1934 Los Angeles atypical polio outbreak

The 1934 Los Angeles County General Hospital epidemic is the first known recorded cluster outbreak resulting in what is now known as myalgic encephalomyelitis.

Los Angeles County General Hospital was a public hospital that served the people of Los Angeles city and county, in California, US. It served an average of 2,000 in-patients and 2,500 out-patients daily.

Outbreak
Between May 1934 and December 15, 1935, one hundred ninety-eight (198) employees of Los Angeles County Hospital came down with an acute onset neurological illness. This accounted for 4.5% of hospital personnel becoming ill including about 10.7% of the nurses and 5.4% of the physicians.

As a poliomyelitis epidemic was occurring in California at this time, the first impression from the medical community was that the illness was polio, especially since the the illness presented with similarities including febrile onset and flaccid weakness.

In a short time, striking deviations from polio began to emerge in five areas:


 * relatively high attack rate (4.5% of all employees fell ill compared to the incidence of 0.07% of polio in the Los Angeles community)
 * low fatality rate (there were 0 deaths compared to a 1.39% fatality rate with polio)
 * low paralytic rate, both in terms of weakness at any time or in residual paralysis (an estimate of 7% of polio cases resulted in residual paralysis in the Los Angeles community)
 * high transmission/communicability rate
 * age selection of adults (only adults were afflicted, whereas polio is predominantly a childhood disease with the highest incidence in those under six years of age)

Seventy-five percent of those who became ill were women, and rates of illness were higher in adults under 30. Rates of illness were 2.5 times higher for staff working in the communicable diseases ward. Investigators determined that the infection was spread by direct personal contact with cases and carriers and not by contamination of the hospital milk or food supply.

Symptoms
The disease onset included the following cluster of symptoms: pain, headache, muscle tenderness, nausea, sensory disturbances, stiff neck or back, localized muscular weakness, vomiting, muscle twitching, sore throat, constipation, fever, cough, diarrhea, urinary retention, vertigo, photophobia, and double vision.

Patients also experienced fatigue on walking short distances and on the least exertion, loss of concentration and lapses of memory, and sleep disturbances. Recurrences of both systemic and neurological symptoms were frequent, and some patients were more disabled by these recurrences than by the original illness.

There was no mortality but compared to polio, morbidity was high: 55% of the staff were still off duty six months after the peak of the epidemic.

Long-term effects
Between 1948 and 1952 Marinacci and Von Hagen examined 21 patients from the LA outbreak, all females, who still had residual muscle pain, fatigue and mental changes. Electromyograms showed generalized, mild, lower motor neuron changes indicative of a radiculopathy. These were quite different from the changes seen in polio patients during the same epidemic. They also found similar changes in a study of over 300 sporadic cases in South California between 1948 and 1965. They observed that recurrences could still occur after seven years of normal health.

Several of the nurses with persistent symptoms received hysterectomies in an attempt to relieve symptoms under the belief that the virus had spread to their uteruses, causing emotional and "hysterical" symptoms.

Publications

 * “Epidemiological Study Of An Epidemic, Diagnosed As Poliomyelitis, Occurring Among The Personnel Of The Los Angeles County General Hospital During The Summer Of 1934” - Public Health Bulletin no.231-240 1936-1938 By: A.G. Gilliam (Full Text)
 * “Observations On The Epidemic Of Polio-Encephalitis In Los Angeles, 1934” - California And Western Medicine By: E.C. Rosenow, MD; F.R. Heilman, M.D.; and C.H. Pettet, M.D.
 * “Poliomyelitis-The Los Angeles Epidemic of 1934” - Western Journal of Medicine By: R.W. Meals, MD; Vernon F. Hauser, MD; and Albert G. Bower, MD
 * “Use of Serum and the Routine and Experimental Laboratory Findings in the 1934 Poliomyelitis Epidemic” - American Public Health Association By: John F. Kessel, Anson S. Hoyt and Roy T. Fisk

Newspaper articles

 * “Los Angeles Polio Epidemic Decreases” - Madera Tribune, Number 55, 6 July 1934
 * “Infantile Paralysis Development Shown” - Madera Tribune, Number 58, 10 July 1934  Editor's Note:  This article reveals that persons over the age of 20 were being described as having "Infantile Paralysis".
 * “Infantile Paralysis Outbreak Not Serious” - Madera Tribune, Number 55, 6 July 1934
 * “Infantile Paralysis Peak Reported Passed” - Madera Tribune, Number 56, 7 July 1934
 * “Real Heros of Paralysis Epidemic: - Healdburg Tribune, Number 290, 11 October 1934

Learn more

 * Los Angeles County Hospital, Wikipedia