Filariasis

Question 1

A 24-year-old man presented with swelling of his left foot. The swelling is diffuse and doughy. He was otherwise well with no fever or systemic upset. There were a few enlarged lymph nodes in his groin. Full blood report revealed eosinophilia with the nodes eosinophilia and swollen. His full blood count revealed an eosinophilia of 1.4 x 10$^9$/L (normal 0.04-0.4).

Answer 1

Diagnosis?
Filariasis (elephantiasis)
Causative organism?
Wuchereria bancrofti

Question 2

Pathophysiology

Answer 2

1-Mosquito bites an infected person and ingests microfilariae (immature larvae) present in the blood.
2. Inside the mosquito, microfilariae mature into infective larvae over 10–14 days.
3. When the mosquito bites another person, the infective larvae enter the skin through the bite wound.
4. These larvae migrate to the lymphatic vessels, where they mature into adult worms.
5. Adult worms live for several years, producing more microfilariae, continuing the cycle.

Question 3

Mosquito Vectors Involved:

Answer 3

Culex (most common for W. bancrofti)

Anopheles

Aedes

Mansonia (

Question 4

Treatment

Answer 4

1-Antifilarial medications (e.g., DEC, albendazole, ivermectin, Doxycycline)
2-Hygiene and skincare to prevent secondary infections
3-Compression therapy and physiotherapy
4-Surgery in advanced or disabling cases

Question 5

Antifilarial medications
قولهم بقي

Answer 5

1-DEC = Diethylcarbamazine”
* The main line of treatment.
* 6mg/kg/day orally in 3 divided doses after meals for 10-14 days.
2- Albendazole:Kill microfilaria but not adult worms.
3-Ivermectin:Used in combination with DEC or Albendazole.
4-Doxycyclines

Question 6

Investigatins

Answer 6

1-CBC : eosinophilia common during the acute phase
2-Giemsa-stained thick blood films at night بالليل
- For microfilarial detection at the peak of microfilarial periodicity (i.e. 10
pm to 2 am for W. bancrofti).
3- DEC provocative test: بالنهار
- Used to induce parasitaemia during the day
- Single dose of DEC provoke microfilaremia then collection of
peripheral blood after 30-60 minutes for staining & examination can
occur
4- ELISA (TropBio-test) & Rapid finger-prick immunochromatographic
card test for detection of circulating W. bancrofti antigen
 These tests are very sensitive, specific
 Diagnose the adult worm infection as well as microfilaria at any
time of the day, thus overcoming the problem of periodicity
5- IgG4 tests
- Bm 14 test for both W. bancrofti & Brugia malayi infections and Bm-
RM test for B. malayi infection
- May be used for monitoring control programs and screening travelers
6- PCR assays
7- Examination of the chylous exudates for microfilariae e.g. chyluria
8- Scrotal U/S scanning:
May be useful for demonstrating live adult worm

Question 7

Special situations

Answer 7

1-Coinfection with Onchocerciasis:
 Doxycycline 100 mg twice daily for 6 weeks followed by oral
dose of Ivermectin 150 µg/kg on completion of the doxycycline
course
 Further dose of Ivermectin 3-6 months after unless
contraindicated
2-Coinfection with Loiasis esp. with high microfilaraemia:
 Albendazole 200 mg twice daily for 3 wks to gradually reduce the
microfilaria followed by a course of DEC or Ivermectin
- Filariasis infection alone
 Doxycycline 100 mg twice daily for 6 weeks followed by a dose
of DEC 6 mg/kg on completion of the doxycycline course
 Further dose of DEC 3-6 months after unless contraindicated.

Question 8

Prevention

Answer 8

1-Vector control – using insecticide-treated mosquito nets and repellents to avoid mosquito bites (especially Culex, Anopheles, and Aedes species).

2. Mass drug administration (MDA) – periodic treatment of at-risk populations with antiparasitic medications such as ivermectin, albendazole, and diethylcarbamazine (DEC).
3. Health education – promoting awareness about mosquito breeding sites and personal protection measures.
4. Environmental management – reducing mosquito breeding habitats by proper waste disposal and drainage.