Vector prevalence and detection of Crimean-Congo haemorrhagic fever virus in Golestan Province, Iran.

BACKGROUND & OBJECTIVES: Crimean-Congo haemorrhagic fever virus (CCHFV) causes severe disease with fatality rate of 30%. The virus is transmitted to humans through the bite of an infected tick, direct contact with the products of infected livestock as well as nosocomially. The disease occurs sporadically throughout many of African, Asian and European countries. Different species of ticks serve either as vector or reservoir for CCHFV. This study was aimed to determine the prevalence of CCHFV in hard ticks (Ixodidae) in the Golestan Province of Iran. METHODS: A molecular survey was conducted on hard ticks (Ixodidae) isolated from six counties in Golestan Province, north of Iran during 2014-15. The ticks were identified using morphological characteristics and presence of CCHFV RNA was detected using RT-PCR. RESULTS: Data revealed the presence of CCHFV in 5.3% of the ticks selected for screening. The infected ticks belonged to Hyalomma dromedarii, Hy. anatolicum, Hy. marginatum and Rhipicephalus sanguineus species. INTERPRETATION & CONCLUSION: The study demonstrated that Hyalomma ticks are the main vectors of CCHFV in Golestan Province. Thus, preventive strategies such as using acaricides and repellents in order to avoid contact with Hyalomma ticks are proposed.

Discrimination of relapsing fever Borrelia persica and Borrelia microtti by diagnostic species-specific primers and polymerase chain reaction-restriction fragment length polymorphism.

Tick-borne relapsing fever (TBRF) is endemic in Africa and Eurasia and attributed to different Borrelia species. In the Central Asia and Middle Eastern countries, TBRF is caused mainly by Borrelia persica; however, other Borrelia species such B. microtti, B. latyschewii, B. baltazardi, and B. caucasica have also been described. The classic taxonomy of Borrelia spp. is based on the cospeciation concept that is very complex and rather confusing. In this study, we report two DNA-based methods to discriminate B. persica and B. microtti, the two main prevalent species in the region. Molecular typing of the species was performed using (i) restriction fragment length polymorphism analysis of polymerase chain reaction (PCR)-amplified fragments of either 16S-rRNA or glpQ genes, and (ii) species-specific PCR of glpQ gene. Sequence analyses of the data obtained in this study indicate that the glpQ gene is more variable than 16S-rRNA (6.9% vs. 1.2%); thus glpQ is a more useful marker for discrimination of B. persica from B. microtti. The 16S-rRNA fragment comprises only one useful species-specific restriction site (TaqI), whereas the glpQ fragment includes several species-specific restriction sites and its digestion by DraI, TaqI, EcoRV, HinfI, or SspI results in distinctively different PCR-restriction fragment length polymorphism patterns for the two species. Further, the species-specific primers amplified a 253-bp fragment for B. persica and a 451-bp one for B. microtti. Phylogenetic analysis of the data revealed that B. microtti and B. persica are associated to the African and new world RF agents, respectively. This study demonstrates that both typing methods are simple, sensitive, and fast, and that they allow one to differentiate between B. persica and B. microtti. This could prove that both methods are important and useful in monitoring of TBRF disease in endemic areas.