Filariasis

Question 1

The Guinea worm

Answer 1

Dracunculus medinensis

• life cycle =no vector
• treatment= pull worm out through hole in skin

Question 2

Filariasis

Answer 2

• four moults
• ovoviviparous
• 9 species of filarial nematodes use humans as the definitive host

Question 3

3 groups according to the niche they occupy

Answer 3

1. LYMPHATIC filariasis - lymphatic system (can cause elephantiasis)
2. Subcutaneous filariasis (African eye worm, Guinea worm, riverblindness)
3. Serous cavity filariasis -serous cavity of abdomen

Question 4

Lymphatic filariasis

Answer 4

• lifecycle involves mosquito, sheathed microfilariae that reach blood stream in humans
• in mosquito–> penetrate midgut, migrate to thoracic muscles
• migrate to mosquitos head

Question 5

Wuchereria and Brugia

Answer 5

• microfilaria are sheathed

- are periodic depending on time of day

Question 6

Filiarsis is a spectral disease (3)

-transgenerational effects

Answer 6

• Microfilaria +ve - usually asymptomatic, defective Tcell proliferative responses
• Chronic Pathology - normal proliferative response- Disease
• Endemi normal - no or very low level infection

Question 7

Wolbachia

Answer 7

• bacterial endosymbiont of many spp of filarial nematode
• killing wolbachia (using tetracycline) sterilizes the worms
• wolbachia essential for worm fertility/viability/survival

Question 8

DRUGS for killing adult lumphatic filarial worms

Answer 8

• Albendazole comb. with invermectin
• Albendazole comb. with diethylcarbamazine (DEC)
• Tetracyclines

Question 9

RIVER BLINDNESS

Answer 9

-insect vector = Simulium damnosum(Dipteran fly), requires oxygenated water for larvae

Question 10

River blindness (Onchocerciasis)

Answer 10

-dipteran fly takes blood meal and L3 larvae enter bite wound
-adults in subcutaneous nodules (humans)
-adults produce unsheathed microfilariae (–>tissues and blood)
-dipteran fly takes blood meal and ingests microfilariae
-migrate to midgut, thoracic muscles and then head of the fly
cont.

Question 11

Other skin manifestations of onchoceriasis

Answer 11

• sowda
• leopard skin
• elephant skin

Question 12

Drugs for Onchocerciasis control

Answer 12

• DEC
• invermectin
• tertracyclin-sterilizes adult F

Question 13

Loa loa - Calabar swellings, African eyeworm

Answer 13

• adults produce sheathed microfilariae that are found in spinal fluid, blood and lungs
• unable to tolerate invermectin therefore no effective treatment for river blindness