2017 Emerging and Re-emerging Infectious Diseases of Livestock __ Coronaviridae_ Infectious Bronchitis Virus

34 Pages·2017·1.04 MB·English

133
© Springer International Publishing AG 2017
J. Bayry (ed.), Emerging and Re-emerging Infectious Diseases of Livestock,
DOI 10.1007/978-3-319-47426-7_5

Coronaviridae: Infectious Bronchitis
Virus

Ahmed S. Abdel-Moneim

5.1
History

Infectious bronchitis was first reported in 1931 who had observed the disease in
North Dakota in the spring of 1930 (Schalk and Hawn 1931), and in 1936, the virus
etiology was established (Beach and Schalm 1936). Initially, IBV was recognized
as primarily a disease of young chickens; however it was later recorded to be com-
mon in semi-mature and laying flocks. Other manifestations of IBV include decline
in egg production in laying flocks noted following the typical respiratory disease in
the 1940s, kidney lesions observed in the 1960s (Cavanagh and Gelb 2008), enteric
lesions observed in 1985, and more recently proventriculus affection in 1998.

5.2
Classification

IBV is a large, enveloped, positive-stranded RNA gammacoronavirus that is related to
the family Coronaviridae, subfamily Coronavirinae, and within the order Nidovirales
(Table 5.1). The coronaviruses possess the largest RNA genome of all RNA viruses
and replicate by a unique mechanism associated with a multiple subgenomic nested
set of mRNAs and high frequency of recombination. The subfamily Coronavirinae
contains four distinct genera: Alphacoronavirus, Betacoronavirus, Deltacoronavirus,
and Gammacoronavirus. To date, viruses of Alphacoronavirus and Betacoronavirus
have been isolated from mammals, while deltacoronaviruses have been isolated from
birds and pigs (Table 5.1) (Woo et al. 2012). Meanwhile, gammacoronaviruses are

A.S. Abdel-Moneim
Department of Microbiology (Virology Division), College of Medicine, Taif University,
Al-Taif 21944, Saudi Arabia

Department of Virology, Faculty of Veterinary Medicine, Beni-Suef University,
Beni-Suef 62511, Egypt
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