Epidemic myalgic encephalomyelitis: Difference between revisions

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Prior to the 1980s, while no infectious was ever isolated, the outbreaks were widely thought to be caused by a virus related to [[poliovirus]], i.e., by another, yet-to-be-unidentified [[enterovirus]]. After the [[1984 Incline Village chronic fatigue syndrome outbreak|Incline Village outbreak]] in 1984, [[herpesviruses]] and in particular, [[Epstein-Barr virus]] was posited as the cause.  
Prior to the 1980s, while no infectious was ever isolated, the outbreaks were widely thought to be caused by a virus related to [[poliovirus]], i.e., by another, yet-to-be-unidentified [[enterovirus]]. After the [[1984 Incline Village chronic fatigue syndrome outbreak|Incline Village outbreak]] in 1984, [[herpesviruses]] and in particular, [[Epstein-Barr virus]] was posited as the cause.  
==History==
==History==
{{Main article|page_name =List of myalgic encephalomyelitis and chronic fatigue syndrome outbreaks}}
{{Main article| page_name =List of myalgic encephalomyelitis and chronic fatigue syndrome outbreaks}}


The first recorded outbreak of epidemic myalgic encephalomyelitis was in [[1934 Los Angeles atypical polio outbreak|1934 in Los Angeles]] and was thought to be an outbreak of atypical polio. After the outbreak in [[Akureyri]], Iceland in 1946, the disease came to be called [[1948-49 Akureyri outbreak|''Akureyri Disease'']] or ''Icelandic disease'' through much of the 1940s and 1950s. It was named [[Myalgic encephalomyelitis|myalgic encephalomyelitis]] after London's [[Royal Free Hospital outbreak]] in 1955. Other names included benign myalgic encephalomyelitis and epidemic neuromyasthenia.
The first recorded outbreak of epidemic myalgic encephalomyelitis was in [[1934 Los Angeles atypical polio outbreak|1934 in Los Angeles]] and was thought to be an outbreak of atypical polio. After the outbreak in [[Akureyri]], Iceland in 1946, the disease came to be called [[1948-49 Akureyri outbreak|''Akureyri Disease'']] or ''Icelandic disease'' through much of the 1940s and 1950s. It was named [[Myalgic encephalomyelitis|myalgic encephalomyelitis]] after London's [[Royal Free Hospital outbreak]] in 1955. Other names included benign myalgic encephalomyelitis and epidemic neuromyasthenia.
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== Onset ==
== Onset ==
The incubation period was generally estimated at 4 to 8 days.<ref name="Sigurdsson1950" /><ref name="Parish1978" /><ref name="Sigurdsson1956">{{Cite journal|url=https://www.ncbi.nlm.nih.gov/pubmed/13320872|title=The Lancet|last=Sigurdsson|first=B|author-link=Björn Sigurdsson|date=May 1956|journal=Clinical findings six years after outbreak of Akureyri disease|volume=270|pages=766-7|via=}}</ref> The illness generally began with a prodromal period of [[Flu-like illness|flu-like symptoms]], symptoms of an upper respiratory tract infection, [[low-grade fever]], [[sore throat]] or [[Gastrointestinal system|gastrointestinal]] distress,<ref name="Pellew1951" /><ref name="Ramsay1978" /><ref name="Levine1997">{{Cite journal|last=Levine|first=P. H.|author-link=Paul Levine|last2=Snow|first2=P. G.|author-link2=|last3=Ranum|first3=B. A.|author-link3=|last4=Paul|first4=C.|author-link4=|last5=Holmes|first5=M. J.|author-link5=|date=1997-04-14|title=Epidemic neuromyasthenia and chronic fatigue syndrome in west Otago, New Zealand. A 10-year follow-up|url=https://www.ncbi.nlm.nih.gov/pubmed/9125006|journal=Archives of Internal Medicine|volume=157|issue=7|pages=750–754|issn=0003-9926|pmid=9125006|quote=|via=}}</ref> followed by a symptom complex involving [[muscle weakness]], [[muscle fatigability]] and [[central nervous system]] involvement in a significant proportion of cases.<ref name="Parish1978" /><ref name="Shelokov, 1957" />
The incubation period was generally estimated at 4 to 8 days.<ref name="Sigurdsson1950" /><ref name="Parish1978" /><ref name="Sigurdsson1956">{{Cite journal| url = https://www.ncbi.nlm.nih.gov/pubmed/13320872 | title = The Lancet | last = Sigurdsson | first = B | author-link = Björn Sigurdsson | date = May 1956|journal=Clinical findings six years after outbreak of Akureyri disease|volume=270 | pages = 766-7|via=}}</ref> The illness generally began with a prodromal period of [[Flu-like illness|flu-like symptoms]], symptoms of an upper respiratory tract infection, [[low-grade fever]], [[sore throat]] or [[Gastrointestinal system|gastrointestinal]] distress,<ref name="Pellew1951" /><ref name="Ramsay1978" /><ref name="Levine1997">{{Cite journal | last = Levine | first = P. H. | author-link = Paul Levine | last2 = Snow | first2 = P. G. | authorlink2 = | last3 = Ranum | first3 = B. A. | authorlink3 = | last4 = Paul | first4 = C. | authorlink4 = | last5 = Holmes | first5 = M. J. | authorlink5 = | date = 1997-04-14 | title = Epidemic neuromyasthenia and chronic fatigue syndrome in west Otago, New Zealand. A 10-year follow-up | url =https://www.ncbi.nlm.nih.gov/pubmed/9125006|journal=Archives of Internal Medicine|volume=157|issue=7 | pages = 750–754|issn=0003-9926|pmid=9125006|quote=|via=}}</ref> followed by a symptom complex involving [[muscle weakness]], [[muscle fatigability]] and [[central nervous system]] involvement in a significant proportion of cases.<ref name="Parish1978" /><ref name="Shelokov, 1957" />


== Symptoms ==
== Symptoms ==
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* [[muscle fatigability|muscle fatigability]]  
* [[muscle fatigability|muscle fatigability]]  
* [[muscle weakness]] / [[paresis]]<ref name="Jackson1957">{{Cite journal|url=http://journals.co.za/content/m_samj/31/21/AJA20785135_45533|title=A disease resembling poliomyelitis; report of an outbreak in Johannesburg|last=Jackson|first=B|date=May 1957|journal=South African Medical Journal|volume=31|pages=514-517|via=}}</ref><ref name="Hill1959">{{Cite journal|url=https://www.ncbi.nlm.nih.gov/pubmed/13642847|title=Epidemic myalgic encephalomyelopathy: the Durban outbreak|last=Hill|first=RC|date=April 4, 1959|journal=The Lancet|volume=1|pages=689-693|via=}}</ref> (10-80%<ref name="Acheson, 1959" /> of cases), commonly occurring in the legs<ref name="Sigurdsson1956" /><ref name="Pellew1951">{{Cite journal |first =R.A.|last=Pellew|url =http://www.cabdirect.org/abstracts/19522700678.html;jsessionid=AA4534CA199AC800732B3877608F5CE0 |title =A Clinical Description of a Disease resembling Poliomyelitis, seen in Adelaide, 1949-1951|journal =Medical Journal of Australia|date =June 30, 1951|volume =1 |issue =26 |pages =944-6}}</ref>  
* [[muscle weakness]] / [[paresis]]<ref name="Jackson1957">{{Cite journal| url = http://journals.co.za/content/m_samj/31/21/AJA20785135_45533 | title = A disease resembling poliomyelitis; report of an outbreak in Johannesburg | last = Jackson | first = B | date = May 1957|journal=South African Medical Journal|volume=31 | pages = 514-517|via=}}</ref><ref name="Hill1959">{{Cite journal| url = https://www.ncbi.nlm.nih.gov/pubmed/13642847 | title = Epidemic myalgic encephalomyelopathy: the Durban outbreak | last = Hill | first = RC | date = April 4, 1959|journal=The Lancet|volume=1 | pages = 689-693|via=}}</ref> (10-80%<ref name="Acheson, 1959" /> of cases), commonly occurring in the legs<ref name="Sigurdsson1956" /><ref name="Pellew1951">{{Cite journal | first =R.A. | last = Pellew|url = http://www.cabdirect.org/abstracts/19522700678.html;jsessionid=AA4534CA199AC800732B3877608F5CE0 | title = A Clinical Description of a Disease resembling Poliomyelitis, seen in Adelaide, 1949-1951|journal =Medical Journal of Australia | date =June 30, 1951|volume =1 |issue =26 | pages =944-6}}</ref>  
* [[ataxia]]  
* [[ataxia]]  
* [[myalgia]]<ref name="Sigurdsson1956" /><ref name="Jackson1957" /> and [[neuralgia]]  
* [[myalgia]]<ref name="Sigurdsson1956" /><ref name="Jackson1957" /> and [[neuralgia]]  
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* sensory symptoms including sensitivity to [[Photophobia|light]] and sound, [[paresthesia|paraesthesiae]],<ref name="Sigurdsson1956" /><ref name="Jackson1957" /><ref name="Hill1959" /> [[hyperaesthesiae|hyperaesthesia]]  
* sensory symptoms including sensitivity to [[Photophobia|light]] and sound, [[paresthesia|paraesthesiae]],<ref name="Sigurdsson1956" /><ref name="Jackson1957" /><ref name="Hill1959" /> [[hyperaesthesiae|hyperaesthesia]]  
* [[Dysautonomia|autonomic symptoms]] such as tachychardia, coldness of the extremities, sweating  
* [[Dysautonomia|autonomic symptoms]] such as tachychardia, coldness of the extremities, sweating  
* [[post-exertional malaise]], worsening of symptoms with exertion<ref name="Sigurdsson1956" /><ref name="Shelokov, 1957" /><ref name="Hill1959" /><ref name="Albrecht1964">{{Cite journal|last=Albrecht|first=Robert|date=March 21, 1964|title=Epidemic Neuromyasthenia Outbreak in a Convent in New York State|url=https://www.ncbi.nlm.nih.gov/pubmed/14100144|journal=Journal of the American Medical Association|volume=187|pages=904-907|via=}}</ref><ref name="Poskanzer, 1957" /> ("fatigue on walking short distances and on the least exertion was prominent"<ref name="Parish1978" />)  
* [[post-exertional malaise]], worsening of symptoms with exertion<ref name="Sigurdsson1956" /><ref name="Shelokov, 1957" /><ref name="Hill1959" /><ref name="Albrecht1964">{{Cite journal | last = Albrecht | first = Robert | date = March 21, 1964 | title = Epidemic Neuromyasthenia Outbreak in a Convent in New York State | url =https://www.ncbi.nlm.nih.gov/pubmed/14100144|journal=Journal of the American Medical Association|volume=187 | pages = 904-907|via=}}</ref><ref name="Poskanzer, 1957" /> ("fatigue on walking short distances and on the least exertion was prominent"<ref name="Parish1978" />)  


== Findings ==
== Findings ==
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* Low-grade [[fever]]<ref name="Sigurdsson1956" /><ref name="Jackson1957" /><ref name="Albrecht1964" /><ref name="Hill1959" />
* Low-grade [[fever]]<ref name="Sigurdsson1956" /><ref name="Jackson1957" /><ref name="Albrecht1964" /><ref name="Hill1959" />
* Abnormal electromyogram showing generalized, mild, lower motor neuron changes indicative of a radiculopathy.<ref name="Parish1978" /><ref name="Marinacci1965">{{Cite journal|last=Marinacci|first=AA|date=October 1965|title=The value of the electromyogram in the diagnosis of Iceland disease|url=https://www.ncbi.nlm.nih.gov/pubmed/5889546|journal=Electromyography|volume=5|pages=241-51|via=}}</ref>
* Abnormal electromyogram showing generalized, mild, lower motor neuron changes indicative of a radiculopathy.<ref name="Parish1978" /><ref name="Marinacci1965">{{Cite journal | last = Marinacci | first = AA | date = October 1965 | title = The value of the electromyogram in the diagnosis of Iceland disease | url =https://www.ncbi.nlm.nih.gov/pubmed/5889546|journal=Electromyography|volume=5 | pages = 241-51|via=}}</ref>
* [[Paresis|Muscle weakness]] measured via quantitative muscular-testing<ref name="Shelokov, 1957">{{Cite journal | last1   = Shelokov       | first1 = Alexis | authorlink1 = | last2   = Habel | first2 = Karl   | authorlink2 = | last3   = Verder               | first3 = Elizabeth             | authorlink3 = | last4   = Welsh | first4 = William               | authorlink4 =   | title = Epidemic Neuromyasthenia — An Outbreak of Poliomyelitis-like Illness in Student Nurses | journal = New England Journal of Medicine   | volume =   | issue = 257   | page = 345-355| date   = August 1957 | url =https://www.cabdirect.org/cabdirect/mobile/abstract/19582700721 | doi     = 10.1056/NEJM195708222570801 }}</ref>
* [[Paresis|Muscle weakness]] measured via quantitative muscular-testing<ref name="Shelokov, 1957">{{Cite journal | last1 = Shelokov | first1 = Alexis | author-link1 = | last2 = Habel | first2 = Karl | authorlink2 = | last3 = Verder | first3 = Elizabeth | authorlink3 = | last4 = Welsh | first4 = William | author-link4 = | title = Epidemic Neuromyasthenia — An Outbreak of Poliomyelitis-like Illness in Student Nurses | journal = New England Journal of Medicine | volume = | issue = 257 | page = 345-355 | date = August 1957 | url = https://www.cabdirect.org/cabdirect/mobile/abstract/19582700721 | doi = 10.1056/NEJM195708222570801 }}</ref>
* Normal or minimal [[cerebrospinal fluid]] findings<ref name="Sigurdsson1956" /><ref name="Shelokov, 1957" /><ref name="Hill1959" /><ref>{{Cite journal|url=https://www.sciencedirect.com/science/article/pii/S0033350657800225|title=Encephalomyelitis simulating poliomyelitis|last=Ramsay|first=Melvin|date=May 26, 1956|journal=The Lancet|volume=270|pages=761-764|via=|last2=O'Sullivan|first2=E}}</ref>
* Normal or minimal [[cerebrospinal fluid]] findings<ref name="Sigurdsson1956" /><ref name="Shelokov, 1957" /><ref name="Hill1959" /><ref>{{Cite journal| url = https://www.sciencedirect.com/science/article/pii/S0033350657800225 | title = Encephalomyelitis simulating poliomyelitis | last = Ramsay | first = Melvin | date = May 26, 1956|journal=The Lancet|volume=270 | pages = 761-764|via= | last2 = O'Sullivan | first2 = E}}</ref>
* Normal or mildly increased [[erythrocyte sedimentation rate]]<ref name="Jackson1957" /><ref name="Hill1959" /><ref name="Ramsay1978" />
* Normal or mildly increased [[erythrocyte sedimentation rate]]<ref name="Jackson1957" /><ref name="Hill1959" /><ref name="Ramsay1978" />
* Mild increase in white blood cell count<ref name="Hill1959" />
* Mild increase in white blood cell count<ref name="Hill1959" />
* [[Dysautonomia|Autonomic nervous system dysfunction]], [[Hypothalamus|hypothalamic]] dysfunction
* [[Dysautonomia|Autonomic nervous system dysfunction]], [[Hypothalamus|hypothalamic]] dysfunction
* [[Postural orthostatic tachycardia syndrome|Orthostatic tachycardia]]<ref name="Hill1959" />
* [[Postural orthostatic tachycardia syndrome|Orthostatic tachycardia]]<ref name="Hill1959" />
* Ulnar neuritis, neuropathy or lesion<ref name="Sigurdsson1950" /><ref name="Levine1994">{{Cite journal|last=Levine|first=PH|date=January 1994|title=Epidemic neuromyasthenia and chronic fatigue syndrome: epidemiological importance of a cluster definition|url=https://www.ncbi.nlm.nih.gov/pubmed/8148446|pmid=8148446|journal=Clinical Infectious Diseases|volume=18|pages=S16-20|via=}}</ref><ref name="White1954">{{Cite journal|last=White|first=D|last2=Burtch|first2=Robert|date=July 1, 1954|title=Iceland Disease: A New Infection Simulating Acute Anterior Poliomyelitis|url=http://n.neurology.org/content/4/7/506.short|journal=Neurology|volume=4|pages=|via=}}</ref>
* Ulnar neuritis, neuropathy or lesion<ref name="Sigurdsson1950" /><ref name="Levine1994">{{Cite journal | last = Levine | first = PH | date = January 1994 | title = Epidemic neuromyasthenia and chronic fatigue syndrome: epidemiological importance of a cluster definition | url = https://www.ncbi.nlm.nih.gov/pubmed/8148446|pmid=8148446|journal=Clinical Infectious Diseases|volume=18| pages=S16-20|via=}}</ref><ref name="White1954">{{Cite journal | last = White | first = D | last2 = Burtch | first2 = Robert | date = July 1, 1954 | title = Iceland Disease: A New Infection Simulating Acute Anterior Poliomyelitis |url = http://n.neurology.org/content/4/7/506.short|journal=Neurology|volume=4| pages=|via=}}</ref>
* Microscopic infiltration of nerve roots with [[lymphocyte]]s and [[Mononuclear cell|mononuclear cell]]s; patchy damage to the myelin sheaths and axon swellings (in monkeys infected with unidentified virus from the [[1949-53 Adelaide outbreak|Adelaide]] outbreak)
* Microscopic infiltration of nerve roots with [[lymphocyte]]s and [[Mononuclear cell|mononuclear cell]]s; patchy damage to the myelin sheaths and axon swellings (in monkeys infected with unidentified virus from the [[1949-53 Adelaide outbreak|Adelaide]] outbreak)
* Raised urinary [[creatine]] excretion<ref name="Albrecht1964" /><ref name="White1954" />
* Raised urinary [[creatine]] excretion<ref name="Albrecht1964" /><ref name="White1954" />
* abnormally high [[lactic dehydrogenase]] and [[glutamic oxaloacetic transaminase]]<ref name="Ramsay1978" />
* abnormally high [[lactic dehydrogenase]] and [[glutamic oxaloacetic transaminase]]<ref name="Ramsay1978" />


In the majority of early epidemics, no viral or bacterial infectious agent was successfully cultured.<ref name="Sigurdsson1956" /><ref name="Jackson1957" /><ref name="Hill1959" /> In a small number of epidemics [[Coxsackie B]]<ref name="Fegan1983">{{Cite journal | last1   = Fegan     | first1 = KG | authorlink1 = KG Fegan | last2   = Behan           | first2 = PO | authorlink2 = Peter Behan | last3   = Bell             | first3 = EJ | authorlink3 = Eleanor Bell | title = Myalgic encephalomyelitis — report of an epidemic | journal = J R Coll Gen Pract | volume = 33| issue = 251| pages = 335–337
In the majority of early epidemics, no viral or bacterial infectious agent was successfully cultured.<ref name="Sigurdsson1956" /><ref name="Jackson1957" /><ref name="Hill1959" /> In a small number of epidemics [[Coxsackie B]]<ref name="Fegan1983">{{Cite journal | last1 = Fegan | first1 = KG | author-link1 = KG Fegan | last2 = Behan | first2 = PO | authorlink2 = Peter Behan | last3 = Bell | first3 = EJ | authorlink3 = Eleanor Bell | title = Myalgic encephalomyelitis — report of an epidemic | journal = J R Coll Gen Pract | volume = 33 | issue = 251| pages = 335–337 | date = Jun 1, 1983 | pmid = 6310104 | url = http://bjgp.org/content/33/251/335 }}</ref><ref name="Calder1984">{{Cite journal | last1 = Calder | first1 = BD | author-link1 = BD Calder | last2 = Warnock | first2 = PJ | authorlink2 = PJ Warnock | title = Coxsackie B infection in a Scottish general practice | journal = Jrnl Royal Coll Gen Pract | volume = 34 | issue = 258| pages = 15–19 | date = Jan 1984 | pmid = 6319691 | url = http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1959663/ }}</ref> or [[Bethesda-Ballerup paracolon organism]]<ref name="Shelokov, 1957" /> were found. In others, infection of animal models with samples from patients results in identifiable nervous system damage on autopsy and in one case, [[myocarditis]], in spite of being unable to identify the agent.<ref name="Parish1978" /><ref name="Pellew1955">{{Cite journal| url = https://www.ncbi.nlm.nih.gov/pubmed/13272481 | title = Further Investigations on a Disease Resembling Poliomyelitis Seen in Adelaide | last = Pellew | first = R.A.A. | date = September 24, 1955|journal=The Medical Journal of Australia|volume=2 | pages = 480-2|via=}}</ref>
| date   = Jun 1, 1983
| pmid   = 6310104 | url     = http://bjgp.org/content/33/251/335 }}</ref><ref name="Calder1984">{{Cite journal | last1   = Calder   | first1 = BD | authorlink1 = BD Calder | last2   = Warnock         | first2 = PJ | authorlink2 = PJ Warnock | title = Coxsackie B infection in a Scottish general practice | journal = Jrnl Royal Coll Gen Pract | volume = 34| issue = 258| pages = 15–19
| date   = Jan 1984
| pmid   = 6319691 | url     = http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1959663/ }}</ref> or [[Bethesda-Ballerup paracolon organism]]<ref name="Shelokov, 1957" /> were found. In others, infection of animal models with samples from patients results in identifiable nervous system damage on autopsy and in one case, [[myocarditis]], in spite of being unable to identify the agent.<ref name="Parish1978" /><ref name="Pellew1955">{{Cite journal|url=https://www.ncbi.nlm.nih.gov/pubmed/13272481|title=Further Investigations on a Disease Resembling Poliomyelitis Seen in Adelaide|last=Pellew|first=R.A.A.|date=September 24, 1955|journal=The Medical Journal of Australia|volume=2|pages=480-2|via=}}</ref>


==Epidemiology==
==Epidemiology==
Many of these outbreaks occurred at institutions for example, hospitals,<ref name="Shelokov, 1957" /><ref name="Gilliam, 1936-38" /><ref name="Hill1959" /> schools, army bases or convents. The pattern of spread suggested a highly infectious agent that spread person to person, rather than through contaminated food or drink or exposure to a single toxic agent.<ref name="Parish1978">{{Cite journal|last=Parish|first=JG|date=1978|title=Early outbreaks of 'epidemic neuromyasthenia'|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2425322/|journal=Postgraduate Medical Journal|volume=54|pages=711-7|issue=|via=|quote=|author-link=Gordon Parish|pmid=370810|pmc=2425322}}</ref><ref name="Gilliam, 1936-38">{{Cite journal | last1   = Gilliam   | first1 = A.G.               | authorlink1 =   | title = Epidemiological Study Of An Epidemic, Diagnosed As Poliomyelitis, Occurring Among The Personnel Of The Los Angeles County General Hospital During The Summer Of 1934 | journal = Public health bulletin, 1936-1938 | volume = | issue = 231-240   | page =  
Many of these outbreaks occurred at institutions for example, hospitals,<ref name="Shelokov, 1957" /><ref name="Gilliam, 1936-38" /><ref name="Hill1959" /> schools, army bases or convents. The pattern of spread suggested a highly infectious agent that spread person to person, rather than through contaminated food or drink or exposure to a single toxic agent.<ref name="Parish1978">{{Cite journal | last = Parish | first = JG | date = 1978 | title = Early outbreaks of 'epidemic neuromyasthenia'| url = https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2425322/|journal=Postgraduate Medical Journal|volume=54 | pages = 711-7|issue=|via=|quote= | author-link = Gordon Parish|pmid=370810|pmc=2425322}}</ref><ref name="Gilliam, 1936-38">{{Cite journal | last1 = Gilliam | first1 = A.G. | author-link1 = | title = Epidemiological Study Of An Epidemic, Diagnosed As Poliomyelitis, Occurring Among The Personnel Of The Los Angeles County General Hospital During The Summer Of 1934 | journal = Public health bulletin, 1936-1938 | volume = | issue = 231-240 | page = | date = 1938 | pmid = | url = http://babel.hathitrust.org/cgi/pt?id=mdp.39015022082260;view=1up;seq=617 }}</ref><ref name="Poskanzer, 1957" /><ref name="Hill1959" />
| date   = 1938
| pmid   = | url     = http://babel.hathitrust.org/cgi/pt?id=mdp.39015022082260;view=1up;seq=617 }}</ref><ref name="Poskanzer, 1957" /><ref name="Hill1959" />


Outbreaks tended to begin in the summer months, with most initial cases reported from April to September in the Northern hemisphere, October to March in the Southern hemisphere.<ref name="Hill1959" /><ref name="Acheson, 1959" />
Outbreaks tended to begin in the summer months, with most initial cases reported from April to September in the Northern hemisphere, October to March in the Southern hemisphere.<ref name="Hill1959" /><ref name="Acheson, 1959" />
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In outbreaks involving both medical personnel and the general community, medical personnel had a higher attack rate and/or greater central nervous system involvement.<ref name="Poskanzer, 1957" /> A similar pattern was seen in hospital outbreaks, where those in roles that involved more frequent or intimate contact with patients or those working in an infectious disease ward were more affected than other hospital staff.<ref name="Parish1978" /><ref name="Gilliam, 1936-38" /> A large proportion of recorded outbreaks have taken place in hospital settings.<ref name="Acheson, 1959" />
In outbreaks involving both medical personnel and the general community, medical personnel had a higher attack rate and/or greater central nervous system involvement.<ref name="Poskanzer, 1957" /> A similar pattern was seen in hospital outbreaks, where those in roles that involved more frequent or intimate contact with patients or those working in an infectious disease ward were more affected than other hospital staff.<ref name="Parish1978" /><ref name="Gilliam, 1936-38" /> A large proportion of recorded outbreaks have taken place in hospital settings.<ref name="Acheson, 1959" />


In many outbreaks including [[1934 Los Angeles atypical polio outbreak|Los Angeles]], [[Akureyri]], [[1953 Maryland outbreak|Rockville, MD]], [[1955 Royal Free Hospital outbreak|Royal Free Hospital]], and [[1956 Punta Gorda outbreak|Punta Gorda, Florida]], women were affected at higher rates.<ref name="Sigurdsson1950" /><ref name="Parish1978" /><ref name="Shelokov, 1957" /><ref name="Gilliam, 1936-38" /><ref name="Acheson, 1959">{{Citation | last1   = Acheson | first1 = E.D.   | authorlink1 =   | title = The Clinical Syndrome Variously Called Benign Myalgic Encephalomyelitis, Iceland Disease and Epidemic Neuromyasthenia | journal = American Journal of Medicine   | volume = 26   | issue = 4   | page = 569–595
In many outbreaks including [[1934 Los Angeles atypical polio outbreak|Los Angeles]], [[Akureyri]], [[1953 Maryland outbreak|Rockville, MD]], [[1955 Royal Free Hospital outbreak|Royal Free Hospital]], and [[1956 Punta Gorda outbreak|Punta Gorda, Florida]], women were affected at higher rates.<ref name="Sigurdsson1950" /><ref name="Parish1978" /><ref name="Shelokov, 1957" /><ref name="Gilliam, 1936-38" /><ref name="Acheson, 1959">{{Citation | last1 = Acheson | first1 = E.D. | author-link1 = | title = The Clinical Syndrome Variously Called Benign Myalgic Encephalomyelitis, Iceland Disease and Epidemic Neuromyasthenia | journal = American Journal of Medicine | volume = 26 | issue = 4 | page = 569–595 | date = 1959 | pmid = | url = http://www.name-us.org/defintionspages/DefinitionsArticles/Acheson1959.pdf }}</ref><ref name="Poskanzer, 1957">{{Cite journal | last1 = Poskanzer | first1 = David C. | author-link1 = | last2 = Henderson | first2 = Donald A. | authorlink2 = | last3 = Kunkle | first3 = E. Charles | author-link3 = | last4 = Kalter | first4 = Seymour S. | authorlink4 = | last5 = Clement | first5 = Walter B. | authorlink5 = | last6 = Bond | first6 = James O. | author-link6 = | title = Epidemic Neuromyasthenia — An Outbreak in Punta Gorda, Florida | journal = New England Journal of Medicine | volume = | issue = 257 | page = 356-364 | date = 1957 | pmid = 13464939 | doi = 10.1056/NEJM195708222570802 | url = http://www.nejm.org/doi/full/10.1056/NEJM195708222570802 }}</ref><ref name="PMC1962472" /><ref name="Levine1997" /><ref name="Jackson1957" /> In other outbreaks, including the 1949-1953 [[1949-53 Adelaide outbreak|Adelaide]] outbreak and an outbreak in [[1955 North of England outbreak|northern England in 1955]], a 1:1 gender ratio was reported.<ref name="Parish1978" /> In hospital epidemics, young female nurses were disproportionately affected, but this may have been due to risk factors like higher repeated exposure to the same infection during an epidemic<ref name="Parish1978" /> and in some outbreaks, gender-segregated living quarters.<ref name="PMC1962472">[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1962472/ An Outbreak of Encephalomyelitis in the Royal Free Hospital Group, London, in 1955 - The Medical Staff Of The Royal Free Hospital]</ref> However, the higher ratio of women were also reported in outbreaks in the general population.<ref name="Acheson, 1959" /> In Akureyri, while the incidence among adults was higher for females, there was no significant difference in incidence between sexes among those under twenty.<ref name="Sigurdsson1950">{{Cite journal| url = https://www.ncbi.nlm.nih.gov/pubmed/14771044 | title = A disease epidemic in Iceland simulating poliomyelitis | last = Sigurdsson | first = B | author-link = Björn Sigurdsson | date = September 1950|journal=American Journal of Hygiene|volume=52 | pages = 222-38|via=}}</ref> This comports with patterns of age and sex distribution in sporadic cases.{{Citation needed}}  
| date   = 1959
| pmid   = | url     = http://www.name-us.org/defintionspages/DefinitionsArticles/Acheson1959.pdf }}</ref><ref name="Poskanzer, 1957">{{Cite journal | last1   = Poskanzer | first1 = David C.   | authorlink1 = | last2   = Henderson         | first2 = Donald A.   | authorlink2 = | last3   = Kunkle           | first3 = E. Charles   | authorlink3 = | last4   = Kalter           | first4 = Seymour S.   | authorlink4 = | last5   = Clement           | first5 = Walter B.   | authorlink5 = | last6   = Bond             | first6 = James O.   | authorlink6 =   | title = Epidemic Neuromyasthenia — An Outbreak in Punta Gorda, Florida | journal = New England Journal of Medicine   | volume = | issue = 257   | page = 356-364
| date   = 1957
| pmid   = 13464939 | doi     = 10.1056/NEJM195708222570802 | url     = http://www.nejm.org/doi/full/10.1056/NEJM195708222570802 }}</ref><ref name="PMC1962472" /><ref name="Levine1997" /><ref name="Jackson1957" /> In other outbreaks, including the 1949-1953 [[1949-53 Adelaide outbreak|Adelaide]] outbreak and an outbreak in [[1955 North of England outbreak|northern England in 1955]], a 1:1 gender ratio was reported.<ref name="Parish1978" /> In hospital epidemics, young female nurses were disproportionately affected, but this may have been due to risk factors like higher repeated exposure to the same infection during an epidemic<ref name="Parish1978" /> and in some outbreaks, gender-segregated living quarters.<ref name="PMC1962472">[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1962472/ An Outbreak of Encephalomyelitis in the Royal Free Hospital Group, London, in 1955 - The Medical Staff Of The Royal Free Hospital]</ref> However, the higher ratio of women were also reported in outbreaks in the general population.<ref name="Acheson, 1959" /> In Akureyri, while the incidence among adults was higher for females, there was no significant difference in incidence between sexes among those under twenty.<ref name="Sigurdsson1950">{{Cite journal|url=https://www.ncbi.nlm.nih.gov/pubmed/14771044|title=A disease epidemic in Iceland simulating poliomyelitis|last=Sigurdsson|first=B|author-link=Björn Sigurdsson|date=September 1950|journal=American Journal of Hygiene|volume=52|pages=222-38|via=}}</ref> This comports with patterns of age and sex distribution in sporadic cases.{{Citation needed}}  


In most outbreaks, those most affected tended to be adults in their twenties,<ref name="Parish1978" /><ref name="Gilliam, 1936-38" /><ref name="Albrecht1964" /><ref name="Hill1959" /> although cases of young children and adults as old as 80 have been recorded in outbreaks.<ref name="Acheson, 1959" /> In Akureyri, the highest attack rate was among ages 15-19.<ref name="Sigurdsson1956" />
In most outbreaks, those most affected tended to be adults in their twenties,<ref name="Parish1978" /><ref name="Gilliam, 1936-38" /><ref name="Albrecht1964" /><ref name="Hill1959" /> although cases of young children and adults as old as 80 have been recorded in outbreaks.<ref name="Acheson, 1959" /> In Akureyri, the highest attack rate was among ages 15-19.<ref name="Sigurdsson1956" />


[[Melvin Ramsay]] observed an absence of cases among sedentary people, and postulated that this might explain why hospital staff frequently became affected, while patients in hospital rarely did.<ref name="Ramsay1978">{{Cite journal|last=Ramsay|first=A. Melvin|date=November 1978|title=Epidemic neuromyasthenia' 1955-1978|url=https://www.ncbi.nlm.nih.gov/pubmed/746017|journal=Postgraduate Medical Journal|volume=54|pages=718-721|issue=|via=|quote=|author-link=Melvin Ramsay|pmc=2425324|pmid=746017}}</ref>   
[[Melvin Ramsay]] observed an absence of cases among sedentary people, and postulated that this might explain why hospital staff frequently became affected, while patients in hospital rarely did.<ref name="Ramsay1978">{{Cite journal | last = Ramsay | first = A. Melvin | date = November 1978 | title = Epidemic neuromyasthenia' 1955-1978| url = https://www.ncbi.nlm.nih.gov/pubmed/746017|journal=Postgraduate Medical Journal|volume=54 | pages = 718-721|issue=|via=|quote= | author-link = Melvin Ramsay|pmc=2425324|pmid=746017}}</ref>   


{| class="wikitable"
{| class="wikitable"
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|Community
|Community
|January
|January
|50%<ref name=":10">{{Cite book|title=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|last=Wallis|first=A. L.|publisher=University of Edinburgh|year=1957|isbn=|location=|pages=}}</ref>
|50%<ref name=":10">{{Cite book | title = 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 | last = Wallis | first = A.L. | publisher = University of Edinburgh| year = 1957|isbn=|location=| pages=}}</ref>
|
|
|13.9%<ref name=":10" />
|13.9%<ref name=":10" />
Line 206: Line 196:
No serological evidence of polio was ever found in these outbreaks and the ultimate pattern of the outbreaks differed in significant ways, chief among them the higher attack rate, the tendency to affect adults rather than children, and the higher [[morbidity]] than poliomyelitis but no [[mortality]].<ref name="Parish1978" /><ref name="Acheson, 1959" /> Findings in several outbreaks seemed to suggest that symptoms were caused by an [[enterovirus]] distinct from but related to polio: findings of mild, diffuse peripheral nervous system damage in monkeys infected with the virus; a stronger response to polio vaccination in children who had been in epidemic areas; and seasonal patterns of infection resembling polio, i.e., the rise in cases during summer months.<ref name="Parish1978" /><ref name="Acheson, 1959" />  
No serological evidence of polio was ever found in these outbreaks and the ultimate pattern of the outbreaks differed in significant ways, chief among them the higher attack rate, the tendency to affect adults rather than children, and the higher [[morbidity]] than poliomyelitis but no [[mortality]].<ref name="Parish1978" /><ref name="Acheson, 1959" /> Findings in several outbreaks seemed to suggest that symptoms were caused by an [[enterovirus]] distinct from but related to polio: findings of mild, diffuse peripheral nervous system damage in monkeys infected with the virus; a stronger response to polio vaccination in children who had been in epidemic areas; and seasonal patterns of infection resembling polio, i.e., the rise in cases during summer months.<ref name="Parish1978" /><ref name="Acheson, 1959" />  


There is indirect evidence of cross-immunity between [[poliovirus]] and the unidentified virus or viruses in epidemic myalgic encephalomyelitis outbreaks. After the Akureyri outbreak, children in areas that had been affected responded to poliomyelitis vaccination with higher antibody titres, as if these children had already been exposed to an agent immunologically similar to the poliovirus.<ref name="Parish1978" /><ref>{{Cite journal|url=https://www.ncbi.nlm.nih.gov/pubmed/13515219|title=Response to poliomyelitis vaccination|last=Sigurdsson|first=B|author-link=Björn Sigurdsson|date=February 15, 1958|journal=The Lancet|volume=1|pages=370-1|via=}}</ref> During the [[1949-53 Adelaide outbreak|outbreak in Adelaide]], cases of classic poliomyelitis dropped by 43%.<ref name="PMC2542300">{{Cite journal |url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2542300/|title = Poliomyelitis in 1953"|journal =Bulletin of the World Health Organization|date =1955|volume =12|issue =4|pages =595-649|pmc=PMC2542300}}</ref>
There is indirect evidence of cross-immunity between [[poliovirus]] and the unidentified virus or viruses in epidemic myalgic encephalomyelitis outbreaks. After the Akureyri outbreak, children in areas that had been affected responded to poliomyelitis vaccination with higher antibody titres, as if these children had already been exposed to an agent immunologically similar to the poliovirus.<ref name="Parish1978" /><ref>{{Cite journal| url = https://www.ncbi.nlm.nih.gov/pubmed/13515219 | title = Response to poliomyelitis vaccination | last = Sigurdsson | first = B | author-link = Björn Sigurdsson | date = February 15, 1958|journal=The Lancet|volume=1 | pages = 370-1|via=}}</ref> During the [[1949-53 Adelaide outbreak|outbreak in Adelaide]], cases of classic poliomyelitis dropped by 43%.<ref name="PMC2542300">{{Cite journal | url = http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2542300/| title = Poliomyelitis in 1953"|journal =Bulletin of the World Health Organization | date = 1955|volume =12|issue =4| pages =595-649|pmc=PMC2542300}}</ref>


== Controversy ==
== Controversy ==
In 1970, a paper by [[Colin McEvedy|Colin P. McEvedy]] and [[William Beard|AW Beard]] claimed that the [[1955 Royal Free Hospital outbreak]] was actually [[mass hysteria]]<ref name="PMC1700894">{{Cite journal|title=Royal Free Epidemic of 1955: A Reconsideration|date=1970-01-03|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1700894/|journal=British Medical Journal|volume=1|issue=5687|pages=7–11|last=McEvedy|first=Colin P.|author-link=Colin McEvedy|last2=Beard|first2=A. W.|author-link2=William Beard|last3=|first3=|author-link3=|last4=|first4=|author-link4=|last5=|first5=|author-link5=|last6=|first6=|author-link6=|last7=|first7=|last8=|first8=|last9=|first9=|doi=|pmc=1700894|pmid=5411611|access-date=|issn=0007-1447|quote=|via=}}</ref><ref name="Apology2015">{{Cite news |url =https://www.telegraph.co.uk/news/health/12033810/Its-time-for-doctors-to-apologise-to-their-ME-patients.html |title =It's time for doctors to apologise to their ME patients|publisher =The Telegraph|first=Charles|last=Shepherd|author-link =Charles Shepherd|date =December 7, 2015}}</ref> despite never examining patients.<ref name="Speight2013">{{Cite journal|last=Speight|first=Nigel|author-link=Nigel Speight|date=2013|title=Myalgic encephalomyelitis/chronic fatigue syndrome: Review of history, clinical features, and controversies|url=http://dx.doi.org/10.4103/1658-631x.112905|journal=Saudi Journal of Medicine and Medical Sciences|volume=1|issue=1|pages=11|doi=10.4103/1658-631x.112905|issn=1658-631X|quote=|via=}}</ref>
In 1970, a paper by [[Colin McEvedy|Colin P. McEvedy]] and [[William Beard|AW Beard]] claimed that the [[1955 Royal Free Hospital outbreak]] was actually [[mass hysteria]]<ref name="PMC1700894">{{Cite journal | title = Royal Free Epidemic of 1955: A Reconsideration | date = 1970-01-03| url = https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1700894/|journal=British Medical Journal|volume=1|issue=5687 | pages = 7–11 | last = McEvedy | first = Colin P. | author-link = Colin McEvedy | last2 = Beard | first2 = A.W. | authorlink2 = William Beard | last3 = | first3 = | authorlink3 = | last4 = | first4 = | authorlink4 = | last5 = | first5 = | authorlink5 = |doi=|pmc=1700894|pmid=5411611|access-date=|issn=0007-1447|quote=|via=}}</ref><ref name="Apology2015">{{Cite news |url = https://www.telegraph.co.uk/news/health/12033810/Its-time-for-doctors-to-apologise-to-their-ME-patients.html | title = It's time for doctors to apologise to their ME patients|publisher =The Telegraph | first = Charles | last = Shepherd | authorlink = Charles Shepherd | date =December 7, 2015}}</ref> despite never examining patients.<ref name="Speight2013">{{Cite journal | last = Speight | first = Nigel | authorlink = Nigel Speight | date = 2013 | title = Myalgic encephalomyelitis/chronic fatigue syndrome: Review of history, clinical features, and controversies |url = http://dx.doi.org/10.4103/1658-631x.112905|journal=Saudi Journal of Medicine and Medical Sciences|volume=1|issue=1 | pages = 11|doi=10.4103/1658-631x.112905|issn=1658-631X|quote=|via=}}</ref>


== Outbreaks of the 1980s and 1990s ==
== Outbreaks of the 1980s and 1990s ==
Line 221: Line 211:
* [[List of myalgic encephalomyelitis and chronic fatigue syndrome outbreaks]]
* [[List of myalgic encephalomyelitis and chronic fatigue syndrome outbreaks]]
* [[Non-cytolytic enterovirus]]
* [[Non-cytolytic enterovirus]]
* [[Eightfold increase in ME/CFS incidence in the 1980s]]


== Learn more==
== Learn more==


*[https://www.newyorker.com/magazine/1965/11/27/in-the-bughouse In the Bughouse] - The New Yorker by Berton Roueché<ref name="NewYorker1965">{{Cite news|publisher=The New Yorker |volume =41 |issue =Part 6 |page =208 |title =In The Bughouse |date=Nov 19, 1965
*[https://www.newyorker.com/magazine/1965/11/27/in-the-bughouse In the Bughouse] - The New Yorker by Berton Roueché<ref name="NewYorker1965">{{Cite news | publisher = The New Yorker |volume =41 |issue =Part 6 | page =208 | title = In The Bughouse | date = Nov 19, 1965 | last = Roueché | first = Berton | url = http://www.newyorker.com/magazine/1965/11/27/in-the-bughouse }} </ref>
|last= Roueché | first = Berton | url =http://www.newyorker.com/magazine/1965/11/27/in-the-bughouse }} </ref>
*[[Osler's Web]] by [[Hillary Johnson]]
*[[Osler's Web]] by [[Hillary Johnson]]



Latest revision as of 21:07, June 16, 2023

Nurses who became ill during an outbreak of "atypical polio" at the Los Angeles County Hospital in 1934.

There have been at least 75 documented outbreaks of myalgic encephalomyelitis and chronic fatigue syndrome since the 1930s. The true number of clusters and outbreaks is likely much higher. Many of these outbreaks occurred in institutions like hospitals and schools, and frequently coincided with outbreaks of poliomyelitis.

The first recorded outbreak of epidemic was in 1934 in Los Angeles and the most recent putative outbreak was in Arizona in 1996. 

Prior to the 1980s, while no infectious was ever isolated, the outbreaks were widely thought to be caused by a virus related to poliovirus, i.e., by another, yet-to-be-unidentified enterovirus. After the Incline Village outbreak in 1984, herpesviruses and in particular, Epstein-Barr virus was posited as the cause.

History[edit | edit source]

The first recorded outbreak of epidemic myalgic encephalomyelitis was in 1934 in Los Angeles and was thought to be an outbreak of atypical polio. After the outbreak in Akureyri, Iceland in 1946, the disease came to be called Akureyri Disease or Icelandic disease through much of the 1940s and 1950s. It was named myalgic encephalomyelitis after London's Royal Free Hospital outbreak in 1955. Other names included benign myalgic encephalomyelitis and epidemic neuromyasthenia.

After the Incline Village outbreak in Nevada in 1984, the disease came to be called and redefined as Chronic Fatigue Syndrome. The most recent was putative outbreak was in Arizona in 1996. 

Onset[edit | edit source]

The incubation period was generally estimated at 4 to 8 days.[1][2][3] The illness generally began with a prodromal period of flu-like symptoms, symptoms of an upper respiratory tract infection, low-grade fever, sore throat or gastrointestinal distress,[4][5][6] followed by a symptom complex involving muscle weakness, muscle fatigability and central nervous system involvement in a significant proportion of cases.[2][7]

Symptoms[edit | edit source]

Reported symptoms could vary considerably from outbreak to outbreak. Common symptoms included:

Findings[edit | edit source]

Findings varied considerably based on the technology of the time and what tests physicians attending to these outbreaks chose or were able to run:

In the majority of early epidemics, no viral or bacterial infectious agent was successfully cultured.[3][8][9] In a small number of epidemics Coxsackie B[17][18] or Bethesda-Ballerup paracolon organism[7] were found. In others, infection of animal models with samples from patients results in identifiable nervous system damage on autopsy and in one case, myocarditis, in spite of being unable to identify the agent.[2][19]

Epidemiology[edit | edit source]

Many of these outbreaks occurred at institutions for example, hospitals,[7][20][9] schools, army bases or convents. The pattern of spread suggested a highly infectious agent that spread person to person, rather than through contaminated food or drink or exposure to a single toxic agent.[2][20][12][9]

Outbreaks tended to begin in the summer months, with most initial cases reported from April to September in the Northern hemisphere, October to March in the Southern hemisphere.[9][10]

In outbreaks involving both medical personnel and the general community, medical personnel had a higher attack rate and/or greater central nervous system involvement.[12] A similar pattern was seen in hospital outbreaks, where those in roles that involved more frequent or intimate contact with patients or those working in an infectious disease ward were more affected than other hospital staff.[2][20] A large proportion of recorded outbreaks have taken place in hospital settings.[10]

In many outbreaks including Los Angeles, Akureyri, Rockville, MD, Royal Free Hospital, and Punta Gorda, Florida, women were affected at higher rates.[1][2][7][20][10][12][21][6][8] In other outbreaks, including the 1949-1953 Adelaide outbreak and an outbreak in northern England in 1955, a 1:1 gender ratio was reported.[2] In hospital epidemics, young female nurses were disproportionately affected, but this may have been due to risk factors like higher repeated exposure to the same infection during an epidemic[2] and in some outbreaks, gender-segregated living quarters.[21] However, the higher ratio of women were also reported in outbreaks in the general population.[10] In Akureyri, while the incidence among adults was higher for females, there was no significant difference in incidence between sexes among those under twenty.[1] This comports with patterns of age and sex distribution in sporadic cases.[citation needed]

In most outbreaks, those most affected tended to be adults in their twenties,[2][20][11][9] although cases of young children and adults as old as 80 have been recorded in outbreaks.[10] In Akureyri, the highest attack rate was among ages 15-19.[3]

Melvin Ramsay observed an absence of cases among sedentary people, and postulated that this might explain why hospital staff frequently became affected, while patients in hospital rarely did.[5]

Outbreak Type Peak months Percent female Most affected age group Attack rate
1934 Los Angeles Institution May to December 75% < 30 years 4.5%
1937 Erstfeld Institution July NA (all male soldier) 14%
1948-49 Akureyri Community Winter 50% (< age 20), 70% ( > age 20) [3] 15-19 years[3] 6.7% (town), 0.8% (rural)[3]
1949-53 Adelaide Community Winter (August) 50%
1950 Louisville Institution October NA (mainly female nurses) 23%
1953 Maryland Institution July NA (mainly female nurses) 13.7%
1954 Johannesburg Community August to March 72%[8]
1955 Dalston Community January 50%[22] 13.9%[22]
1955 Durban Institution late summer (February) NA (mainly female nurses) < 25 years
1955 London Institution July to November
1956 Punta Gorda Mixed mid-March to June 74%[12] 20-49 years[12] 6.1%[12] (community), 42% (hospital)
1961 New York State Institution July to January NA (all female nuns) < 30 years 37.7%

Pathophysiology[edit | edit source]

Due to limited of objective findings, very little was known about the pathophysiology of the disease. Several investigators postulated damage to the hypothalamus[5] owing to the symptoms of orthostatic tachycardia, abnormal glucose regulation, circulatory impairment, and problems with temperature regulation.

Prognosis[edit | edit source]

Although many patients improved over time, in follow-up studies, a large percentage were still ill months to years later. Many case studies note long periods of convalescence with relapses following exertion[3][7][9][11][12] or before or during menstrual periods.[7][11][12]

Outbreak Time after outbreak Subjective recovery rate Objective recovery rate
1948-49 Akureyri outbreak 7 years 13%[3] 31%[3]
1953 Maryland outbreak 5 months 0%[7]
1955 Durban outbreak 3 years 89%*[9]
1961 New York State outbreak 1 year 35%[11]
  • Follow-up was with those patients considered disabled. Others may have been more mildly affected.

Relationship to polio[edit | edit source]

Prior to the poliovirus vaccine, several outbreaks of what later came to be called myalgic encephalomyelitis coincided with confirmed outbreaks of poliomyelitis including the 1934 Los Angeles outbreak, the 1948 Akureyri, Iceland outbreak, and 1949 outbreak in Adelaide, Australia.[4] Many outbreaks were initially misinterpreted as clusters of poliomyelitis or abortive poliomyelitis, hence one of ME's earliest names, atypical polio. It is not known whether there is a direct relationship between polio outbreaks and ME or if outbreaks of ME were more likely to be reported when public health authorities were already mobilized for an earlier crisis.

No serological evidence of polio was ever found in these outbreaks and the ultimate pattern of the outbreaks differed in significant ways, chief among them the higher attack rate, the tendency to affect adults rather than children, and the higher morbidity than poliomyelitis but no mortality.[2][10] Findings in several outbreaks seemed to suggest that symptoms were caused by an enterovirus distinct from but related to polio: findings of mild, diffuse peripheral nervous system damage in monkeys infected with the virus; a stronger response to polio vaccination in children who had been in epidemic areas; and seasonal patterns of infection resembling polio, i.e., the rise in cases during summer months.[2][10]

There is indirect evidence of cross-immunity between poliovirus and the unidentified virus or viruses in epidemic myalgic encephalomyelitis outbreaks. After the Akureyri outbreak, children in areas that had been affected responded to poliomyelitis vaccination with higher antibody titres, as if these children had already been exposed to an agent immunologically similar to the poliovirus.[2][23] During the outbreak in Adelaide, cases of classic poliomyelitis dropped by 43%.[24]

Controversy[edit | edit source]

In 1970, a paper by Colin P. McEvedy and AW Beard claimed that the 1955 Royal Free Hospital outbreak was actually mass hysteria[25][26] despite never examining patients.[27]

Outbreaks of the 1980s and 1990s[edit | edit source]

The case reports of the 1980s and 1990s differed substantially from those of earlier decades. Whereas reports from the 1930s-1960s focused heavily on neurological and muscle symptoms and findings, and compared and contrasted the disease to poliomyelitis, reports of the 1980s focused far more heavily on fatigue and the possible relationship to herpesviruses.

See also[edit | edit source]

 Learn more[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 Sigurdsson, B (September 1950). "A disease epidemic in Iceland simulating poliomyelitis". American Journal of Hygiene. 52: 222–38.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 Parish, JG (1978). "Early outbreaks of 'epidemic neuromyasthenia'". Postgraduate Medical Journal. 54: 711–7. PMC 2425322. PMID 370810.
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 3.15 3.16 Sigurdsson, B (May 1956). "The Lancet". Clinical findings six years after outbreak of Akureyri disease. 270: 766–7.
  4. 4.0 4.1 4.2 4.3 4.4 Pellew, R.A. (June 30, 1951). "A Clinical Description of a Disease resembling Poliomyelitis, seen in Adelaide, 1949-1951". Medical Journal of Australia. 1 (26): 944–6.
  5. 5.0 5.1 5.2 5.3 5.4 Ramsay, A. Melvin (November 1978). "Epidemic neuromyasthenia' 1955-1978". Postgraduate Medical Journal. 54: 718–721. PMC 2425324. PMID 746017.
  6. 6.0 6.1 Levine, P. H.; Snow, P. G.; Ranum, B. A.; Paul, C.; Holmes, M. J. (April 14, 1997). "Epidemic neuromyasthenia and chronic fatigue syndrome in west Otago, New Zealand. A 10-year follow-up". Archives of Internal Medicine. 157 (7): 750–754. ISSN 0003-9926. PMID 9125006.
  7. 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 Shelokov, Alexis; Habel, Karl; Verder, Elizabeth; Welsh, William (August 1957). "Epidemic Neuromyasthenia — An Outbreak of Poliomyelitis-like Illness in Student Nurses". New England Journal of Medicine (257): 345-355. doi:10.1056/NEJM195708222570801.
  8. 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 Jackson, B (May 1957). "A disease resembling poliomyelitis; report of an outbreak in Johannesburg". South African Medical Journal. 31: 514–517.
  9. 9.00 9.01 9.02 9.03 9.04 9.05 9.06 9.07 9.08 9.09 9.10 9.11 9.12 9.13 9.14 9.15 9.16 9.17 9.18 Hill, RC (April 4, 1959). "Epidemic myalgic encephalomyelopathy: the Durban outbreak". The Lancet. 1: 689–693.
  10. 10.0 10.1 10.2 10.3 10.4 10.5 10.6 10.7 Acheson, E.D. (1959), "The Clinical Syndrome Variously Called Benign Myalgic Encephalomyelitis, Iceland Disease and Epidemic Neuromyasthenia" (PDF), American Journal of Medicine, 26 (4): 569–595
  11. 11.0 11.1 11.2 11.3 11.4 11.5 11.6 Albrecht, Robert (March 21, 1964). "Epidemic Neuromyasthenia Outbreak in a Convent in New York State". Journal of the American Medical Association. 187: 904–907.
  12. 12.0 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 Poskanzer, David C.; Henderson, Donald A.; Kunkle, E. Charles; Kalter, Seymour S.; Clement, Walter B.; Bond, James O. (1957). "Epidemic Neuromyasthenia — An Outbreak in Punta Gorda, Florida". New England Journal of Medicine (257): 356-364. doi:10.1056/NEJM195708222570802. PMID 13464939.
  13. Marinacci, AA (October 1965). "The value of the electromyogram in the diagnosis of Iceland disease". Electromyography. 5: 241–51.
  14. Ramsay, Melvin; O'Sullivan, E (May 26, 1956). "Encephalomyelitis simulating poliomyelitis". The Lancet. 270: 761–764.
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