Filariae Flashcards
Where does the filariae adult worms live?
Tissue or Lymphatic system
Two known morphologic forms of Filariae?
- Adult worms
2. Larva Stage: Microfilaria
Adult filariae produce larvae called what? And where it is usually detected?
Microfilariae; Blood
What is the morphologic structure of the adult filariae?
Creamy white and a Threadlike appearance
Size of adult worms
Male: 20-500 mm in length; Female: half of it
Morphologic form of microfilariae
slender
What are the two key characteristics that are helpful in speciating the microfilariae forms?
- Distribution of nuclei within the tip of the tail
2. Presence or absence of a delicate transparent covering known as sheath
How many are injected by an infected arthropod at the feeding site, are required to initiate human infection?
One to four infected larvae
Resulting adult worms may reside where?
Lymphatics
Subcutaneous tissue
Internal body cavities
Definitive host of Filariae
Adult sexual phase/ development of the parasite
Intermediate host of filariae
Larval phase of the parasite
A phenomenon whereby the parasites are present in the bloodstream during a specific time period; helpful in selecting the appropriate time for specimen collection
periodicity
Nocturnal periodicity
Night (9pm-4am)
Diurnal
During the day (10:15am-2:15pm)
Subperiodic
timing of occurrences not clear-cut (depends on the corresponding vector’s feeding schedule
Primary method of filarial diagnosis in microscopic examination of the microfilariae
Giemsa-stained smear of blood or tissue scraping of an infected nodule
True about Wuchereria bancrofti? (Bancrofti’s Filaria)
I. 240-300um long
II. Culex ______ Anopheles
III. Sheath ________
IV. Tip of tail is ___________
V. _________ Appearance Females are larger
Nocturnal Periodicity (__pm-___am)
Aedes PRESENT nuclei- free White Thread-like Nocturnal Periodicity (9pm-4am)
True about Brugia malayi? (Malayan Filaria)
I. 200-280um long
II. Aedes Anopheles ________
III. Sheath _________
IV. Two distinct in the tip of tail; ________
V. Resembles mostly like _______
___________- periodicity
Mansonia PRESENT bulges W. Bancrofti Nocturnal Sub-
True about Loa loa? (Eye Worm) I. 248-300um long II. \_\_\_\_\_\_\_ III. Sheath \_\_\_\_\_\_ IV. Distinct \_\_\_\_\_\_\_ row of nuclei, \_\_\_\_\_\_\_ to tip of tail V. \_\_\_\_\_\_\_\_ Females are larger \_\_\_\_\_\_\_\_ Periodicity (10:15am-2:15pm)
II. Chrysops Fly III. Sheath IV. continuous, extends V.. Females are larger Diurnal (10:15am-2:15pm)
True about Onchocerca volvulus? (Blinding Filaria) I. 150-355um long II. \_\_\_\_\_ spp. (Black Fly) III. Sheath is ABSENT IV. \_\_\_\_\_\_\_ to the tip of the tail IV. \_\_\_\_\_\_\_\_\_\_\_ up in knots in skin nodules Females are larger Causing \_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_\_ Found in Sub-Q tissue
II. Simulium spp. (Black Fly) III. ABSENT IV. Does not extend IV. Thin (Wirelike) Coil River Blindness
True about Mansonella ozzardi? (New World Filaria)
I. 220um in length
II. ________ or Simulium
III. Sheath is _________
IV. _________ nuclei, does not extend to tip of tail
V. Location of adults in humans is __________
Found in _______ ________
_____ Periodicity
I. 220um in length II. Culicoides III. ABSENT IV. Numerous nuclei, does not extend to tip of tail V. unknown blood specimen No Periodicity
True about Mansonella perstans (Perstans Filaria)
I. About 200um in length
II. _______
III. Sheath is _________
IV. ________, extend to tip of tail
V. Resides in _________ and ________ cavities, as well in __________
I. About 200um in length II. Culicoides III. ABSENT IV. Numerous V. peritoneal and pleural cavities, as well in Mesentery
Speciation of the microfilariae can be done by recognition of the distribution of nuclei in the tip of the tail and the presence ore absence of a delicate transparent covering known as the?
Sheath
What type of periodicity is exhibited if microfilariae appear in the blood of an individual at 2:00 P.M. each day?
Diurnal
Which of the following is similar for all microfilariae discussed? A. Presence of sheath B. Ability to exhibit periodicity C. Location of the adult worms D. The basic life cycle
The basic life cycle
Diagnosis of infection with Wuchereria bancrofti is best accomplished with?
Examination of stained peripheral blood taken during the night
What drug, in combination with albendazole, has proven to be an important drug for the treatment of Bancrofti’s filariasis?
Ivermectin
What can be used in the differentation and identification of Brugia malayi?
Presence of two terminal nuclei in the tail
Ideal time period to collect blood samples for examination for the presence of the microfilariae of Brugia malayi?
10:00 pm to 4:00 am
A small threadlike worm is observed under the conjunctiva of the eye. What organism is most likely?
Loa loa adult
What type of periodicity does Loa loa exhibit?
Diurnal
How do the microfilariae of Onchocerca volvulus differ from those of other filarial?
They are found in the skin rather than blood
Skin snips are the specimen of choice for diagnosis of infection with?
Onchocerca volvulus
How are the microfilariae of Mansonella ozzardi differentiated from those of Onchocerca volvulus?
Location of the microfilariae
Which of the following filarial drugs is effective against Mansonella ozzardi if therapy is necessary?
Diethylcarbamazine
If a physician suspects an individual has the potential for an infection with Mansonella perstans, what specimen type would you suggest for recovery of the organism?
Blood
What type of periodicity does Mansonella perstans exhibit?
None
You live by a fast moving river in Eastern Africa. What filarial nematodes poses the greatest risk of infection for you?
Onchocerca volvulus
What filarial nematodes is known as the blinding filaria?
Onchocerca volvulus
The microfilariae of Brugia malayi are recognized by the?
presence of a sheath and two distinct terminal nuclei in the tail
What filarial nematodes uses the mosquito as its vector?
Wuchereria bancrofti
Swelling of the lower extremities due to obstruction of the lymphatic system by adult filarial nematodes is known as?
Elephantiasis
All of the following microfilariae lack a sheath except? A. Mansonella ozzardi B. Mansonella perstans C. Onchocerca volvulus D. Brugia malayi
Brugia malayi
Diagnosis of infection with Wuchereria bancrofti can be accomplished by all of the following methods except? A. Serologic testing B. Tissue Biospies C. Knott technique D. Thick and thin peripheral blood smear
Tissue biopsies
What filarial nematode is transmitted by the Chrysops fly?
Loa loa
What filarial nematode infections is diagnosed by using skin snips rather than a peripheral blood smear?
Onchocerca volvulus
If an individual was planning to visit Africa, what filarial nematodes would NOT be a concern for potential infection?
Brugia malayi
