avian leukosis

avian leukosis

(1) Marek’s disease. 
(2) See Avian leukosis-sarcoma virus group.

avian

pertaining to or emanating from members of the class Aves. See also bird.

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avian air sacs

see air sacs.

avian broodiness

the desire to sit on eggs and hatch them is very strong in birds after they have laid a few eggs at the beginning of a new egg laying season. The procedure is a disaster for the commercial egg producer because egg laying ceases. Temporary measures are available to discourage hens from going broody but the long-term practice has been to select against it so that modern egg laying strains of birds do not show broodiness.

avian diseases

diseases affecting birds. For individual diseases see under etiological or pathoanatomic keyword, e.g. avian arizonosis, myeloblastosis (2).

avian hepatitis B-like virus

see avihepadnavirus.

avian incubation periods

quail hatch in 16-18 days, chickens in 21, ducks in 28 days (Muscovies are an exception—33-35 days) and turkeys in 28 days. In some wild species hatching is synchronized by communication between the eggs.

infectious avian nephrosis

see infectious avian nephrosis.

avian influenza

a highly contagious disease caused by influenza A virus, affecting fowl, turkeys, pheasants and some wild birds, but rarely waterbirds or pigeons. Clinically there is a short course and very heavy mortality; birds that survive have a nasal discharge, white necrotic spots on the comb and wattles, and edema of the head and neck. Called also fowl plague. Some strains, notably H5N1 and H7N7, have emerged as the cause of fatal, but relatively rare, human infections.

avian leukosis

see avian leukosis.

avian lymphoid leukosis

see lymphoid leukosis.

avian malaria

a disease affecting most species of birds and caused by Plasmodium spp. (P. gallinaceum in fowl, P. juxtanucleare in fowl and turkeys, P. durae and P. griffithsi in turkeys). The disease is characterized by anemia which may be fatal. Transmission is by mosquitoes. See also plasmodium.

avian molt

see molting.

avian nesting

a strong biological urge to prepare a nest and lay eggs in it occurs in only some domestic birds. The building of a nest is stimulated by the previous laying of an egg.

avian oogenesis

the process from the time that the oocyte leaves the ovary until is produced with the typical avian flourish as a finished egg takes 25-26 hours. The yolk is added to the oocyte in the ovary and over a period of 60-70 days before the ovum is released. The oocyte is enveloped with albumen in the albumen-secreting section or magnum of the oviduct. The two shell membranes are added to the egg as it passes through the isthmus of the oviduct. The shell is added during a stay of about 15-20 hours in the shell gland, the last stop before the vagina. See also egg (4).

avian pox

see fowlpox.

avian reticuloendotheliosis virus

pathogenic avian retroviruses that are antigenically and genetically unrelated to avian leukosis/sarcoma retroviruses.

avian tuberculosis

see Mycobacterium aviumtuberculosis.

avian type C retroviruses

includes avian leukosis viruses and avian sarcoma viruses.

avian vibrionic hepatitis

see avian vibrionic hepatitis.

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leukosis

proliferation of leukocyte-forming tissue; the basis of leukemia.

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avian leukosis

a complex of related diseases caused by retroviruses (oncornaviruses). lymphoid leukosis, erythroblastosis, myelocytomatosis and myeloblastosis are the principal component diseases. There are in addition a series of tumors of connective tissue, epithelium, endothelium and other miscellaneous related tumors.

cutaneous bovine leukosis

see bovine viral leukosis.

enzootic bovine leukosis

see bovine viral leukosis.

leukosis-sarcoma neoplastic diseases

includes lymphoid leukosis, erythroblastosis, myeloblastosis, myelocytomatosis, connective tissue tumors, nephroma, nephroblastoma, miscellaneous epithelial and endothelial tumors, osteopetrosis of birds caused by avian type C oncoviruses.