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Epidemic typhus is caused by:

A. Rickettsia typhi

B. Rickettsia felis

C. Rickettsia prowazeckii

D. Bartonella quintana

E. Both A and B

C. The causative organism in epidemic typhus is Rickettsia prowazeckii. The vector is Pediculus humanus corporis (body louse). In contrast to epidemic typhus, Xenopsylla cheopis has been considered the classic vector of endemic typhus which is caused by Rickettsia typhi and Rickettsia felis. Endemic typhus has emerged as more common in South Texas, where the vector is Ctenocephalides felis and oppossums serve as a disease reservoir.

Body lice carry:

A. Epidemic typhus

B. Trench fever

C. Relapsing fever

D. Bacillary angiomatosis

E. All of the above

E. While head and pubic lice are not clearly linked to the spread of disease, body lice are important disease vectors, especially in refugee populations. They carry epidemic typhus, trench fever, relapsing fever, and the bacillary angiomatosis organism. When transmitted by a louse, the latter organism is more likely to cause endocarditis.

Sand flies are vectors in which disease(s):

A. Leishmaniasis

B. Oroya fever

C. River blindness

D. Loa loa

E. Both A and B

E. Sand flies (Lutzomyia and Phlebotomus species) serve as vectors for Leishmaniasis and Oroya fever. River blindness (onchocerciasis) and Loa loa (loiasis) are filarial diseases carried by black flies and deer flies, respectively.

The first stage of sleeping sickness is characterized by a (an):

A. Chancre

B. Buboe

C. Lymphadenitis

D. Persistent fever

E. Enlargement of the spleen

A. The organisms that cause sleeping sickness are related to those that cause leishmaniasis. Both produce chancriform lesions. Sleeping sickness also causes urticaria, pruritus, facial edema, fever, and arthralgias, CNS manifestations occur in the second phase of illness.

Mosquitoes are not the vector for:

A. Filariasis


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