Gaby Eshkar, DVM
Private Practitioner
Rishon Le'Zion, Israel
Megabacteria
Megabacteria are very large, Gram-positive, rod-shaped bacteria found in
many avian species, but especially in passerines(canaries) and small
psittacines, filling the proventricular glands and causing elevated
gastric pH and proventricular disease.
Infected Birds
The pathological signs in infected birds were: cachexia, green and
sometimes watery diarrhea, abnormal feathering, impacted crop, undigested
grains in the gastrointestinal tract and sometimes in defecated material,
or in marked contrast, an empty gastrointestinal tract, a dilated
proventriculus with thickened gastric wall, either very thin, blackish,
bloody stomach contents or an apparent vomito negro, mucous, gelatinous
exudate in the proventriculus, ulcers in the proventriculus and
ventriculus. Of 23 canary aviaries (different sites), 48 tested positive
for megabacteria. It was also found in many cage bird species but also in
poultry and ostriches.
Treatment
There has been no consensus regarding treatments for megabacteria, but
some anti-fungal drugs may be effective. Acidifying the gastrointestinal
contents may help prevent megabacteria infection.
Biological Therapeutic Trial
A commercial colony of approximately 300 breeding budgerigars, in which
recurrent cases of megabacterial infections were observed over several
years and currently tested positive for megabacteria with some mortality
were studied. Three groups including untreated controls, treated orally
(by crop gavage) with Lactobacilli suspension, treated in drinking water
with Lactobacillus suspension. All three groups tested negative for
Lactobacillus prior to the study. The Lactobacillus were procured from a
sick cockatoo, cultured and standardized for treatment.
Trial Results
Crop gavage with Lactobacillus suspensions significantly (p<.001) reduced
the megabacteria infection rate as compared to the control group.
In-water treatment with Lactobacillus was not effective.
Conclusions
The successful treatment by crop gavage with Lactobacillus compared to
the water treatment may be explained by the number of bacteria needed for
effective treatment. The study recommends Lactobacillus crop gavage as
the most effective treatment against megabacteria. Even though
megabacteria may be opportunistic pathogens, it may cause severe disease
or aggravate existing infections. Therefore, an efficient treatment
regime for its elimination or reduction must be followed.
Comments By Linda Hogan
I have long been a proponent for use of avian-derived Lactobacillus in
canaries. In my experience over 16 years, I have been able to prevent
diseases which I attribute to use of avian-derived Lactobacillus and good
nutrition. Avian-derived Lactobacillus (Bene-Bac) are available in the US
being manufactured by Pet Ag 1-800-323-0877.
Passerine Protozoal Sinusitis: An Infection You Should Know About
Judy St. Leger, DVM
D. H. Read
California Veterinary Diagnostic Laboratory System
San Bernadino, CA
H. I. Shivaprasad, BVSc, MVSc, MS, PhD
California Veterinary Diagnostic Laboratory System, Fresno Branch
Fresno, CA
Case presentation:
Eleven passerines (9 Canaries, 1 Gouldian Finch, 1 Zebra Finch) were
examined because of sinusitis. Four of the birds came from a large
facility experiencing 33% mortality (200/600) birds.
Clinically the birds demonstrated coughing, sneezing, fluffing, and
death. Treatment with antibiotics (enrofloxacin and tetracycline)
produced a mild reduction in clinical signs and mortality. Gross
examination of the sinuses revealed thick, yellow, caseous cores often
filling one or both periorbital sinuses.
Extensive investigation including histopathology, bacterial, Mycoplasma,
Chlamydia, and paramyxovirus serological and cultural studies, and
electron microscopy for organism in sinus exudate were conducted.
Trichomonas gallinae was found. Previously, passerine infections with
Trichomonas have been associated with digestive tract conditions.
The pathogenesis of the respiratory changes may be associated with one or
more of the following factors:
Comments: Numerous agents can be responsible for causing sinusitis and
associated mortality. Finding Trichomonas as the cause is new and
significant. As expected standard antiprotzoal medication was proven safe
and effective in the management of this condition.
As mentioned in this paper, contact with infected birds was the mode of
transmission. This again is a reminder of the importance of quarantine.
New birds should be quarantined for six weeks to introducing them into
the aviary.
R Kilner
Proceedings of the Royal Society of London Series B Biological Sciences
264(1384): 963-968, 1997
Begging passerine chicks display brightly coloured mouths as they solicit
food from their parents. The author reports that mouth colour functions
as a signal of need in canary nestlings, in the days immediately
following hatching. Changes in mouth colour accurately reflect a
nestling's state of need: the more food deprived the chick, the more
intensely coloured its mouth.
In controlled experiments with two nestlings, parents were offered the
opportunity to choose which nestling to feed. When the mouth colour of
one offspring was artificially reddened using food colouring, parents
gave it more food. These results demonstrate a novel function for
nestling mouth colour and are consistent with recent models of resolution
of parent-offspring conflict.
Comment: Isn't this interesting? You can bet that I am going to test this
out next breeding season.
The Air Sac Mite, Sternostoma tracheacolum, is a respiratory parasite which is often seen in passerine type birds, causing severe respiratory distress in the affected individuals. The Air Sac Mite can be located anywhere along the respiratory tract of infested birds, whether it be in the region of the paranasal sinuses or the air sacs themselves. Birds which appear to be most severely affected by this parasite are Lady Gouldian Finches and Canaries. Although there have been other various reports of Air Sac Mites infestation in other species of birds, none are affected as much as the Canary and Lady Gouldian Finch.
As far as it is known, the Air Sac Mite lives and reproduces on the epithelial surface of the respiratory tract, including the areas of the paranasal sinuses, trachea, syrinx, bronchi, lungs and air sacs. The complete life cycle of the Air Sac Mite is approximately fourteen to twenty one days. As mentioned earlier this takes place along the surface of the respiratory tract of affected birds. One interesting aspect of the Air Sac Mite life cycle, is that the female is Larviparous, this means that the Nymph stage occurs within the adult female Air Sac Mite, thus the female "gives birth" to Larvae which soon go on to mature into adults. Larvae and adult Air Sac Mites are very motile and can easily move through mucous and other respiratory debris. This is because they are specially equipped with long jointed legs.
Transmission of Air Mite occurs through direct contact via the oral route, from one bird to another. By far, the most common method of Air Sac Mite transmission occurs when infested adult birds feed regurgitated food to young nestlings. Another method of mite transmission occurs during courtship behavior when male canaries can be observed feeding females. Transmission can also occur by drinking water from contaminated water bottles in flight cages.
Clinical signs of Air Sac Mites includes open mouth breathing which has a characteristic clicking sound. Breathing can be severely affected, and some birds can be observed gasping for air. Other signs that may be observed include loss of song, coughing, nasal discharge, vocalization changes, tail bobbing, weakness and weight loss. Death can also occur, and is seen in severely affected birds due to mucous build up and accumulation of other respiratory exudates, leading to the obstruction of the respiratory airways.
Treatment to eradicate Air Sac Mites can be successfully accomplished by the use of a drug called Ivermectin. There are three methods which can be employed to rid infested birds of Air Sac Mites. These include a topical application, injection into the pectoral muscles, and an oral dosing. My own personal preference is the topical application, in which a small drop of the Ivermectin preparation is placed directly on the skin over the area of the right jugular vein. The treatment is repeated again every two weeks for a total of three treatments per bird. Unfortunately, treatment with Ivermectin is not always as rewarding as we would like for it to be. Some heavily infested birds can die five to seven days after treatment with Ivermectin due to Asphyxiation, resulting from the accumulation of dead Air Sac Mites obstructing the air ways.
Diagnosis of Air Sac Mites is based on history, physical examination, clinical signs, treatment response, necropsy and histopathology findings. Air Sac Mites can often be visualized by trans illumination of the trachea with a light source. A light source is gently placed onto the lateral surface of the trachea to facilitate the observation of the mites. Trans illumination will reveal the Air Sac Mites which appear as black dots moving about on the tracheal wall surface. Necropsy findings will often reveal tracheal inflammation, air sacculitis, excess exudate or mucous along the respiratory tract, and the mites themselves which appear as black dots. The Air Sac Mites can also be visualized by low power microscopic examination of tracheal washings or exudate.
Control and prevention of Air Sac Mites includes the employment of non infested foster parents for hatching and rearing eggs of affected birds, and segregating infested birds from healthy birds. Also one word which is worth mentioning in reference to Ivermectin, is that this drug is not approved or labeled for use in pet birds. Consulting with your veterinarian is recommended before you initiate any treatment for your birds since accidental toxicity can occur from the use of Ivermectin as could occur with any drug if used incorrectly. As always consult with your veterinarian before you treat them if you suspect your birds may be affected with any illness or disease.
Frank Scandaglia, DVM is a practicing veterinarian in New York who has been involved with birds most of his life. This article originally appeared in Finch & Canary World magazine.