Summary

The use of untreated surface water that has been contaminated by waterfowl has been implicated in outbreaks of highly pathogenic avian influenza (HPAI) in commercial poultry in Australia and overseas. This report describes methods for the  treatment of surface water to reduce the risks of introduction of avian influenza (AI) viruses to commercial poultry farms in Australia.

Fortunately, Australia is not in the high-risk migratory pathways for waterfowl (ducks, swans and geese), the recognised reservoirs for AI viruses in the  northern hemisphere. However, migratory shore birds still present a low risk of introducing overseas AI strains to Australian birds when they mix with local waterfowl, and the latter share water sources with commercial poultry. Wild bird surveillance programs in Australia have also detected low pathogenicity AI (LPAI) viruses in resident Australian populations of wild water birds.

This report describes the water sources most commonly used by the Australian poultry industry, and water sanitation systems applicable for use on commercial poultry farms. These primary sources of water are mains water, bore or underground  water, surface water and rain water.

The highest risk of contamination is associated with  the use of surface water (including bore water stored in dams), particularly surface waters that  provide habitat for waterfowl. Mains water is identified as the most biosecure water source for poultry.

Chicken meat farms mostly use mains water, however commercial layer farms may use other sources because of their distance from mains water supplies. Other poultry farms rely on either mains or a mix of mains and non-mains water supply. This report provides a description of various methods of surface water sanitation, and the advantages and disadvantages associated with each method.

Effective sanitation requires:

• effective pre-treatment of water (to reduce organic  load)
  
  
• correct dosage of sanitiser
  
  
• an adequate duration of chemical concentration level  in water (contact time)
  
  
• reliable operation of equipment
  
  
• accurate monitoring (of flow rates, dosing volumes  and other parameters)
  
  
• avoiding contamination of water after it has been  sanitised
  
  
• adequate water storage facilities.

The most common deficiencies seen in water sanitation are:

• intermittent use of sanitation systems
  
  
• no sanitation of surface water
  
  
• minimal monitoring of sanitiser levels
  
  
• open storage systems
  
  
• incorrect dosing of sanitiser
  
  
• inadequate pre-treatment of water
  
  
• problematic equipment (or poor maintenance)
  
  
• ineffective products
  
  
• mixing of unsanitised rainwater or recycled water with sanitised water
  
  
• inadequate contact time.

The poultry industry should identify and use water sanitisers and application systems that are reliable and effective, economical, user-friendly and with technical support readily available.