Hyperendemic bancroftian filariasis in the Kingdom of Tonga: the application of the membrane filter concentration technique to an age-stratified blood survey
Desowitz, R.S.; Hitchcock, J.C.
American Journal of Tropical Medicine and Hygiene 23(5): 877-879
1974
ISSN/ISBN: 0002-9637 PMID: 4615596 Document Number: 70455
A survey carried out in Tonga, compared the efficiency of membrane-filtration and stained blood film techniques in the diagnosis of Wuchereria bancrofti infections in individuals of various ages. Membrane filter concentration revealed microfilariae in about 70% of persons in each age group, from 5 to 9 years to >50 years old, but many fewer infections were detected using the other technique. The difference was greatest in the youngest group where examination of blood films gave an incidence almost 8 times lower than that obtained using membrane filter concentration. In the older age groups the frequency of high-density microfilaraemias was higher and the ratio of positive diagnoses was only 1.6:1 in favour of the membrane-filter technique. Microfilariae were found in stained blood films of only one of 8 individuals with gross elephantiasis while membrane filtration gave 5 positive results.