Page 493 - Review of Medical Microbiology and Immunology ( PDFDrive )

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PART VI Parasitology
482

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(Source: Dr. Alexander J. da Silva and Melanie Moser, Centers for Disease Control and Prevention.) mebooksfree.com

FIGURE 56–16
Wuchereria bancrofti. Life cycle. Right side of figure describes the stages within the human (blue arrows). Humans are
infected at step 1 when mosquito bites human and larvae enter blood stream. Adult Wuchereria worms are formed in lymphatics. Mosquito is
infected at step 4 when it ingests microfilariae in human blood. Left side of figure describes the stages within the mosquito (red arrows).

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Tropical pulmonary eosinophilia is characterized by
coughing and wheezing, especially at night. These symp-
Diethylcarbamazine is effective only against microfilariae;
toms are caused by microfilariae in the lung that elicit an
no drug therapy for adult worms is available. Treatment of
immediate hypersensitivity reaction characterized by a
patients with Wuchereria (and Onchocerca) infections with
high IgE concentration and eosinophilia.
doxycycline to kill Wolbachia results in a significant
decrease in the number of microfilariae in the patient.
Epidemiology
This disease occurs in the tropical areas of Africa, Asia, and
Latin America. The species of mosquito that acts as the
Prevention involves mosquito control with insecticides and
vector varies from area to area. Altogether, 200 to 300 mil- Prevention
the use of protective clothing, mosquito netting, and
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lion people are infected.
repellents.
Laboratory Diagnosis
Thick blood smears taken from the patient at night reveal
Disease
the microfilariae (see Figure 56–18). Serologic tests are not
Onchocerca volvulus causes onchocerciasis.
useful.

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