Mercury

Source:-

• Mercurous chloride commonly called “calomel” which is used as purgatives.
• Mercuric chloride used as antiseptics.
• Mercuric oxide used as eye ointments.
• Mercuric iodide used as counter irritant and fungicides.
• Mercurochrome used as eye lotion.
• Mersalyl used as diuretics.
• Phenyl mercury acetate, methyl mercury acetate, chloride and hydroxide are used in seed dressing or fungicides.
• Inorganic mercury is converted to the organic alkyl forms, methylmercury and ethylmercury, by microorganisms in the sediment of rivers, lakes, and sea. Fish and other marine living organisms take up organic mercury from water and this mercury gets accumulated in these living things. This is known as bioaccumulation of mercury.

Mode of action:-

The mechanism of action may be summarized by the following 3 ways:-

• Mercury gives the irritation to the gastro-intestinal mucous lining.
• Mercury increases the capillary permeability and simultaneously causes the dilatation of blood vessels, which brings the lower blood pressures. As a result, in per acute cases, animal may die suddenly without showing any clinical sign.
• Mercury binds the pyruvic oxidase enzymes and its co-factor as a result TCA cycle and oxidative phosphorylation process is disrupted.

Clinical Signs:

• Bloody diarrhoea.
• Violet gastro-enteritis.
• Severe colic.
• Sub normal temperature.
•  
• Circulatory shock, collapse and death
• Oliguria and azoturia are also observed. With organic mercurial toxicity, erythema of the skin, conjunctivitis, lachrymation, stomatitis and neurological seizures are reported.

PM Lesions :

• Gastrointestinal ulcers, necrotic enteritis and colitis are noticed during post mortem.
• Pale and swollen kidney with renal tubular necrosis and fibrinoid degeneration of cerebral arterioles are also noticed.

Diagnosis:

Diagnosis is based on the level of mercury in the renal cortex, brain and liver.

Treatment:-

• Egg albumin, activated charcoal and 0.9% saline should be administrated to prevent further absorption. 3-5mg Dimercaprol or BAL per Kg body weight intramuscularly for first two days at four hours intervals.
• Then from 3^rd days six hours interval and 12 hours interval until recovery. Here, Dimercaprol acts as chelating agents.
• Na-thiosulphate may be used which replaces the thio groups.

Differential Diagnosis:

• Tremor
• Ataxia
• Feline Parvovirus
• hog cholera erysipelas.
• Lead and thallium poisoning