Part 2

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Bug Vectors - Ticks and Human Babesiosis continued...

[infect Med 16(5):319-320, 326, 1999. © 1999 SCP Communications,

Inc.]

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Clinical and Laboratory Findings

Babesiosis is clinically very similar to malaria. In fact,

confusion between the two diseases is often reported in the

scientific literature.[7] Headache, fever, chills, nausea,

vomiting, myalgia, altered mental status, disseminated

intravascular coagulation, anemia with dyserythropoiesis,

hypotension, respiratory distress, and renal insufficiency are

common to both diseases. However, symptoms of babesiosis do not

show periodicity. The incubation period varies from 1 to 4 weeks.

Physical examination of patients is generally unremarkable,

although the spleen and liver may be palpable. Laboratory

findings may include hemoglobinuria, anemia, and elevated serum

bilirubin and transaminase levels.[2,5]

Diagnosis of babesiosis is based on recognition of the organism

within erythrocytes in Giemsa- or -stained blood smears.

They vary in size from 1-5µ in length. B divergens is slightly

larger (4µ x 1.5µ) than B microti (2µ x 1.5µ). The small

parasites, several of which may infect a single red blood cell,

appear much like Plasmodium falciparum; they can be

differentiated from malarial parasites by the absence of pigment

(hemozoin) in Babesia-infected erythrocytes.[2] Laboratory

animals may be useful in diagnosis of babesiosis as well.

Specialized laboratories have the capability to inject patient

blood into hamsters and subsequently to detect parasitemias 2 to

4 weeks after inoculation. Indirect fluorescent antibody (IFA)

tests can be used to detect specific antibodies in patient serum.

Serologic diagnosis is established by a four-fold or greater rise

in the serum titer between the acute phase and the convalescent

phase.

continued...