Fowlpox virus: The type species of the genus AVIPOXVIRUS. It is the etiologic agent of FOWLPOX.Fowlpox: A poxvirus infection of poultry and other birds characterized by the formation of wart-like nodules on the skin and diphtheritic necrotic masses (cankers) in the upper digestive and respiratory tracts.Poxviridae: A family of double-stranded DNA viruses infecting mammals (including humans), birds and insects. There are two subfamilies: CHORDOPOXVIRINAE, poxviruses of vertebrates, and ENTOMOPOXVIRINAE, poxviruses of insects.Vaccinia virus: The type species of ORTHOPOXVIRUS, related to COWPOX VIRUS, but whose true origin is unknown. It has been used as a live vaccine against SMALLPOX. It is also used as a vector for inserting foreign DNA into animals. Rabbitpox virus is a subspecies of VACCINIA VIRUS.Avipoxvirus: A genus of the family POXVIRIDAE, subfamily CHORDOPOXVIRINAE, comprising bird poxviruses. The type species is FOWLPOX VIRUS. Transmission is mechanical by ARTHROPODS.Reticuloendotheliosis Viruses, Avian: A group of viruses in the genus GAMMARETROVIRUS comprising a few isolates from birds, with no known corresponding endogenous relatives.Atadenovirus: A genus of ADENOVIRIDAE that comprises viruses of several species of MAMMALS and BIRDS. The type species is Ovine adenovirus D.Vaccines, Synthetic: Small synthetic peptides that mimic surface antigens of pathogens and are immunogenic, or vaccines manufactured with the aid of recombinant DNA techniques. The latter vaccines may also be whole viruses whose nucleic acids have been modified.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Reticuloendotheliosis virus: A species in the group RETICULOENDOTHELIOSIS VIRUSES, AVIAN of the genus GAMMARETROVIRUS that causes a chronic neoplastic and a more acute immunosuppressive disease in fowl.Reticuloendotheliosis, Avian: A group of pathologic syndromes found in avian species caused by RETICULOENDOTHELIOSIS VIRUS. The distinct syndromes include non-neoplastic runting, acute neoplastic disease, and chronic neoplastic disease. Humans and mammals appear resistant.Viral Vaccines: Suspensions of attenuated or killed viruses administered for the prevention or treatment of infectious viral disease.Genes, Viral: The functional hereditary units of VIRUSES.Immunization, Secondary: Any immunization following a primary immunization and involving exposure to the same or a closely related antigen.Chick Embryo: The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Reading Frames: The three possible sequences of CODONS by which GENETIC TRANSLATION may occur from one nucleotide sequence. A segment of mRNA 5'AUCCGA3' could be translated as 5'AUC.. or 5'UCC.. or 5'CCG.., depending on the location of the START CODON.Genetic Vectors: DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.RNA Viruses: Viruses whose genetic material is RNA.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Poultry Diseases: Diseases of birds which are raised as a source of meat or eggs for human consumption and are usually found in barnyards, hatcheries, etc. The concept is differentiated from BIRD DISEASES which is for diseases of birds not considered poultry and usually found in zoos, parks, and the wild.Newcastle disease virus: The most well known avian paramyxovirus in the genus AVULAVIRUS and the cause of a highly infectious pneumoencephalitis in fowl. It is also reported to cause CONJUNCTIVITIS in humans. Transmission is by droplet inhalation or ingestion of contaminated water or food.