Life Cycle
Babesiosis is similar to malarial infections except for
a fever cycle, and some call the disease the “malaria of
the northeast.” As in malaria, the parasites of the Babesia
species reproduce inside red blood cells. There they
can sometimes be cross-shaped inclusions where four
merozoites are asexually budding but are attached together
to form a figure similar to that of a Maltese cross.
This distortion of the red blood cells results in hemolysis
(destruction) of the red blood cells, which produces anemia
in a manner similar to that of malaria. Asexual reproduction
takes place in human or other mammalian hosts
and sexual reproduction occurs in the vector (several species
of the ixodid tick). Because the sexual reproductive
stage takes place within the tick, this is where the infective
sporozoites are formed. The infective stage involving
sporozoites are then injected into the host during the
blood meal of the tick. These injected organisms spread
throughout the circulatory system and invade RBCs (red
blood cells) where they undergo asexual reproduction
and form intracellular ring forms that approximate those
of the Plasmodium (malarial) genus. However, gametocytes
are not visible in the peripheral blood in the manner
they are in malarial infections.
Disease Transmission
Babesia organisms are spread chiefly by the ixodid tick
Ixodes scapularis, the same vector for Lyme disease,
although a number of species are capable of transmitting
the Babesia organisms. A tick must be embedded
for at least 12 hours before transmission takes place, so
daily body surveys are necessary to avoid infection. The
disease is rarely fatal and is usually resolved without
treatment.
Laboratory Diagnosis
Just as in the case of the better-known Lyme disease, the
organism for babesiosis, regardless of species, is spread
chiefly by deer ticks except for blood transfusions from
asymptomatic carriers. The disease requires several
Babesiosis is similar to malarial infections except for
a fever cycle, and some call the disease the “malaria of
the northeast.” As in malaria, the parasites of the Babesia
species reproduce inside red blood cells. There they
can sometimes be cross-shaped inclusions where four
merozoites are asexually budding but are attached together
to form a figure similar to that of a Maltese cross.
This distortion of the red blood cells results in hemolysis
(destruction) of the red blood cells, which produces anemia
in a manner similar to that of malaria. Asexual reproduction
takes place in human or other mammalian hosts
and sexual reproduction occurs in the vector (several species
of the ixodid tick). Because the sexual reproductive
stage takes place within the tick, this is where the infective
sporozoites are formed. The infective stage involving
sporozoites are then injected into the host during the
blood meal of the tick. These injected organisms spread
throughout the circulatory system and invade RBCs (red
blood cells) where they undergo asexual reproduction
and form intracellular ring forms that approximate those
of the Plasmodium (malarial) genus. However, gametocytes
are not visible in the peripheral blood in the manner
they are in malarial infections.
Disease Transmission
Babesia organisms are spread chiefly by the ixodid tick
Ixodes scapularis, the same vector for Lyme disease,
although a number of species are capable of transmitting
the Babesia organisms. A tick must be embedded
for at least 12 hours before transmission takes place, so
daily body surveys are necessary to avoid infection. The
disease is rarely fatal and is usually resolved without
treatment.
Laboratory Diagnosis
Just as in the case of the better-known Lyme disease, the
organism for babesiosis, regardless of species, is spread
chiefly by deer ticks except for blood transfusions from
asymptomatic carriers. The disease requires several
