DIROFILARIA REPENS - CLONING AND CHARACTERIZATION OF A REPEATED DNA-SEQUENCE FOR THE DIAGNOSIS OF DIROFILARIASIS IN DOGS, CANIS-FAMILIARIS

A highly repetitive DNA element from the genome of the filarial nemato de Dirofilaria repens has been cloned and sequenced. The 176-base pair repeating units are arranged in direct tandem and are clustered in th e parasite genome. All repeats appear to belong to a single family alt hough some elements have diverged significantly. The repeats are prese nt in about 15,000 copies and constitute approximately 3.0% of the par asite genome. The cloned repetitive sequence hybridized only to D. rep ens DNA and was sensitive enough to detect 250 to 500 pg of D. repens DNA, a single microfilariae in infected blood samples, and a single th ird stage larvae in mosquitoes. The high specificity and sensitivity o f the cloned fragment makes it ideal as a diagnostic probe for detecti ng D. repens in both the host and the vector. (C) 1994 Academic Press, Inc.