Infection with mosquito-born filarial nematodes occurs when hosts are bitten by a vector carrying the infective third stage larvae (L3) of the parasites. These larvae, deposited on the skin by the feeding mosquito, are presumed to enter the skin via the vector-induced puncture wound. Larvae of Brugia spp. must then migrate from the entry site, penetrate various skin layers, and locate . Brugia is a genus for a group of small roundworms. They are among roundworms that cause the parasitic disease filariasis. Specifically, of the three species known, Brugia malayi and Brugia timori cause lymphatic filariasis in humans; and Brugia pahangi and Brugia patei infect domestic cats, dogs and other animals. They are transmitted by the bite of mosquitos.
To determine if exogenous retinoic acid is taken up by filarial parasites, adult male and female Brugia malayi were exposed to [3H] retinoic acid. Results indicated that retinoic acid was taken up by adult parasites in a specific and dose-dependent manner. In tissue sections of [3H] retinoic acid-labeled B. malayi, label was shown to localize. The adult worms resemble those of Wuchereria bancrofti but are smaller. Female worms measure 43 to 55 mm in length by to μm in width, and males measure 13 to 23 mm in length by 70 to 80 μm in width. Adults produce microfilariae, measuring to μm in length and 5 to 7 μm in width, which are sheathed and have nocturnal periodicity.
The adult worms reside in lymphatic vessels of the human host. Female W. bancroftimeasure 80– × mm and males 40 × mm; adult Brugiaspp. are about half as long. Usual Adult Dose for Cutaneous Larva Migrans. mg/kg orally once. Usual Adult Dose for Filariasis. mg/kg orally once Study (n=26,) Mass treatment in Papua, New Guinea: Bancroftian filariasis: mg/kg orally once yearly (with a single annual dose of diethylcarbamazine 6 mg/kg), for 4 to 6 years. Usual Adult Dose for Scabies.