Environmental Engineering Reference
In-Depth Information
or packaging for pesticides and/or the visible presence of granules in the bait), will be of immense
use when determining whether poisoning took place. Some of this information can also be obtained
through inquiries made in nearby villages.
As veterinarians, we the authors have come across several cases of accidental and malicious expo-
sure to carbofuran or OPC compounds in domestic cattle. The pain/agony which an animal undergoes
after ingestion of a cholinesterase (ChE) inhibitor has to be seen in order to fully grasp its extent
and severity. A prognosis will depend on the amount of poison that has been ingested. Common
symptoms/effects noted are classifi ed as 'muscarinic' (of the toxic alkaloid muscarine), 'nicotinic'
(having an affi nity for nicotine compounds) and central. The muscarinic effects include hypersaliva-
tion, miosis (constriction of the pupils), frequent urination, colic, diarrhoea, bradycardia (slowed
heartbeat), and dyspnoea (breathlessness), in which breathing by mouth is often noticed. Nicotinic
effects include muscular fasiculations (involuntary muscular contractions) and weakness, and central
effects are indicated by nervousness, ataxia (lack of muscular coordination) and seizures (Cheeran
2007). These common symptoms are caused by the accumulation of acetylcholine which follows
cholinesterase inhibition by OPCs or carbamates. A positive response to parenteral administration
(i.e., through the vein) of atropine sulphate can be very dramatic.
As discussed in Chapter 2, the mode of inhibition of cholinesterase caused by carbamates and
OPC differs: carbamate-induced inhibition is reversible, while OPCs essentially inhibit the enzyme
irreversibly. Consequently, the cause of poisoning must ideally be confi rmed before treatment with
an oxime is initiated. In fact, the possibility that a potential treatment will further confound the toxic
effects makes it essential that a specifi c diagnosis of the etiological factor is made in any suspected
case of poisoning. Cheeran (2007) suggests several precautions that should be taken when treating
wild elephants exposed to suspected poisons. The reader is referred to this work for further informa-
tion and general guidelines regarding poison diagnosis and treatment in elephants.
In India, samples tend to be submitted separately, in sealed containers containing a saturated
salt solution (along with a control container with salt solution alone). Samples commonly col-
lected include the brain, liver, kidney, stomach, intestine and lung, as well as stomach and intestinal
contents and the suspected bait used (sampled from the carcass or any other source of exposure).
Circumstantial evidence in the form of packaging or containers found in the vicinity is also provided
where possible. When a carcass has been exhumed, the soil beneath the gastrointestinal tract is
sampled, as is any ash (if the carcass has been burnt). The quantity of sample collected must be suffi -
cient for confi rmation and quantifi cation. As a general guideline, Cheeran (2007) suggests collecting
1 kilogram of liver and a proportionate amount of other tissue.
Several authors have suggested using the brain cholinesterase reactivation technique to confi rm
exposure to carbofuran and differentiate this exposure to that of other OPC compounds (Smith,
Thomas and Hulse 1995; Elliott, Langelier, Mineau et al. 1996). At postmortem, the pattern of
cholinesterase reactivation changes, and knowledge regarding normal values for different species
of wildlife are required in order to reliably use this technique. Collecting a sample of brain (in a par-
tially frozen state) which is suitable for such analysis requires an experienced taxidermist. However,
in India, we lack both the laboratory facilities and the skilled manpower required to perform the
cholinesterase reactivation test for confi rmation of carbofuran ingestion.
In India, most wildlife necropsies are conducted by wildlife veterinarians posted within Protected
Areas. However, confl icts do occur in other Managed Forests where local veterinarians are respon-
sible for conducting necropsies. Attending veterinarians must be suffi ciently trained to investigate a
given case of poisoning, especially with regard to collecting and sending samples as required by a
Forensic Laboratory. Cheeran (2007) again provides details regarding the procedure which should
be used to collect samples for analysis of different types of wildlife poisoning.
Kholkute (2003) has also described the precautions that should be taken when submitting
samples to a State Forensic Laboratory. Bottles containing tissue samples, and the accompanying
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