''Avibirnavirus'' is a genus of
virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
es in family ''
Birnaviridae
''Birnaviridae'' is a family of double-stranded RNA viruses. Salmonid fish, birds and insects serve as natural hosts. There are currently 11 species in this family, divided among seven genera. Diseases associated with this family include infec ...
''.
There is a single species in this genus: ''
Infectious bursal disease virus
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmiss ...
'', which infects chickens and other fowl. It causes severe inflammation of the
bursa of Fabricius In birds, the bursa of Fabricius (Latin: ''bursa cloacalis'' or ''bursa fabricii'') is the site of hematopoiesis. It is a specialized organ that, as first demonstrated by Bruce Glick and later by Max Dale Cooper and Robert Good, is necessary for ...
, and causes considerable morbidity and mortality.
History
Initially, the virus was discovered in 1957 in
Gumboro,
Delaware
Delaware ( ) is a state in the Mid-Atlantic region of the United States, bordering Maryland to its south and west; Pennsylvania to its north; and New Jersey and the Atlantic Ocean to its east. The state takes its name from the adjacent Del ...
,
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
Later, the disease was termed
Gumboro disease. Since its discovery, the virus has been found to have a worldwide distribution.
Structure
Avibirnaviruses are non-enveloped, and their single shelled icosahedral capsid exhibits a T=13 symmetry. The diameter of the capsid is around 70 nm.
Genome
The double-stranded RNA genome of Avibirnaviruses is linear and segmented into two segments (A and B).
The combined lengths of the two segments is around 6,000 nucleotides, almost entirely composed of reading-frames. The genome codes for 4-5 proteins depending on the strain.
The high degree ofÂ