Page 259 - parasitology for medical and clinical laboratoryprofessionals

Organisms Borne by Ticks and Other Vectors 239

A thorough history of recent travels along with a should be consulted immediately. Because some patients
high degree of suspicion may be necessary in order to may develop severe cases of babesiosis, especially when
diagnose babesiosis. Babesiosis may develop in patients the immune system is weak, hospitalization may be re-
who live in or travel to an endemic area, but also is possi- quired for advanced treatment. Those who have a more
ble for those who may have received a blood transfusion severe case of babesiosis are usually treated with one of
contaminated with the causative organism for babesiosis two antibiotics that are administered orally, including
within the previous few weeks. This component of medi- clindamycin or azithromycin. Most people with symp-
cal history is of utmost importance as a number of other toms of babesiosis may be treated with a drug called
infective diseases may be transmitted through blood atovaquone, with oral antibiotics, or with an anti-malarial
transfusions and it is not uncommon for patients to suf- drug called quinine. Those patients without spleens and
fer from more than one infective organism. who develop substantial symptoms and signs may also
Babesiosis may be suspected when a person who require an exchange transfusion of blood in order to re-
has had exposure to an endemic area also develops move infected and damaged blood cells.
persistent fever cycles accompanied by hemolytic ane-
mia. The only definitive diagnostic test for babesiosis to Prevention of Babesiosis
date involves the identification of parasites on a Wrights- During the months of May through September and some-
Giemsa-stained thin blood smear. An observation of times beginning in April and extending past September
“Maltese cross formations” on a stained blood film may in the southern states of the United States, staying away
be presumptively diagnostic of babesiosis and at the from places where ticks are common, such as the edges
same time will rule out malaria when examining blood of woods and fields can be rather effective in prevent-
samples from a patient with symptoms and signs related ing infection with the B. microti organism. The elderly,
to babesiosis. the very young, and those who have had their spleen
The parasites of the Babesia species reproduce in removed or have had an organ transplant should in par-
red blood cells. There they can be seen as cross-shaped ticular avoid areas where ticks are likely to live. These
inclusions where four merozoites produce asexual bud- groups are especially in danger of complications when
ding but are attached together to form a figure similar babesiosis has been contracted.
to that of a “Maltese Cross.” This structural formation The use of a safe and effective insect repellent when
results in hemolysis (destruction) of the red cells, resulting camping or working outdoors, especially in wooded or
in anemia, in a similar manner to that of malaria. But care- grassy places, will help to prevent most tick infestations.
ful scrutiny of multiple blood smears may be required, as Early removal of both roaming and embedded ticks is
B. microti may be easily overlooked because the organism important. A tick must remain attached to the body for
typically infects fewer than 1 percent of the circulating red at least 24 hours before it can transmit the parasite that
blood cells. A reported increase in babesiosis diagnoses in causes babesiosis. For those who spend extended peri-
recent years is thought to be due to more widespread test- ods of time outdoors in areas where ticks live, the body
ing rather than to an actual increase in cases. In addition, should be carefully examined daily for ticks that may
due to better treatment and longer lives for those suffering be moving about the body or those who have become
from immunodeficiencies and a more active lifestyle by embedded. Pets that enter the home should also be
these patients may afford this group more opportunity for examined for both mobile and embedded ticks, as pets
contact with ticks, the disease vector. may also contract babesiosis. Because there are approxi-
mately 80 species of hard ticks and perhaps 10 species
Treatment for Babesiosis of soft ticks, it may be wise to save any ticks found on the
In people who have healthy immune systems and only body. These can be taken to a health care professional
mild cases of babesiosis, no treatment is typically needed. who may be able to identify the species and thus gauge
The body’s immune system is able to effectively and the potential for insect’s harboring of a disease agent.
successfully combat the infection when the general health To remove an attached tick, use fine forceps
of the infected person is adequate. However, in the event (tweezers) to obtain a secure grasp at the head or as
that shortness of breath occurs or if an allergic reaction close to the head as possible and gently pull or tease
begins after an initial dose of antibiotics, the physician the tick from its attachment to the skin. It is not a wise