Microfilaraemia survey in Vientiane, Laos.

During the period June 1977-January 1978 a microfilariaemia survey was conducted for the first time in 27 villages (population: 9,300) of Vientiane province of Laos. A total of 2,339 persons, 1,372 males, 967 females, mostly adults, were blood tested between 2000--2400 hours; one thick smear, approximately 20 c.mm, was collected from each one and stained with 10% Giemsa for 30 minutes; only one positive was detected with microfilaria of W. bancrofti in a 22-year-old male; unusually the sheath was well stained. Two cases of elephantiasis of the left leg in two middle-aged women were also diagnosed during the clinical survey. All the three cases were probably infected in the north-eastern province of Houa Phanh.