This infection, probably the commonest respiratory disease of chickens, was first described in the USA (N. Dakota, 1931). Its affects vary with: the virulence of the virus; the age of the bird; prior vaccination; maternal immunity (young birds); and complicating infections (Mycoplasma, E. coli, Newcastle disease).

Morbidity may vary 50-100% and mortality 0-25%, depending on secondary infections. The cause is a Coronavirus that is antigenically highly variable; new sero-types continue to emerge. About eight sero-groups are recognized by sero-neutralization. Typing by haemagglutination-inhibition is also used. These differences are due to structural differences in the spike proteins (S1 fraction).

Infection is via the conjunctiva or upper respiratory tract with an incubation period of 18-36 hours. The infection is highly contagious and spreads rapidly by contact, fomites or aerosol. Some birds/viral strains can be carriers to 1 year. The virus, which may survive 4 weeks in premises, is sensitive to solvents, heat (56°C for 15 mins), alkalis, disinfectants (Formal 1% for 3 mins). Poor ventilation and high density are predisposing factors.

Signs

• Depression
• Huddling
• Loss of appetite
• Coughing, gasping, dyspnea
• Wet litter
• Diarrhea
• Diuresis

Post-mortem lesions

• Mild to moderate respiratory tract inflammation.
• Tracheal oedema.
• Tracheitis
• Airsacculitis
• Caseous plugs in bronchi
• Kidneys and bronchi may be swollen and they and the ureters may have urates

Diagnosis

Tentative diagnosis is based on clinical signs, lesions and serology. Definitive diagnosis is based on viral isolation after 3-5 passages in chick embryo, HA negative, with typical lesions, fluorescent antibody positive and ciliostasis in tracheal organ culture.

Serology: HI, Elisa (both group specific), SN (type specific), DID (poor sensitivity, short duration, group specific).

Differentiate from Newcastle disease (lentogenic and mesogenic forms), mycoplasmosis, vaccinal reactions, Avian Influenza and Laryngotracheitis.

Treatment

Sodium salicylate 1gm/liter (acute phase) where permitted - antibiotics to control secondary colibacillosis (q.v.).

Prevention

Live vaccines of appropriate sero-type and attenuation, possible reactions depending on virulence and particle size. Maternal immunity provides protection for 2-3 weeks. Humoral immunity appears 10-14days post vaccination. Local immunity is first line of defense. Cell-mediated immunity may also be important and the implementation of strict biosecurity principles.

"Terminal flock turnaround biosecurity measures are commonplace but are the biosecurity products currently selected, genuinely capable of decontaminating farms where there is a pre-existing IB virus challenge?"

Choosing the right disinfectant is important, as poultry housing surfaces and disinfection application methods vary, and the speed of decontamination action under specific environmental and temperature challenges can be critical when ensuring flock protection.

"The challenges of temperature in poultry production must be considered carefully."

In summer, poultry houses are warm environments. This means that a disinfectant applied to a warm surface can evaporate and dry within 20 minutes. These fast-drying conditions require the disinfectant to work effectively within minutes. However, some disinfectants can take an hour to be effective and in hot climates, they may well be ineffective.

In the winter, when water temperatures can be less than 4°C, the diluted disinfectant must demonstrate ‘speed of kill’ and superior efficacy even at lower temperatures. Many disinfectants however struggle when faced with the combination of colder weather and organic challenges.

Poultry producers can be confident that ViralFX™ is highly effective on all surfaces across a wide range of temperatures. With quick activity when applied in recommended volumes (300ml per square meters) and at a dilution of 1:100, if used as part of the terminal/clean out/turn around biosecurity programme, and following the operator’s cleaning of the surfaces with a compatible detergent.

ViralFX™ should also be an integral part of the operator’s continual biosecurity protocol (at a 1:100 dilution), to reduce the potential cross contamination challenges between poultry houses and farm buildings.

ViralFX™ is a scientific breakthrough that continues to define biosecurity performance standards. It is not surprising that based on its flexible, fast-acting disinfection performance in a wide range of biosecurity uses, ViralFX™ is selected.

"This new performance assessment marks the start of a series of new ViralFX™ efficacy updates across a range of bacterial and viral infection challenges in poultry production and underlines ongoing commitment to supporting poultry producers."