Molecular evidence of ovine (G1) and camel (G6) strains of Echinococcus granulosus in Tunisia and putative role of cattle in human contamination

• Published in: Veterinary parasitology Vol. 129; no. 3; pp. 267 - 272
• Main Authors: M’rad, S., Filisetti, D., Oudni, M., Mekki, M., Belguith, M., Nouri, A., Sayadi, T., Lahmar, S., Candolfi, E., Azaiez, R., Mezhoud, H., Babba, H.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.05.2005
• Subjects: Animals; Base Sequence; camels; Camelus - parasitology; Cattle; Cattle Diseases - epidemiology; Cattle Diseases - parasitology; Cattle Diseases - transmission; Coccidiosis - epidemiology; Coccidiosis - parasitology; Coccidiosis - transmission; Coccidiosis - veterinary; Cytochrome c oxidase I gene (CO1); cytochrome oxidase I gene; DNA, Protozoan - chemistry; DNA, Protozoan - genetics; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; echinococcosis; Echinococcus granulosus; Echinococcus granulosus - classification; Echinococcus granulosus - genetics; Echinococcus granulosus - growth & development; Electron Transport Complex IV - chemistry; Electron Transport Complex IV - genetics; epidemiological studies; genotype; host strains; Humans; Hydatidosis; intermediate hosts; internal transcribed spacer 1; Molecular Sequence Data; Nuclear rDNA ITS1; nucleotide sequences; PCR-RFLP; polymerase chain reaction; Polymerase Chain Reaction - veterinary; Polymorphism, Restriction Fragment Length; restriction fragment length polymorphism; RNA, Ribosomal - chemistry; RNA, Ribosomal - genetics; Sequence Alignment; sheep; Sheep Diseases - epidemiology; Sheep Diseases - parasitology; Sheep Diseases - transmission; strain identification; Tunisia; Tunisia - epidemiology; zoonoses; Zoonoses - epidemiology; Zoonoses - parasitology; Zoonoses - transmission; Tunisia; Cytochrome c oxidase I gene (CO1); PCR-RFLP; Hydatidosis; Tunisia; Nuclear rDNA ITS1; Echinococcus granulosus
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/j.vetpar.2005.02.006

Three hundred and seventy-two cysts coming from 50 humans, 166 cattle, 153 sheep and 3 camels were collected in order to establish some epidemiological molecular information in Tunisia for the first time. The analysis by PCR-RFLP of ITS1 sequence showed that all the human, ovine and bovine cysts were due to the common sheep strain of Echinococcus granulosus. The sequencing of the CO1 gene of 37 isolates confirm the G1 genotype of this strain. For seven of these isolates, we found the mutation C56T which is present in the three principal intermediate hosts: human (three cysts), cattle (three cysts) and sheep (one cyst). With regard to the G1 genotype, we identified three other point mutations. The camel strain G6 is uniquely found in the three camels isolates and not in the other intermediate hosts analysed. The fertility of the bovine cyst represents 48% that means that this host is involved in a bovine-dog cycle and consequently represents a reservoir of sheep strain in Tunisia. Our results confirm the importance of the prophylaxis measures in order to disrupt the cycle of transmission sheep–dog in Tunisia. Nevertheless, the supervision of bovine infection should be reinforced because this intermediate host may constitute an important link with the human contamination.