Carbofuran: Toxicity, diagnosing poisoning and rehabilitation of poisoned birds - Carbofuran and Wildlife Poisoning: Global Perspectives and Forensic Approaches - page 34

insecticide-cholinesterase bond in the case of organophosphorous compounds. However, (as
reviewed by Shlosberg and colleagues (1997)) standard veterinary textbooks vary tremendously in
relation to their recommendations regarding carbamates. Some merely indicate that oximes will not
be of any benefi t when carbamates are involved, whereas others explicitly warn against their use.
Shlosberg, Bellaiche, Hanji et al. (1997) found no enhanced toxicity occurred when using 2-PAM
on methomyl-poisoned broiler chicks, and hence suggested that oximes may be safe with many car-
bamates. 2-PAM is certainly not safe with carbaryl, the carbamate on which the most work has been
done in this regard. Since it is commonly diffi cult to identify the offending cholinesterase-inhibiting
agent (when a poisoned bird is brought into a rehabilitation centre), an oxime may still be used
(despite the above contraindications).
Supportive therapy is important in any case, and this can include fl uids and gastrointestinal
protectants that contain activated charcoal (such as Toxiban ® or Liquichar ® ). In some cases,
where these products were administered to bald eagles before the crop was emptied, the birds regur-
gitated. Although aspiration of the activated charcoal product and/or the crop content is a potential
risk to a neurologically compromised bird, the administration of activated charcoal prior to physi-
cally emptying the crop may prevent the need for anaesthesia and/or surgery. Long term nutritional
support is also necessary, and if affected birds do not eat on their own, hyper-alimentation will be
needed.
If a bird has been sprayed by a carbamate, or had contact with contaminated surfaces, its feet and
feathers should be washed thoroughly with warm 5 to 10% dishwashing detergent solution (Dawn ®
is the commercial brand usually recommended; it is also used for oiled bird recovery). Otherwise,
the bird will re-ingest the toxicant while preening and clinical signs will return.
Generally, even if a bird's clinical signs are totally alleviated, the bird will still not be neurologi-
cally normal. Affected birds must therefore demonstrate the ability to fi nd and/or kill prey before
they are released. This usually requires up to two weeks in captivity.
2.9 Conclusion
This chapter provided a review of acute toxicity values of carbofuran in birds and mammals, listed
exposure routes to both liquid and granular formulations of the product and discussed the timeline
of intoxication, in birds at least, although the situation is similar in mammals. We also described the
effects of intoxication, outlined typically associated signs, summarised clinical and fi eld evidence
that one should be on the lookout for, discussed biochemical diagnosis of carbofuran poisoning and
considered rehabilitation approaches. We hope that this information will be useful to colleagues who
encounter scenarios of intoxication such as those detailed in the rest of this topic.
Acknowledgements
We thank Rafael Mateo Soria of the Grupo de Toxicología de Fauna Silvestre at the Instituto de
Investigación en Recursos Cinegéticos (Spain), as well as J. Christian Franson and Kimberly Miller
from the USGS National Wildlife Health Center, for providing feedback on earlier versions of this
manuscript. We also thank M. Studeny and Iñigo Fajardo for permission to use the photographs.
Use of trade or product names does not imply endorsement by the US Government.
References
Balcomb, R. (1983) Secondary poisoning of red-shouldered hawks with carbofuran. Journal of Wildlife
Management , 47 , 1129-1132.