avian

(ā'vē-ən)

[From Latin avis, bird.]

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Of, relating to, or characteristic of birds.

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

• a. air sacs — see air sacs.
• a. 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.
• a. diseases — diseases affecting birds. For individual diseases see under etiological or pathoanatomic keyword, e.g. avian arizonosis, myeloblastosis (2).
• a. hepatitis B-like virus — see avihepadnavirus.
• a. 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 a. nephrosis — see infectious avian nephrosis.
• a. 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.
• a. leukosis — see avian leukosis.
• a. lymphoid leukosis — see lymphoid leukosis.
• a. 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.
• a. molt — see molting.
• a. 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.
• a. 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).
• a. pox — see fowlpox.
• a. reticuloendotheliosis virus — pathogenic avian retroviruses that are antigenically and genetically unrelated to avian leukosis/sarcoma retroviruses.
• a. tuberculosis — see Mycobacterium avium tuberculosis.
• a. type C retroviruses — includes avian leukosis viruses and avian sarcoma viruses.
• a. vibrionic hepatitis — see avian vibrionic hepatitis.

• Animal Types and Parts - avian: (adj) of or like a bird