Influenza Virus & Genetic Change in Viruses

M.9, W.1, L.9

Define enzootic

a disease that is constantly present in a specific animal population w/in a defined geographic area

define epizootic

a disease temporarily prevalent and widespread in an animal population

When are there commonly outbreaks of swine influenza?

Fall and winter

How long does swine influenza typically last?

~ 7 days

What are the clinical signs of swine influenza?

• high fever

• runny nose

• lethargy

• goose honk cough

• reduced appetite

What are the control measures for swine influenza?

Biosecurity and vaccines

How long does equine influenza typically last?

5-10 days

What are the clinical signs of equine influenza?

• Fever

• dry cough

• conjunctivitis

• runny nose

• muscle soreness

What are the control measures for equine influenza?

Biosecurity and vaccines

How long does canine influenza typically last for mild cases?

10-14 days

What are the clinical symptoms of canine influenza?

Fever, runny nose and pneumonia (rare)

what is the control method for canine influenza?

vaccines

How canine influenza be diagnosed?

PCR and serology

How does bovine influenza differ from the other strains?

Typically infects mammary tissue

What are the clinical signs of bovine influenza?

• Low appetite

• reduced milk production

• abnormal appearance of milk

• abortions?

How is bovine influenza diagnosed?

PCR (milk)

How is bovine influenza controlled?

Biosecurity

What are the clinical signs of low pathogenicity avian influenza in poultry?

• Mild resp. disease

• anorexia

• lethargy

• decreased egg production

• ruffled feathers

What are the clinical signs of high pathogenicity avian influenza in poultry?

• sudden death

• cessation of egg laying

• resp. distress

• diarrhea

• cyanosis

• head edema

How is avian influenza in poultry controlled?

Biosecurity

What is the main reservoir for influenza?

Wild birds

How is avian influenza in wild birds spread?

Fecal-oral route

What are the clinical signs of avian influenza in wild birds?

• swollen heads

• resp distress

• neurological signs

How does influenza spread?

• Direct

• indirect (fomites)

• aerosol

What makes up the influenza genome?

8 chromosome like nucleotides

Describe influenza virus

• Pleomorphic (spherical and filamentous)

• negative-stranded RNA virus

• segmented genome

• encapsidated into ribonucleoprotein complexes (RNPs)

• form enveloped virions

What are the two surface proteins on influenza?

hemagglutinin (HA) and neuraminidase (NA)

How many HA surface proteins are there currently recorded?

19

How many NA surface proteins are currently recorded?

11

what do HA’s bind to on a host?

A2,3 or a2,6 sialic acid

• mediates virus attachment and entry

list two ways in which we confirm influenza?

• virus detection

• antibody detection

when is serology informative?

• if virus is exotic

• if no vaccination with similar strains

• if detection of raise in Ab levels

what is your antibody target when detecting antibodies?

• conserved proteins

• subtype-specific proteins (HA/NA)

what are two different methods of influenza diagnosis

1. Real-time PCR (qPCR)

2. Serology

what does a real-time PCR detect?

detects viral nucleic acids

When is qPCR ineffective in diagnosing influenza?

Incorrect sample and if animal is not longer shedding virus

what does a serology detect?

detects antibodies directed against viral proteins

What is the benefit to using serology to diagnosis influenza?

Determines attack rate and prevalence

What are the two strategies that influenza viruses use to evolve?

Mutation and Reassortment