Onchocerca volvulus: Limited heterogeneity in the nuclear and mitochondrial genomes

West African populations of Onchocerca volvulus endemic to the rain forest and savanna bioclimes of West Africa differ in their ability to induce ocul ar disease in infected individuals. in recent years, both clinical- and ani mal-model-based studies have implicated particular parasite antigens in the development of ocular onchocerciasis. To test the hypothesis that the diff erence in pathogenic potential of blinding and nonblinding parasites might be reflected in qualitative differences in antigens that have been implicat ed in the development of ocular onchocerciasis, we compared the sequences o f two parasite antigens implicated in the development of ocular disease in blinding- and nonblinding-strain parasites. The results demonstrated a high level of homogeneity between the parasite strains in these genes. The stud y was extended to include additional nuclear genes encoding antigens that a re commonly recognized by individuals infected with O. volvulus and to the mitochondrial genome of the parasite. The results demonstrate a high degree of homogeneity in both the nuclear and the mitochondrial genomes among O. volvulus isolates collected from several different sites in Africa and in t he Americas. This high degree of genetic homogeneity may reflect the passag e of the parasite through a recent genetic bottleneck. (C) 1999 Academic Pr ess.