Filariasis is a parasitic disease caused by microscopic, thread-like filarial worms. It was first recorded in India in the 6th century BC and is spread by mosquitoes. There are three main types classified by the location of the worms: lymphatic, subcutaneous, and serous cavity. Lymphatic filariasis, caused mainly by Wuchereria bancrofti, is one of the leading causes of long-term disability and is commonly known as elephantiasis. Diagnosis involves blood smears, antigen testing, antibody detection, and PCR. Control relies on mass drug administration with drugs like diethylcarbamazine, ivermectin, and albendazole, as well

1. Filariasis

2. ➢ a parasitic disease caused by microscopic, thread-like worms
➢ Recorded in India as early as 6th century B.C. by the famous Indian physician, Susruta in his book Susruta Samhita.
➢ In 1709 - Clarke called elephantoid legs in Cochin as Malabar legs.
➢ Discovery of microfilaria in the peripheral blood was made first by Lewis in 1872 in Kolkata
➢ Based on pathogenicity and habitat it classified into:
❖ Lymphatic filariasis – worms occupy Lymphatic system
❖ Subcutaneous filariasis – worms occupy the subcutaneous layer of the skin and eye
❖ Serous cavity filariasis - occupy the serous cavity of the abdomen
Disease Causative agent
Lymphatic Wuchereria bancrofti, Brugia malayi, Brugia timori
Subcutaneous Onchocerca volvulus, Loa loa, Dracunculus medinensis
Serous cavity Mensonella perstans, M. ozzardi

3. ➢ Lymphatic filariasis –one of the cause of long-term disability.
➢ Commonly known as elephantiasis
➢ In India, 99.4% of the cases are caused by the species – Wuchereria bancrofti
0.6% of the cases - Brugia malayi
➢ Indigenous cases have been reported in more than 20 Indian states/Union Territories
➢ spreads from person to person by mosquito bites – Anopheles, Culex, Aedes and Mansonia
➢ Clinical Manifestations:
• Asymptomatic features
• Acute inflammation in lymph glands & vessels
• filarial fever,
• Lymphangitis - an inflammation of the lymphatic system
• Lymphadenitis - enlargement in lymph nodes
• Lymphoedema - swelling in the body's tissues
• Epididymo orchitis(male) - an inflammation of the epididymis and/or testicle
• Permanent structural changes due to fibrosis and obstruction of lymphatic vessels
• Main clinical features - hydrocele, elephantiasis & chyluria.
Occult filariasis - hypersensitivity reaction to filarial antigens - Tropical pulmonary eosinophilia
*Acute
Chronic

6. Diagnosis
➢ Clinical examinations for symptoms
➢ Detection of microfilaria in blood smears – Giemsa staining
➢ Antigen testing – ELISA or Iummunochromatographic test - Og4C3 antigen
➢ Antibody Detection - Bm14, WbSXP and BmR1
➢ PCR
FILARIA SURVEY
➢ Mass blood survey – Diethylcarbamazine induction – 100 mg
➢ Clinical survey
➢ Serological tests
➢ Xenodiagnosis
➢ Entomological survey

7. Control Measures:
1. Chemotherapy - Albendazole, Ivermectin, Diethylcarbamazine (DEC)
2. Vector control
Diethylcarbamazine (DEC)
➢ a piperazine derivative- the most common and widely used orally administered drug
➢ strong antimicrofilarial activity
➢ completely absorbed after oral administration – widely distributed in non-fatty tissues.
➢ plasma half-life - 6–12 hours
➢ dose of 6 mg/ kg daily for 12 days
➢ Adverse effects: nausea, GIT upset, malaise, body aches, and anorexia (systemic reactions).
abscess formation, lymphadenitis and transient lymphedema
➢ Targets: sensitizing the microfilariae to phagocytosis
arachidonic acid metabolic pathway
5-lipoxygenase pathway
cyclooxygenase pathway and COX-1.

8. Ivermectin
➢ effective microfilaricide - also known as mectizan
➢ broad-spectrum activity against nematodes as well as arthropods
➢ along with DEC or individually, has shown efficacy in producing long-term
suppression of microfilariae in bancroftian filariasis
➢ targets glutamate gated Cl and K+ ion channels in nematodes, which leads to an increase in cell membrane permeability to
chloride ions, resulting in a hyperpolarization that causes paralysis of the body wall muscle and pharynx. The drug also
affects ligand-gated chloride ion channels gated by GABA (gamma aminobutyric acid)
➢ Substantial adverse effect- pruritus, urticaria, dermatitis, fever, myalgia, oedematous swelling of the limbs and face, or
postural hypotension; reactions mostly arise within 1–2 days of treatment

9. Albendazole
➢ a benzimidazole derivative that is generally used to treat helminthiasis
➢ more effective when administered in combination with either DEC or IVM
➢ Albendazole (400 mg) + ivermectin (150–200 mg/ kg)
Albendazole (400 mg) + diethylcarbamazine (DEC) (6 mg/kg)
➢ blockage of tubulin polymerization and thereby inhibiting microtubule formation by this drug further inhibits mitosis in
the worm such that its embryogenesis and egg hatching is inhibited
➢ inhibit parasite intestinal cells, preventing glucose uptake
➢ Adverse effect- Embryotoxicity and teratogenicity- prohibited during pregnancy
Headache, dizzyness, temporal hair loss, nausea, vomiting