Epidemiologic Notes and Reports
Babesiosis -- Connecticut
Since August 1988, six cases of babesiosis--a rare protozoan
parasitic
disease-- have been reported to the Connecticut Department of
Health
Services (CDHS); only two cases thought to have been acquired in
Connecticut were reported before 1988.
The first person became ill in August 1988; onset of illness in
the
other five persons occurred between late June and mid-August 1989.
Ages
ranged from 68 to 86 years; five were men. All six persons had
fever,
headache, and fatigue. Two of the patients were taking oral
corticosteroids for chronic obstructive pulmonary disease; none
were
otherwise immunosuppressed, and none were asplenic. Four patients
were
treated with both quinine and clindamycin; one received quinine
without
clindamycin; the sixth received no specific therapy for babesiosis.
All
six are now asymptomatic, and their parasitemia has cleared.
Five of the patients (including the first case-patient) lived
within 3
miles of each other; the sixth lived 22 miles away. None of the
patients gave a history of recent travel to areas with known
endemic
babesiosis, and none had received blood transfusions before
becoming
ill. Gardening near the home was the principal outdoor activity of
four
persons; the other two walked in fields near their homes. Only one
person recalled being bitten by a tick before becoming ill, and all
six
had observed mice in the areas around their homes.
For all six persons parasites were detected on peripheral blood
smears. In addition, each had IgG antibody titers to Babesia
microti of
greater than or equal to 1:1024. B. microti was isolated (by
hamster
inoculation) from the blood of two patients and from eight (73%) of
11
mice trapped near four of the patients' homes. A statewide survey
conducted in 1976-77 detected B. microti antibodies in mice
collected
in four of 22 sites (1). Three of these four sites are within 20
miles
of five of the patients' homes and within 45 miles of the other
patient's home.
The CDHS has alerted Connecticut physicians to the presence of a
newly
recognized focus of babesiosis within the state and has advised
physicians to report all suspected cases. Surveys are planned to
determine the extent of the infection in humans and rodents.
Reported by: JJ Gadbaw, MD, Lawrence and Memorial Hospital, New
London;
JF Anderson, PhD, Connecticut Agricultural Experiment Station, New
Haven; ML Cartter, MD, JL Hadler, MD, State Epidemiologist,
Connecticut
Dept of Health Svcs. Div of Parasitic Diseases, Center for
Infectious
Diseases; Div of Field Svcs, Epidemiology Program Office, CDC.
Editorial Note
Editorial Note: Babesia is a protozoan parasite of red blood cells.
In
the United States, babesiosis is most commonly caused by B.
microti.
Babesiosis was recognized in the Northeast in the 1960s and is
endemic
in Nantucket, Martha's Vineyard, Shelter Island, and parts of Long
Island (2).
In humans, B. microti infection may be subclinical or may present
as a
febrile illness with constitutional symptoms and anemia.
Manifestations
are most severe in elderly, immunosuppressed, or asplenic persons
(3).
The natural hosts for B. microti include the white-footed mouse
and
the meadow vole. Tick bite by Ixodes dammini is the usual source of
human infection. In addition, infection can be transmitted by blood
transfusion (3). Entomologic surveys have detected increases in I.
dammini and its spread to new areas (4). Physicians should be aware
that babesiosis could occur in areas where Babesia was not
previously
considered endemic.
References
Anderson JF, Magnarelli LA, Kurz J. Intraerythrocytic parasites
in
rodent populations of Connecticut: Babesia and Grahamella species.
J
Parasitol 1979;65:599-604.
Golightly LM, Hirschhorn LR, Weller PF. Fever and headache in a
splenectomized woman. Rev Infect Dis 1989;11:629-37.
Ruebush TK III. Babesia. In: Mandell GL, Douglas RG Jr, Bennett
JE,
eds. Principles and practice of infectious diseases. 2nd ed. New
York:
Wiley, 1985:1559-60.
Spielman A, Wilson ML, Levine JF, Piesman J. Ecology of Ixodes
dammini-borne human babesiosis and Lyme disease. Annu Rev Entomol
1985;30:439-60.
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