Page 627 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

592 SECTION | VIII Rodenticides

VetBooks.ir did not. Brodifacoum, diphacinone, and chlorophacinone halogenated biphenyl side chain has been suggested as a
way
to
determine
to
rodenticides
soil
were detected at concentrations ranging from trace
exposure
amounts to 1120 parts per billion, but were not correlated
(Townsend et al., 1995).
with any recorded parameter. Dogs with toxicosis had a Insects: Diphacinone ranging from 0.8 to 2.5 and from
survival rate of 98.7%. The most common diagnoses in 1.3 to 4.0 ppm has been detected in snails and slugs,
48 dogs without detectable anticoagulant rodenticides respectively, in Hawaii (Primus et al., 2006). The mean
were neoplasia (15), immune-mediated disease (7), and brodifacoum concentration in cockroaches immediately
gastrointestinal bleeding (5) (Waddell et al., 2013). after bait exposure of 2626 131 μg/kg wet weight decreased
Prevalence of nontarget animal exposures has also quickly in the following 2 weeks, and then continued at a
been reported in the Netherlands, Spain, France, and slower rate over the following 4 weeks. Woodlice recorded
Mongolia. Dogs suspected of anticoagulant rodenticide a similar brodifacoum concentration and a similar time
poisoning in the Netherlands had brodifacoum (19), bro- course for the postexposure decline. Diphacinone has been
madiolone (14), difenacoum (8), difethialone (6), and detected in snails after broadcast, (Johnston et al., 2005)and
chlorophacinone (1) (Robben et al., 1997). Assessment a concentration of 0.39 μg/g has been reported from a pool
of potential toxicity of pindone for domestic animals has of carrion beetles (Dermestes spp.) in a nonbaited farm area.
also been made (Martin et al., 1991). Anticoagulant Birds: A number of experimental and field studies of
rodenticides were detected in the liver of 401 wild and bird exposures to anticoagulant rodenticides have been
domestic animals found dead in Spain, including two reported.
species of reptiles (n 5 2), 42 species of birds (n 5 271), Experimental: Owls, kestrels, and stone martens have
and 18 species of mammals (n 5 128) (Sa ´nchez-Barbudo been experimentally exposed.
et al., 2012). Hernandez-Moreno et al. (2013) reported Eastern screech-owls (Megascops asio) fed 10 μg
the deaths of three birds in an ornithological zoo in diphacinone/g wet weight food for 7 days were monitored
Galicia (NW Spain) by difenacoum and brodifacoum. A for 21-day postexposure. Liver and kidney diphacinone
retrospective analysis of French human and animal poi- elimination was initially rapid, then followed by slower
son control center data from 2004 to 2007 reported no loss rate, with overall half-lives of 11.7 and 2.1 days,
mortality in humans, and less than 1% mortality in respectively (Rattner et al., 2014; Rattner et al., 2012).
domestic animals. Dogs represented 60% of domestic The acute oral toxicity of diphacinone was found to be
species, while hares and rabbits represented 50% of more than 20 times greater in American kestrels (Falco
wildlife cases, followed by predators and scavengers. In sparverius) with a median lethal dose of 96.8 mg/kg
wildlife, bromadiolone and chlorophacinone were most body weight compared to Northern bobwhite (Colinus
frequently observed (Berny et al., 2010 a,b). In 2002, virginianus) and mallards (Anas platyrhynchos).
hundreds of nontarget wildlife deaths reportedly occurred Chlorophacinone has also been studied in captive kestrels
in Mongolia following aerial applications of bromadio- (Radvanyi et al., 1988), and bromadiolone-poisoned mice
lone to control eruptive Brandt’s vole (Microtus brandti) in stone martens (Martes foina)(Lund and Rasmussen,
populations. 1986). Diphacinone, dicoumarol, and pival have all been
Environmental Approximately 700 kg of cereal bait shown to increase the PT in chicks (Charles et al., 1966),
containing 20 ppm of the anticoagulant rodenticide and a 100% mortality occurred in 1-week-old chicks fed
brodifacoum was spilled into a southern New Zealand coumestral in wood-straw mats (Munger et al., 1993). A
lake in 2010 from a helicopter being used to transport “no observed effect” concentration of chlorophacinone of
containers of brodifacoum bait for an aerial baiting 1 mg chlorophacinone/kg feed is reported for Japanese
operation. In the month after the spill, no residual quail (Coturnix japonica)(Riedel et al., 1990).
brodifacoum was detected in samples of lake water, Six owls fed difenacoum-intoxicated mice survived
sediment, benthic invertebrates, eels, and two birds and coagulation times returned to normal in 5 23 days;
(Fisher et al., 2012). however, four of six owls fed brodifacoum-intoxicated
Anticoagulant rodenticides may be detected in water, mice died 6 17 days after feeding. Dead owls had
soil, and invertebrates. A method of detecting warfarin in 630 1250 ng/g brodifacoum in their livers (Newton
water has recently been reported (Badia and Diaz-Garcia, et al., 1990).
1999), perhaps since anticoagulant rodenticides are used Field: Numerous studies of birds exposed to anticoag-
in rice paddies (Baskaran et al., 1995), and accidental dis- ulant rodenticides in the field have been reported. These
charges of brodifacoum bait may occur in fresh water or studies are summarized here, transitioning from those
marine environments (Primus et al., 2005). The toxicity birds that primarily ingest grain to birds of prey to present
of anticoagulant rodenticides in soil may be related to the the author’s inferences of the potential routes of exposure
portion not bound to humic acid. Testing for the to the anticoagulant rodenticide bait.