Brugia malayi

The Filarial Genome Network

Brugia malayi: The causative agent of Brugian lymphatic filariasis of humans

Biology and Epidemiology

Distribution:

The endemic range of Brugia malayi is confined to South and South-East Asia from India in the west to Korea in the east. LikeW. bancrofti its distribution is dependent on its mosquito vectors. The nocturnally periodic form is found in areas with rice fields and the nocturnally subperiodic form is found in rural villages and plantations along the lower reaches of major rivers in swamp forests (see HERE for some comments on periodicity). Partono has proposed the subdivision of B. malayi into zoophilic and anthropophilic strains. The former is transmissible to cats, monkeys, and laboratory gerbils


Life Cycle:

The life cycle of B. malayi is almost identical to that of Wuchereria bancrofti. However B. malayi is transmitted by different mosquito vectors in the Mansoniodes and Anopheles families. The microfilaria of B. malayi can be distinguished from those of W. bancrofti by the two isolated nuclei at the tip of the tail and the absence of nuclei in the cephalic spaces (picture taken from Peters and Gilles 1991) .


Pathology

The clinical picture of B. malayi infection is somewhat different than that of W. bancrofti. The symptoms of Brugian filariasis begin earlier than those of Bancroftian filariasis, often within a month or less. Immune responses to the worms quickly lead to lymphoedema and swelling of the legs is a prominent early symptom. Bouts of fever and lymphangitis are common and often more frequent than those found in patents infected with W. bancrofti. Unlike bancroftian infection the lyphoedema in the legs is below the knees and in the arms below the elbows. Gross elephantiasis is very uncommon. However, when it does occur it generally develops more quickly in Brugian (1 to 2 years) than the Bancroftian (3 or more years) filariasis. The pictures below show both early (left) and late (right) stages of Brugian elephantiasis.


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    last modified 01/01/96