Page 545 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

512 SECTION | IV Insecticides

VetBooks.ir TOXICITY should be administered orally. An alternative but less effec-
For oral exposure to OCs, activated charcoal (1 2g/kg)
Cats are the most sensitive species to OC insecticides,
tive treatment is mineral oil. The insecticide can dissolve in
with the LD 50 for endrin in cats of 3 6 mg/kg. The
mineral oil, which decreases its absorption systemically.
cyclodiene OC insecticides cause more seizure activity
The approximate oral dose of mineral oil is 2 6mL in
and have a lower LD 50 than the DDT-type insecticides in
cats, 5 15 mL in dogs, and 1 3 L in large animals.
most species.
Charcoal or nonabsorbable oils are most effective when
The oral LD 50 for DDT in rats is 113 2500 mg/kg
given within 4 h of ingestion of the pesticide (Aslani,
and the IV LD 50 is 47 mg/kg. In humans, toxic signs from
1996).
oral exposure to OCs can be observed at 10 mg/kg.
General supportive care includes the use of antiseizure
The acute toxicity to rats and rabbits of other chlori-
medications such as diazepam, phenobarbital or pento-
nated insecticides is shown in Table 38.2.
barbital. Animals should be placed in a warm and
In addition to the effects on the nervous system, DDT
comfortable area to minimize trauma when they are sei-
metabolites can inhibit the output of the adrenal gland by
zuring. Animals recovering from OC insecticide exposure
selective necrosis of the zona fasciculata and the zona
may have to be monitored long-term because OCs can
reticularis.
persist in the body for months or years. The source of the
Following an acute or chronic exposure, OCs can pro-
exposure must be identified and removed to stop expo-
duce a variety of reproductive and developmental effects
sure. One decontamination strategy is to reduce feed
in animals as well as humans (Gupta, 2009; Malik et al.,
intake so that the animal loses body fat, thereby reducing
2017). Chronic exposure to DDT has been documented to
OC residues in adipose tissue. Lactating animals rapidly
cause eggshell thinning and reduced fertility in wild birds.
eliminate OC residues because the residues are excreted
in milk. An additional treatment option in large animals is
to feed activated charcoal (500 1000 g/day) to reduce
TREATMENT enterohepatic recycling.
No specific antidotes for OC insecticides are available
(Osweiler, 1996). The treatment is mainly supportive. CONCLUDING REMARKS
Detoxification is the most essential component of therapy AND FUTURE DIRECTIONS
for OC toxicity. If dermal exposure has occurred, the ani-
mal should be thoroughly washed with a detergent and The use of OC insecticides is decreasing in the United
water to remove the insecticide so absorption ceases. The States but they are still used worldwide. In the United
hair of heavily contaminated long-haired animals should States, with the ability of these compounds to persist in
be clipped. Personnel treating animals should exercise the environment and bioaccumulate, the OC insecticides
caution and prevent themselves from becoming contami- will continue to be an important toxicant for many years
nated with the insecticide by wearing gloves, aprons, or (Custer et al., 2005).
raincoats.
REFERENCES
TABLE 38.2 Toxicity Data for Some Organochlorines Aslani, M.R., 1996. Endosulfan toxicosis in calves. Vet. Hum. Toxicol.
38, 364.
Compound Rat Acute Oral Rabbit Dermal
Backer, L.C., Grindem, C.B., et al., 2001. Pet dogs as sentinels for envi-
LD 50 (mg/kg) LD 50 (mg/kg)
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Lindane 76 190 500 Beasley, V.R., Dorman, D.C., Fikes, F.D., et al., 1994. A Systems
Approach to Veterinary Toxicology. University of Illinois,
Aldrin 39 60 65
Champagne, IL.
Dieldrin 40 65 Bloomquist, J.R., Soderlund, D.M., 1985. Neurotoxic insecticides inhibit
Endrin 3 12 GABA-dependent chloride uptake by mouse brain vesicles.
Biochem. Biophys. Res. Commun. 133, 37 43.
Chlordane 283 1100 580
Bonner, J.C., Yarbrough, J.D., 1988. Vertebrate cyclodiene insecticide
Endosulfan 18 76 74 resistance: role of gamma-aminobutyric acid and diazepam binding
sites. Arch. Toxicol. 62, 311 315.
Mirex 235 . 3000 800
Booth, N.H., McDowell, J.R., 1975. Toxicity of hexachlorobenzene and
Kepone 95 125 345 associated residues in edible animal tissues. J. Am. Vet. Med.
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Buck, W.B., 1970. Lead and organic pesticide poisonings in cattle. J.
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