Keshan disease

Keshan disease is a congestive cardiomyopathy caused by a combination of dietary deficiency of selenium and the presence of a mutated strain of Coxsackievirus, named after Keshan County of Heilongjiang province, Northeast China, where symptoms were first noted. These symptoms were later found prevalent in a wide belt extending from northeast to southwest China, all due to selenium-deficient soil. The disease peaked in 1960–1970, killing thousands of people.

Often fatal, the disease affects children and women of child-bearing age, characterized by heart failure and pulmonary edema. Over decades, supplementation with selenium reduced this condition.

It had been linked to the coxsackie B virus. Current research suggests that the lack of selenium results in a more virulent strain of the coxsackievirus becoming the dominant viral species present in the population of virus, but the mechanism of this selection event is unclear.

Keshan disease can also lead to higher rates of cancer, cardiovascular disease, hypertension, and strokes. In addition, an individual can experience eczema, psoriasis, arthritis, cataracts, alcoholism, and infections.^{[citation needed]}

There are four main types of Keshan disease: acute, subacute, chronic, and latent.

Some signs and symptoms of acute Keshan disease include dizziness, malaise, nausea, chills, loss of appetite, projectile vomiting, pallor, low arterial blood pressure (less than 80/60 mmHg), dyspnea, precardiac (anterior to the heart) or substernal (behind or below the sternum) discomfort, cardiogenic shock, and constricted veins in one's extremities.

Some signs and symptoms of subacute Keshan disease include malaise, restlessness, gallop rhythm, facial edema, heart dilation, and cardiac shock.

Some signs and symptoms of chronic Keshan disease include palpitations, dyspnea, cough (with blood), pain in one's right upper quadrant, edema, oliguria, enlargement of the heart, systolic murmur, gallop rhythm, and hepatomegaly.