IB infectious bronchitis https://www.udemy.com/course/poultry-farming-viral-diseases-threaten-poultry-industry/?referralCode=EAFBDC5B623DADAAFD25

1. infectious Bronchitis
IB
IB is defined as a rapidly transmissible
disease caused by coronaviruses affecting the
respiratory, urogenital, and intestinal tracts of hybrid
layer, meat type, and fancy chickens of all age
groups. Lateral spread of IBV may also affect quails,

2. ETIOLOGY
Coronaviruses contain a single
molecule of linear single-stranded,
positive sense RNA of an
extremely large size.

3. EPIDEMIOLOGY
The predominant ways of virus entry into susceptible
birds are the respiratory and conjunctival routes
After replication in various internal organs,

4. The airborne spread
of IBV is the most common and most significant
mode of transmission in areas with a dense chicken population.

5. Insects (e.g., darkling beetle Alphitobius
diaperinus) and spiders can serve as mechanical
vectors and contribute to the lateral spread within
farms and between successive flocks
contaminated eggs and multiple-use
packing material.

6. CLINICAL SIGNS
Types and severity of clinical signs depend on the
particular
strain of IBV
host resistance,
sex,
levels of dust and noxious
gases (ammonia, carbon dioxide,
hydrogen sulfide) in the air, and types and levels of
secondary
bacterial and/or fungal infections.

7. incubation period of 18 to 36 hours
difficulties to breath develop. At
the beginning of the disease,
serous nasal discharge is observed.
Subsequently,
secondary bacterial infections result
in purulent discharge and
aggravation of the disease

8. chicks that have recovered and reached
egg-laying age may turn out to be
“false layers”
which is the result of an acute inflammation
of the epithelium of the infundibulum

9. Nephritogenic strains
Respiratory strains
Enteric strains
Respiratory signs

10. Eggs laid during the acute phase of
the disease contain watery egg
white.
The color
thickness
stability of these egg

11. IB. On left, nephritis with renal
hypertrophy.
Compare with normal kidney on
right (Chicken)

12. False layer” with large watery cyst in the
oviduct (variant QX).

13. B. Comparison of normal ovary (on
the left) and IB. Abdominal laying
can be seen in infected hens.
infected ovary (on the right).

14. Eggs are discolored
Small
deformed
altered eggshell
tend to break easily.

15. DIAGNOSIS
Clinical signs and gross pathological lesions are
suggestive
but not pathognomonic for the presence of IB.
inoculation of the
allantoic cavity of 9 to 11 day-old
eggs. Specific lesions

16. reverse transcriptase polymerase
chain reaction (RT-PCR) has been
developed.
Cytopathic changes
in chicken kidney cells (CKC) consist
of rounding and subsequent lysis of
cultured kidney epithelial cells.

17. An important prerequisite of a
successful vaccination
program is reliable information on
the serotypes involved in a given
region. Such information is usually
obtained by constant and long-term
flock
monitoring for sero- and
pathotypes of IBV.
The amino acid sequence at the
cleavage site may also be useful for
epidemiological investigations.

18. vaccine
If one of the newly emerged
serotypes is diagnosed, the
attenuated virus of these strains
should be used as a live vaccine. It
is also common practice
to apply an oil emulsion vaccine
containing formalin-inactivated
IBV by intramuscular injection
prior to the point of lay. Such
vaccines may contain
additional inactivated viruses as
well, e.g., Newcastle disease virus,
egg-drop syndrome virus,
and infectious bursal disease virus.

19. In high density poultry areas,
broiler and layer chicks are usually
vaccinated with highly attenuated
Massachusetts serotype IBV (H
120). The vaccine is administered
at the hatchery by spray
application. Pullets are
revaccinated once or twice
during the rearing period by less
attenuated
Massachusetts virus (H 52).

20. The duration of immunity following
application of live and inactivated IB
vaccines is estimated to be
one year