Question 1

MATCHING&#10;Match the organism with the vector of transmission.Answers may be used more than once.&#10;a.Tabanid fly&#10;b.Biting midges&#10;c.Anopheles mosquito&#10;d.Black fly&#10;Mansonella spp.

Accepted Answer

Mansonella spp. is transmitted by biting midges.

Question 2

A 36-year-old man who has been traveling through the orient is experiencing a tender region in the inguinal region.A blood film is made,and sheathed microfilariae with four to five subterminal nuclei and two terminal nuclei in the tail are identified using Giemsa stain.The organism is most likely:

A)W.bancrofti.
B)Onchocerca volvulus.
C)Loa loa.
D)Brugia malayi.

Accepted Answer

B.malayi is the most likely organism.The Brugia spp.are distributed throughout the Far East,including China,Indonesia,Korea,Malaysia,Japan,India,and the Philippines.The B.malayi microfilariae are sheathed and contain four to five subterminal nuclei and two terminal nuclei in the tail.

Question 3

MATCHING&#10;Match the organism with the vector of transmission.Answers may be used more than once.&#10;a.Tabanid fly&#10;b.Biting midges&#10;c.Anopheles mosquito&#10;d.Black fly&#10;L.loa

Accepted Answer

L.loa is transmitted by the Tabanid fly.

Answer: D
 L.loa is also transmitted by the black fly.

Question 4

Chyluria is a result of lymphatic rupture and fluid entering the urine.Another lymphatic condition caused by W.bancrofti is:&#10;A)calabar swelling.&#10;B)elephantiasis.&#10;C)river blindness.&#10;D)pruritic rash.

Accepted Answer

Chyluria is a result of the lymphatic rupture and fluid entering the urine in infections caused by W.bancrofti.The urine appears milky white.The resulting infection and changes in the skin may increase bacterial infections.W.bancrofti causes Bancroftian filariasis and elephantiasis,which is a crippling condition that is a result of extended periods of filarial infection.The adult worm resides in the lymphatic vessels distal to the lymph nodes.The obstruction of the lymphatic vessels results in fibrosis and a proliferation of dermal and connective tissue,resulting in the wrinkled,dry appearance of an "elephant" extremity.Lymphedema may also occur in the arms,female breasts,and scrotum of infected men.

Question 5

A Giemsa stain is performed on an eye exudate on a patient with calabar swelling,eosinophilia,and a recent travel history to Africa.L.loa is suspected;however,the sheath in the adult worm recovered does not stain.Which one of the following statements explains this discrepancy?

A)The worm recovered is not L.loa.
B)The specimen should have been stained with trichrome stain.
C)The Giemsa stain is most likely expired.
D)No discrepancy is present.The sheath does not stain with Giemsa stain.

Accepted Answer

The identification of the adult worm from the eye,in tissue,or in the peripheral blood provides a definitive diagnosis.The L.loa organism contains a sheath that does not stain with Giemsa.The adult females are larger than the adult males.The nuclei extend to the tail in an irregularly arranged fashion.

Question 6

MATCHING&#10;Match the organism with the vector of transmission.Answers may be used more than once.&#10;a.Tabanid fly&#10;b.Biting midges&#10;c.Anopheles mosquito&#10;d.Black fly&#10;Brugia spp.

Accepted Answer

Brugia spp., which causes lymphatic filariasis, is transmitted by mosquitoes, including the Anopheles species.

Question 7

The definitive host and reservoir for Wuchereria bancrofti is:&#10;A)mosquito.&#10;B)microfilaria.&#10;C)humans.&#10;D)tabanid fly.

Accepted Answer

W.bancrofti is the most common identified species of filarial worms that infect humans.The mosquito vectors have complex life cycles that include laying eggs and the development of larvae on the surface of a water source.When the larvae mature into adult mosquitos,the male and females swarm in the evening and mate.The female requires feeding on a blood meal to reproduce.The mosquito becomes the intermediate host for the microfilaria parasite.Humans are the definitive host and the reservoir for W.bancrofti.

Question 8

MATCHING&#10;Match the organism with the vector of transmission.Answers may be used more than once.&#10;a.Tabanid fly&#10;b.Biting midges&#10;c.Anopheles mosquito&#10;d.Black fly&#10;W.bancrofti

Accepted Answer

Anopheles mosquito is the vector of transmission for W. bancrofti.

Answer: B
 Biting midges are the vector of transmission for W. bancrofti.

Answer: D
 Black fly is the vector of transmission for W. bancrofti.

Question 9

MATCHING&#10;Match the organism with the vector of transmission.Answers may be used more than once.&#10;a.Tabanid fly&#10;b.Biting midges&#10;c.Anopheles mosquito&#10;d.Black fly&#10;O.volvulus

Accepted Answer

O. volvulus is transmitted by the black fly.

Answer: A
 Tabanid flies can also transmit O. volvulus, but it is less common than transmission by black flies.

Question 10

A skin snip is performed,and microfilariae with tapered tails,no nuclei,and unsheathed are microscopically observed.The recommended therapy for this infection is:&#10;A)ivermectin.&#10;B)diethylcarbamazine.&#10;C)antihistamines.&#10;D)mebendazole.

Accepted Answer

The organism is O.volvulus.Definitive diagnosis is made with the identification of the adult worm from tissue such as in a nodule or skin snip.The microfilaria lacks a sheath.The tail is tapered,appears bent or flexed,and does not include nuclei .Ivermectin is the recommended treatment.

Deck 51: Blood Nematodes