The outbreak of Minamata disease (methyl mercury poisoning) in cats on Northwestern Ontario Reserves

Mechanisms of methylmercury-induced neurotoxicity: Evidence from experimental studies

“…In the early 1950s, an epidemiological investigation at the Minamata district showed that several cats fed a diet that primarily consisted of fish presented a severe condition named “dancing disease”, which was characterized by movement disorders, convulsions and death (Kitamura et al, 1957). Another epidemiological report showed that fish-feeding cats that lived on Indian Reserves in Northwestern Ontario, Canada, developed acute neurological symptoms characterized by ataxic gait, abnormal movements, uncontrolled howling, and seizures (Takeuchi et al, 1977). The foregoing evidences (Kitamura et al, 1957; Takeuchi et al, 1977) pointed to motor impairment as an important behavioral sign observed in MeHg-poisoned animals, corroborating data in humans (Ekino et al, 2007; Murata et al, 2007).…”

Bridging conceptual “silos”: bringing together health promotion and sustainability governance for practitioners at the landscape scale

“…The local epidemic of Minamata disease in Grassy Narrows, Ontario, which was linked to the consumption of fish contaminated by mercury (Takeuchi et al 1977, D'Itri and D'Itri 1978, Wheatley et al 1997, Harada et al 2005, Takaoka et al 2014) is an extreme yet in important ways a typical example of a situation where public health and well-being are threatened by the local biophysical and socio-economic conditions. Because of pollution caused by the chemical, pulp, and paper industries decades ago (Howard 1980), combined with current clear-cut logging practices, the mercury levels in the local watershed remain severely hazardous for human health (Garcia and Carignan 2005, Desrosiers et al 2006, Kinghorn et al 2007, Harada et al 2011.…”

Assessing the neurotoxicological risk of methylmercury exposure for beluga whales (delphinapterus leucas) harvested in the Mackenzie Delta Estuary.

“…Behavioural changes associated with Hg toxicosis in one wild river otter were ataxia, scleral injection (red eyes) and lack o f fleeing response (Sleeman et al, 2010). One cat with 16.4 mg kg'1 total Hg from White Dog, ON developed convulsions, ataxia, jumping and circling around ('dancing') after it was fed fish entrails from the English River (Takeuchi et al, 1977). Therefore, we would expect a lack of motor coordination (ataxia), convulsions and abnormal behaviour from whales suffering mercury toxicosis.…”

“…Clinical symptoms o f Hg toxicity include cerebellar ataxia, constriction o f the visual field and damage to the auditory region o f the temporal lobe (Clarkson, 1997;Ekino et al, 2007). Clinical symptoms o f Hg intoxication include the loss o f motor coordination (Bellum et al, 2012), abnormal movements and convulsions (Takeuchi et al, 1977) and loss o f balance (Farina et al, 2005). Macaque monkeys had impaired high-frequency hearing and visual damage following postnatal MeHg exposure (Newland and Paletz, 2000).…”

“…We would expect clinical symptoms of Hg intoxication to include the loss o f motor coordination (Bellum et al, 2012), abnormal movements and convulsions (Takeuchi et al, 1977), loss of balance (Farina et al, 2005), and reduced passive avoidance. The harvesters did not observe any abnormal movements or behaviour in the beluga whales prior to harpooning, which suggests that Hg exposure in the eleven whales analyzed in this study were not exhibiting clinical symptoms of Hg intoxication.…”