Serotype variation in vibrio cholerae el tor diarrhoea in northern Nigeria.
Serotyping of Vibrio cholerae organisms causing epidemics in Zaria and environs since 1975 to 1986 shows that Hikojima serotype was prevalent from 1976-1978, but Ogawa became prevalent from 1984 till 1986. The internal and external pressures responsible for these selections are unclear.