Cloning and characterization of a species-specific repetitive DNA sequence from Onchocerca armillata.

Two clones, pOA1 and pOA5, have been isolated from a genomic DNA library prepared from pools of Onchocerca armillata adults in the plasmid vector pUC12. In dot-blot hybridisations, these two clones do not cross-hybridise significantly with total genomic DNA from O. volvulus, O. gutturosa, O. ochengi, O. gibsoni, O. lienalis, bovine, human, Culicoides nubeculosus, Simulium species or Brugia pahangi, but do hybridise with as little as 100 pg of DNA from two separate geographic isolates of O. armillata. The sequence of pOA1 and pOA5 has been determined and found to contain a repetitive DNA sequence 147 bp in length. These clones can be used as specific and sensitive DNA probes for the identification of O. armillata capable of identifying a single L3 larva.