RESUMEN
In the Logone Valley, Yagoua and the surrounding area, the prevalence of the bancroftian filariasis was measured by means of determinating the microfilarian rate: 22,1 p. 100 in males and 9,8 p. 100 in females. The immunofluorescence test on D viteae frozen sections showed the presence of antibodies in 61,5 p. 100 of the males and 68,2 p. 100 of the females. A balance between the microfilarial rate and the percentage of inhabitants with specific antibodies was observed. Parasitological and immunological examinations appeared to be complementary. The microfilarial density is 19 microfilariae/20 microliter of blood in males and 13 microfilarae/20 microliter in females. Elephantoid extremities of scrota was observed in 13,2 p. 100 of the adult males, all of them having more than 40 years of age. Females are less affected than males. At the beginning of the rainy season, females of A. gambiae were the mosquitos the most frequently caught in the houses.