The pattern of species and strain variation within the genus Echinococcus is complex and controversial. In an attempt to characterise objectively the various species and strains, the sequence of a region of the mitochondrial cytochrome c oxidase subunit I (CO1) gene was determined for 56 Echinococcus isolates. Eleven different genotypes were detected, including 7 within Echinococcus granulosus, and these were used to categorise the isolates. The 4 generally accepted Echinococcus species were clearly distinguishable using this approach. In addition, the consensus view of the strain pattern within E. granulosus, based on a variety of criteria of differentiation, was broadly upheld. Very little variation was detected within Echinococcus multilocularis. Remarkable intra-strain homogeneity was found at the DNA sequence level. This region of the rapidly evolving mitochondrial genome is useful as a marker of species and strain identity and as a preliminary indication of evolutionary divergence within the genus Echinococcus.

Background In order to verify the infectivity of rodents with endoparasites in Germi (Dashte-Mogan, Ardabil Province) the current study was undertaken. Methods Using live traps, 177 rodents were trapped during 2005–2007. In field laboratory, all rodents were bled prior to autopsy, frozen at −20°C, and shipped to the School of Public Health, Tehran University of Medical Sciences, Iran. In parasitological laboratory, every rodent was dissected and its different organs were examined for the presence of any parasite. Blood thick and thin smears as well as impression smears of liver and spleen were stained with Geimsa and examined microscopically. Results Two species of rodents were trapped; Meriones persicus (90.4%) and Microtus socialis (9.6%). The species of parasites found in M. persicus and their prevalences were as follows: Hymenolepis diminuta (38.8%), Hymenolepis nana (2.5%), Trichuris sp.(40.6), Mesocestoides larva (=tetrathyridium) (3.1%), Capillaria hepatica (6.9%), Moniliformis moniliformis (11.3%), Syphacia obvelata (2.5%), Taenia endothoracicus larva (0.6%), Physaloptera sp. (0.6%), Dentostomella translucida (0.6%), Heligmosomum mixtum (0.6%), Strobilocercus fasciolaris (0.6%),and Aspiculuris tetraptera (0.6%). The species of parasites found in M. socialis and their prevalences were as follows: H. diminuta (17.6%), Trichuris sp. (5.9%), Mesocestoides larva (5.9%), S. obvelata (11.8%), S. syphacia (11.8%), H. mixtum (17.6%), and Aspiculuris tetraptera (11.8%). There were no statistical differences between male and female for infectivity with parasites in either M. persicus or M. socialis. No blood or tissue protozoan parasite was found in any of the rodents examined. Conclusion Among different species identified, some had zoonotic importance. Therefore, the potential health hazard of these species needs to be considered to prevent infectivity of humans.