Avian Pox Fowl Pox (FP) Chicken Pox Sore head Avian diphteria

Avian Pox
Fowl Pox (FP)
Chicken Pox
Sore head
Avian diphtheria (wet form)
Canker
Dr./ Wafaa Abd El-ghany
Assistant Professor of poultry dis.,
Fac. Vet. Med., Cairo Univ.
Definition
• AP is a contagious viral diseases of
poultry characterized by contagious
eruptions on the un-feathered parts of the
body and/or by diphtheritic lesions on the
mucous membrane of the upper digestive
and respiratory tract.
Etiology
• Pox viruses from family Poxviridae (DNA).
• Fowl pox virus (FPV), Turkey pox virus (TPV),
Pigeon pox virus (PPV) and Canary pox virus
(CPV).
• Theses viruses are serologically related but
differed in some biological and immunological
characters.
• It is the largest known virus (300mm), brick rd
shape.
• The virus shows great resistant to environmental
conditions (live 3-4 years in dry scab form).
Etiology
• The virus propagates on the chrioallantoic
membrane (CAM) of ECE produce grayish
foci of cell proliferation (Pock lesions).
• This virus show tropism to epithelial cells
of the skin and mucous membranes.
• The virus produces round o oval
cytoplasmic inclusions (Intracytoplasmic
inclusion bodies) (Bollingers bodies) which
could be seen histopathologically..
Susceptibility
• Natural infection occur in the skin of
chickens, turkeys, pigeons, canaries,
quails, pheasants, sparrows and some
other wild species in all ages.
• Ducks and geese are almost resistant, but
ducks are susceptible to turkey pox not to
chicken pox.
Mode of infection and
transmission
•
•
•
•
Wound infection via skin abrasions.
By direct contact.
Mechanically by mosquitoes.
Air born infection.
Pathogenesis
1. Pox virus enters epithelial cells (after infection
through wound or abrasion, spread from one
cell to cell locally inducing cell proliferation and
blood viraemia.
2. Then the virus spread to the internal organs
without pathological gross changes.
3. Finally the virus re-localized in the epithelial
cells iducing clinico-pathological changes.
Signs and lesions
•
The incubation period naturally 4-8 days
but experimentally 5-7 days.
•
The disease induces several forms:
I. Skin ( cutanous or dry) form.
II. Mucous membrane (wet, diphtheritic)
form.
III. Mixed form.
•
The disease course 3-4 weeks and in
complications 8-9 weeks.
Signs and lesions
I.
1)
2)
Skin (cutanous or dry) form:
Wart like nodules (grayish blister white spots)
on the un-feathered parts of the bird’s body
(comb, wattles, around eyes, base of the peak,
legs, under the wings and around the vent).
Firstly papules (due to increase epithelial cells),
then vesicles, pastules (yellowish caseous
material due to bacterial infections), later on
become crusts (yellow brown or dark brown),
the fall down (desquamated) leaving scar
tissues.
Signs and lesions
II.
1)
2)
Mucous membrane (wet, diphtheritic)
form:
Diphtheritic membrane (pastule like nodules)
on the upper digestive, upper respiratory tract
and nasal cavity.
Yellow pastules changed to caseous necrotic
material invade the epithelium with fibrin and
necrotic cells forming what is called
pseudomembrane (diphtheritic membrane). It
is difficult to be removed (detached) and leave
a haemorrhagic surface (bloody erosions or
ulcers) due to fibrin threads.
Signs and lesions
III. Mixed form:
1) Cutanous lesion and diphtheritic lesion
in the same time.
2) This form is most frequently occur.
3) According to the number and location of
the lesions the birds may show slight to
severe systematic disturbance
(restlessness, inappetance, loss of
weight and drop in egg production).
Signs and lesions
• If the diphtheritic membrane present in:
1. Buccal cavity and pharynx: prevent the bird to
close its peak leading to inability to swallow the
food and water which resulting in gradual loss
of weight and may death from starvation.
2. Larynx and trachea: Difficult breathing
(dyspnae) which may lead to death from
suffocation (false or pseudo-respiratory
disease).
NB: Pure pox virus infection don’t lead to death.
Signs and lesions
•
•
•
If the skin lesions with the diphtheritic
membrane is present around the eye: coalesce
in the conjunctival mucous membrane leading
blindness of the bird and consequently
starvation and death.
Mortality rate 3-10% and may reach to 30-50%
in case of generalized lesions or complication
with other infections (Pasteurella, E. coli and
Mycoplasma).
These complications may result from lowering
of the bird’s resistance in the respiratory tract
from the diphtheritic membrane.
Diagnosis
• The lesions are suggestive.
• Histopathological sections from the lesions
revealed presence of intracytoplasmic
inclusion bodies (Bollingers bodies).
• Inoculation of the suspected material on
CAM of ECE gives pock lesions after 5-7
days ten confirm by histopathology.
• Identification by IGPT, NT passive HA and
ELISA test.
Differential diagnosis
• The wet for of FP should be differentiated from:
1. Vit. A def.: the diphtheritic membrane easily to
be removed leaving smooth and intact mucosa
under it.
2. Trichomoniasis in pigeons: flagellated motile
protozoon parasite.
3. Candidiasis: yeast like fungi.
4. T2 toxins: detection and determination of the
toxins.
5. ILT: Intranuclear inclusion bodies..
Prevention
1. Sanitation and sound management.
2. Vaccination:
• Living attenuated virus vaccine; Fowl pox
vaccine (FPV) for chickens and turkeys
(propagated in CAM), pigeon pox vaccine (PPV)
for chickens and turkeys and pigeons
(propagated in TC) and turkey pox vaccine
(TPV).
• These vaccines are given through wing web
sticking or stabbing (chickens and pigeons),
brushing of feather follicles in the upper part of
thigh or breast muscles (chickens and pigeons),
or through scarification of thigh (turkeys).
Prevention
Fowl pox vaccine (FPV):
• Fowl pox vaccine is commonly applied by
the wing-web method to 4-week-old
chickens and to pullets about 1-2 months
before egg production is expected to start.
It is also used to revaccinate chickens held
for the second year of egg production. The
vaccine is not to be used on hens while
they are laying.
Prevention
Fowl pox vaccine (FPV):
• Turkeys may be vaccinated by the wing-web
method, but the virus may spread and infect the
head region. The site of choice for vaccination is
about midway on the thigh.
• Initially, turkeys are vaccinated when they are 2-3
months old, but those to be used as breeders
should be revaccinated before production.
• Revaccination at 3-4-month intervals during the
laying season might be of some advantage,
depending on the level of risk.
• Fowl pox vaccine is not to be used on pigeons.
Prevention
• Vaccination against FPV is indicated under three
conditions:
a) When a flock on the premises was infected the
previous year, all young stock produced on the
premises or introduced from other sources should
receive fowl pox vaccine.
b) If pox was present the previous year and pigeon
pox vaccine was used, birds should be
revaccinated with fowl pox vaccine, because
immunity from pigeon pox vaccine is not of long
duration.
c) In areas where pox is prevalent, fowl pox vaccine
should be used for protection against infection
from neighboring flocks.
Prevention
Pigeon pox vaccine (PPV):
• Pigeon pox vaccine contains live, non attenuated,
naturally occurring virus from pigeons. If used
improperly, the vaccine can cause a severe
reaction in these birds. The virus is less pathogenic
for chickens and turkeys.
• Pigeon pox vaccine may be applied by the wingweb method and can be used on chickens of any
age. It is generally applied to chickens at 4 weeks
of age and about 1month before egg production is
expected to start.
Prevention
Pigeon pox vaccine (PPV):
• When birds younger than 4 weeks are vaccinated,
they should be revaccinated before the start of
production.
• Birds held for the second year of production
should be revaccinated.
• Turkeys can be vaccinated at any age by the
wing-web or thigh stick methods.
• Day-old poults can be vaccinated if necessary, but
it is better to wait until they are about 8 weeks old
so that a better immune response is obtained.
Prevention
Pigeon pox vaccine (PPV):
• Revaccination may be necessary and advisable
during the growing period.
• Turkeys retained as breeders should be
revaccinated.
• Pigeons can be vaccinated by the wing-web
method. The vaccine can be applied by the
feather follicle method, but this is not generally
employed. Differences in the immunizing
properties of pigeon pox vaccines have been
observed.
Prevention
Turkey Pox Vaccine:
• A live non attenuated vaccine is
commercially available for use in turkeys.
• The vaccine does not provide adequate
protection against fowl, pigeon, or quail
pox viruses.
Canary Pox Vaccine:
Quail Pox Vaccine:
Recombinant FPV vaccine:
Prevention
Vaccinal takes:
• The flock should be examined about 7-10 days after
vaccination for evidence of "takes”.
• " A "take" consists of swelling of the skin or a scab at the
site where the vaccine was applied and is evidence of
successful vaccination.
• Immunity will normally develop in 10-14 days after
vaccination. If the vaccine is properly applied to susceptible
birds, the majority of the birds should have takes.
• In large flocks, at least 10% of the birds should be
examined for takes.
• The lack of a take could be the result of vaccine being
applied to an immune bird, use of a vaccine of inadequate
potency (after the expiration date or subjected to
deleterious influences) or improper application.
vaccine takes on the chickens wing web. A take is a swelling
of the skin or scab in the site where the vaccine was applied
and is evidence of a successful vaccination.
Prevention
In ovo Vaccination:
• Recent success with in ovo administration
of FPV vaccines to 18-day·old chicken
embryos has provided encouraging results.
• With increasing use of in ovo vaccination,
the cost of vaccination and stresses
associated with handling the birds will be
reduced significantly.
Control
• Emergency vaccination:
1. It should be applied as early as possible from
the first appearance of signs (out-break).
2. Start vaccination with un-exposed birds.
3. The morbidity rate should not exceed 30-40%.
4. using living virus vaccine (pigeon pox vaccine)
because it induces mild post-vaccinal reaction
less than fowl pox vaccine.
5. The vaccine is given intradermal through wing
web or feather follicle method.
Control
•
•
•
•
1.
2.
3.
4.
5.
Eradication of ectoparasites or insects.
Removal of causes of abrasions, wounds as
cannibalism and the causes of mechanical trauma.
Avoid complicating factors as Pasteurella, E. coli and
Mycoplasma.
Treatment of valuable birds:
Removal of lesions.
Wash or paint with Tr. Iodine with glycerin (1:4).
Antibiotic course for secondary bacterial infections.
Multi-vitamins especially vit. A to repair damaged
epithelium and vit. E to increase the bird resistance.
Stimulate the appetite by giving wet mash.
Prevention
•
1.
2.
3.
Precautions of vaccination:
Follow the preservation and dilution of the vaccine.
Prepare the vaccine away from the farm.
Vaccinate at 1-2 month before egg production to avoid
drop in egg production.
4. Separate vaccinated from non-vaccinated birds to avoid
contact infection.
5. The vaccinal vial should be opened before immediate
use.
6. Only one vial should be opened and the contents should
be used within 2 hrs.
7. Vaccine should be in contact with birds only at the time
of vaccination.
8. Wash hands after vaccination.
9. All contaminated vaccine equipments, empty vials should
be condemnated by incineration.
10. No prepared vaccine should be saved for later use.