CHROMOSOMAL DIAGNOSTIC-CRITERIA FOR SOME MEMBERS OF SIMULIUM-DAMNOSUMCOMPLEX IN EAST-AFRICA

Identification of Simulium damnosum s.l. vectors of onchocerciasis dem ands adequate knowledge of the chromosomal features that distinguish h uman-biting members from nonanthropophilic forms. In this study, 955 S . damnosum larvae collected from various geographical locations in Tan zania were chromosomally analyzed. 358 larvae from small mountain stre ams in the northeast and central regions of Tanzania, were identified as mainly Nyamagasani and Sanje forms, with only one Kiwira form. 378 larvae from plain and lowland rivers, also in the northeast and centra l regions, were identified as Nkusi, Kisiwani and Kibwezi forms. Chrom osomal examination of 219 larvae from the southern highlands zone reve aled the presence of Kiwira and Nyamagasani forms. A further 27 larvae of S. damnosum complex collected from 5 rivers in Uganda were identif ied as Sebwe and Nkusi forms. Chromosomal photomicrographs on which th e distinguishing characters were based are provided. These observation s are discussed in the light of previous studies carried out on the S. damnosum cytological forms in Eastern Africa.