Causative Agents of Malaria and Filariasis

Transmission and Pathogenesis of Filariasis

Filariasis is a parasitic disease caused by thread-like filarial worms, primarily Wuchereria bancrofti, Brugia malayi, and Brugia timori. It is transmitted through mosquito bites, where infected larvae enter the human bloodstream and develop into adult worms in the lymphatic system.

Modes of Transmission

• Vector-borne Transmission: Mosquitoes from the genera Culex, Anopheles, and Aedes serve as vectors, spreading filarial parasites through their bite.
• Lifecycle Stages: Larvae (microfilariae) enter the bloodstream, mature, and obstruct lymphatic vessels, leading to lymphedema.

Pathogenesis

Upon infection, filarial worms trigger an immune response, leading to inflammatory reactions. Chronic infections result in lymphatic damage, causing elephantiasis—severe swelling of the limbs and genitals.

Clinical Manifestations

• Acute febrile episodes with lymphadenopathy
• Skin thickening due to chronic lymphatic blockage
• Hydrocele formation (in males)

Prevention and Control

Preventive measures include vector control, mass drug administration (MDA) with antifilarial medications like ivermectin, diethylcarbamazine (DEC), and albendazole, and improved sanitation practices.