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Treatment Issues for Rehabilitators





Treatment Issues for Rehabilitators

 

Can or Even Should Finches with MG be Treated?

Whether MG can or even should be treated in finches remain unresolved and controversial issues. As one leading researcher in this field recently wrote me, "The practice of confining affected birds for the purpose of treating and releasing is loaded with contentious issues impacted by diverse philosophical and biological viewpoints." Both the US Fish and Wildlife Service and the National Wildlife Health Center, as well as many state wildlife offices, continue to caution against the release of treated finches with MG. Their reasoning is based on the fact that so little is known yet on how MG is spread among finches. In poultry, MG cannot be cured, despite the fact that its symptoms can be alleviated with medication. Though apparently symptom free, such birds nevertheless carry the organism and can still shed the disease to others. By extension, it is felt that such may yet be true of finches with MG as well. Apparently, their concern is such that not even the recent Ley EID MG DNA Study, which found no link between the finch strain of MG with any of the poultry strains or vaccines they tested, was sufficient cause for these wildlife officials to change their positions.

No medical treatment is known to completely cure house finches infected by this organism. There are medications that at least temporarily heal the conjunctivitis, but the disease organism may persist in the host and be shed to other previously uninfected house finches at a later time. At this time the Service recommends that house finches not be released to the wild, following treatment.

- US Fish & Wildlife Service, draft Briefing Statement, August 1996.

[A copy of this document is available as a text file; see the "Web Links and Other Resources" page.]


However others found encouragement in an article appearing in the Summer, 1996 issue of the National Wildlife Rehabilitators Association Quarterly, reporting on a study done by North Carolina State University and the Tri-State Bird Rescue and Research Center, which cited their finding that MG had not found following the treatment protocol being studied:

As the "Finch eye" epornitic continues to spread throughout the eastern United States, many rehabilitators are faced with the question of how to treat this disease, and at what point the birds can be released without endangering wild flocks. A cooperative study ... examined the effects of one treatment protocol. The study did not find evidence for Mycoplasma gallisepticum infection in house finches following [this treatment].

- Miller E, DVM, Mycoplasma gallisepticum infections, National Wildlife Rehabilitators Association Quarterly, Vol. 4, No 2, Summer 1996, page 6.


The actual study referred to has only recently been formally published and indeed confirms that MG was not found in tested house finches following the treatment tested.  It notes:

Poultry are considered to be persistent carriers of M. gallisepticum, once infected, even after antibiotic therapy. If this occurs in house finches, release of treated birds to the wild would be inadvisable. However, M. gallisepticum-infected house finches are treated at rehabilitation centers with the expectation of eventual release. Therefore, the effectiveness of a therapeutic protocol in eliminating infection from affected house finches must be examined. ... [page 20-21]

Reports of assessment of rehabilitated animals for infectious agents before release are rare, despite the potential risks of disseminating diseases. To determine the degree of risk associated with the release of house finches infected with M. gallisepticum to the wild, basic epidemiologic information such as prevalence, incidence, species susceptibility, and mode of transmission are required. In our study, we did not find evidence of M. gallisepticum infection in house finches after combination of treatment [with the medications described].  [page 24]


However the study closes on a very cautious note:

We caution that the presence of a M. gallisepticum carrier state in treated house finches cannot be ruled out on the basis of this study. [page 24]

- Mashima TY, Ley DH, Stoskopf MK, Miller EA, Welte SC, Berkhoff JE, Degernes LA, Fleming WJ, Evaluation of Treatment of Conjunctivitis Associated with  Mycoplasma gallisepticum In House Finches (Carpodacus Mexicanus), Journal of Avian Medicine and Surgery, 11(1):20-24, 1997


In fact, one of the authors of this study expressed in a letter to me that the "results of this study should[not] be taken as an endorsement for treating and releasing birds with MG epizootic conjunctivitis." 

Nevertheless, others still feel that the potential number of finches that may be treated and returned to the wild is so small that their impact would be insignificant. Some wildlife veterinarians, moreover, cite their oaths to treat injured and sick animals, even in such cases as these. Wildlife rehabilitators in many areas, in turn, face the difficult dilemma of either disregarding the advice of their own federal and state wildlife offices by treating and releasing finches with MG, thereby possibly risking spread of the disease to the very birds they wish to help, or instead reluctantly withholding such treatment, while realizing medications such as those in the above-referenced study have been shown to be very effective in relieving symptoms of the disease. For those dedicated to relieving the suffering of sick and injured wildlife, this must be a truly painful dilemma.

Perhaps for that reason, since so much remains unknown, the position of wildlife officials who advise against the release of treated finches express this concern in the form of a "caution," rather than as a "prohibition" against releasing treated finches. Thus, rightly or wrongly, finches with MG are being treated and released to some extent throughout the area affected by the outbreak. Wildlife rehabilitators who have not yet had to confront the question of whether or not to treat and release finches with MG should familiarize themselves with the position of their own state wildlife office so that they can make a fully informed decision on this very difficult issue.

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For those Choosing to Treat Finches with MG

 

Which Protocol is Best?

In the mean time, until this issue is more fully resolved, for those wildlife veterinarians, rehabilitators and researchers who are choosing to treat finches with MG, there have been at least three treatment protocols posted on the internet or published in journals. In order to help clear up some confusion over which of these treatment protocols is the more "preferred" version, I asked Dr. Erica Miller of Delaware's Tri-State Bird Rescue and Research Center, a wildlife veterinarian who participated in NCSU/Tri-State study noted above, which of them she would recommend to those choosing to treat finches with MG. She replied:

... the only treatment regimen we have used at Tri-State, and thus the only one I can recommend, is the one [recently published in the Journal of Avian Medicine and Surgery ], which is also what we printed in the NWRA Quarterly.

...I have found that topical ophthalmic antibiotics and oral Tylosin are sufficient to treat the MG infections.

-Dr. E. Miller, DVM (from correspondence dated June 25, 1997)


For this reason, and since it can not be found (as far as I know) on the internet anywhere else, I have made a text file of the NCSU/Tri-State Study MG Treatment Protocol available on this web site, by clicking on the foregoing hyperlink.  [It is my hope to add the text of Dr. Miller's NWRA Quarterly article in its place in the near future.]

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Cautions raised involving other protocols

The other two protocols for treating MG I have found thus far list systemic Tetracycline antibiotics as one medication. For those who are using this medication, I have been asked by Dr. Miller to caution that such medication is contraindicated in young birds and can cause abnormal bone plate formation. This is all the more serious in that, from her experience, the largest numbers of finches with MG have been first year birds. Additionally, such protocols also suggest the use of two systemic antibiotics concurrently (Tetracycline and Tylosin). While, as one veterinarian told me, these are not contraindicated, using two systemic antibiotics at the same time is not advised in cases where only MG is being treated. (Another veterinarian familiar with treating MG in finches told me he had never used these two systemic antibiotics at the same time.) Lastly, concern was also raised regarding the length of time these protocols suggest for administering these systemic antibiotics. If dosages need to be extended, under these other protocols, it was suggested the bird should first be examined again by a veterinarian.

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Need for quarantine 

One other note for those choosing to treat finches with MG, the Southeastern Cooperative Wildlife Disease Study issued a caution to rehabilitation and wildlife labs housing finches with MG, that they be strictly quarantined:

... there is an additional risk associated with rehabilitation that must be considered. Mycoplasmal conjunctivitis is highly transmissible, a fact that has been clearly demonstrated by field observations and captive studies. The possibility that the disease could be transferred from sick house finches to other bird species in the close quarters of rehabilitation centers must be realized and prevented. ...

... Thus, rehabilitation facilities that choose to rescue house finches must be capable of strict quarantine to prevent cross-contamination of MG to other birds. Otherwise, well-intentioned efforts to save individual animals may be offset by disease adaptation to other wild bird populations.

-  SCWDS Quarterly Briefs, Summer, 1996

[A copy of this document is available as a text file; see the "Web Links and Other Resources" page.]


Continuing need for testing

One other factor should be kept in mind by rehabilitators receiving songbirds with conjunctivitis. If MG has not been confirmed to have arrived in ones area, rehabilitators may wish to have any such birds they come across tested in order that the disease's arrival may be confirmed. The same is true for any non-house finch or goldfinch songbirds rehabilitators may come across with symptoms of MG, especially those known to share feeders with finches. In such cases contact your state wildlife office or the NWHC.

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"For what it's worth ..."

Finally, while I am admittedly neither an avian disease microbiologist nor even a rehabilitator, one finch I did catch and brought to my local wildlife veterinarian back in late summer, 1994, had its symptoms successfully treated by him. She was released in my yard where I had caught her by hand (this was before I learned of the concern over releasing treated finches). For what it is worth, 33 months later she still visits my feeders and has suffered no relapses (she had apparently smashed her beak while nearly blind with MG and for that reason has remained easy to spot.*) Since her release, she has taken a mate and has had a number of broods, at least two of which I witnessed her bring to my feeders shortly after they had fledged. I never noticed any symptoms associated with MG in her mate when they appeared together, nor in any of the fledglings I observed her bring to my feeders in all this time. (As noted previously, one characteristic of MG in poultry is its ability to spread to the young through the egg, before being laid.) Admittedly, on the other hand, I had seen MG at my feeders in other birds almost continually until January of this year and I have no way of ever knowing whether she had been silently spreading the disease to other finches these past three years or not.

* See link to "Beakmin" in the Postscript section of "About the Author" for photos.

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© 1997 James Cook
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