EQUINE 3 Reportables
EQUINE INFECTIOUS ANEMIA
ETIOLOGY
• Equine infectious anemia virus (EIAV)
◦ Genus: Lentivirus
◦ family: Retroviridae
• Species affected ➞ Horses, mules, donkeys, zebras, ponies
TRANSMISSION
(1) Vector (mechanical) ➞ biting insects (horseflies & deerflies)
(2) Iatrogenic ➞ blood transfusions; contaminated needles/syringes/IV sets/surgical instruments/dental equipment
(3) In utero
(4) Ingestion ➞ milk
(5) Venereal ➞ semen
COMMON PRESENTATION
• Classic case: recurrent fever, petechiae, anemia, edema
• Three presentations of EIA
(1) Acute ➞ Signs within 1-4 wks of Infection ➞ Fever, anorexia, Petechiae, edema, mild thrombocytopenia ➞ death
(2) Chronic ➞ recurrent fever, cachexia, hemolytic anemia, marked thrombocytopenia ➞death
(3) Inapparent carrier ➞ NO Signs
• Other signs ➞ ataxia, encephalomyelitis, abortion, immune-mediated lesions
DIAGNOSIS
• Differential diagnoses:
◦ EVA
◦ PH
◦ AIHA
◦ Immune-mediated thrombocytopenia
◦ internal abscesses, heart failure, chronic liver disease, Anaplasma
• Definitive diagnosis: Coggins test
◦ If positive ➞ cant move the horse between states
TREATMENT
• None, carriers for life
• Euthanasia OR quarantine
◦ quarantine in fly proof area > 200 meters from other horses
PROGNOSIS
• Grave ➞ infected for life
PREVENTION/CONTROL
• Fly control
• EIA negative donors for blood transfusions
• Eliminate or quarantine carriers
• USDA recommends testing every equid annually
• NO vaccine available
REPORTING
• Call your veterinarian
• Move suspected horse at least 200 yards away from other horses
• Reduce exposure to biting flies
Resources:
1. Sellon DC. Equine Infectious Disease. W. B. Saunders; 2007. Pages 213-217
2. https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/equine/eia/equine-infectious-anemia
3. https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/nvap/NVAP-Reference-Guide/Equine/Equine-Infectious-Anemia
EQUINE VIRAL ARTERITIS
ETIOLOGY
• Equine arteritis virus (EVA)
◦ Genus: Arterivirus; family: arteriviridae
TRANSMISSION
(1) Aerosol ➞ droplet spread of respiratory secretions from infected horses
(2) Direct contact ➞ placental membranes, fetal fluids, and tissues from abortions
(3) Venereal
◦ Mare, gelding or sexually immature colts ➞ Self-limiting; immunity to reinfection
◦ Stallions ➞ chronic asymptomatic carriers ➞ transmit to mares during breeding
(4) In utero ➞ late gestation ➞ infected fetus ➞ fetal death ➞ abortion
(4) Fomites ➞ breeding equipment, contaminated twitches, hands of animal care personnel
• Species affected ➞ Horses, donkeys, mules, zebras
◦ Standardbreds > Thoroughbreds > Warmbloods > Quarter horses
COMMON PRESENTATION
• Clinical signs ➞ similar to any infectious agent that causes vasculitis
◦ fever (up to 106°F)
◦ edema ➞ limbs, ventrum, periorbital/supraorbital, scrotum, mammary glands
◦ conjunctivitis, epiphora, rhinitis
◦ leukopenia
◦ urticaria
◦ abortion; fatal pneumonitis in neonatal/young foals
DIAGNOSIS
• Differential diagnoses
◦ EHV-1 & EHV-4
◦ Equine influenza
◦ Equine rhinitis virus A & B
◦ Purpura hemorrhagica
◦ EIA
• Definitive diagnosis:
◦ Viral isolation ➞ nasal secretions, blood, semen
◦ RT-PCR ➞ nucleic acids
◦ immunohistochemistry or histopathology ➞ Antigen detection
TREATMENT
• None available
• Most healthy horses (except young foals) recover on their own
• Good nursing and symptomatic treatment for severe cases ➞ reduce swelling, inflammation, edema
• Vaccination can help contain outbreaks
PREVENTION/CONTROL
• Isolate infected horses and carrier stallions to reduce spread
• Venereal transmission
◦ separate pregnant mares from other horses
◦ isolate new arrivals
◦ vaccinate mares being bred to 1. known to be infected 2. carrier stallions 3. with semen containing EVA
• Modified live vaccination in US
◦ Vaccinate uninfected stallions prior to breeding
◦ isolate vaccinated horses as per the manufacturer recommendation as viral shed post-vaccination is possible
• Carrier stallions ➞ physically isolate from uninfected horses
OUTBREAKS & REPORTING
• Call your veterinarian ➞ Isolate sick horses immediately ➞ Suspend all breeding and semen collection activities
• 1. Notify State Veterinarian
◦ In jurisdictions where EVA is not a reportable disease + self-imposed quarantine should be implemented immediately
• 2. Farm outbreaks
◦ Isolate all affected horses ➞ Notify the veterinarian immediately ➞ Laboratory confirmation of diagnosis ASAP
◦ Suspend breeding and training operations until the outbreak is over
• Vaccinate all at-risk horses
Resources:
1. Spickler, Anna Rovid. 2009. Equine Viral Arteritis. Retrieved from http://www.cfsph.iastate.edu/DiseaseInfo/ factsheets.php.
2. https://www.aphis.usda.gov/animal_health/animal_diseases/eva/downloads/eva-umr.pdf
GLANDERS
ETIOLOGY
• Burkholderia mallei
◦ Gram −, bacillus (rod), non-motile, non-spore
• Species affected
◦ Equidae ➞ donkeys > mules > horses; Humans; Felidae ➞ particularly susceptible
◦ Bears, camels, wolves, jackals, hyenas, dogs
TRANSMISSION
(1) Direct contact ➞ contamination of skin abraisons or mucous membranes
(2) Inhalation ➞ contaminated aerosols
(3) Ingestion ➞ food or water contaminated with respiratory droplets or ulcerated skin lesions from carrier animals
(4) Fomites ➞ readily spread
(5) Reproductive
◦ Venereal ➞ stallion to mare
◦ Vertical ➞ mare to foal
(6) Vectors ➞ flies = mechanical vectors
COMMON PRESENTATION
(A) Acute cases ➞ die within a few day to weeks (1-4) ➞ donkeys and mules (mules more resistant + slower)
(1) Nasal Glanders
‣ Begins with high fever, loss of appetite, and labored breathing with cough
‣ Highly infectious, viscous yellow-green mucopurulent discharge is present +/- crusts around nares
‣ purulent ocular discharge
‣ ulcerated nodules in nasal mucosa
‣ unilateral or bilateral submaxillary lymphadenopathy
‣ Nasal infections spread + involves lower respiratory tract
(2) Pulmonary glanders
‣ fever, dyspnea
‣ paroxysmal coughing or persistent dry cough accompanied by labored breathing
‣ nodules + abscesses develop in lungs, or bronchopneumonia if severe
‣ some infections inapparent
‣ diarrhea & PU may occur
(B) Chronic cases ➞ horses
(3) Cutaneous (farcy) glanders
‣ associated with periods of exacerbation ➞ progressive debilitation
‣ initially: fever, dyspnea, coughing, and enlargement of lymph nodes
‣ multiple nodules in the skin, along the course of lymphatic vessels
• rupture and ulcerate ➞ thick yellow oily exudative discharge
• ulcers heal very slowly & discharge fluid
‣ swelling of the joints, painful edema of the legs or glanderous orchitis
‣ skin lesions commonly found inner thighs, limbs, and abdomen
(C) Latent ➞ few signs: nasal discharge; dyspnea
DIAGNOSIS
• Differential Diagnoses:
◦ Strangles (streptococcus equi)
◦ Ulcerative lymphangitis (corynebacterium pseudotuberculosis)
◦ Botrymycosis
◦ Sporotrichosis (sprortrix schenkii)
◦ Epizootic lymphangitis (histoplasma farciminosum)
◦ tuberculosis (mycobacterium tuberculosis)
• Definitive diagnosis:
◦ ID of the agent
‣ whole lesions or secretions of lesions, respiratory exudates, smears from fresh lesions
‣ morphology of Burkholderia mallei
• ID of methylene blue or gram-stained organisms from fresh lesions
• presence of capsule-like cover has been demonstrated by electron microscopy
‣ cultural characteristics
• numerous in smears from fresh lesions but scarce in older lesions
• bacteria grow aerobically ➞ prefer media with glycerol
• confirmation of ID is by PCR
‣ PCR + RT-PCR
◦ Serological tests
‣ Complement fixation ➞ horses, donkeys, & mules
• positive results within 1 week post-infection; recognizes exacerbated chronic cases
‣ ELISA
‣ Immunoblot assays ➞ Best serological test
◦ Cellular immunity test ➞ Mallein test
‣ positive reaction = eyelid swelling 1-2 days after intrapalpebral injection of protein fraction or conjunctivitis
TREATMENT
• Antibiotics ➞ effective, but is usually only given in endemic areas
• Treatment is risky ➞ risk of spread to human and animal + risk of animals becoming asymptomatic carriers
• Humans ➞ long-term antibiotic treatment (1-12 months) + multiple drug therapy + drain abscesses
PROGNOSIS
• Euthanasia is mandatory in many countries, including the US
• No vaccine available for humans or animals
PREVENTION/CONTROL
• Horses ➞ early detection + quarantine with disinfection
• Humans ➞ eliminate disease in animals
REPORTING
• IMMEDIATELY notify authorities + quarantine
◦ federal ➞ Area Veterinarian in Charge (AVIC)
◦ State ➞ state veterinarian
• Eradicated in USA ➞ Still present in Asian, African, Middle eastern, and South American countries
• Transboundary + OIE disease in the USA ➞ reportable to USDA & State animal health officials in all 50 states & territories
• Can be used as a biological weapon
Resources:
1. https://www.oie.int/app/uploads/2021/03/glanders.pdf
2. Spickler, Anna Rovid. 2018. Glanders. Retrieved from http://www.cfsph.iastate.edu/DiseaseInfo/factsheets.php.
BOVINE 3 Reportables
Johne's Disease
ETIOLOGY
• Mycobacterium avium subspecies paratuberculosis
◦ Gram +, aerobic, rods, lack flagella, Acid-fast (ziehl-neelson stain)
◦ TOUGH BUG-Survives > 1yr in soil, longer in water; survives pasteurization!
• Species affected ➞ Cattle, sheep, goats, camelids
◦ animals <6 months ➞ Adult/older animals less susceptible
TRANSMISSION
(1) Direct contact ➞ feces or saliva
(2) Ingestion ➞ fecal/oral or milk from infected dams
(3) In utero ➞ fetal infection if dam is in late stages of disease
COMMON PRESENTATION
• Subclinical infection in cattle ➞ decreased milk + reproduction
• Clinical signs
◦ Classic for Cattle ➞ chronic, watery D+ (“pipestream” watery & projectile)
◦ Classic for sheep & goats ➞ weight loss despite good appetite
• Gross lesions
◦ cattle
‣ intestinal thickening (34 x normal) characteristic
‣ affected mucosa appears corrugated
‣ thickened & reddened ileocecal valve
‣ enlarged, edematous mesenteric lnn.
◦ Sheep
‣ thickened, but NOT corrugated intestinal mucosa
‣ necrosis & calcification of mesenteric lnn.
DIAGNOSIS
• Differential diagnoses:
◦ parasitism
◦ Copper deficiency
◦ Bovine Leukosis
◦ Salmonellosis
◦ Amyloidosis
◦ Chronic reticuloperitonitis/peritonitis
• Definitive diagnosis:
◦ Organism detection tests
‣ Culture M. paratuberculosis ➞ GOLD STANDARD
• feces or postmortem specimen
• hard to culture ➞ takes weeks at USDA approved labs
‣ PCR ➞ feces
‣ Histopathology ➞ breeding animals or for confirmation
◦ ELISA ➞ control programs + known positive herds
‣ milk, serum, plasma
‣ False negatives possible
TREATMENT
• No useful treatment ➞ Cull clinical animals
• Control ➞ takes several years
• Prevention ➞ isolate, herd screening, quarantine
• Vaccines ➞ some may interfere with TB tests
PROGNOSIS
• Once clinical signs are evident DEATH is inevitable
PREVENTION/CONTROL
• Key to disease control ➞ stop MAP transmission from shedders (adults) to susceptible (young)
• minimize risk of spread via colostrum/milk ➞ DON'T share colostrum/milk between young + separate weaned from adults
• Infected Animals ➞ culled or managed so they to spread
REPORTING
• Control programs present in many nations ➞ serious economic impact
• REPORTABLE in US
◦ Sheep/Goats ➞ ALL US states
◦ Cattle ➞ some states
• Potential zoonotic risk to humans ➞ possibly related to Crohn’s disease
Resources:
1. Zuku Review FlashNotes. Johne's Disease. Extended Version.
2. https://www.thecattlesite.com/diseaseinfo/173/johnes-disease/
Lumpy Skin Disease
ETIOLOGY
• Lumpy skin disease virus (LSDV)
◦ Family: Poxviridae; Genus: Capripoxirus
• Species affected ➞ cattle & buffalo only
◦ highly host-specific; NOT zoonotic
TRANSMISSION
(1) Vector ➞ Mechanical; arthropod vector (mosquitoes-culex; flies-Stomoxys; male ticks-Riphicephalus+Amblyomma)
(2) Direct contact ➞ skin lesions, saliva, nasal discharge, milk, or semen
(3) Ingestion ➞ contaminated feed and water
COMMON PRESENTATION
• Younger animals = more SEVERE
• Clinical signs
◦ Fever, nasal and ocular discharge, drop in milk production, weight loss
◦ Multiple nodules ➞ muzzle, nostrils, head, neck, back, legs, scrotum, perineum, udder, eyelids, oral mucosa, tail
‣ +/- abomasal nodules, trachea, lungs (pneumonia)
‣ Pulmonary edema + atelectasis; Pleuritis + mediastinal lymphadenopathy
◦ Lameness ➞ Synovitis/ tenosynovitis
◦ Mastitis or damage to teats and mammary glands
◦ Reproductive tract infection can occur
‣ +/- Abortion and intrauterine infection
‣ +/- Sterility of bulls and cows (Temporary or permanent)
DIAGNOSIS
• Differential diagnoses:
◦ Bovine herpes mammillitis (bovine herpesvirus 2)
◦ Bovine papular stomatitis (Parapoxvirus)
◦ Pseudocowpox (Parapoxvirus)
◦ Vaccinia virus and Cowpox virus (Orthopoxviruses)
◦ Dermatophilosis
◦ Demodicosis
• Definitive diagnosis:
◦ agent identification
‣ PCR ➞ inexpensive and quickest; samples Skin nodules, scabs, saliva, nasal secretions, blood
‣ Virus isolation + PCR ➞ advantage = detects live virus
‣ Electron microscopy ➞ classic poxvirus virion ID but CANNOT differentiate to genus or species level
◦ Serology
‣ Unable to distinguish between Sheeppox, Goatpox, LSDV
‣ Virus neutralization ➞ GOLD STANDARD for detection of ABs
‣ Western blot ➞ sensitive + specific but $$ + difficult to perform
‣ ELISA ➞ commercial kits for AB detection in development
TREATMENT
• No specific treatment
• Strong antibiotic therapy to avoid secondary infection
PREVENTION/CONTROL
• Successful control and eradication relies on early ID of index cases then widespread vaccination
• Sanitary prophylaxis
◦ Free countries ➞ import restrictions on livestock, carcasses, hides, skins and semen
◦ Infected countries ➞ Restrict movement in infected regions ➞ Cull all sick and infected ➞ vaccinate
• Medical prophylaxis: live attenuated LSD vaccine strains
REPORTING
• Africa + middle east
• NOT found in the US currently
• Veterinary Authorities should require the conditions relevant to the LSD status of the cattle of the exporting country to
authorize import or transit of the commodities.
• LSD free country ➞ NOTIFIABLE!
◦ No case of LSD has been confirmed nor any vaccination against LSD performed for the past 3 years
Resources:
1. https://www.cfsph.iastate.edu/FastFacts/pdfs/lumpy_skin_disease_F.pdf
2. https://www.oie.int/fileadmin/Home/eng/Media_Center/docs/pdf/Posters/EN_Poster_LSD_2016.pdf
3. https://www.oie.int/app/uploads/2021/03/lumpy-skin-disease.pdf
Foot & Mouth Disease (FMD)
ETIOLOGY
• Aphthovirus (genus)
◦ Family: Picornaviridae
• Species affected ➞ cloven-hoofed domestic + wild animals: cattle, pigs, sheep, goats, camelids, and water buffalo
• One of the most contagious, with important economic losses
TRANSMISSION
(1) Aerosol ➞ inhalation
(2) Direct contact
(3) Fomites ➞ hands, footwear, clothing, vehicles, etc
(4) Ingestion ➞ untreated contaminated meat products (swill feeding - primarily pigs) + contaminated milk
(5) Venereal ➞ AI with contaminated semen
(6) Airborne ➞ Long distance spread, especially in temperate zones
COMMON PRESENTATION
• Classic: malaise, salivation, lameness; vesicles, erosions, ulcers on muzzle, in mouth/on tongue, teats, & coronary bands
• Clinical signs
◦ Depression, anorexia, fever >104°F
◦ Hypersalivation, lip smacking, bruxism
◦ Lameness, reluctance to move, ‘stomping’, shifting feet ➞ hoof deformation
◦ Decreased milk production, mastitis, agalactia
◦ Vesicles, erosions on: tongue, lips, gums, teats, between claws
‣ After 24 hours ➞ vesicles rupture ➞ erosions
◦ Pressure points – hocks, above claws
◦ Abortions; Neonatal disease/death ➞ infertility
◦ Myocarditis ➞ death in young
◦ loss of thermoregulation (‘panters’)
DIAGNOSIS
• Differential diagnoses - Bovine:
◦ Bluetongue
◦ Malignant catarrhal fever
◦ Bovine Herpes-1
◦ Bovine parapox virus (papular stomatitis)
◦ Vesicular stomatitis
◦ Rinderpest
◦ Bovine Viral Diarrhea
◦ Infectious Bovine Rhinotracheitis
• Positive diagnosis for FMD ➞ find either of the following
(1) Viral antigen
‣ ELISA: Used for ➞ acute, carrier, and surveillance
‣ Complement fixation ➞ Not sensitive
‣ Virus isolation ➞ followed by ELISA, CF, PCR
‣ Electron microscopy ➞ on tissue, often myocardium
(2) Nucleic acids
‣ RT-PCR ➞ fast
‣ PCR ➞ used more often for FMD Dx
• Samples for Testing:
◦ Fluid from vesicles; Affected epithelium; Nasal/oral secretions; Serum; milk; semen;
◦ Necropsy - myocardium
◦ Esophageal/pharyngeal fluids (use when no vesicles are present and to identify carriers)
TREATMENT
• No specific treatment
• Supportive care ➞ antibiotics for mastitis; foot care, etc.
PROGNOSIS
• Good ➞ survival of infected individuals
• Poor ➞ overall health of herd and economic outcome
• Guarded ➞ neonates, nursing animals
PREVENTION/CONTROL
• FMD-free countries ➞ Euthanasia ➞ all positive & in-contact animals ➞ burn or bury carcasses
• Countries that can't depopulate positive herds ($$$) ➞ Quarantine +/- vaccination (Killed vaccine useful but short immunity)
• Within/around affected areas ➞ Movement restriction with warning signs ➞ animals AND people
◦ PEOPLE can be temporary CARRIERS ➞ if exposed, cannot leave for ~3-5 days
REPORTING
• REPORTABLE Disease – worldwide
◦ Endemic in Southern Asia, Africa, Middle East, some of Latin America
◦ NOT found in the Americas, Australia, New Zealand, Indonesia, Chile, Western Europe
• When FMD is suspected FIRST step ➞ Notify regulatory officials
◦ US - The Area Veterinarian in Charge (AVIC), & the State Veterinarian
◦ UK - The duty vet at local Animal Health Veterinary Laboratories Agency (AHVLA)
• DVM is the first line of defense vs. foreign animal disease, but a Foreign Animal Disease Diagnostician (FADD) from
Veterinary Services (VS) always directs the protocol for diagnosis of FMD cases in the US
Resources
1. Zuku Review FlashNotes. Foot and Mouth Disease (FMD). Extended Version.
2. https://www.oie.int/app/uploads/2021/09/foot-and-mouth-disease-1.pdf
AVIAN 3 Reportables
INFECTIOUS LARYNGOTRACHEITIS (ILT)
ETIOLOGY
• Gallid herpesvirus I
◦ subfamily: Alpha herpesvirus – double stranded DNA virus
• Species affected ➞ ALL chickens + pheasants > 4 weeks of age
TRANSMISSION
(1) Direct contact ➞ mm, respiratory, or ocular contact carriers
(2) Aerosol
(3) Fomites ➞ mechanical (contaminated feed/water, clothing/footwear, handling equipment, housing/litter/bedding, soil)
(4) Vector ➞ darkling beetles, mealworm
• Clinically recovered birds (carriers) are most important vector; Human traffic-associated problem
COMMON PRESENTATION
• Classic case: Coughing, conjunctivitis, +/- bloodstained beaks, decreased egg production
• Acute → UPPER respiratory signs
◦ Neck extension during inspiration
◦ Loud gasping, coughing, marked dyspnea
◦ Conjunctivitis, periorbital swelling
◦ Blood-stained mouth, beak (tracheal exudate)
◦ Decreased egg production
• Subacute
◦ Nasal and ocular discharge
◦ Tracheitis
◦ Conjunctivitis
◦ Mild rales
• Chronic: poor weight gain in broilers
• Latent infection in survivors, can recrudesce when birds stressed
• Mortality variable, often high
DIAGNOSIS
• Differential diagnoses:
◦ diphtheritic form of avian pox virus
◦ Newcastle disease virus
◦ avian influenza virus
◦ infectious bronchitis virus
◦ fowl adenovirus
◦ Aspergillus spp.
• Definitive diagnosis:
◦ Presumptive diagnosis based on history + necropsy (blood, mucus, caseous exudate, or hollow cast in trachea)
◦ Histopathology of the trachea or Virus isolation required for Positive diagnosis
◦ Cultivate on chorioalllantoic membrane of 10-day-old chicken embryos
◦ Screen flocks with ELISA or virus neutralization (VN) serological tests
TREATMENT
• No treatment available
• Immediately vaccinate adults during outbreak with attenuated MLV vaccine ➞ Shortens course of disease
• Supportive Care; Decrease stress; Lower dust levels
• Mild expectorants
PROGNOSIS
• Good ➞ Mild forms, high morbidity, low mortalitiy
• Poor to Grave ➞ Severe forms with tracheal occlusion
PREVENTION/CONTROL
• Vaccination during outbreaks and in endemic areas
◦ MLV attenuated; ILT recombinant
• Strict biosecurity & sanitation protocols
REPORTING
• Highly contagious
• Worldwide ➞ economically important due to decreased egg production
• Pheasants and peafowl can get ILT, but less common in them
• REPORTABLE
Resources
1. Zuku Review FlashNotes. Infectious laryngotracheitis (ILT). Extended Version.
2. https://partnersah.vet.cornell.edu/content/infectious-laryngotracheitis
INFECTIOUS BRONCHITIS VIRUS (IBV)
ETIOLOGY
• Infectious bronchitis virus (IBV)
◦ Coronavirus ➞ single stranded RNA virus
• Species affected ➞ CHICKENS ONLY
TRANSMISSION
(1) Aerosol ➞ inhalation viral particles indirect contact
(2) Ingestion ➞ aerosolized droplets, fecal or urinary contamination & ingestion viral particles
(3) Fomites ➞ mechanical (contaminated feed/water, clothing/footwear, handling equipment, housing/litter/bedding, soil)
(4) Vector ➞ darkling beetles, mealworm
◦ Clinically recovered/ asymptomatic birds (carriers) are most important vector
• Persistent viral shedding in the environment ➞ shed in nasal excretions and feces of infected birds
COMMON PRESENTATION
• Highly contagious acute upper RESPIRATORY disease
• Strains predilection for ➞ 3 R’s
◦ Respiratory tract
◦ Renal system
◦ Reproductive tract
• YOUNGEST ➞ most SEVERE RESPIRATORY signs
• OLDER ➞ decreased egg production, subtle respiratory signs
• Virulence ➞ Nephropathogenic strains (Up to 60% mortality) ➞ interstitial nephritis
• Clinical signs:
◦ < 2 weeks old
‣ Depression, ruffled feathers, huddling near heat, coughing, sneezing, nasal discharge, tracheal rales
‣ Epiphora, Decreased feed intake, weight loss
‣ +/- Permanent damage to oviduct ➞ Impairs egg-laying capacity
◦ > 6 weeks of age ➞ Similar signs; LESS severe
‣ Facial swelling with concurrent 2° bacterial sinusitis
◦ Adults ➞ More subtle respiratory signs
‣ Nephropathogenic strains
‣ Birds recover from early respiratory signs ➞ diarrhea ➞ +/-Fatal secondary urolithiasis
◦ Broilers ➞ Poor feed conversion and reduced growth rate
‣ Condemnation of meat at processing
◦ Layers ➞ decreased egg production (up to 50%)
‣ Abnormal eggs ➞ Misshapen, ‘Wrinkled’ eggs; Thin shell; Watery albumen; Abnormal color, surface
DIAGNOSIS
• Differential diagnoses: Acute respiratory
◦ Avian influenza
◦ infectious coryza
◦ infectious laryngotracheitis
◦ Newcastle disease
• Definitive diagnosis:
◦ Field diagnosis ➞ Clinical signs, lesions
◦ Necropsy
‣ Respiratory tract ➞ Trachea, bronchi, sinuses, conjuctiva
• Edema; Serous, catarrhal or yellow caseous exudate
• NON-hemorrhagic
‣ Nephropathogenic strains ➞ Pale, swollen kidneys; White urates in distended tubules, ureters
‣ Reproductive ➞ Occluded, hypoglandular, cystic oviducts; Egg yolk peritonitis
◦ Virus Isolation via inoculation of chick embryos
‣ Negative hemagglutination reaction with chicken RBCs
◦ Paired serology ➞ Rise in IBV AB titer ➞ infection
‣ ELISA; Virus neutralization (VN);Modified hemagglutination inhibition (HI); Immunodiffusion
◦ Electron microscopy or IFA (RAPID) ➞ tracheal samples; Does not distinguish serotype
◦ Identification of serotype ➞ RT-PCR; Monoclonal antibody (MAb) ➞ Serotype-specific
TREATMENT
• No specific treatment
• Supportive care
• Antibiotics ➞ During initial stages of disease
PROGNOSIS
• Most birds recover
• Substantial economic losses ➞ decreased egg prod. and growth rate, meat condemnation, permanent damage to layers
PREVENTION/CONTROL
• Difficult to control ➞ Highly contagious
• Vaccination
◦ Attenuated live vaccine ➞ via water, spray, or eye drop; may increase in virulence after back passage in chickens
◦ Killed oil-emulsion vaccine ➞ Reduces viral replication in respiratory tract & prevents egg production loss
‣ maternal immunity to newly hatched chicks first 1-3 weeks of life
• Strict biosecurity & sanitation protocols ‘All-in, All-out’ management
REPORTING
• REPORTABLE IN SOME STATES
• Economically important disease worldwide, NOT Zoonotic
• Thought to be the most infectious of the diseases of poultry
Resources:
1. https://partnersah.vet.cornell.edu/content/infectious-bronchitis
2. Swayne DE, Glisson JR. Diseases of Poultry. 13th ed. John Wiley & Sons; 2013.
3. Zuku Review FlashNotes. Infectious Bronchitis Virus (IBV). Extended Version.
AVIAN INFLUENZA
ETIOLOGY
• Avian Influenza Virus
◦ Type A orthomyxovirus
◦ 1. Hemagglutinin (H1-H16) proteins 2. Neuraminidase (N1-N9) proteins 3. Ability to produce disease
• Species affected ➞ Chickens, turkeys, pheasants, quail, ducks, geese, guinea fowl, free-flying species
• Natural reservoir ➞ Wild waterfowl and aquatic birds
TRANSMISSION
(1) Aerosol
(2) Direct contact
(3) Fomites
• Excreted from ➞ nares, mouth, cloaca, conjunctiva
• Replication in respiratory, intestinal, renal, and/or repro organs, also found in feathers and epidermis
COMMON PRESENTATION
• Classic case: Chickens with sneezing, coughing, conjunctivitis, decreased egg production
• Two Scenarios in POULTRY flocks:
(1) Low Pathogenic Avian Influenza (LPAI) virus ➞ MAJORITY
‣ Upper respiratory infection, Decreased egg production, Minor health threat to people
(2) Highly Pathogenic Avian Influenza (HPAI) virus: FOWL PLAGUE ➞ MINORITY
‣ H5 & H7 HPAI subtypes ➞ REPORTABLE: ZOONOTIC POTENTIAL
‣ Peracute death, high morbidity, high mortality
‣ RAPID spread through flocks
‣ Drastically reduced egg production, soft-shelled or misshapen eggs
‣ Severe URI ➞ sinusitis, conjunctivitis, dyspnea; cyanotic edematous combs, wattles, & shanks
‣ Neurologic signs ➞ Droopy wings, incoordination, paralysis, opisthotonus, torticollis
‣ Greenish, watery diarrhea
DIAGNOSIS
• Differential diagnoses:
◦ Newcastle disease
◦ infectious bronchitis
◦ infectious laryngotracheitis
◦ avian pneumovirus
◦ infectious coryza
◦ Differentiate AI from ➞ Mycoplasmosis, Chlamydiosis and fowl cholera in young turkeys
• Presumptive Dx in Field ➞ Hx, PE, CS, Necropsy ➞ REPORT suspected outbreak to state vet
◦ Edema, hemorrhage, necrosis of multiple visceral organs, skin, and CNS
• Definitive diagnosis:
◦ Sample collection ➞ tracheal & cloacal swabs & trachea, lung, spleen, tonsils, brain tissue + Blood for serum testing
◦ Submission to Accredited diagnostic laboratory ➞ AGID or ELISA
‣ Subtype testing: (1) Hemagglutinin (HA) (2) Neuraminidase (NA) inhibition (3) rRT-PCR ➞ specific viral RNA
TREATMENT
• LPAI ➞ Supportive care, warm environment, Broad spectrum abx
• HPAI ➞ CULL infected flock
• Antiviral medications NOT approved or recommended
PROGNOSIS
• Good ➞ Most uncomplicated LPAI cases
• Grave ➞ LPAI w/ secondary complications + HPAI outbreaks
PREVENTION/CONTROL
• Eradication ➞ Strategy for controlling HPAI H5 & H7
• Vaccination ➞ Requires approval of State veterinarian
◦ prevent clinical signs & death, Decreases viral replication and shedding from respiratory & GI tracts
◦ Vaccines licensed in USA ➞ 1. Inactivated whole AI virus 2. Recombinant fowlpox AI-H5
◦ Specific protection ➞ Autogenous virus vax
• Strict biosecurity & sanitation “All-in, All-out” management; Quarantine new birds before flock introduction
REPORTING
• Report all suspected cases of LPAI & HPAI to State & Federal veterinary authorities
• H5 & H7 subtypes are NOTIFIABLE Avian influenza (NAI)
• Zoonotic potential ➞ Human Fatalities with H5N1, H7N7
◦ Treat all HPAI, NAI as potentially zoonotic
◦ Risk factors for humans ➞ 1. Direct contact w/ poultry (COMMON) 2. contaminated uncooked poultry products
Resources:
1. https://partnersah.vet.cornell.edu/content/avian-influenza
2. Zuku Review FlashNotes. Avian Influenza (AI). Extended Version.