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Bordetella Avium in Cockatiels

Alan & Donna Mason
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I. Introduction
Bordetella avium is a gram negative aerobic bacterium responsible for the avian disease referred to as bordetellosis. This disease is highly contagious producing an upper respiratory tract infection that most often leads to death in cockatiel chicks. This bacterium was first isolated from young turkeys in 1967 and officially named Bordetella avium in 1984. Clubb et al report isolation of B. avium from infected cockatiel chicks in late 1993. This study also reports isolation of B. avium from two Wagler’s conures, a jenday conure, a muluccan cockatoo and a nobles macaw that showed similar signs for bordetellosis. There are further reports of B. avium being isolated from numerous other species of birds to include chickens, finches, budgerigars, noble macaws, Japanese quail, ostriches, etc. This disease is worldwide and some speculate that it is being carried within 80% of caged cockatiels.

B. avium commences a path of infection by colonizing the ciliated epithelium of the cockatiel’s tracheal mucosa. As the disease progresses, it will destroy this outer layer of tissue along the respiratory tract and while doing so produce toxins that can affect other groups of tissue in the body. This infection will also predispose the cockatiel to other infectious diseases. B. avium acts quite similar to its human counterpart – Bordetella pertussis (whooping cough) however, there is no evidence that B. avium can infect humans.

Most research to date on the effects of B. avium has focused around the turkey because of the economic impact of this disease on the poultry industry. This research on turkeys, which is well documented, will be provided, where appropriate, throughout this presentation to gain a better understanding of the potential effect of this disease on cockatiels. We are aware of only one formal study thus far performed on bordetellosis in cockatiels. Pertinent information from this study of bordetellosis in cockatiels performed by Clubb et al is included. In addition, we present data and observations from our personal experience in dealing with a cockatiel aviary infected with this disease to include what would appear to be a successful treatment of B. avium carriers.
II. Sign of the disease
B. avium does not appear to be capable of establishing a disease state within adult cockatiels. This has been our personal observation and is consistent with all our conversations with other aviaries experiencing a B. avium epidemic. Bordetellosis has a severe effect on the very young cockatiel. Symptoms of this disease that we have observed specific only to the young and unweaned cockatiel are as follows:

  • Sneezing with significant mucoid exudates (serious nasal discharge)
  • Lethargic behavior
  • The beak gradually closes over a period of 12-24 hours to a point of being “locked” shut (temporomandibular rigidity or “lock jaw” syndrome)
  • The birds appearance becomes pasty and pale
  • Dehydration and weight loss becomes apparent
  • Constant begging for food
  • Protruding eyes that appear half shut. This is due to swelling of the suborbital chamber of the infraorbital sinus, which forces the lower eyelid upward.
  • Eyes are glassy looking
  • The head appears swollen due to inflammation of the skeletal (voluntary) muscles adjacent to the inflammed nasal cavity and infraorbital sinus. Inflammation of the skeletal muscle responsible for opening the beak creates the “lock-jaw” condition.


We have observed these symptoms of the disease occurring as young as 3 days old and as late as 4 weeks old. If the birds are breeding and producing chicks with the above mentioned signs then the adult pair should be considered carriers of the disease until proven otherwise. The only sure way to know if an adult is a carrier of B. avium is to have it tested by a qualified laboratory.
III. Morbidity and Mortality
Morbidity (sickness) may or may not occur when the young cockatiel is directly exposed to B. avium. Some newborn cockatiels will survive being raised in an infected clutch without any signs of the disease as shown in the data of Table 1 suggesting a resistance to the disease. This is supported by the study performed by Clubb et al in which B. avium could be isolated from 30% of asymptomatic chicks within an infected aviary. These asymptomatic carriers can infect other chicks within the aviary. In studies with young turkeys morbidity was on the range of 80 to 100%.

In studies of young turkeys, the mortality (death) rate from bordetellosis was normally less than 10%, however in cases of high mortality (>40%) Escherichia coli was also isolated. There was also a study (Hinz et al) that examined an outbreak of B. avium in combination with Chlamydia psittaci in several turkey flocks. Mortality in these affected flocks ranged from 7 – 20%. The high mortality was attributed to secondary infections from Klebsiella pneumoniae, E. coli, and Pseudomonas fluoreszenz.

Similar to the study performed by Hinz et al, we experienced an outbreak in our flock of B. avium in combination with Chlamydia psittaci (Psittacosis). Upper respiratory swabs taken from infected cockatiels produced cultures of both Klebsiella and Pseudomonas on agar plates. Since B. avium produces a toxin (tracheal cytotoxin (TCT)) that damages the ciliated epithelial cells of the respiratory tract, the cockatiel is unable to adequately clear these opportunistic bacterium from its lungs. Mortality among our adult cockatiels was 3%. This low mortality may have been attributed to quick recognition of the psittacosis problem once it became active followed by prompt treatment.

The severity of bordetellosis varies with different species of birds. Studies have shown that the disease is less severe in chickens than in turkeys. Our results would indicate that cockatiels experience symptoms similar to turkeys but suffer a higher mortality rate from bordetellosis than any other bird so far studied and reported.

The histopathology of bordetellosis within turkeys is well documented. The bacteria first colonizes the ciliated epithelium on the nasal mucosa, from here it works it way into the trachea then into the primary bronchi within 7 to 10 days. B. avium has only been found attached to cilia and not to any other type of cell. During the third and fourth week of the disease, the tracheal mucosa becomes distorted by folds and abnormal epithelial growth. The epithelium returns to normal after the disease has run its course, typically 4 to 6 weeks from the onset of the disease. Also accompanying this respiratory lining problem is softening and distortion of the tracheal cartilage. This condition will create folds that can accumulate mucoid exudate and lead to death by suffocation. This condition of the tracheal cartilage will persist for at least 53 days after infection. The turkey’s immunological system will develop antibodies to the bacteria and eventually prevent the bacteria from attaching to newly developed ciliated epithelium. This immunological response will diminish over the next 4 to 8 weeks allowing any residual B. avium in the nasal cavity or sinus to once again expand and produce another case of bordetellosis. We have observed a couple of cockatiels (6 to 9 months of age) in our flock that had persistent re-occurrences of upper respiratory infections until treated for bordetellosis and psittacosis. Although we are not sure which pathogen continued the infection (i.e., B. avium or Chlamydia psittaci), it does demonstrate the difficulty within some cockatiels to be able to rid respiratory infection on their own.

In a limited study by Clubb et al of directly infecting 2 1/2 week old cockatiel chicks with B. avium the following sequence of events was observed:

  • Sneezing after one day of infection
  • Nares erythemic after the second day of infection
  • By the fourth day of infection the chick refuses food
  • By day five suborbital swelling and the jaw starts to lock shut


Table 1 is a reconstruction of our breeding records during the time of our experience with this disease. It spanned over the course of a year. From this data there does not appear to be a seasonal variance in this disease. In the study performed by Clubb et al mortality occurred primarily during the summer months. This difference in mortality, that is, one seasonal and the other not seasonal, could be attributed to the two different climates, Florida and Idaho respectively.

In Table 1 we placed deaths under the Bordetellosis Death column if the young cockatiel developed “locked jaw”. All the other unknown deaths were placed in the Inconclusive Death column. The survivors from each clutch are numbered in the Survivors column. It should be noted that the first survivor (#1) was breed later in the table on two occasions and experienced a 100% mortality rate of offspring. It would appear that #1’s ability to survive exposure to this bacterium was not passed to his offspring.

In the last two columns of the table the data was scored. All deaths in the Bordetellosis column and all inconclusive deaths, except for one day old deaths, were placed in the Bordetellosis Death column. All one day deaths and survivors were placed in the Non-Bordetellosis column. We attributed the one day old deaths to psittacosis since this disease can effect the cockatiel while still in the shell. Death from bordetellosis within 1 day of hatching is not a reasonable expectation. As shown, the scoring produces a 52% mortality rate. If the one day old deaths are removed from the scoring then the mortality rises to 58%. The definitive bordetellosis deaths alone (numbering sixteen) account for a mortality rate of 25%.

The data of Table 1 shows that bordetellosis can cause death in the young cockatiel within 3 to 30 days of exposure. The study by Clubb et al found death to usually occur between 2 to 4 weeks and not all of the deaths displayed the lock jaw syndrome prior to death. Also, of interest to note from the Clubb et al study was a lack of any Chlamydia or viral infection upon postmortem testing of chicks. From our observation of the disease exposure after 30 days of life appears to either cause no infection or worse case produce a persistent upper respiratory tract infection that will not go away on its own or with the assistance of the regular remedies that can be purchased from the local pet shop. The persistent infection may have been the result of another pathogen (i.e., Chlamydia psittaci).

Both parents F5 and F7 along with an offspring from the last clutch (#24 at age 11 days) were put down and necropsy performed for disease infection. F5 and F7 were chosen because they both showed signs of psittacosis (i.e., conjunctivitis and lime green droppings). All were found positive for B. avium and psittacosis.

It should also be noted that on 8/6/96 four birds (three of them from Table 1 – M3, F3 and F7) were taken to a University Veterinary Hospital for testing. All were given blood tests for psittacosis and all were negative for the disease. In addition, CBC and Chem Panel testing was performed with no unusual results.

Following the treatment discussed in section VI, all, except M3, F2, F5, F6, and F7 were bred again. To date there has been no re-occurrence of this disease or its symptoms. We have noticed a significant reduction in DIS; better weight chicks; and a more active and noisier flock. In addition, we have bred the offsprings #1, #6 and #15 which have all produced healthy chicks with none showing any signs of bordetellosis
Table 1
Data Scoring
Date of First HatchingMale ParentFemale ParentBordetellosis Deaths/Life Spans Inconclusive Deaths/Life SpansSurvivors/ DesignationBordetellosis DeathsOthers & Survivors
4/2/96 M1 F1 0 0 2 / #1
#2
0 2
5/8/96 M1 F1 0 4 / 12 days
12 days
17 days
22 days
1 / #3 4 1
5/31/96 M2 F2 0 1 / 1 day 1 / #4 0 2
7/19/96 M3 F3 2 / 9 days
17 days
0 0 2 0
7/31/96 M2 F4 1 / 9 days 1 / 11 days 3 / #5
#6
#7
2 3
8/13/96 M1 F1 0 0 3 / #8
#9
#10
0 3
9/16/96 M2 F4 0 2 / 1 day
9 days
1 / #11 1 2
9/20/96 M1 F1 2 / 6 days
10 days
3 / 1 day
1 day
9 days
2 / #12
#13
3 4
10/15/96 M4 F5 0 0 3 / #14
#15
#16
0 3
11/30/96 #1 F6 1 / 11 days 3 / 3 days
6 days
9 days
0 4 0
12/1/96 M2 F3 0 1 / 1 day 1 / #17 0 2
12/12/96 M4 F4 0 2 / 1 day
4 days
2 / #18
#19
1 3
1/8/97 #1 F6 0 5 / 5 days
6 days
7 days
9 days
10 days
0 5 0
2/8/97 M1 F1 0 0 2 / #20
#21
0 2
3/6/97 M2 F7 5 / 4 days
6 days
9 days
10 days
10 days
0 0 5 0
3/10/97 M4 F5 0 0 2 / #22
#23
0 2
3/14/97 M1 F1 1 / 30 days 1 / 17 days 0 2 0
5/30/97 M2 F4 4 / 4 days
5 days
7 days
9 days
0 1 / #24 4 1
IV. Disease Transmission
B. avium is transmitted through close contact with an infected bird or through exposure to litter or water contaminated by infected birds. Current studies indicate that aerosol transmission is unlikely since healthy birds in cages next to infected birds do not contract the disease.
Parenting cockatiels carrying the disease will pass it to their young after they have hatched from the egg (unlike psittacosis). The disease appears to develop in the young cockatiel within 3 days of exposure to the carrier parent. We have found that newborn cockatiels are very susceptible to bordetellosis.
V. Bacterium Susceptibility to Environment and Chemicals
One study performed within turkey houses has shown that B. avium survives best under the conditions of low temperature, low humidity and neutral pH. The bacterium was able to survive for 25 – 33 days within feces at 10 C and relative humidity 32 – 58%. When the temperature was raised to 40 C survival of the bacteria was less than two days. Another study reported survival of the bacteria for at least 6 months in undisturbed damp litter.
B. avium appears to be vulnerable to most commonly used disinfectants.
VI. Treatment
To date there is no treatment for cockatiel chicks that contract B. avium and develop the disease symptoms. We have found that once the “lock-jaw” syndrome sets in death within a couple of days is inevitable. Until there is a cure, euthanizing “lock-jaw” chicks is the humane solution.
The adult carriers of B. avium can be treated with reasonable assurance of success. We first learned about Bordetella avium after extensive research with trying to solve the cause for a high mortality rate among our cockatiel chicks. This research also led to receipt of a treatment which we employed on our flock. For over a year following this treatment, we have maintained a closed flock and have not had any reoccurrence of bordetellosis. Others have reported reoccurrence using the treatment we received and we suspect this is due to introduction of an untreated carrier into a clean flock.
The treatment we used on our flock is as follows:
  • A Tylan 50© (Tylosin injectable) solution (8 cc of Tylan©50 mixed to one gallon of water) was the only drinking water source for the first ten days of treatment.
  • Also during the first ten days of treatment a Garcin Pig Pump © (Gentamicin Sulfate Veterinary) solution (1 cc Garcin to one pint of water) was used as an airborne treatment. The treatment we received suggested spraying the bird, one good direct shot, in the face twice a day. We modified the procedure by using a vaporizer filled with the Garcin© in water mixture. All the birds and vaporizer were placed in a flight cage. The cage was covered with sheets and the vaporizer operated for at least 20 minutes. This vaporizing procedure was performed three times a day. This vaporization treatment is essential since ingestion of antibiotics will not come in contact with the site of the origin (sinus epithelium).
  • When the 10-day treatment was completed we mixed a 1” squeezed out ribbon of Mycolex–7© (feminine yeast cream – but not the 1 or 3 day treatment) to 1 gallon of water. A blender was used to obtain the mixture. The stability of this mixture is short and needs to be made fresh every 12 hours. This mixture was the only drinking water source for the next three days. The purpose of this mixture is to treat any yeast infections that may develop during the antibiotic treatment.

Since B. avium is usually accompanied by psittacosis a tissue culture from necropsy of a recent death should be performed to determine if psittacosis is present. In our case, psittacosis was present, therefore after the 13 day treatment we proceeded with a psittacosis treatment for our birds. Had the results been negative for psittacosis we would have still proceeded with the psittacosis treatment to be on the safe side.
The treatment we used for psittacosis was as follows:
  • A Terramycin© solution (1 tablespoon of Terramycin© to 1 gallon of water) was the only source of drinking water for 45 days. All calcium (cuttle bones) was removed during this treatment since it will bind with the antibiotic and render it useless.
  • Also during these first 45 days of Terramycin, treatment the aviary was thoroughly disinfected on days 15, 30 and 45. We used a 1:100 clorox bleach solution. Using a pressurized spray container, everything was disinfected – floor, wall, ceiling, cages, net, vacuum cleaner, air cleaner, etc. To minimize our workload, after the first cleaning anything that could be set aside until after the treatment was placed in another area of the house and therefore, if not exposed to the aviary, it did not require repeat of the disinfecting process.
  • After the 45-day treatment, we repeated the Mycolex–7© treatment to clear up any yeast. We waited 2 weeks after the last treatment and then retested our previously ill birds through blood testing to make sure the infection was gone. The lab results were negative for any infection, confirming the success of the treatment.

We obtained the Tylan ©50 (Tylosin injectable) Catalog # 00014 and the Garacin© (Gentamicin Sulfate Veterinary) Catalog # 02231 from the Omaha Vaccine Company, PO Box 7228, Omaha, NE 68107, phone number 1-800-367-4444. The Terramycin© (oxytetracycline HCL) soluble powder was obtained from a local feed and seed store.
After 24 hours of starting the initial treatment, signs of improvement were noted. By day four, the symptomatic birds (i.e., those showing signs of psittacosis infection) looked nearly recovered.
Different strains of B. avium have been identified in turkeys. The differences exist in toxin production, adherence to tracheal mucosa, plasmid profiles, antibiotic sensitivity, pathogenicity and colony morphology. It would be reasonable to assume that various strains of B. avium infect cockatiels, therefore, treatment results may vary.
Attempting to treat bordetellosis by testing and eliminating those cockatiels that culture positive for the disease will most likely result in failure to eradicate the disease from the aviary. Since not all chicks symptomatic for bordetellosis show positive for B. avium on a culture test, one could assume the same for carriers of B. avium. Treating the entire flock for the disease is the best approach.

VII. Prevention
The best method of prevention is to be very careful of the new birds you introduce to your flock and be mindful if you were around other birds/aviaries that could potentially be contaminated with the disease. A disinfectant foot bath, change of clothing and even a shower is recommended to prevent spread from one flock to another. Bordetellosis is disheartening in what it does to cockatiel chicks and its treatment for the carriers of the disease is laborious and lengthy for the owner. Bird keepers have the option of quarantining new birds and treating them for carrier diseases (i.e., bordetellosis and psittacosis) before introduction to their aviary or introducing them to the aviary and hoping these diseases are not present to infect their entire flock.
VIII. References

1. Skeeles, J.K. and Arp, L.H. 1997. Bordetellosis (Turkey Coryza). In: Diseases of Poultry. Calnek, B. 10th ed., 13:275-287
2. Clubb, S.L., Homer, B.L., Pisani, J. and Head, C. 1994. Outbreaks of Bordetellosis in Psittacines and Ostriches. In: Proceedings of the Association of Avian Veterinarians, pp 63-68