1948-49 Akureyri outbreak

The Akureyri outbreak was an outbreak of Myalgic Encephalomyelitis in Northern Iceland during the winter of 1948-1949. It was after this outbreak that the term "Icelandic disease," an early name for myalgic encephalomyelitis, was coined.

The systemic form of the illness was present in 70% of patients with the characteristic low fever, muscle tenderness and marked lassitude. 30% had muscle weakness. Infectious disease testing failed to find evidence of poliovirus, Coxsackie or other known encephalitis viruses.

In 1955, neurologist Kjartan Gudmundsson reexamined 39 patients affected by the outbreak. He found that of the most severely affected, only 25% had completely recovered, 52% had residual muscle tenderness, and 65% had objective neurological signs. Many patients still complained of nervousness, abnormal fatigability of muscles, muscle pain, sleeplessness and loss of memory. Of those mildly affected in 1948 only 44% had fully recovered, 50% had muscular tenderness, and 19% had residual objective neurological signs.