Keshan

Keshan may refer to Keshan County (克山县) in Heilongjiang Province, China, an administrative division under the prefecture-level city of Qiqihar. The county is part of the northeastern region of the country and is largely rural, with agriculture forming a significant part of its economy. The name Keshan is also encountered in the historical record of Keshan disease, a form of endemic cardiomyopathy that was first described in this area.

Keshan disease is an illness historically observed in parts of China where soil selenium content is low and dietary intake is limited. It was identified in the 1930s in Keshan County, and later found to be associated with selenium deficiency. Research has indicated that the condition results from a complex interaction between nutritional status and infections with certain viruses, particularly enteroviruses. Clinically it presented as a progressive heart failure with myocardial damage, and several regional outbreaks occurred in rural areas during winter months when nutritional status could be further compromised.

Public health responses to Keshan disease focused on improving selenium nutrition and overall diet, alongside measures to reduce infection risk. Selenium supplementation, dietary diversification, and soil and agricultural interventions helped reduce incidence in affected regions. Today, the recognition of selenium's role has influenced broader discussions of micronutrient deficiencies and their impact on infectious and cardiopulmonary diseases, though the condition is far less common in areas with adequate selenium intake and public health support.