MOLECULAR CHARACTERIZATION OF CRYPTOSPORIDIUM ISOLATES FROM HUMANS AND OTHER ANIMALS USING RANDOM AMPLIFIED POLYMORPHIC DNA ANALYSIS

Genetic variation in 25 Cryptosporidium isolates was analyzed using th e random amplified polymorphic DNA (RAPD) technique. Simple reproducib le polymorphisms were generated (using five primers) from Cryptosporid ium DNA that was free of contaminating bacterial DNA. The results gene rated by four of the five primers were statistically correlated (P < 0 .001). The combined data from three primers were used to construct a p henogram using Jaccard's distance. Four groupings could be distinguish ed. Two C. serpentis isolates from snakes formed a distinct group of t heir own, whereas C. parvum isolates were divided into two main groups : one containing most human isolates and the other containing mostly d omestic animals plus two remaining human isolates. Due to the sensitiv ity of the RAPD technique, isolates can now be analyzed genetically, d irectly from fecal samples without further biological amplification. T his represents a significant advance on current techniques.