Epidemiologic Notes and Reports Investigation of a
Smallpox Rumor -- Mexico
On August 13, 1984, CDC was notified by the Infectious Disease
Section, California Department of Health Services, of a possible
smallpox case. The Contra Costa County (California) Health
Department
had received the report from a participant in a multinational
seminar
in Ixtapa, Mexico. On August 10, the last day of the seminar, the
course's organizers had recommended that the 250 attendees consult
their physicians on their return home, because a course participant
had been diagnosed by a hotel doctor as having smallpox.
A seminar staff person told CDC she had understood the hotel
doctor to say that, on August 9, he had diagnosed smallpox, and on
August 10, he had clarified his diagnosis to "little pox," a form
of
chickenpox intermediate in severity between chickenpox and smallpox
and not found in the United States. CDC alerted officials at the
Pan
American Health Organization (PAHO) headquarters in Washington,
D.C.
PAHO staff and Mexican health authorities investigated the rumor
and
determined that the hotel doctor reported he had told the seminar
organizers that he had diagnosed varicella. Apparently, there was
confusion in the use of Spanish terms for chickenpox and smallpox.
The patient, a woman from England, had traveled to Mexico on a
flight from London via Los Angeles. Within a few days of arrival,
she
developed a severe clinical illness with high fever, prostration,
and
a vesiculo-pustular skin rash. When seen by health officials on
August 15, she had recovered, and only scabbed skin lesions
remained.
A report received by PAHO from Mexican authorities confirmed the
diagnosis of chickenpox (varicella) by electron microscopic
examination of scabs. PAHO reported to the World Health
Organization
(WHO), Geneva, Switzerland, that the illness rumored to be smallpox
was chickenpox.
Adapted from California Morbidity (August 31, 1984) as reported by
B
Benda, F Wise, Contra Costa County Health Dept, R Roberto, MD, J
Chin,
MD, State Epidemiologist, California Dept of Health Svcs; Pan
American
Health Organization, Washington, D.C.; International Health Program
Office, CDC.
Editorial Note
Editorial Note: In 1980, the World Health Assembly (resolution
WHA33.4) endorsed the recommendation of the Global Commission for
the
Certification of Smallpox Eradication, which states: "In order to
maintain public confidence in the fact of global eradication, it is
important that rumors of suspected smallpox, which can be expected
to
occur in many countries, should be thoroughly investigated.
Information should be provided to WHO, if requested, so that it can
be
made available to the world community."
Between 1979 and 1984, 179 reports of suspected smallpox cases
were received by WHO (1,2). All these rumors were investigated and
found not to be smallpox. The time required for national health
authorities to investigate the cases varied considerably, partly in
relation to the apparent seriousness of the rumors. For example, a
report from Kenya caused some public concern because the patient,
who
died 3 days after developing a rash, had been a variolator who used
material from smallpox patients to immunize others when smallpox
was
endemic in Kenya. Prompt investigation and laboratory analysis of
specimens collected by Kenyan health officials proved within a week
he
had chickenpox. A report from sub-Saharan Africa required 9 months
of
investigation to establish that rumors of smallpox in several
countries were false.
The smallpox rumor in Mexico illustrates how rumors can be
generated and rapidly spread internationally. Because this case
involved a pustular rash illness associated with high fever
apparently
diagnosed as smallpox by a physician, it was more compelling than
other rumors of second- or third-hand stories of reported smallpox
cases. Prompt reporting, investigation, and diagnosis of all
smallpox
rumors are essential to maintain confidence in global eradication.
WHO Smallpox Eradication Unit. Personal communication.
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