INDICATION OF THE PRESENCE OF 2 DISTINCT STRAINS OF ECHINOCOCCUS-GRANULOSUS IN IRAN BY MITOCHONDRIAL-DNA MARKERS

Sixteen isolates of Echinococcus granulosus, collected from Iranian pa tients at surgery, and from domestic animals, including sheep, goats, cattle, and camels at slaughterhouses in Tehran and central and southe rn Iran were analyzed for DNA nucleotide and predicted amino acid sequ ence variation within regions of the mitochondrial cytochrome c oxidas e I (COI) and NADH dehydrogenase subunit I (NDI) genes. A polymerase c hain reaction-restriction fragment length polymorphism method, based o n the DNA sequence variation in the NDI gene, was also used to rapidly survey the E. granulosus isolates. The isolates were categorized into two distinct and uniform genotype groupings. The analysis clearly ind icated that the camel/dog strain (G6 genotype) of E. granulosus as wel l as the cosmopolitan, common sheep strain (G1 genotype) occur in Iran . The G1 genotype was found present in all four human isolates examine d and it was more prevalent in domestic animals than the camel-restric ted G6 genotype. In E. granulosus-endemic areas of Iran it is evident, therefore, that the majority of E. granulosus-infected livestock anim als can potentially act as reservoirs of human infection, and this has important implications for hydatid control and public health.