With all these viruses floating around (avian influenza, Newcastle disease, etc) biosecurity is the watchword and disinfection remains a major part of this. Unfortunately many myths about different disinfectant compounds exist and failure to understand how disinfectants work (or don’t work!) has often lead to apparent failure of the compound and the appearance of disease.
Firstly, what is a disinfectant? For the purposes of this article it can be defined as a chemical compound capable of killing micro-organisms. Heat and radiation may also be used as part of a disinfection programme in certain conditions, but these are not generally appropriate for the keeper with only a small collection of birds!
In principle chemical disinfection sounds easy; you buy the agent, wash it around everywhere, it kills the bugs and no more disease! Sadly life is never this simple and there are many other factors that need to be taken into account:

1. What does it kill? Not all disinfectants kill all bugs. This information must be taken into account when you are considering what you want to kill! Table 1 shows some of the activity of different types of micro-organism.

So a clean with spirit will be pretty effective against many bacteria but will not have much effect against Aspergillus spores.

1. Resistance to disinfection. As can be seen in Table 1 different organisms are sensitive to different compounds. This is partly due to the method of action of the disinfection and partly due to differences in the structure of the organism to allow the chemical to kill it. Therefore as well as needing to consider which agent to use you must also consider the concentration of disinfectant to use and the contact time, i.e. the amount of time the disinfectant must contact the bug to kill it. These factors vary widely between organisms, agents and formulations so you must read the information on the packet before deciding on the dilution of disinfectant and the amount of time before you wash it away. Organisms can become resistant to disinfectants if:
1. You do not vary the compound that is being used
2. They are exposed to disinfectants at sub-lethal doses and/or for inadequate periods of time.
2. Inactivation of the disinfectant. Many of the agents may be de-activated by various factors:
1. Sunlight
2. Acid/ alkaline conditions
3. Low temperature can make the agent less active
4. Organic Matter; dirt, faeces, whatever you want to call it! This is the main reason (in my experience) that disinfectants “fail”. Unless you clean thoroughly first the disinfectant stands no chance! Often I have seen conditions that have been thoroughly disinfected but are caked in “organic material” and the bacteria are thriving!
3. Failure to penetrate. Materials such as wood or leather are, essentially impossible to thoroughly disinfect as the chemicals cannot penetrate adequately into all the cracks and crevices. Methods such as fogging may aid penetration of wood especially if it has been sealed. Leather equipment (including gloves) should be discarded after an infectious illness and should never be transferred between birds if infection is suspected.
4. Safety. Many of these compounds may be dangerous to users especially at high concentrations. They may also be corrosive to aviary materials! You should therefore thoroughly read any safety instructions and wear whatever safety equipment is recommended! You must also consider safety of the birds and any potentially toxic or corrosive chemicals must be thoroughly washed away before birds are allowed near these areas.

So, a thorough plan is needed rather than ad hoc use of whichever agent is closest to hand or whichever is current “flavour of the month”. As well as disinfection of aviaries, water/feed bowls and perches on a regular basis, attention should be paid to overall cleanliness of equipment and housing, the bird’s feet and beak (after feeding), and of yourself.
It is vital that surfaces should be as smooth as possible to prevent material building up and make it as easy as possible for disinfectants to penetrate. Food preparation areas should all consist of “wipe clean” surfaces although, conversely, the safest chopping boards for meat are made of wood (this contains natural anti-microbials).
It is also important not to introduce potentially dangerous bacteria and viruses. Food should be obtained from known and controlled sources and food preparation and storage areas, equipment, containers, pouches, bags etc. should be kept scrupulously clean and disinfected.
New birds should be quarantined and this quarantine strictly maintained with no equipment, dishes, perches, etc being transferred between quarantine and the rest of the birds. The quarantine area should always be the last to be fed/ cleaned/ etc and, ideally different clothing and boots should be worn while working in these areas. Failing this, disinfectant footbaths should be set up to be used on entering and leaving quarantine.
If this option is used disinfectant MUST be used at appropriate strength and MUST be changed regularly. We’ve all seen footbaths half-full of muddy “water”. These are of no use whatsoever and merely give a false sense of security!
Similarly it is vital to exclude other sources of potential disease. No disinfection regime can cope if there are rodents, flies and cockroaches contaminating food and food preparation areas.

A special case is the travelling box. I am a great fan of these new plastic boxes that are extremely easy to wipe clean.
Travelling boxes are often a major source of fungal spores and hence a major factor in the development of aspergillosis especially if the box is left dirty between uses. Often, the box is quickly disinfected with a low concentration of disinfectant immediately before use (you need it and have just realised how dirty it is!). Table 1 shows that fungal spores are pretty resistant to most agents. Therefore it will usually require thorough cleaning and a prolonged contact with a high concentration of an appropriate disinfectant. In the situation just described, wetting the spores induces them to grow. Then as the box dries and the bird is put in the spores start to be released and the bird will inhale these.
How do you avoid this? Immediately AFTER use the box should be thoroughly cleaned. The material on the floor (paper, carpet, etc) should be discarded. The box should then be soaked in an appropriate disinfectant for the relevant time and dried. It is then stored clean.
When it is next needed a simple clean or even a brief fogging is all that is needed.

You will have noticed that I have not, so far, mentioned any brand names or given any specific recommendations. This is deliberate as there is no single “ideal”. Instead a plan should be drawn up with your vet and with those in the disinfection industry to design a protocol for your situation. This should identify which organisms you wish to kill and provide advice on which agents to use in which situations as well as the concentration to use and appropriate methods, safety etc.

So, in summary, disinfection is a useful and essential tool for the raptor keeper. It must, however, be used properly as part of a properly planned regime.
Most importantly, it must be remembered that disinfection is only a part of a thorough biosecurity and disease prevention plan.
REMEMBER! CLEANLINESS IS THE PRIORITY!

John Chitty BVetMed CertZooMed MRCVS