Viral respiratory disease in birds Flashcards
Name 4 major diseases affecting poultry that are caused by RNA viruses:
Avian influenza
Newcastle disease
Avian infectious bronchitis
Avian rhinotracheitis
Name 3 major diseases affecting poultry that are caused by DNA viruses:
Avian infectious laryngotracheitis
Fowl pox
Quail bronchitis
Avian influenza (AI) s a highly contagious orthomyxovirosis that is characterized by the
involvement of the respiratory,
digestive, and nervous systems.
◦ Mostly in birds, can infect mammals
◦ Registrable (WOAH)
Viral genus and family for avian influenza.
DNA type?
genus Alphainfluenzavirus
Family Orthomyxoviridae
single-stranded RNA virus
Avian influenza subtypes are divided according to (2)?
How many of each type are there?
hemagglutinin (H, 18 types) and
neuraminidase (N, 11 types).
- More pathogenic are H1 (pigs), H5 and H7 (birds).
Epidemiology of avian influenza virus.
All birds are susceptible.
◦ Wild birds more resistant.
Source of infection: sick, recovered birds.
◦ Excrete the virus for up to 2 months after
clinical recovery.
Route of infection: respiratory,
alimentary.
Morbidity 80-100%
Mortality 10-100%
Localized or generalized forms.
Incubation period 1-7 days
Avian influenza:
form?
Incubation period?
Localized or generalized forms.
Incubation period 1-7 days
Clinical signs of avian influenza in birds.
Lack of coordination neurological issues
Ruffled feathers
Difficulty in breathing, gasping
Loss of appetite, depression and droopiness, fever.
Bluish coloring of wattles and comb (cyanosis)
Edema and swelling of head, eyelids, comb, wattles, hocks
Bloody or watery discharge from nose or beak
Watery (greenish) diarrhea
Pin-point hemorrhages
Sudden drop in egg production
Eggs with soft or deformed shells
Diagnosis and prevention of avian influenza.
Diagnosis: laboratory analysis
◦ Swab samples of upper and/or lower
respiratory tract, fecal samples, blood
samples
◦ RT-PCR, microneutralization, virus isolation
Treatment: no specific treatment
◦ Sick and suspected birds are culled
Prevention:
◦ Biosecurity and hygiene requirements,
notification of birds suspected of being infected
◦ Vaccination is allowed since 1.01.2024
Avian influenza trends.
The epidemiology of avian influenza has changed.
Previously, there has been no continuous monitoring of the virus circulating in nature.
- A(H5N1) is mutated, more dangerous to humans:
◦ Prefers lower temperature
◦ European and African strains have the mutation - An A(H7N9) strain has emerged, which is dangerous for humans
Risk factor for human infection: direct or indirect contact with the virus.
Newcastle disease (ND) is an acute avian paramyxovirosis, characterized by (4)
respiratory disease,
encephalitis,
hemorrhagic diathesis,
and high mortality
Newcastle disease causative agent, genus and family, DNA type?
agent Avian orthoavulavirus 1, AOaV-1
genus Orthoavulavirus
Family Paramyxoviridae
Enveloped RNA virus
is agent Avian orthoavulavirus 1 zoonotic or nah?
this is the agent causing Newcastle disease
Mainly threatens birds, but can infect humans.
Newcastle disease agent genotypes and pathogenicity.
Avian orthoavulavirus 1
Two classes:
- Class 2 isolates are divided into 20 genotypes (I-XXI)
According to pathogenicity: velogenic (causing disease), mesogenic and
lentogenic strains
Registrable disease (WOAH)
Epidemiology of Newcastle disease
The virus binds to erythrocytes.
Transmission: direct, aerogenic or
alimentary.
The virus penetrates the eggshell – the embryo becomes infected.
Survives for weeks in a moist, warm environment.
In frozen material can be stored indefinitely.
Clinical signs of newcastle disease.
The signs are very variable, depend on age and species of birds, virulence of the strain.
Development of the clinical picture: from
moderately acute to sudden death.
◦ Respiratory signs
◦ Redness of the conjunctiva, swelling of the head.
◦ Nasal and ocular secretions
◦ Decrease in egg production
◦ Dyspnea, greenish to bloody diarrhea
◦ Nervous symptoms: depression or
hypersensitivity, imbalance, tremors, partial to complete paralysis.
◦ Weakness, ruffled feathers, fever
Diagnosis and prevention of newcastle disease.
Epidemiological situation, clinical
picture, pathological changes, laboratory
tests:
◦ Tracheal or cloacal swab, stool, blood
◦ Necropsy: spleen, lungs, cecal tonsils, liver, kidneys, heart,
brain
◦ Isolation, RT-PCR, hemagglutination
inhibition, virus neutralization
There is No treatment
Prevention: biosecurity and hygiene
rules, vaccination.
Avian infectious bronchitis (IB) is primarily an acute coronavirosis of the gallinaceous birds, characterized by
respiratory disease in chicks and anomalies in ovogenesis in adult birds.
◦ Spread around the world, registrable (WOAH)
◦ Antibodies against IBV found in humans
Causative agent of IB.
genus, family, DNA type.
Avian infectious bronchitis virus
Family Coronaviridae
genus Gammacoronavirus
single-stranded, enveloped RNA virus
◦ Lots of serotypes
Morbidity and mortality of IB?
(avian) infectious bronchitis
morbidity up to 100%
Low mortality
The severity depends on the strain of the virus and the infected organ system.
Epidemiology of (avian) infectious bronchitis.
Mainly affects the respiratory system.
◦ Some strains also affect the urogenital or
digestive systems.
Susceptible species: chicken, pheasant,
turkey, geese, etc.
Excretion: respiratory secretions and
feces.
Transmission: aerosol, contaminated feed,
water, fomites.
Incubation period 18-48 h.
Forms of disease seen in avian infectious bronchitis.
respiratory, renal, genital
Avian rhinotracheitis (ART) is also known as? (2)
turkey rhinotracheitis (TRT) or
avian metapneumovirosis
◦ Turkeys, chickens, pheasants, muscovy ducks, guinea fowl, wild birds.
Avian rhinotracheitis (ART) is a highly contagious viral infection mainly of
turkeys and chickens, usually causing
acute upper respiratory tract
infection and a drop in egg quality.
Widespread, highly contagious
Notifiable (WOAH)
Avian rhinotracheitis causative agent.
Genus, family, DNA-type.
Avian metapneumovirus, AMPV
genus Metapneumovirus
Family Pneumoviridae
single-stranded RNA virus
Subtypes A, B, C, D
Inactivates fairly quickly in the environment
Epidemiology of avian rhinotracheitis.
Transmission: aerosols, droplet infection, direct contact, fomites.
All age groups are susceptible, especially
the younger ones.
Incubation period 3 -7 days.
Morbidity up to 100%, mortality 1-30%.
◦ In chickens: morbidity rarely above 4%
Avian infectious laryngotracheitis (ILT) is an acute herpesvirosis of chickens and pheasants characterized by
severe dyspnoea, cough and respiratory rales,
or
subacute disease with nasal and ocular discharge, tracheitis, conjunctivitis, and mild rales.
Chicken, guinea fowl, pheasant, turkey
Carriers: water birds, wild birds.
Avian infectious laryngotracheitis causative agent.
Genus, family, DNA-type.
Gallid alphaherpesvirus 1 (GaAHV-1)
genus Iltovirus
Family Herpesviridae
Enveloped DNA virus
Epidemiology of Avian infectious laryngotracheitis.
Common in many countries, notifiable
(WOAH).
Outbreaks at any time of the year.
Source of infection: sick and recovered birds.
◦ can Excrete the virus for 2 years.
10-week-old and 1st-season laying birds are affected
Transmission: droplets, contaminated air,
feed, drinking water, litter, equipment.
Carriers: blood-sucking insects, rodents, game birds, humans.
Incubation period 2-15 days,
morbidity up to 100%,
mortality 5-70%.
Diagnosis of Avian infectious laryngotracheitis.
Epidemiological situation, clinical
symptoms, pathological changes.
Laboratory analysis:
◦ Swab sample from trachea or larynx,
blood sample
◦ Virus isolation
◦ ELISA, serum neutralization reaction etc.
◦ PCR, DNA hybridization
Treatment and prevention of Avian infectious laryngotracheitis.
There is no specific treatment.
◦ Quarantine
◦ Sick and susceptible birds are culled.
◦ Room disinfection.
Lifelong immunity in recovered birds.
Prevention:
◦ Buy chicks from a disease-free area.
◦ Use Attenuated virus vaccine
Fowlpox is a slowly spreading poxvirus infection of poultry and wild
birds, characterized by
papulopustular rash and crust formation
on the skin and proximal part of the respiratory and gastrointestinal tract.
Fowlpox causative agent.
genus, family, DNA-type.
Fowlpox virus, FWPV
genus Avipoxvirus
Family Poxviridae
Enveloped DNA virus
Epidemiology of fowlpox.
Birds of both sexes and all ages are infected.
The disease is spread all over the world.
Source of infection: sick birds
The virus enters the body orally, through respiratory and mechanical injuries.
Incubation period is 4-10 days, lasts on average 4 weeks.
Forms of fowlpox disease.
skin, diphtheric and catarrhal
Diagnosis and prevention of fowlpox.
Clinical signs, necropsy findings and laboratory test results.
Inclusions of the poxvirus can be found in post mortem preparations.
There is no specific treatment.
Implementation of biosecurity measures.
Live and recombinant vaccines are used in
◦ Chickens, pigeons, turkeys, canaries
Clinical signs of Quail bronchitis.
Breathing difficulties, tracheal rales,
sneezing, cough.
Decreased feed and water consumption,
depression.
Conjunctivitis, swelling of the infraorbital
sinuses.
Mucus in airways, open mouth breathing.
Ruffled plumage
Older birds: liquid feces, subacute illness
Rarely, neurological signs
Pathological findings in Quail bronchitis.
Necrotic tracheitis (the trachea may be
completely filled with mucus).
Swelling of the mucous membraanes
Bronchitis, pneumonia, inflammation of
the air sacs, congestion of lung tissue.
Hepatitis
Several whitish pin-point (Ø 3mm) foci
of necrosis in the liver, marbled liver
Caseous, mucous intestinal contents
Spleen enlargement, marbled spleen
