INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute,...
Transcript of INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute,...
![Page 1: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/1.jpg)
Infectious Laryngotracheitis
(ILT OR LT)
• An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread and high mortality.
• Airsacculitis in uncomplicated outbreaks is uncommon.
• Doesn’t occur in birds less than 2-weeks-old and most commonly occurs in chicks over five weeks of age.
• Can be a serious problem in roasters.
• Occurs naturally in pheasants.
• Reported from most countries.
![Page 2: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/2.jpg)
HERPESVIRUS - an enveloped virus
The virus is heat labile but can remain
viable in cool weather.
Etiology
![Page 3: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/3.jpg)
Incubation Period
• 6 to 12 days following natural exposure
The long incubation period allows easy spread of
the virus prior to the onset of clinical signs
![Page 4: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/4.jpg)
Comment
• Herpesviruses may remain dormant in the host
• LT virus exhibits this. It’s site of latency is in the
dorsal root ganglion
• Chickens may become infected, lose immunity,
and show clinical signs again when stressed. This
explains “mystery outbreaks”. Vaccinated or field
infected birds can shed the virus indefinitely.
![Page 5: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/5.jpg)
Course of the Disease
• Most chickens recover in 10-14 days. Mortality will
usually decline within one week of onset of clinical
signs.
• Extremes of 1-4 weeks.
![Page 6: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/6.jpg)
Mortality
• Ranges from 5 to 70%
• Usually between 10 & 20%
• Mortality in broiler flocks may double daily until it
reaches 200 per day.
![Page 7: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/7.jpg)
Method of Spread
• Contact with infected birds within a house through the upper respiratory tract or intraocular route
• From carrier birds for up to 2 years
• Vaccinated flock (2 wks.) chicken embryo origin (CEO) vaccine spreads readily while the tissue culture (TCO) vaccine is less likely to spread
• Mechanical transmission – Contaminated equipment & litter spreads the virus from farm to farm
• Live-haul trucks
• There is evidence of wind transmission
![Page 8: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/8.jpg)
Signs
• Sudden death with bloody beaks (choked)
• Swollen, watery eyes with most rales, coughing, and
gasping
• Extended head with mouth breathing and “squawking”
• Bloody tracheal casts on equipment & house walls
• 10-20% decrease in egg production
• May have mild forms of above with low virulence strains
![Page 9: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/9.jpg)
Conjunctivitis
![Page 10: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/10.jpg)
Conjunctivitis
![Page 11: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/11.jpg)
Conjunctivitis
![Page 12: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/12.jpg)
Conjunctivitis
![Page 13: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/13.jpg)
Gasping
![Page 14: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/14.jpg)
Postmortem Lesions
• Edema and congestion of the conjunctiva and infraorbital sinus
• Sticky, blood tinged mucus in the laryngeal area
• Varying amounts of blood and blood-tinged mucus in the trachea
• In the late stages and in dead birds, cheesy cores may be in the trachea
• Very few carcasses condemned but there will be a high number of DOAs
![Page 15: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/15.jpg)
Blood in Trachea
![Page 16: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/16.jpg)
Chronic Tracheitis
![Page 17: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/17.jpg)
Chronic Tracheitis
![Page 18: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/18.jpg)
Differential Diagnosis
• Infectious bronchitis
• Newcastle disease
• Fowl pox
![Page 19: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/19.jpg)
Diagnosis
• History + below (i.e., birds which are coughing with expulsion of blood will show the most severe gross lesions)
• Histopathology of tracheas should be taken from birds with very mild or early signs because once the tracheal mucosa sloughs, there will be no diagnostic inclusions – typical intranuclear inclusion bodies. Syncytial cells will be formed. And look for inclusions in the eye lid.
• VI from trachea in CAM of embryos (<3 days) (Plaques). Send this for histopathology.
• Inoculate suspect material into susceptible chickens.
![Page 20: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/20.jpg)
Pocks on CAM
![Page 21: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/21.jpg)
Pocks on CAM
![Page 22: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/22.jpg)
Syncytial Cell & Inclusions
![Page 23: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/23.jpg)
Treatments
• None specific
• Broad spectrum antibiotics to reduce secondary
infections
• You can vaccinated ahead of the disease
![Page 24: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/24.jpg)
Prevention
• Vaccination – Vaccine costs approximately $3-$4 /
1000 doses
Eye drop vaccine – for lasting immunity administered at 10
and 16-18 weeks of age (layers and breeders) – use tissue
culture origin or CEO vaccine.
Water vaccine – quick method for layers, breeders, &
broilers – CEO vaccine titer must be over 105 for successful
mass application. TCO is not recommended for mass
application.
Spray – to establish good lasting immunity – should
vaccinate at 3-4 weeksd & 12-13 weeks and after molt.
![Page 25: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/25.jpg)
Comment
• Since the incubation period of LT is long, 6-12 days,
vaccination ahead of an outbreak is feasible.
• Vaccination crews should clean thoroughly and
change clothes and decontaminate between
premises.
• Catch nets and other equipment should be properly
decontaminated.
![Page 26: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/26.jpg)
Comment
• Keep in mind that LT can be spread very easily from
farm to farm by mechanical fomites (bags, egg flats,
and equipment). Personnel and chicken carriers are
the most likely methods of spread.
• Backyard flocks are extremely hazardous as they
may serve as a reservoir to carry the disease
organism over from outbreak to outbreak.
![Page 27: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/27.jpg)
Comment
• Even vaccinated flocks can spread the disease so
once one company starts vaccinating broilers, every
company in the area most also do it.
• It can cost $0.05 in lost body weight to vaccinate a
flock for LT.
![Page 28: INFECTIOUS LARYNGOTRACHEITIS (ILT OR LT)Infectious Laryngotracheitis (ILT OR LT) • An acute, highly contagious disease of fowl, characterized by respiratory distress, slow spread](https://reader034.fdocuments.net/reader034/viewer/2022042620/5f4968bb890f793f73445c2e/html5/thumbnails/28.jpg)
Comment
• This virus is heat sensitive. After an outbreak, the
house should be closed up with brooders turned on
to raise the internal temperature of the house to 100°
F for 100 hours.