Molecular Characterization and Analysis of 16S Ribosomal DNA in Some Isolates of Demodex folicullorum.

BACKGROUND: Demodicosis is one of the most prevalent skin diseases resulting from infestation by Demodex mites. This parasite usually inhabits in follicular infundibulum or sebaceous duct and transmits through close contact with an infested host. METHODS: This study was carried from September 2014 to January 2016 at Tehran University of Medical Sciences, Tehran, Iran. DNA extraction and amplification of 16S ribosomal RNA was performed on four isolates, already obtained from four different patients and identified morphologically though clearing with 10% Potassium hydroxide (KOH) and microscopical examination. Amplified fragments from the isolates were compared with GeneBank database and phylogenetic analysis was carried out using MEGA6 software. RESULTS: A 390 bp fragment of 16S rDNA was obtained in all isolates and analysis of generated sequences showed high similarity with those submitted to GenBank, previously. Intra-species similarity and distance also showed 99.983% and 0.017, respectively, for the studied isolates. Multiple alignments of the isolates showed Single Nucleotide Polymorphisms (SNPs) in 16S rRNA fragment. Phylogenetic analysis revealed that all 4 isolates clustered with other D. folliculorum, recovered from GenBank database. Our accession numbers KF875587 and KF875589 showed more similarity together in comparison with two other studied isolates. CONCLUSION: Mitochondrial 16S rDNA is one of the most suitable molecular barcodes for identification D. folliculorum and this fragment can use for intra-species characterization of the most human-infected mites.

Serological evaluation of Crimean-Congo hemorrhagic fever in humans with high-risk professions living in enzootic regions of Isfahan province of Iran and genetic analysis of circulating strains.

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral disease that is asymptomatic in infected livestock, but causes a serious threat to humans with a mortality rate up to 50%. Although the CCHF virus (CCHFV) is often transmitted by ticks, livestock-to-human and human-to-human transmission also occurs. In the current study, we focused on CCHF in the province of Isfahan, located in the center of Iran and deemed to be the second most infected province. Human and livestock sera and resident ticks in the livestock are collected from different regions of the province and analyzed with specific IgG ELISA and RT-PCR tests. Overall, 12% and 12.7% of studied human and livestock populations were IgG positive, respectively. The genome of CCHFV was detected in 9% of ticks resident in livestock involved in this survey. The CCHFV isolates from infected ticks were genetically examined. Nucleotide sequence of the S-segment revealed that the different isolates were closely related to each other, with nucleotide sequence identities higher than 98%. Phylogenetic analysis demonstrated that a variant isolate clustered with the Iraq strain. This high proportion of IgG-positive sera and nearly high proportion of infected ticks increases the risk of CCHF outbreaks in the province and probably posits a great danger to other provinces.

Sequence diversity of the C-terminal region of Plasmodium falciparum merozoite surface protein 1 in southern Iran.

The C-terminal region of the merozoite surface protein 1 (MSP-1) of Plasmodium falciparum is a strong vaccine candidate as it is associated with immunity to the parasite. This corresponds approximately to the conserved 17th block of the gene and is composed of two EGF- like domains. These domains exhibit only four single amino acid substitutions which show several potential variants in this region of the gene. As the variations might be important for a regional vaccine design, a study was carried out to determine the variations present in P. falciparum isolates from southern Iran. Besides the usual E-T-S-R-L and the Q-K-N-G-F types, we found Q-T-S-R-L, E-K-N-G-F, E-T-S-G-L, Z-T-S-G-L and Z-T-S-R-L types, where Z was E or Q signifying the presence of mixed clones in single isolates.