Between April 21 and June 17, 1983, 16 human plague cases,
resulting from exposure to wild-rodent plague, were reported in the
western United States (Table 2). The plague season began with two
cases reported in late April, two in the first 2 weeks of May, four
in
the last 2 weeks of May, and eight in the first 2 weeks of June.
Four patients (25%) have died, two (13%) have contracted
secondary
plague pneumonia, and at least two (13%) have become septicemic.
Disease has not spread to contacts of patients with plague
pneumonia,
and no cases of primary pneumonic plague have occurred. Nine
patients
were American Indians, three (33%) of whom died; seven were
Caucasians, accounting for one (14%) fatality. Eight patients were
under 20 years old (three fatalities), four were 21-50 years old,
and
plague pneumonia, and at least two (13%) have become septicemic.
Disease has not spread to contacts of patients with plague
pneumonia,
and no cases of primary pneumonic plague have occurred. Nine
patients
were American Indians, three (33%) of whom died; seven were
Caucasians, accounting for one (14%) fatality. Eight patients were
under 20 years old (three fatalities), four were 21-50 years old,
and
four were over 50 years old (one fatality). Thirteen patients were
male.
Seven patients each were exposed to wild-rodent plague in
Arizona
and New Mexico, and one each, in Utah and Oregon. Although most
patients were exposed in areas reporting plague in previous years,
three acquired infection in locations where human plague has not
previously been reported--the southwestern quadrant of New Mexico
(one
case) and north central Arizona near Lake Powell (two cases).
Surveillance for evidence of wild-rodent plague indicates
increased levels of activity in many areas of Arizona, New Mexico,
Nevada, Utah, California, and Oregon. Animal plague also has been
detected in Colorado, Wyoming, western Texas, and Washington.
Wyoming
is currently experiencing a widespread plague epizootic among
ground
squirrels in and near Cheyenne.
Reported by Respective state health depts; Plague Br, Div of
Vector-Borne Viral Diseases, Center for Infectious Diseases, CDC.
Editorial Note
Editorial Note: The large number of plague cases this season
appears
to reflect widespread epizootic plague in 10 western states.
Unseasonably cool, moist weather in the western United States early
in
1983 appears to have resulted in longer survival for infective
fleas,
thus extending the plague season in areas where it normally would
have
subsided earlier.
Human plague infections occur most frequently in the
southwestern
states, particularly northern New Mexico, northeastern Arizona,
southern California, Colorado, and southen Utah because of
sociocultural factors that increase human exposure to the
rodent/flea
environment and the propensity for fleas of certain wild rodents to
bite humans. Clinicians in the other western states should
maintain a
high degree of suspicion when a compatible clinical/ epidemiologic
syndrome is seen, despite the apparent paucity of cases in these
states. Physicians in nonendemic areas in the eastern two-thirds
of
the United States should consider plague in the differential
diagnosis
for febrile patients who have recently traveled to the western
states. If plague is reasonably included in the differential
diagnosis, acute-phase serum and blood and other appropriate
specimens
for culture should be obtained. Oral tetracycline is effective
early
in the course of illness and in relatively uncomplicated bubonic
plague cases. Streptomycin is the drug of choice for inpatient
therapy. If intravenous antibiotics are indicated, as for
hypotensive
patients, gentamicin or chloramphenicol are preferred. When
outpatient treatment is given, the patient should be followed
actively
for 1-3 days to ensure he has responded satisfactorily and to mount
an
appropriate public health response if laboratory tests support the
diagnosis of plague.
In response to the current increase in plague in wild rodents
and
humans, public health authorities are initiating a number of
preventive measures. These include: 1) educating the public to
avoid
sick or dead rodents and rabbits, to avoid burrows, to deflea
household pets (cats and dogs) that can transport fleas of wild
rodents to humans, and to eliminate trash, which can harbor
rodents,
near living areas; 2) conducting surveillance for evidence of
wild-rodent plague; 3) dusting with insecticides to eliminate
wild-rodent fleas in populated, residential, or recreational areas
where plague is found or appears active. Suspected cases of human
or
animal plague should be reported to CDC through state and local
health
departments.
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