Filiarial Worms

Question 1

What is the epidemiology of Lymphatic Filariasis?

Answer 1

Sub-Saharan Africa
South East Asia
Small pockets of South America
Increased incidence age
120 million cases
2nd commonest cause of disability worldwide

Question 2

What are the parasites that cause Lymphatic Filariais?

Answer 2

Wuchereria Bancrofti
Brugia Malayi
Brugia Timori

Question 3

What vectors are associated with W. Bancrofti?

Answer 3

Anopheles, Culex, Adaes, Mansoni

Question 4

What vectors are associated with Brugia Malayi

Answer 4

Mansoni

Question 5

What is the periodicity of Brugia Malayi?

Answer 5

Some have nocturnal periodicity
Some have sub-periodic periodicity

Question 6

Which parasite of Lymphatic Filariasis also infects animal hosts like monkeys, cats

Answer 6

Brugia Malayi

Question 7

What is the most prevalent Parasite of Lymphatic Filariasis?

Answer 7

Wuchereria Bancrofti (90% of cases)

Question 8

What bacteria has a symbiotic relationship with LF and Onchocerciasis?

Answer 8

Wolbachia

Question 9

What is the lifecycle of Lymphatic Filariasis?

Answer 9

L3 Larva –> Enter into lymphatics –> Sheathed microfilariae which live in blood and lymphatics –> taken up by mosquito at a further feed –> Enter into the mosquito gut and develop into L1 larvae –> L3 larvae in the probiscis, ready for the next feed

Question 10

What is the pathophysiology of lymphatic filariasis and scarring?

Answer 10

Adult filarial worms provoke huge inflammatory responses when they die –> Granuloma formation and lymphatic scarring –> Lymphangitis and Lymphadenitis

Question 11

How does Lymphatic Filariasis present?

Answer 11

Most cases are asymptomatic

Filarial Fever (occurs when adult worms are dying):
- Acute lymphadentitis
- Fever
- Lymphoedema
- Pulmonary eosinophilia (microfilariae in the blood tend to hang out in the pulmonary vasculature)

Question 12

How do you diagnose LF?

Answer 12

Lymph Node Aspirate and serum microscopy
(Periodic samples required)

VEGF (not used clinically, but in studies has been shown as a good way of determining the extent of lymphatic involvement

Rapid Antigen Diagnostic test (only works for W. Bancrofti)

Question 13

How do you manage lymphatic filariasis?

Answer 13

DEC (6mg/kg for 12/7)
+ Ivermectin 150mcg/kg
+ Albendazole 400mcg
+ Doxycyline 200mg/d for 6 weeks

Question 14

What part of the lifecycle does DEC target?

Answer 14

Marco and Microfilariae

Question 15

What part of the lifecycle does Ivermectin treat?

Answer 15

Microfilariae

Question 16

If you cannot use DEC due to concurrent Onchocerciasis infection, how does your management change?

Answer 16

Doxycycline + Ivermectin + Albendazole

Ivermectin needs to be repeated for at least 10 years as it does not target adult worms

Question 17

There has been lots of work in recent years to try and eliminate LF. What measures are recommended?

Answer 17

Vector Control
MDA
MMDP (morbidity management and disability prevention)

Question 18

What WHO programme is focused on Lymphatic Filariasis?

Answer 18

GPELF: Global program for elimination of Lymphatic Filariasis

Question 19

What is the recommended MDA in:

• Areas with LF with no risk of Onchocerciasis or Loiasis

Answer 19

Annual:
DEC (6mg/kg stat) + Albendazole (400mg stat)

Question 20

What is the recommended MDA in:
- Areas with LF and Onchocerciasis

Answer 20

*** DEC cannot be used in Onchocerciasis, as causes rapid macrofilarial death and inflammatory response –> Blindness

SO

Ivermectin + Albendazole Annually

Question 21

What is the recommended MDA in areas of Lymphatic Filariasis and Loiasis?

Answer 21

Albendazole

**Rapid macrofilarial death from DEC can be harmful in Loiasis

**Ivermectin is assocaited with meningoencephalitis and cannot be used

Question 22

What is onchocerciasis?

Answer 22

River Blindness

Question 23

What is the epidemiology of Onchocerciasis

Answer 23

• River breeding sites
• M > F (fishermen)
• West and central africa

Question 24

What is the parasite in Onchocerciasis?

Answer 24

Onchocerca Volvulus

Question 25

What is the vector in Onchocerciasis?

Answer 25

Black Fly (Simulium spp)

Question 26

How big can adult female onchocerca be?

Answer 26

up to 80cm thats bloody mental

Question 27

What bacteria co-infects onchocerca volvulus and acts commensally to make its life cycle more efficient

Answer 27

Wolbachia

Question 28

What is the pathophysiology of Onchocerciasis?

Answer 28

disease symptoms occur when there is macrofilarial death –> large inflammatory response. Macrofilarial death is what leads to eye blindness

Question 29

What is the lifecycle of Onchocerca Volvulus

Answer 29

L3 Larva injected by black fly –> enters in subcutaenous tissue –> released microfilariae –> re-ingested by black fly at further feed

Question 30

How long can onchocerca worms live for?

Answer 30

12-18 months

Question 31

How does Onchocerciasis present?

Answer 31

Skin changes –> Leopard skin, Lizard Skin, Pruritis, inflammation and ‘troublesome itch’
Punctate and sclerosing ketatitis
Sowda
Hanging Groin
Nodding Syndrome (epilepsy)
Hypopituitary disease

Question 32

How do you diagnose Onchocerciasis?

Answer 32

Skin Snip Biopsy
DEC Patch Test (Maziotti sign)
Eosinophilia (all filarials)

Question 33

?How do you manage Onchocerciasis

Answer 33

Ivermectin +/- Doxycycline

Question 34

Which medications do you have to avoid in Onchocerciasis to prevent blindness as a result of filarial death?

Answer 34

DEC and Albendazole

Question 35

How do you prevent Onchocerciasis?

Answer 35

Vector Control
MDA
Test and Treat

Question 36

What is Loiasis?

Answer 36

Eye worm

Question 37

What is the epidemiology of Loiasis?

Answer 37

DRC, Congo, Gabon
rainforests

Question 38

What is the parasite in Loiasis?

Answer 38

Loa Loa

Question 39

What is the vector in Loa Loa

Answer 39

Deer tick (Chrysops)

Question 40

How does Eye worm present?

Answer 40

Soft tissue inflammation
Eye worm
Meningoencephalitis (rare)

**people used to think it was harmless but no we think it probably causes a lot of inflammatory changes

Question 41

How do you diagnose Loa Loa?

Answer 41

Direct visualisation
Microscopy of Blood/CSF/ Urine/Sputum

*** Quantitative Blood Smears are reqiured to determine how to treat

Question 42

How do you manage Loa Loa?

Answer 42

> 30000 worms - Albendazole
8000 - 30000 - Albendazole + Ivermectin
2000-8000 - Ivermectin
<2000 - DEC

**DEC is the ultimate treatment you need to give to get rid of Loiasis

Question 43

What are calabar swellings?

Answer 43

Transient swellings under the skin associated with Loa Loa infection

Question 44

What is the incubation of Loa Loa?

Answer 44

5 months (minimum)

Question 45

How does WHO recommend you diagnose Onchocerciasis?

Answer 45

Skin Snip
Eye Slit Lamp
Serology: IgG4, OvAg (no other serology is good enough)

Question 46

How should you treat onchocerciasis monoinfection?

Answer 46

For individual treatment, ivermectin is provided as a single dose of 150 μg/kg PO.

±6/52 doxycycline

Treatment should be repeated in 3- to 6-month intervals for 10-15 years

Question 47

How can you diagnose Loa Loa rapidly in areas with lots of Onchocerciasis?

Answer 47

Mobile LoaScope

For regions co-endemic of onchocerciasis and L. loa, a mobile phone-based, point-of-care microscopy tool – the LoaScope – has proven helpful to easily identify patients with high parasitaemia of L. loa and to exempt them from mass treatment with ivermectin. This technology has increased the acceptance of ivermectin MDA for onchocerciasis and lymphatic filariasis in L. loa co-endemic areas.