BACK

Medeiros, Z., Dreyer, G., Andrade, L., Pires, M.L., Mendes, J. and Pimentel, R.

WUCHERERIA BANCROFTI MICROFILARIAL DENSITY OF AUTOCHTHONOUS CASES AND NATURAL CULEX INFECTIVITY RATES IN NORTHEAST BRAZIL .

Journal of Tropical Medicine and Hygiene , 95(3): 214-217, 1992.

SUMMARY

Autochthonous Wuchereria bancrofti microfilaraemic cases from three neighboring cities of Northeast Brazil ( Recife , Jaboatao and Olinda ) were selected from thick smear or filtration positive individuals and classified by their microfilarial (mf) densities through polycarbonate membrane blood filtration. Individuals were subdivided into two groups: autochthonous cases without any previous specific drug administration (group A) and those with one or more previous DEC treatments (group B). In Recife , unlike Jaboatao and Olinda (P<0.05), the majority of autochthonous cases were over 20 years old and no microfilaraemics were found under the age of 10. The majority of cases in Recife had lower levels of mf density (66.6%), while in Jaboatao and Olinda higher mf carriers (65.6%) pre-vailed when group A (n = 141) individuals were rearranged in mf density above and below 500 mf ml -1 (P<0.01). All subjects in group B (n = 110) had less than 501 mf ml -1 and the great majority less than 100 mf ml -1 , but a significant difference (P<0.05) between Recife and the two other cities was observed.

Captured mosquitoes in Recife , Jaboatao and Olinda totaled 7856, 8010 and 8003 respectively. The infectivity rate found in Recife (0.61%) was significantly lower than in Jaboatao (1.21%) and Olinda (1.31%) (P<0.001). The authors discuss the possible influences of previous disease control programmes (medicated salt and individual treatments) applied only to the city of Recife in relation to the outcome of this investigation.