"Babesia Infection In Humans"
Infection of humans in the U.S. with Babesia organisms has been
reported as early as 1957. Increased numbers of cases, however,
have occurred since that time in Nantucket Island and Martha's
Vineyard in Massachusetts, Shelter island, New York as well as in
Wisconsin. The causative agent has been Babesia microti, a normal
parasite of small mammals transmitted by Ixodes scapularis ticks.
Recently, possible cases have been seen in the south-central
states. Patients that have been splenectomized or are
immunocompromized are especially susceptible to infection. Recent
findings in the Pacific Northwest indicate that a species of
Babesia that appears to be distinct from B. microti has been
involved in human cases. The epidemiology of this parasite is still
under investigation.
Clinical signs of human babesiosis mimic mild cases of malaria,
appearing as a hemolytic anemia. Diagnosis is based on observing
the organism in stained blood film.
Treatment with chloroquine has been reported effective although
not completely tested. Tick control and prevention of infestation
appears to be the best method of preventing infection.
This report and the one featured below are from research
not performed by Dr. Emerson, but found through internet
search. The authors of these articles were not
indentified. To my knowledge, all other authors are
identified.
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Babesia is a tick transmitted protozoan parasite that can cause
MALARIA-LIKE symptoms and HEMOLYTIC anemia. Asplenic, elderly, and
immunocompromized patients are at greatest risk for severe disease;
however babesiosis can be serious in immunologically normal
persons. Babesiosis is emerging as a disease of public health
significance in the U.S.A, with increased reports of clinical, even
fatal, cases in areas where the risk of infection with Babesia was
not recognized previously. Until recently, human Babesia infections
in this country have been attributed to Babesia microti, derived
from rodents. There is increasing evidence to suggest that human
babesiosis in the U.S.A may be caused by Babesia parasites that are
antigenically and genotypically distinct from Babesia
microti.
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DIVERSITY OF BABESIA INFECTING DEER TICKS
(IXODES DAMMINI)
Philip M. Armstrong, Paula Katavalos, Diane A. Caporale, Robert
P. Smith, Andrew Spielman and Sam R. Telford III
Department of Tropical Public Health, Harvard School of Public
Health, Boston, Massachusetts; Research Department, Maine Medical
Center, Portland, Maine
Abstract.
To determine whether the presence of nonpathogenic piroplasms
may confound field estimates of risk of Babesia microti infection,
we identified sporozoites infecting the salivary glands of deer
ticks (Ixodes dammini) by parallel microscopy and polymerase chain
reaction assays.
Piroplasms were evident in 14.4% of adult ticks from sites in
the northcentral and northeastern United States. Of these, 83.3%
contained DNA characteristic of Ba. odocoilei. This cervid
piroplasm was detected in all of the sites examined and generally
was more prevalent than was Ba. microti. Because deer ticks
transmit both Ba. odocoilei and Ba. microti, estimates of pathogen
prevalence based solely on microscopy may overestimate the risk of
human babesiosis.
