Mark Hagen, M Ag.
Department of Animal and Poultry Science
University of Guelph
Guelph, Ontario, Canada
Disease prevention is achieved by proper planning, quarantine, housing, feeding, immunization, and sanitation. Hygiene must be constantly maintained making cleaning and disinfection an important part of any animal production facility. If the numbers of pathogenic micro-organisms in a facility are allowed to build up, the chances of an individual bird coming into contact with sufficient organisms to cause a clinical infection is increased.
Sanitation includes the proper set-up of drainage, ventilation, and cages working towards hygienic conditions. An efficient and routine program is required to remove wasted food, feces and dust from the birds' environment.
Bacteria and fungi should not be a problem in an aviary that is kept clean with proper sanitation. However mixed collections of wild-caught exotic birds can harbour carriers of highly contagious viruses. Viruses are difficult to control without disinfectants. If a bird dies from a contagious virus immediate and effective disinfection of the environment must be done.
Disinfection refers to the destruction of pathogenic microorganisms on inanimate objects by chemical or physical means. There may still remain spores or traces of microorganisms but these should not result in disease to healthy birds. Sterilization means nothing less than the removal and complete destruction of all living microorganisms; every single one. This can rarely, if ever be achieved in the cleansing of the animals' environment though it is the aim.
When describing an agent's effect on a type of microorganism the suffix -stat means that it prevents the multiplication of an organism and -cide means it kills that organism (Sainsbury and Sainsbury, 1988). For instance a bactericide kills bacteria; a fungicide, fungi and a viricide, viruses.
Physical means of destruction includes steam, ultraviolet light, extremes of pH and high heat. Chemical disinfectants are more commonly used and there are many types each with different characteristics.
Current Disease Situation
In the exotic bird industry disease continues to cause great hardship as rare, valuable or companion birds are lost. This may be attributed to the following factors:
- Rapid expansion in the keeping and breeding of exotic wild-caught birds without adequate and careful planning and preparation. Errors have occurred in the design of aviaries or flights, bird rooms, ventilation and in their management.
- A lack of experienced breeders with most operations on a trial and error management system and word of mouth information gathering.
- Laboratory difficulty in diagnosing even some common psittacine diseases such as Psittacosis, and most viral caused diseases plus the reluctance of some breeders to post their dead birds.
- A lack of experienced avian exotic veterinarians mainly due to college emphasis on animals of agricultural importance.
- Smuggling of birds which by-passes quarantine and is usually more stressful resulting in higher disease rates.
The use of drugs is no substitute for good sanitation. The continuous or massive administration of drugs to maintain health will sooner or later fail with the emergence of drug resistant strains.
Horizontal disease transmission may be by external vectors such as insects, wild birds, rodents and handling; by means of contaminated feed, water, or cages; and by the air from dust, dried feces, feather dander or water particles. Eliminating horizontal transmission requires a consistent and persistent reduction of the micro-organisms in the bird's environment.
Vertical disease transmission is by infection of the reproductive organs of the breeding stock and subsequent contamination of the hatching egg. Vertical transmission can be reduced by breeding from captive-bred disease free birds and not breeding birds whose young die from a vertically transmitted disease.
Exotic Birds Versus Commercial Poultry Operation
Poultry operations can select healthy, vigorous, disease-free birds from one source while most parrot breeders are working with wild-caught birds from many parts of the world. Wild-caught birds are easily weakened by stress to the point of being susceptible to infection. Both new and resident stock may contain carriers of contagious micro-organisms to which they are themselves resistant but may still shed under stress.
An "all birds in all out" program is not feasible with parrots since they take years to begin breeding, are long lived and expensive. Fumigation is also not possible as the stress of removing the birds from the building and temporarily housing them may trigger a disease outbreak.
There should be good control of the micro-climate in the room using ventilation/fan control, humidification with misters or other equipment and air filters. Excessively dry conditions allow excreta to dry up and possibly aerosolize as dust leading to cross-contamination. A buildup of disease-causing organisms can be harbored in fine dust on rafters, window sills, walls and ceiling. The room design should avoid the existence of these types of surfaces.
A bird room should have a disinfection/entrance room before it, for visitors to change shoes or add disposable plastic boots. A foot bath can also be located here for dipping footwear into a strong disinfectant that is not inactivated by organic matter. However an improperly maintained foot bath is an ideal method of spreading disease.
The baby rearing room should be well away from the main bird room housing the breeders and the isolation room. Air flows should be separate. Cleaning equipment used in the adult rooms should not be used to clean the baby room.
Many associate hygiene with cleaning but it should start with cage design and enclosure construction. The cage set up should allow cleaning and disinfection to be done easily and efficiently. Suspended flights keep the birds away from their droppings and those of their neighbors. The space between cages should minimize the chance of a bird defecating onto the next cage; a foot being a reasonable distance to reduce this cross-contamination between cages.
To allow for a more thorough cleaning the walls, ceiling and floor should be water resistant and also withstand the force of a high pressure washer, if one is used. The floors should be concrete and sloping towards a drain. Poor floor drainage contributes to bad sanitation by making the removal of waste difficult. Wet and damp areas are unpleasant and provide breeding areas for flies.
The "cleanability" of surfaces is an important consideration when selecting building materials. Dirt and micro-organisms settle into the pores of surfaces and hide in cracks. These are difficult to remove even with brushing and high pressure. A smooth finish is preferable.
Morgan-Jones (1981) examined the levels of bacterial load on various cleaned surfaces and recovered significantly more bacteria from brick, painted wood and other surfaces than from plastic (Table 1). PVC plastic sheeting with a slippery like finish is available from Mauco Industries Ltd. in 0.040 inch thickness, four foot widths and lengths up to 50 feet.
Table 1. Levels of bacteria recovered from cleaned materials from farm buildings.
Surface Total bacterial
count (at 22°C)/100 cm2
Plastic ................. 100
from Morgan-Jones (1981)
Wash-down and General Cleaning
An effective sanitation program should be executed in logical steps on a continuing basis. A thorough cleaning helps to control diseases by eliminating organic matter which interferes with disinfectant activity, by reducing the number of pathogenic organisms and exposing the rest for disinfection.
The use of vacuum cleaners in bird rooms should be avoided. They tend to blow around the dust and can scatter microorganisms. Viruses can also pass through the vacuum bag and back into the air. Floors should be swept as needed and mopped with a disinfectant periodically, perhaps once a week. To keep down dust and fluff during its removal, surfaces can be prewetted with a light spray.
To reduce the chance of zoonotic disease transmission or long term allergy and lung disease, a mask should be worn when working under dusty conditions. The 3M AseptexTM molded surgical mask (distributed by White Cross / VenTech Healthcare Inc.) is comfortable and appears to be effective under these conditions.
If masses of feces have started to build up on cage wire they should be scraped off. Gross filth should be removed mechanically as much as possible without creating too much dust. If no floor drainage exists then the plastic sheets or paper under the cages should be discarded and replaced with clean material.
Cages must be sprayed to soak and remove the remaining feces and gross filth. In this wash-down phase a germicidal detergent/ disinfectant that remains relatively effective in the presence of organic matter could be used.
Water Bowls and Feeders
To minimize fecal contamination of food and water the birds' feeding area should not be below perches or a favorite roosting site. Water bowls should be cleaned and disinfected whenever dirty. To avoid cross-contamination bowls should go back into the same cage they came from or a second set can be used while the dirty set is soaking over night in disinfectant. Some birds may dirty their bowls with feed or feces more than others. If the bowls are not fouled, cleaning can be bi-weekly rather than daily. Nutrient supplementation of the water requires daily cleaning and refilling with fresh solutions. Bowls should be scrubbed with an abrasive pad to remove all slime and organic matter then soaked in a disinfectant that suits the circumstances (see below).
Gravity feeders should be periodically removed from the cage and completely cleaned. There may be areas within feeders where little movement of the feed occurs, either due to the birds eating only out of one side or their design. These areas can become breeding grounds for moths or can become moldy.
Feeders and water cups should not be dipped into a common bucket for filling. A feed scoop and water pitcher makes filling containers a sanitary procedure.
High Pressure Washers
The washing ability of high pressure cleaners is unmatched by brushes or other mechanical methods. Conventional cage cleaning with a hose/pail and sponge/brush is slow and tiresome and not as effective as with a powerful blast of water. The home use of high pressure cleaners is much more common in Europe where most of the machines are manufactured. The features required for cage cleaning and disinfecting include; an adjustable working pressure, a pencil jet and fan jet nozzle and most importantly a foaming nozzle.
Most high pressure washers have a variable flow chemical intake to allow the mixing of some liquid compound into the spray water. However, the addition of detergent to the power wash does not assist in the reduction of surface bacteria (Morgan-Jones, 1981) which is significantly reduced by more than 90% just by the physical force of the spray. This is also not an efficient way to apply disinfectant. Much of the product is aerosolized or lost with the spray run off and is not in contact with surfaces long enough to properly disinfect.
The important disinfection occurs during the final phase of the sanitation program. Here products with a high level of disinfection may be required especially if there is a viral problem. The efficient and safe application of these disinfectants is important.
Foaming appears to have many benefits over sprayer application of disinfectants. Foaming is achieved by mixing the proper brand of disinfectant with water and converting this solution into a thick clinging blanket of foam with the use of a special nozzle attached to a high pressure cleaner machine.
The following benefits are achieved:
- Extended Contact Time - the foam, due to its nature, remains in contact with cage and wall surfaces for a longer time thus is more effective in disinfecting and cleaning as most disinfectants are based on at least a 10 minute exposure period;
- Increased Penetration - results in more effective germicidal activity aiding in the killing of resistant organisms.
- Complete Coverage - the chance of contaminated areas being missed is eliminated due to the visual aspect of foam allowing you to see where you've applied the disinfectant.
- Greater Coverage - foam is projected up to three meters so all crevices and corners can be reached in large cages with poor access.
- No Aerosol Effect - because foam is applied with special nozzles there is no atomizing mist to irritate personnel or birds such as occurs with sprayers.
- Uses less Water - produces less moisture in areas with limited drainage.
- Residual Effect - when allowed to dry without rinsing, a micro-thin coating will remain on the surface and will continue to disinfect for at least seven days, according to some product manufacturers.
Of course there is concern for the welfare of the birds coming into contact with the disinfectants. When a pair is removed from their cage or flight it can be thoroughly cleaned before different birds are placed into it. However most of the time cleaning is performed with the birds left in their cages.
When we foam some species, such as moluccan and umbrella cockatoos, remain in their nest boxes where they usually hide when people are around, while most of the others, including the macaws and amazons, stay in the upper level or in the back of their flights on top of their nest boxes. With these birds the lower areas of their cages, where most of the contaminated cage wire occurs, can be foamed without the birds coming into contact with the disinfectant. A problem occurs with skidish birds, such as hawk headed parrots, goffin's cockatoos and some amazons, which fly around during the foaming possibly getting the foam in their face.
If a bird gets some foam on its eye remove it from the cage and flush the eye with sterile water. Birds may rub irritated eyes with toe nails and a collar may reduce periophthalmic swelling.
Micro-organisms of Concern
A post mortem should be performed on all dead birds in order to determine which microorganisms are to targeted against. Here in Ontario the Veterinary Laboratory Services Branch (VLS) of the Ministry of Agriculture and Food provides complete post mortem services including virology and histopathology. Your veterinarian can be mailed copies of the reports directly from VLS and should be consulted on the findings.
An examination of the cause of mortality at HARI indicates that viruses are the major cause of death. Our records show that since our establishment in October 1985 the cause of mortality in our breeding stock was diagnosed as some viral agent in 65 % of the cases, 11 % as bacterial, 7 % as mate aggression, 5 % as management errors and 12 % of other, or unknown causes or were not posted. The viruses isolated have been the enveloped or lipophlic type herpes and paramyxo-virus (not the Newcastle type) 95 % of the time with the rest being reo virus.
Half of the birds that were found to have high levels of pathogenic bacteria were lories fed a liquid diet high in simple sugars. We now feed lories our dry Tropican Mash which has solved this problem and firmed up their droppings.
Bacterial infections have been more common in hand-fed babies with Pseudomonas and E. coli being the organisms causing mortality. We isolated Pseudomonas from our well water source and it was growing in our brooder water.
The routine treatment of new birds with 1 % cholortetracyline (CTC) pellets for 45 days should eliminate carriers of psittacosis caused by Chlamydia psittaci. Cages and feeding equipment should be completely disinfected before birds are taken off the medicated pellet so they are not reinfected.
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