Viruses Flashcards
Gumboro
Infectious bursal disease
serotype 1 - subclinical, virulent or very virulent
shed in faeces, transmitted by fomites
morbidity 100%
mortality 5-60%
most susceptible 3-6w old
signs = incoordination, prostration, diarrhoea, vent picking. B cell response affected
PM = bursa edematous with yellow transudate and hemorrhage. congestion of pectoral and leg muscles and atrophy of the bursa
Gumboro diagnosis
gross bursal lesions and micro lymphocyte depletion, PCR and VI on 9-11d chorioallantoic
DD = mareks, IBH, aflatoxicoses
No treatment
Chicken anemia
CIAV
trans = feco-oral, maybe resp and through infected feather follicle epithelium. Vertical, in semen
SOI = contaminated litter
signs = anemia, weakness, weight loss, depress
PM = pale organs, atrophy of thymus and bursa, yellow bone marrow. BLUE WING - haemorrhage under skin
chicken anemia diagnosis
PCR, decreased hematocrits, history and signs
no treatment
prevent = live vaccine injection or in water before start of laying. maybe natural exposure but risky. vaccinate 7d old broilers in USA
very resistant to disinfectants and heat
lots of synergy with other immunosuppressive viruses so control those
Mareks epidemiology
alphaherpesviridae - MDV1 are mild, virulent and avirulent and MDV2 and 3 are avirulent
ubiquitous in environment
highly contagious and survives months in litter and dust - matures to infective form in epithelium in the feather follicle and then released to environment
affects older than 4w old
mareks pathogenesis
1 early cytolytic infection
2 latent
3 second phase of cytolytic infection - permanent immunosuppression
4 proliferative phase - lymphoid neoplasms
affects CD4 lymphocytes
mareks signs
transient paralysis, depression, atherosclerosis, death due to paralysis as birds can’t reach food
PM = enlarged nerves - vagus, brachial and siatic, tumours in liver, spleen, heart, lungs, enlarged feather follicles
mareks diagnosis
diagnose tumours not infection as ubiquitous. enlarged nerves, PCR
DD = reticuloendotheliosis (older chickens and no nerve changes) LL (no bursal tumour in LL, also 14w+ in LL)
mareks control
vaccine in hatchery or in ovo on 18th day of incubation
Lymphoid leukosis
avian retrovirus
affects B lymphocytes and 16w+ chickens
trans = shed in to yolk (congenital infection) and horizontal in faeces
not too highly contagious, trans decreased by good sanitation
outcomes:
1 no viremia, no antibody
2 no viremia with antibody
3 viremia with antibody
4 viremia no antibody
LL pathogenesis
transforms in intact bursa 4-8w PI
tumours detectable until 14w old, death around sexual maturity
subclinical decreases egg production with no tumours
signs of LL
inappetence, weakness, diarrhoea, emaciation
PM = tumours in liver, spleen, bursa, kidney
diagnosis of LL
history, signs, PM, histopath, IHC, VI, serology
control = no treatment or vaccine, eradicate from breeding stock (test eggs for antigen)
reticuloendotheliosis
reticuloendotheliosis virus 3 subtypes
trans = horizontal most common but vertical too, mosquitos and insects
pathogenesis reticuloendotheliosis
non neoplastic runting - 4-10 w old
acute neoplastic - after 6-8w latent period, T cells
chronic - B cells affected, looks like LL
signs reticuloendotheliosis
weight loss, paleness, occasional paralysis and abnormal feathering
PM = abnormal feathers, bursa and thymic atrophy, tumours in liver, spleen
diagnosis reticuloendotheliosis
history, signs, difficult PM, PCR
control = none practiced
no treatment
egg drop syndrome
duck adenovirus 1
spread by contaminated Mareks disease vaccine
trans = vertical most frequent, horizontal
most susceptible = broiler parents and brown egg layers
in ovo infected show signs at sexual maturity
signs egg drop
transient diarrhoea, apathy, decreased egg production, rough/thin shells, loss of shell pigment
diagnosis egg drop
IHA test, gel immunodiffusion
DD = Newcastle, IB, AE
prevent = inactivated vaccine at 14-20w
age LL
older than 16w
age reticuloendotheliosis
older than 17w
age mareks
older than 4w
bursa lesions neoplastic diseases
LL nodular changes
RE rare atrophy
M rare diffuser atrophy
cells affected neoplastic diseases
LL B lymphocytes
RE B and T lymphocytes
M CD4 lymphocytes
avian encephalomyelitis
AEV - epidemic tremor
trans = vertical and horizontal (feco-oral)
morbidity and mortality up to 50%
AE signs
ataxia, tremors, weakness, paralysis, biphasic mortality pattern
PM = no gross lesion on Brian, maybe cataracts in survivors
diagnosis AE
history, signs, PM, RT-PCR, IHC, VI of brain, duodenum or pancreas
DD = bacterial/mycotic encephalitis, neurotropic Newcastle, rickets, nutritional encephalomalacia
prevent AE
no treatment
vaccinate broiler pullets at 8w old or 4w before laying, often combined with fowl pox and given by wing web stab
IBH and hydropericardium syndrome
fowl adenovirus
trans = vertical and horizontal
signs = sudden mortality in less than 6w old chicks, lethargy, huddling, ruffled feathers, yellow mucoid droppings
PM IBH and hydropericardium
swollen enlarged liver w yellow discolouration. HHS = straw coloured transudate in pericardial sac
diagnosis IBH and HHS
mortality pattern and gross lesions
histopathology and PCR
no treatment
prevent = live or inactivated vaccine
hemorrhagic enteritis
Turkey adenovirus 3 (siadenovirus)
trans = feco-oral/cloacal and contam equipment
signs hemorrgaic enteritis
100% morbidity, 1-60% mortality
7-9w old turkeys, depress, pallor, bloody faeces, 2nd bacteria infections 2w later so second wave of mortality
PM = congestion and haemorrhage in SI and enlarged friable mottled spleen
diagnosis hemorrhagic enteritis
signs, PM and PCR
DD = colibacillosis, pasteurellosis, RE, Newcastle
prevent = live vaccine in water at 4-5w old
marble spleen disease
turkey adenovirus 3 (siadenovirus)
trans = feco-oral maybe resp
signs = 3-8w old pheasants, acute dyspnea, asphyxiation 2-3% mortality
PM = splenomegaly, vascular congestion
diagnosis and prevent same as hem enteritis
infectious bronchitis
IBV - avian gammacoronavirus
disease in chickens, subclinical in pheasants
shed in resp discharge and faeces for 20w
trans = aerosol, ingestion, clothing, equipment
incubation 24-48h
IB signs
chicks = cough, sneeze, tracheal rales, depress, conjunctivitis, dyspnea, bacterial infection of sinuses
nephropathogenic strains - wet faeces, ruffled feathers, death. permanent damage to oviduct so never reach normal production (false layer)
decreased egg production and thin, wrinkly rough shells
PM = exudate in sinuses and resp tract, cystic oviducts
IB diagnosis
9-11d old embryos - chicks stunted with curling and urates in mesonephros
RT-PCR
typing important for vaccine
IB control
no medication
live attenuated vaccinate 1-14d old chicks by spray, water, eye drop then 2w after
adjuvant inactivated vaccine given to breeders and layers to prevent egg losses and to protect progeny
runting-stunting syndrome
broilers and turkeys
unknown cause - enteroviruses, reoviruses, mycotoxins, astroviruses
trans = vertical, feco-oral after hatching
signs runting stunting
1-3w old broilers
uneven growth, lack of pigmentation of skin, beak or feet, broken/twisted feathers (helicopter wings), undigested feed in faeces
lameness, ostodystrophy
PM = enlarged proventriculus, atrophy of pancreas, thymus and bursa, orange mucus in SI lumen
diagnosis runting stunting
signs and PM
no treatment
no vaccine (yes for reoviruses)
prevent = good nutrition and sanitation, analyse feed for mycotoxins
transmissible viral Proventriculitis
cause = chicken proventricular necrosis virus (birnavirus)
signs = decrease growth, poor feed conversion, organ rupture at processing (extra costs due to condemnation)
diagnosis = PCR
fowl pox
fowl pox virus (avipoxvirus)
trans = contact through skin abrasions, mosquitos mechanical vectors
resistant in environment and survives in dry scabs
slow spreading, low mortality in cutaneous , higher in diphtheritic or systemic
signs fowl pox
cutaneous - nodules on unfeathered skin and head and neck of turkeys, become thick dark scabs
diphtheritic - lesions on mm of mouth, oesophagus, trachea, caseous patches/proliferative masses ( DD= larngotracheitis)
systemic = lesions on internal organs, decreased egg production
diagnosis fowl pox
gross and micro lesions
isolate on 9-12d chorioallantoic membrane
PCR
prevent fowl pox
no treatment
prevent = vaccinate, live attenuated at a few weeks old and again at 12-16w old
check for swelling and scab at site of vaccine (wing web)
turkey coronavirus
few week old turkeys
trans = feco-oral, house flies mechanical vectors. shed for weeks after recovery
signs turkey coronavirus
sudden 100% morbidity
decreased egg production, chalky white eggs without normal pigment, depress, anorexia, weight loss, diarrhoea
PM = pale, thin walled intestines, atrophy of bursa
diagnosis turkey coronavirus
serology, PCR
DD = astroviruses, rotavirus, salmonella, cryptosporidia
no treatment, no vaccine
prevent = biosecurity, depop, clean and disinfect then rest for 3-4w
rhinotracheitis
avian metapneumovirus (AMPV)
Paramyxoviridae
causes turkey rhinotracheitis and swollen head syndrome.
trans = direct or indirect contact with contam things, aerosol,
wild birds are reservoirs and distribute it
AMPV A and B = chickens and turkeys
AMPV C = turkeys and ducks
signs rhinotracheitis
turkeys = serous ocular and nasal discharge, frothy eyes, conjunctivitis, depress, anorexia. mortality 1-50%
chickens = swelling of infraorbital sinuses, nasal discharge, opisthotonus. cough leads to uterus prolapse. decreased eggs
ducks = resp signs, decreased eggs and shell quality
PM = mucus in sinuses, swelling and hyperaemia of resp tract
diagnosis rhinotracheitis
tracheal or choanal swab before 6th day ( once signs obvious sit harder to detect)
inoculate on 6-8 d egg
RT-PCR, IF, ELISA
DD = Newcastle, IB, AI, Mycoplasma
prevent rhinotracheitis
good management, ventilation,
live vaccine spray or in water
inactivated to boost layers after live
viral enteritis
related with runting stunting
rotavirus, astrovirus, arboviruses
avian rotavirus
less than 6w old
trans = feco-oral
often co infection with astro
signs = unrest, ingestion of litter, watery faeces, diarrhoea, runting stunting
diagnosis = PCR
no vaccine
prevent = strict biosecurity as v resistant
avian astroviruses
v young birds most susceptible
trans = feco-oral and vertical (deformed embryos or hatch w high viral loads)
signs = diarrhoea, enteritis, frothy cecal contents, abnormal feathering
diagnosis = RT-PCR
DD = avian nephritis virus, IB
no vaccine
arbovirus
arthropod borne virus
transmitted by hematophagous arthropod
causes = encephalitis - turkey Isreal meningoencephalitis
poult enteritis mortality syndrome
cause unknown but viruses and poor housing
signs = decreased food, increased water, slow growth, mucus yellow faeces, osteoporosis
morbidity 100% mortality 25-96%
survivors never reach full size
diagnosis = signs, PCR
duck circoviruses
causes = immunosuppression, growth disorders and feather abnormalities
affects 40-60d old ducks
trans = horizontal
duck hepatitis B
used to make vaccine for human hepatitis B
trans = vertical and horizontal - immune mediated hepatic damage
hemorrhagic nephritis enteritis virus
cause = goose hemorrhagic polyomavirus
signs = hemorrhage in kidneys, intestines and lungs, edema of SC tissue, SC haemorrhage, ataxia, head tremor, bloody faeces
stays in flocks for 2w 30% mortality
avian influenza
type A orthomyxovirus -16HA and 9NA subtyes
LPAI = subclinical in wild
HPAI = mutation of H5 N7 LPAI
trans = ingestion or inhalation spread by fomites and bad biosecurity
sporadic H5 HPAI in dogs/cats/foxes
signs of AI
LPAI = sneezing , cough, ocular and nasal discharge, swollen infraorbital sinuses, decreased egg production
HPAI = death w no signs, cyanosis or edema of head, comb and wattle, red discolouration of shanks and feet, green diarrhoea. if survive acute, then torticollis, paralysis, incoordination
diagnosis of AI
oropharyngeal or cloacal swab and internal organs if HPAI
allantoic cavity 9-11d embryos
agglutinate RBC
RT-PCR
DD = IB, laryngotracheitis, low virulent Newcastle, coryza
prevent AI
biosecurity, report outbreaks, depop, antigenically matched inactivated vaccines
zoonosis of AI
yes, eurasian lineage of H5N1 HPAI can be fatal
risk = contact w dead birds or close contact w human cases
resp infections or conjunctivitis
Newcastle
Newcastle disease virus ( avian paramyxovirus type 1)
virulent = velogens and mesogens - reportable
low virulent - lentogens - used as live vaccine
epidemiology Newcastle
trans = shed in exhaled air, resp discharge, faeces. vertical unclear
waterfowl shed w no signs
young chickens most susceptible
incubation = 4-6d
signs Newcastle
rapid onset, none pathognomic, depends on tropism
high virulent viscero = lethargy, anorexia, whistling noise, mucus discharge, head edema, cyanotic comb, green diarrhoea, no eggs, watery albumen 100% mortality
high neuro = resp signs, tremors, paralysis, torticollis, 50% mortality
mesogenic = resp, decreased egg, neuro, low mortlaity
low virulent = inapparent/mild resp, decreased eggs w soft shells and abnormal shape
pigeons = conjunctivitis, dyspnea, diarrhoea, cyanosis
PM Newcastle
petechiae on serous membranes, haemorrhage of proventricular mucosa, congestion and haemorrhage on trachea and lungs, egg peritonitis
diagnosis Newcastle
oropharyngeal or cloacal swab on allantoic cavity 9-11d
real time RT-PCR (swab, tissue, faeces)
DD = HPAI, IB, laryngotracheitis, metapneumovirus, coryza
prevent Newcastle
biosecurity, disinfect, clean, cull infected and susceptible
vaccinate - live lentogenic in water or spray nares in DOC
inactivated after live in breeders or layers
vectored recombinant in ovo
zoonosis = conjunctivitis in humans
duck viral enteritis
duck plague
cause = antatid herpesvirus 1
trans = direct from sick to susceptible, indirect w contam environment (water)
recovered are life carriers
duck viral enteritis signs
3-7d incubation
sudden high mortality, unable to stand, weakness, photophobia, extreme thirst, ataxia, males have penile prolapse
PM = DIC, necrosis of GI tract and lymphoid tissue, free blood in body cavities, mucosal eruptions yellow plaques to green scabs to diphtheritic membranes, enlarged copper liver, hemorrhagic annular bands in intestines
diagnosis duck viral enteritis
history and lesions, PCR, IM inoculation of day old ducklings
DD = duck hepatitis, pasteurellosis, necrotic/hemorrhagic enteritis
prevent duck viral enteritis
no treatment
prevent = stop contact w wild waterfowl or free flowing water. MLV vaccine SC or IM in older than 2w duckling and revac breeders every year
control = depop, remove from environment, sanitation
infectious larynogotracheitis
gallid herpesvirus 1 (ILTV)
signs = gasping, coughy bloody mucus, extended neck, decreased activity, suffocation. mortality up to 50%
after recovery carriers for life
diagnosis = PM, PCR, history
control = biosecurity, live attenuated vaccine in eye or spray. recombinant vaccine in ovo, submit or wing web
avian nephritis virus
astrovirus
trans = direct or indirect contact, vertical but less common
shed in kidneys and faeces for 10d PI
signs = none- mortality from kidney disease or severe growth retardation diarrhea
PM = nephritis, swollen pale kidneys, excessive urate deposition, intestinal lesions
diagnosis = RT-PCR
no treatment, no vaccine
prevent = fogging house, clean and disinfect
paramyxoviruses
PMV1 = Newcastle, 21 others
MOT = feco-oral from contact w wild birds, spread through flock slow
AMPV5 = serious disease in budgies
signs = 2,3,6 = resp, decreased eggs and watchability
2 = resp and sinusitis, more severe in turkeys
7= rhinitis and airsacculitis
3, 7= enlarged liver and spleen
diagnosis = oropharyngeal and cloacal swabs, inoculate on 9-11d, RT-PCR. no serology as cross reaction w Newcastle
DD = LPAI, IB, metapneumovirus
prevent = bird proof houses, vaccines for AMPV3 in turkey breeders
duck viral hepatitis
cause = DHV A type 1
signs = 18-48h incubation. lethargic, lose balance, paddle, opisthotonus, death. no signs in older than 7w old . mortality 95%
PM = enlarged liver w hemorrhagic foci, enlarged and mottled spleen, congested vessels
diagnosis = history, lesions, PCR
no therapy
prevent = strict isolation for first 5w, rat control, avoid waterfowl
MLV vaccine SC in neck of breeders at 16, 20 and 24w then 12w after throughout layer
inactivated 1x IM after MLV
antibody from hyperimmunised chickens given SC to protect flock
parvo in waterfowl
goose parvovirus, muscovy duck parvovirus - anseriform dependoparvovirus 1
trans = vertical from infected adults
shed in faeces - lateral spread
signs Parvo
less than 1w old - anorexia, death in 2-5d mortality up to 100%
2-4w old - ocular//nasal discharge, white diarrhoea, weakness, decreased growth, loss of feathers, 10% mortality
PM = fibrinous pseudomembrane on tongue, SI, pul edema, pericarditis, rounded apex of heart
diagnosis of Parvo
clinical course, age, PM, isolate on eggs, PCR, ELISA, IF
DD = duck viral enteritis, duck viral hepatitis
no treatment
prevent = hatch goslings together from 1 flock (dont mix), vaccinate breeders
prevention of gumboro
live attenuated in eye, water or SC 1-21d old
vectored vaccine/immune complex vaccine in ovo or hatchery
breeders = live then with inactivated before start of laying
