
Microfilaria of eye specimen on the way of direct wet mount showing
incomplete image due to highly motile under microscopic field as shown above image.
Filariasis is an infectious disease caused with nematodes of the Filarioidea type e.g. Wuchereria bancrofti, Brugia malayi, Oncocerca volvulus and Loa loa. These are spread by blood-feeding insects such as black flies and mosquitoes. The filarial worms reside in the subcutaneous tissues, lymphatic system, or body cavities of humans.
Microfilaria
The females of parasites are viviparously giving birth to larvae so-called microfilaria. This parasite includes four genera and species are parasitic to human. These filarial nematodes are as follows: 1. Wuchereria bancrofti 2. Brugia malayi 3. Oncocerca volvulus and 4. Loa loa but mainly two genera i.e. Wuchereria and Brugia are encountered in peripheral blood.
Loa loa filariasis is a skin and eye disease caused by the nematode worm Loa loa. Humans contract this disease through the bite of a deer fly or mango fly , the vectors for this parasite. The adult Loa loa filarial worm migrates throughout the subcutaneous tissues of humans, occasionally crossing into subconjunctival tissues of the eye where it can be easily observed. It does not normally affect one’s vision but can be painful when moving about the eyeball or across the bridge of the nose. The disease can cause red itchy swellings below the skin called “Calabar swellings”. The disease is treated with the drug diethylcarbamazine (DEC), and when appropriate, surgical methods may be employed to remove adult worms from the conjunctiva.
But according to researches performed in India the causative agents of ocular filariasis are Brugia malayi and Wuchereria bancrofti detected (Ref. 8 and 9)