1955 Dalston outbreak

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Beginning in January 1955, an outbreak of disease thought to be consistent with myalgic encephalomyelitisoccurred, centered around the village of Dalston in Cumbria, England and affected 233 people (14% of the practice population). Males and females were equally affected. (https://www.jstor.org/stable/4457588?seq=1#page_scan_tab_contents)

An epidemiological study of the outbreak was published by Dr. A. L. Wallis, a general practitioner that covered the areas concerned.[1]

Onset[edit | edit source]

Symptoms[edit | edit source]

  • lymphadenopathy
  • hepatosplenomegaly
  • abnormal lymphocytes
  • Paresthesias
  • blurred vision
  • vertigo
  • depression as a significant problem
  • myalgia
  • muscle weakness (especially in lower limbs)
  • joint pain
  • cognitive dysfunction (loss of concentration manifested, inability to read, knit)
  • locomotor dysfunction
  • reticuloendothelial involvement
  • ulnar neuropathies

Findings[edit | edit source]

Wallis initially thought the infection was glandular fever, but tests came back negative.[1]

Epidemiology[edit | edit source]

The attack rate during the epidemic was 13.9%.[1] Endemic cases continued to appear several years after the initial outbreak and incidence of the disease spread to surrounding villages.

Prognosis[edit | edit source]

There were no fatalities. Relapses occurred in a proportion of those infected; in some cases, several relapses occurred over a period of months, symptoms being minimal or absent between the recurrences.[1]

"Recurrences of symptoms of the disease became a well marked feature of the epidemic, and it was noted that in some instances a contact of the primary host, who was having a recurrent attack, would develop the typical disease, suggesting, therefore, that, at the time of the recurrent attack, the host was again infectious."[1]

See also[edit | edit source]

Learn more[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 1.4 Wallis, A.L. (1957). An investigation into an unusual disease seen in epidemic and sporadic form in a general practice in Cumberland in 1955 and subsequent years, M.D. Thesis. University of Edinburgh.