Brugia malayi
Brugia malayi
Brugia malayi is a tropical nematode from the group of filaria. He parasite in humans and can cause lymphatic filariasis and the clinical picture of elephantiasis.
Features
The adult worms have the nematode typical elongated structure. They are up to 2.5 cm ( males ) or 6 cm (females ) long.
The larvae ( microfilariae, Larva 3) have a size of 200-300 microns and have a sheath, which is already above the egg and is resolved only in the digestive tract of the infected insect. In this form it circulates in the human blood stream.
Dissemination
Brugia malayi is a tropical disease whose distribution area is located in Southeast Asia. The colonization of focus is in India and China, other countries affected are Indonesia, Thailand, Malaysia, the Philippines and Vietnam.
Life cycle
Transmission is by mosquitoes of the species Aedes, Culex, Anopheles and Mansonia.
The adult filarial sit in the lymphatic vessels, there are enveloped microfilariae ( via a short egg stage ) was formed. Depending on the diurnal activity of microfilariae there are two groups of B. malayi. :
- Active night rhythm:
- Active Sub - night rhythm:
In the digestive system of the mosquito, the shell dissolves to the microfilariae. Using a chitinase they can leave the midgut and become lodged in the chest. There, the L1 ( 1 larva ) develops. From then the L1 L3 ( 3 larva ) emerges, which is positioned in the salivary gland of the mosquito. The number of microfilariae that reach the L3 stage in the insect is very low, therefore not enough for the infection of the vertebrate host (humans, domestic cat, etc.) a unique engraving from. In addition, only about 10% of L3 to the adult worm that can get stuck in the lymphatic vessels develop .. The development of infective larvae in mosquitoes requires high temperatures and humidity. After an infection, the filarial settle in lymphatics. The adult worms set after about 3 months of microfilariae. About uptake of microfilariae by a new mosquito bite come full circle. The adult worms can survive 5 to 15 years in a host.
System
Brugia malayi was first defined in 1927 by Lichtenstein and Brug within the filarial and described as filaria malayi. Previously, they were counted as due to the similarity to Wuchereria bancrofti. This definition was based on the microfilariae ( the larval stage ) of the nematodes. Generally accepted, this hypothesis only when Rao and Maple Stone in the 1940s, two copies of the worm adults in India found that differed from Wuchereria bancrofti. They described the new species malay as Wuchereria.
The current division into two genera Wuchereria and Brugia comes from parasitologists JS Buckley.