was propagated on embroynated chicken eggs (ECE) and chicken embryo fibroblast (CEF), the virus was inoculated in ECE and CEF without DEAE-dextran nor MgCl, and with DEAE-Dextran and MgCl separately. The time of harvestion was early as one day post inoculation in CEF. The virus titer were higher in case of treated inoculums with DEAE-dextran and MgCl reaching (6.2 and 7.5 log10TCID50/ml respectively) on CEF and (6.2 and 6.7 Log10EID50 respectively) on ECE. Fowl pox vaccines (FPV) were prepared before and after DEAE-Dextran and MgCl treatment. The application of quality control assays revealed the safety, sterility and potency of the prepared vaccines. Immune response of the prepared FPV vaccines were evaluated in chickens using virus neutrization test (VNT). It was found that, the use of DEAE-Dextran and MgCl with the recommended concentrations could result in increasing the virus titer with reduction in the time of harvestation and accordingly increase the vaccine production and decrease its cost.

Efficacy of fowl pox vaccines against Egyptian isolated strain during 2012

Aim: This study was designed to evaluate the protection induced by different commercial fowl pox (FP) vaccines against local FP virus isolated from Giza governorate in Egypt during 2012. Materials and Methods: Efficacy of FP vaccines against local field isolates was determined in seven groups of (20 birds/ group) 6 weeks old specific-pathogen free chicks. Each group was vaccinated via wing web with one of different FP living vaccines and (20) chicks in group (8) did not receive any FP vaccine and served as controls. At the 3rd, 5th, 7th and 10th-day post-vaccination (DPV), all birds were examined for the presence of takes at the site of vaccination. Three weeks post vaccination, serum samples were collected, and the levels of induced antibodies were detected by passive hemagglutination (PH) test. All birds in Groups (1-8A) were challenged individually via the wing web with EID50 103.0 of the Egyptian isolated strain during 2012. Results: Takes detected at the site of vaccination at the 3rd day were ranging from 45 to 70%. This percent increased to 80-95% at the 5th DPV with a maximum elevation of takes at the 7th DPV (90-100%). Geometric mean titer of PH assay antibody titer, 3 weeks post vaccination, was ranging between 5.60 and 9.60 according to the type of vaccine used and with protection 90-100%. Conclusion: Efficacy of some commercial FP vaccines used in the poultry field against the Egyptian isolated strain during 2012 ranged between 90% and 100% according to the type of used vaccine.

Integration of Reticuloendotheliosis Virus in Most of Tanzanian Fowl Pox Virus Isolates is not attributed to Imported Commercial Fowl Pox Vaccines

Aim: To investigate integration of reticuloendotheliosis virus (REV) in the Tanzanian fowlpox virus (FWPV) field isolates, and the imported commercial fowl pox vaccines currently used in the country. Study Design: Experimental. Place and Duration of Study: Faculty of Veterinary Medicine, Sokoine University of Agriculture, Morogoro, Tanzania; between June 2012 and October 2013. Methodology: Fifty five samples of FWPV isolates from naturally infected chickens, and two isolates of FWPV from samples of the imported commercial fowl pox vaccines were analyzed for integration of REV envelope (env) gene and REV 5'long terminal repeat (5'LTR). The study involved polymerase chain reaction (PCR) amplification of FWPV P4b gene, REV env gene, and REV 5'LTR; agarose gel electrophoresis of PCR products, Original Research Article British Biotechnology Journal, 4(6): 659-669, 2014 660 purification of PCR products, sequencing of the purified PCR products, and sequence analysis using standard procedures. Results: Out of 55 analyzed field isolates 53 (96.36%) were found to have REV inserts. Most of them [38 (69.09%)] contained both REV env gene and REV 5'LTR inserts, 10 (18.18%) contained inserts of REV env gene only, and 5 (9.09%) contained inserts of REV 5'LTR only. Two isolates (3.64%) were found to be integrated with neither REV env gene nor REV 5'LTR. None of the screened FWPV isolates from the imported commercial vaccines was found to have REV inserts. Sequence analysis revealed that genomic fragments of REV integrated in the Tanzanian FWPV isolate were closely related (99– 100% identity) to REV sequences integrated in FWPV isolates from other countries. Conclusion: Currently there is a heterogeneous population of FWPV in Tanzania comprising of REV-integrated FWPV strains and REV-free FWPV strains. Since strain(s) of REV-integrated FWPV are more virulent than strain(s) of REV-free FWPV, further studies on the REV-integrated Tanzania FWPV isolates aiming at obtaining the appropriate isolate for development of autogenous fowl pox vaccine are highly recommended.

Phylogenetic and histological variation in avipoxviruses isolated in South Africa

Thirteen novel avipoxviruses were isolated from birds from different regions of South Africa. These viruses could be divided into six groups, according to gross pathology and pock appearance on chick chorioallantoic membranes (CAMs). Histopathology revealed distinct differences in epidermal and mesodermal cell proliferation, as well as immune cell infiltration, caused by the different avipoxviruses, even within groups of viruses causing similar CAM gross pathology. In order to determine the genetic relationships among the viruses, several conserved poxvirus genetic regions, corresponding to vaccinia virus (VACV) A3L (fpv167 locus, VACV P4b), G8R (fpv126 locus, VLTF-1), H3L (fpv140 locus, VACV H3L) and A11R–A12L (fpv175–176 locus) were analysed phylogenetically. The South African avipoxvirus isolates in this study all grouped in clade A, in either subclade A2 or A3 of the genus Avipoxvirus and differ from the commercial fowlpox vaccines (subclade A1) in use in the South African poultry industry. Analysis of different loci resulted in different branching patterns. There was no correlation between gross morphology, histopathology, pock morphology and phylogenetic grouping. There was also no correlation between geographical distribution and virus phenotype or genotype.

Mixed Infections of Marek's Disease and Reticuloendotheliosis Viruses in Layer Flocks in Argentina

The presence of reticuloendotheliosis virus (REV) was examined in flocks affected with Marek's disease (MD). Sera were positive to REV antibodies by agar gel precipitation. However, these findings were not conclusive since fowlpox vaccines can have REV fragments or the whole genome inserted. Frozen sections from tumors were positive for MD virus (MDV) but negative for REV. Chicken embryo fibroblast (CEF) and chicken kidney cell (CKC) culture inoculated with buffy coat cells or blood from the affected birds were examined. Positive cells were shown for REV and MDV by fluorescent antibodies tests in CEF and CKC, respectively, indicating the presence of REV in Argentinean layer flocks. This is the first report of REV in Argentina and also in South America.

Evaluation of the pathogenicity of avipoxvirus strains isolated from wild birds in New Zealand and the efficacy of a fowlpox vaccine in passerines

Avipoxvirus (APV) infection is a highly contagious disease of birds and has been reported in more than 200 bird species, affecting both domesticated and free-ranging birds around the world. In New Zealand, at least three different strains of Avipoxvirus (APV) have been identified in a range of bird species.The pathogenicityof two APV strains isolated from wild birds in New Zealand, representing subclade A1 and subclade B1 were compared in zebra finches (Taeniopygia guttata). The efficacy of fowlpox vaccine at preventing clinical disease in passerines was also evaluated. Twenty-five zebra finches were divided into five groups (I-IV and a control group). Birds from Groups II and IV were vaccinated using fowl poxvirus vaccine prior to challenge. Subsequently two groups (I and II) were inoculated with a silvereye isolate (A1) and the other two groups (Group III and IV) were inoculated with a blackbird isolate (B1). Both inocula were previously propagated in chicken fibroblast cell culture. Birds in the control group were inoculated with sterile PBS. Skin thickness at the inoculation sites was measured and the development of additional skin lesions was monitored. Antibody development was measured by ELISA pre- and post virus inoculation. Both APV strains caused either swelling or hyperplasia at the inoculation site of non-vaccinated birds (4/5 in Group I and 5/5 in Group III). The swelling was milder and no foot lesions were observed in vaccinated birds before or after challenge with the silvereye or blackbird APV strains. These findings indicated that the fowlpox vaccine provided safe and appropriate protection for zebra finches exposed to the two wild APV strains and suggest that the vaccine has the potential to be used where APV threatens the captive management or translocation of endangered passerines.

The effects of vaccination, antibiotic and vitamin therapy on some clinical parameters associated with natural outbreak of fowlpox in chickens

The management of field outbreak of fowlpox in chickens was studied in a batch of 1050, five weeks old white cockerels. Post infection or emergency vaccination and the oral administration of antibiotics, and vitamins were investigated on how they can reduce the clinical parameter associated with fowl pox infections in chickens. Natural outbreak of fowlpox was observed in the birds at the age of five weeks and clinical signs of nodules and papules on the head and comb and the production of pocks on the chorio allantoic membranes (CAM) of embryonated chicken eggs was used to diagnose the infection. On observing the clinical signs, the birds were immediately divided into four groups. Group 1 received fowlpox vaccine only. Group 2 received the vaccine and Neoceryl® plus, a combination of antibiotics and vitamins. Group 3 received Neoceryl® plus only, while Group 4 did not receive any treatment. Birds in all the groups were monitored for the progress of the disease up to five weeks. Best results were obtained with birds in Group 2. This was closely followed by those in Group 1. Worst results were shown by birds in Group 4 and this was followed by those in Group 3. The result shows that post infection vaccination is good in the control of fowlpox in chickens especially when it is noticed early and a small percentage of the flock is infected. Controlling secondary bacterial infection and boosting immune responses with Neoceryl® plus played a good role. Key words: Post infection vaccination, antibiotic/vitamin supplementation, natural fowlpox.