Serological and growth rate responses to the use of chicken Newcastle disease vaccines in pigeons.

OBJECTIVE: In the face of an outbreak of pigeon paramyxovirus (PPMV), a vaccination response study was undertaken to determine if pigeons in Australia would produce a serological response similar to that considered protective in chickens. DESIGN: A vaccination study evaluated serological response and safety criteria in groups of 20 pigeons. METHODS: One group served as unvaccinated controls; one group was vaccinated with a live V4 strain of Newcastle disease virus (NDV) and subsequently revaccinated 28 days later with an inactivated La Sota strain vaccine; the third group was vaccinated twice with the inactivated La Sota strain vaccine 28 days apart. Serum was collected from the birds for serology 28, 56, 120 and 196 days after each treatment. Safety of the vaccines was determined using observation of the birds and body weight change. Serology was performed using three variations of the haemagglutination inhibition (HI) test, including chicken red blood cells (RBC) with either V4 NDV or PPMV as the antigen and pigeon RBC with V4 NDV as the antigen. A commercial NDV ELISA test was also used. RESULTS: At 28 days after the second vaccination, the geometric mean titres were 6.8 and 7.3 for the live/inactivated vaccine regimen and the inactivated/inactivated regimen, respectively. The serological response of birds vaccinated with the inactivated/inactivated regimen was significantly greater than that of the controls for all of the serological tests used. CONCLUSION: Vaccination of pigeons with two doses of chicken NDV vaccine 28 days apart was safe and resulted in antibody levels considered protective for NDV in chickens.

Behavioural responses of poultry during kosher slaughter and their implications for the birds' welfare.

Measurements were made during Shechita (kosher) slaughter of 692 meat chickens, including the behaviour of the birds during the procedure and the times from their removal from the crate, to neck cutting, bleed-out and shackling. Four of 100 birds showed a mild physical response to neck cutting but the others showed no response. Approximately 60 per cent of the birds showed a physical response to touching the eye or eyelid at up to 5 seconds after neck cutting, but by 15 seconds none showed this response. The birds became unable to retain their posture and suffered involuntary muscular contractions at 12 to 15 seconds after neck cutting and had lost approximately 40 per cent of their total blood volume by 30 seconds after neck cutting.

Safety and efficacy of two live Pasteurella multocida aro-A mutant vaccines in chickens.

Two auxotrophic aro-A mutants of Pasteurella multocida designated PMP1 (serotype 1) and PMP3 (serotype 3) were tested as vaccine candidates to protect chickens against fowl cholera. A reliable intratracheal challenge method was established that resulted in > or = 75% mortality in both specific-pathogen-free chickens and commercial broiler breeders 24 hr after challenge. Dose protection studies indicated that at least 10(6) colony-forming units (CFU) of PMP1 and 10(8) CFU of PMP3 were required to provide complete protection against challenge in all birds. Although high doses of 10(9) CFU of the vaccine strains produced some endotoxinlike reactions, lower but protective dose levels produced no clinical sign or lesion in any chicken. Both vaccine strains provided cross-protection with a heterologous challenge strain PM206 (serotype 4). Future studies will examine the duration of protective immunity induced by the two vaccine candidates, PMP1 and PMP3, and cross-protection against other serovars.

Safety of a temperature-sensitive clone of Mycoplasma synoviae as a live vaccine.

A temperature-sensitive (ts+) clone derived from the Australian Mycoplasma synoviae (MS) field isolate 86079/7NS was produced by chemical mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine and assessed for safety as a live vaccine. This clone, designated MS-H, was assessed for pathogenicity in three different models with air sac lesions as the criterion. No air sac lesions were observed when MS-H was administered to specific-pathogen-free hybrid white leghorn (HWL) chickens by eyedrop at 10 times the normal dose or directly into the thoracic air sacs or as an aerosol administered to specific-pathogen-free Webster white leghorn chickens with concurrent intratracheal T-strain infectious bronchitis virus (IBV). MS-H did not revert to virulence or lose the ts+ phenotype when passaged through five in vivo and 10 in vitro passages. No adverse effects were seen when HWL chickens were vaccinated concurrently with MS-H and combinations of Mycoplasma gallisepticum ts-11 vaccine, IBV vaccine, and infectious laryngotracheitis virus vaccine. Lateral transmission of MS-H was found to occur when vaccinated HWL chickens were mixed with unvaccinated chickens 2 wk after vaccination. At 1 wk after mixing, one out of two unvaccinated chickens had seroconverted to MS and was culture positive for MS. At 2 wk after mixing, both contact chickens were positive for MS by culture and serology.

Field evaluation of the safety and efficacy of a temperature-sensitive Mycoplasma synoviae live vaccine.

Mycoplasma synoviae (MS) strain MS-H was used in three separate commercial flocks for large-scale evaluation of the safety and efficacy of the vaccine under commercial conditions. MS-H successfully colonized meat and layer-breeders vaccinated by eyedrop and persisted for up to 55 wk after vaccination. Restriction fragment length polymorphism analysis showed that MS-H was the only strain isolated from two vaccinated flocks. In a third flock, challenge with a wild-type MS occurred, and this strain was isolated from both vaccinated and unvaccinated birds. Vertical transmission of MS-H was investigated by culturing pipped embryos and testing broiler progeny for MS antibody at processing (56 days old). No evidence of vertical transmission was detected. Lateral transmission of MS-H strain from vaccinated to unvaccinated birds occurred in one of the commercial flocks. Forty-one of 50 isolates of MS-H obtained from vaccinated flocks maintained their temperature-sensitive phenotype, but nine isolates showed a nontemperature-sensitive phenotype.

Serum total calcium, phosphorus, 1,25-dihydroxycholecalciferol, and endochondral ossification defects in commercial broiler chickens.

The research described in this paper relates the changes in serum concentration of calcium, phosphorus, and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] to changes in tibial ash percentage and the incidence of endochondral ossification defects (EOD) in flocks of commercially reared broiler chickens at 14 d of age. Sequential studies of six Australian broiler flocks representing three major genetic lines were undertaken at weekly intervals from 1 to 28 d of age. Serum collected from birds was analyzed for total calcium, inorganic phosphorus, and 1,25(OH)2D3. Tibial ash percentage was also determined at weekly intervals, and the incidence of EOD was determined at 14 d of age by examining sagittal sections of the proximal tibiotarsus. The EOD observed in the 14-d-old broiler chickens were characterized by enlarged zones of proliferating chondrocytes, similar to that which occurs during calcium- or vitamin D-dependent rickets. Three flocks had a 50% incidence of EOD at 14 d of age and were classified as severely affected. The other three flocks had incidences ranging from 12 to 16% and were classified as mildly affected. Broiler flocks severely affected with EOD (50% incidence at Day 14) had lower (P < or = .05) concentrations of 1,25(OH)2D3 than flocks mildly affected (12 to 16% incidence). Tibial ash percentages were lower (P < or = .05) in the severely affected flocks between Days 14 to 28, and it is likely that a lower rate of ash accretion between Days 7 to 14 precedes the development of the EOD.(ABSTRACT TRUNCATED AT 250 WORDS)

Some unusual diseases in the birds of Victoria, Australia.

The following unusual diseases were diagnosed in birds submitted to the Veterinary Research Institute, Victoria, between 1978 and 1987: the viral diseases beak and feather disease of psittacines, infectious laryngotracheitis in peafowls, a papovavirus-like inclusion body disease in psittacines, and pox; chlamydiosis; the bacterial diseases actinomycosis, listeriosis and mycobacteriosis; the fungal diseases favus, yeast infections and systemic zygomycosis; the protozoan diseases cryptosporidiosis, hexamitiasis, suspected leucocytozoonosis, sarcosporidiosis, toxoplasmosis, trichomoniasis and an unidentified protozoan-like organism which caused pneumonia in ducks; a variety of parasites; the metabolic disorders curled-toe paralysis in pheasant poults, encephalomalacia and parenchymatous goitre; toxicity due to dimetridazole and the ingestion of the leaves of the tobacco tree; and other non-infectious conditions including asphyxiation, burns, cataracts, cerebellar degeneration and atrophy, cystic right oviducts and exertional rhabdomyolysis.

The nucleotide sequence and evolution of ovine MHC class II B genes: DQB and DRB.

The nucleotide sequences of one Ovar-DQB gene, excluding exon 1 and parts of the introns, and one Ovar-DRB pseudogene are presented. The structure of the Ovar-DQB gene is typical of a major histocompatibility complex (MHC) class II B gene and demonstrates considerable sequence similarity with that of humans including such characteristics as the less common polyadenylation signal, ATTAAA. The ovine sequence has a typical 5' acceptor splice signal for exon 5, thus potentially encoding a full length cytoplasmic tail. The Ovar-DRB gene identified in this study was found to be a pseudogene, lacking a defined exon 2 and containing premature termination codons in both exons 3 and 4. The 3' donor splice site of exon 3 is also atypical. A purine-pyrimidine microsatellite repeat, (dC.dA)15, in the 3' region of the pseudogene may be a hotspot for recombination within the ovine DR subregion.

Nucleotide sequence, polymorphism, and evolution of ovine MHC class II DQA genes.

The nucleotide sequence of all exons and introns, excluding exon 1, of the ovine major histocompatibility complex (MhcOvar) genes analogous to the HLA-DQA1 and -DQA2 genes has been determined and the gene structure found to be similar to that reported for other species. The predicted amino acid sequences of the Ovar-DQA genes have been compared with the equivalent DQA genes in man, mouse, rat, rabbit, and cattle and used to determine the evolutionary relationships of the sheep class II genes to these other species. Northern blot analysis of sheep mRNA using exon specific probes for each of the two Ovar-DQA genes show that both genes are transcribed, whereas in humans there is no evidence that HLA-DQA2 is transcriptionally active. Restriction fragment length polymorphisms (RFLPs) have been used to define a polymorphic series of alleles in both Ovar-DQA genes and have indicated that the number of DQA genes is not constant in sheep as it is in humans, but varies with the haplotype.

Genetic selection for disease resistance and traits of economic importance in animal production.

Significant advances have been made in recent years in improving animal stocks by selective breeding. However, existing selection techniques still rely on laborious and time-consuming progeny-testing programs and often depend on subjective assessment of the phenotype. New techniques in molecular genetics are being developed, aimed at the isolation and identification of DNA markers linked to genes for economically important production traits and disease resistance. When available, these markers will provide animal breeders with an objective test system to identify, at birth or even earlier, animals carrying desirable genes. This review outlines some of these new techniques and how they may be applied to the animal industries. Consideration is also given to some of the recent advances in our understanding of the immune system and of possible mechanisms of genetic control of animal disease resistance or susceptibility. The current knowledge of major histocompatibility complex (MHC) and non-MHC associated disease resistance/susceptibility in domestic animals is summarised and mechanisms which may be responsible for these associations are presented. Genes that control such factors as macrophage activation, cytokines, cytokine receptors and gamma delta-T cell receptors are also presented as potential candidates for analysis in genetic disease association studies. Ultimately, the goal will be to identify genes or DNA markers which can be used to select for or to genetically engineer disease resistance and enhanced production traits.

Parasitic enteritis in superb lyrebirds (Menura novaehollandiae).

Ten free-living superb lyrebirds (Menura novaehollandiae) from forest habitat in southern Victoria, Australia were examined at necropsy over a 10 yr period. The acanthocephalan Plagiorhynchus menurae was identified in two lyrebirds from forest habitat in southern Victoria, Australia. There was necrotic enteritis in the duodenum associated with the acanthocephalans, with secondary bacterial involvement. The lesions probably resulted in the observed emaciation and debilitation of the birds. Probably the forest-floor habitat and insect diet of lyrebirds exposes them to these infections.

Biochemical and molecular analysis of sheep MHC class II molecules.

A panel of monoclonal antibodies was used for structural and immunodepletion analysis of sheep MHC class II molecules. The results indicate the antibodies recognize molecules of molecular weight 32-34,000 (alpha chain) and 26-28,000 (beta chain). Immunodepletion analysis indicates that the antibodies may recognize up to four distinct class II molecules some of which are structurally distinguishable using SDS-PAGE. Southern blot analysis using HLA-D region DR, DQ, DP, DO and DZ cDNA probes showed that a number of the cDNA probes hybridized specifically to sheep DNA indicating the presence of closely related genes in sheep. Together the results suggest that the sheep MHC class II region contains distinct MHC class II genes similar to those found in man.

Genetic organization of the ovine MHC class II region.

To study the class II genes of the major histocompatibility region of the sheep genome, human HLA class II genes corresponding to the known subregions in man (DR, DQ, DP, DO, and DZ) were used for Southern hybridization analysis of sheep DNA and to probe a sheep genomic library. Hybridizing bands were noted for all probes except DP alpha. DQ alpha and beta and DR beta appear to be present as multicopy genes, while DR alpha-, DZ alpha-, and DO beta- like genes appear to be single copy. All bands detected with the DP beta probe were also detectable with other beta chain probes. From eight lambda-bacteriophage clones of a sheep genomic library nine distinct class II genes were identified. These genes were characterized by differential hybridization analysis and restriction mapping. Two genes were DR beta-like, three DQ alpha-like and four DQ beta-like. The extensive cross-hybridization observed with beta chain probes was not seen with alpha chain probes. The results of this study suggest that the major histocompatibility complex class II region of the sheep has a similar genetic organization to that of man, with the provisional exception of the DP subregion.

Toxicity episodes involving agricultural chemicals and other substances in birds in Victoria, Australia.

A series of case reports detailing observations on toxicity episodes in birds caused by a variety of agricultural chemicals and other substances is presented. These problems arose as a result of ignorance, accident and malicious intent. The episodes involved maldison, monocrotophos, fenitrothion, trichlorofon, dieldrin, chlordane, endrin, metaldehyde, bromadiolone, arsenic, lead and zinc. An unresolved episode where toxicity was implicated is also included.