Background Currently available anti-influenza drugs are often associated with limitations such as toxicity and the appearance of drug-resistant strains. Therefore, there is a pressing need for the development of novel, safe and more efficient antiviral agents. In this study, we evaluated the antiviral activity of zinc oxide nanoparticles (ZnO-NPs) and PEGylated zinc oxide nanoparticles against H1N1 influenza virus. Methods The nanoparticles were characterized using the inductively coupled plasma mass spectrometry, x-ray diffraction analysis, and electron microscopy. MTT assay was applied to assess the cytotoxicity of the nanoparticles, and anti-influenza activity was determined by TCID50 and quantitative Real-Time PCR assays. To study the inhibitory impact of nanoparticles on the expression of viral antigens, an indirect immunofluorescence assay was also performed. Results Post-exposure of influenza virus with PEGylated ZnO-NPs and bare ZnO-NPs at the highest non-toxic concentrations could be led to 2.8 and 1.2 log10 TCID50 reduction in virus titer when compared to the virus control, respectively (P < 0.0001). At the highest non-toxic concentrations, the PEGylated and unPEGylated ZnO-NPs led to inhibition rates of 94.6% and 52.2%, respectively, which were calculated based on the viral loads. There was a substantial decrease in fluorescence emission intensity in viral-infected cell treated with PEGylated ZnO-NPs compared to the positive control. Conclusions Taken together, our study indicated that PEGylated ZnO-NPs could be a novel, effective, and promising antiviral agent against H1N1 influenza virus infection, and future studies can be designed to explore the exact antiviral mechanism of these nanoparticles.

Aim: We aimed to determine the possible inhibitory effects of zinc oxide nanoparticles (ZnO–NPs) and polyethylene glycol (PEG)-coated ZnO–NPs (ZnO–PEG–NPs) on herpes simplex virus type 1 (HSV-1). Materials & methods: PEGylated ZnO–NPs were synthesized by the mechanical method. Antiviral activity was assessed by 50% tissue culture infectious dose (TCID50) and real-time PCR assays. To confirm the antiviral activity of ZnO–NPs on expression of HSV-1 antigens, indirect immunofluorescence assay was also conducted. Results: 200 μg/ml ZnO–PEG–NPs could result in 2.5 log10 TCID50 reduction in virus titer, with inhibition rate of approximately 92% in copy number of HSV-1 genomic DNA. Conclusion: ZnO–PEG–NPs could be proposed as a new agent for efficient HSV-1 inhibition. Our results indicated that PEGylation is effective in reducing cytotoxicity and increasing antiviral activity of nanoparticles.

Leishmania RNA virus (LRV) was first detected in members of the subgenus Leishmania (Viannia), and later, the virulence and metastasis of the New World species were attributed to this virus. The data on the presence of LRV in Old World species are confined to Leishmania major and a few Leishmania aethiopica isolates. The aim of this study was to survey the presence of LRV in various Iranian Leishmania species originating from patients and animal reservoir hosts. Genomic nucleic acids were extracted from 50 cultured isolates belonging to the species Leishmania major, Leishmania tropica, and Leishmania infantum. A partial sequence of the viral RNA-dependent RNA polymerase (RdRp) gene was amplified, sequenced and compared with appropriate sequences from the GenBank database. We detected the virus in two parasite specimens: an isolate of L. infantum derived from a visceral leishmaniasis (VL) patient who was unresponsive to meglumine antimoniate treatment, and an L. major isolate originating from a great gerbil, Rhombomys opimus. The Iranian LRV sequences showed the highest similarities to an Old World L. major LRV2 and were genetically distant from LRV1 isolates detected in New World Leishmania parasites. We could not attribute treatment failure in VL patient to the presence of LRV due to the limited number of specimens analyzed. Further studies with inclusion of more clinical samples are required to elucidate the potential role of LRVs in pathogenesis or treatment failure of Old World leishmaniasis.

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Objective: Leishmania RNA virus (LRV) is a double-stranded RNA (dsRNA) virus that circulates within many species of the Leishmania parasite. In this study, we aimed to investigate the presence of LRV2 circulating in Leishmania isolates in an old focus of ZCL located in northeastern of Iran. Methods: Leishmania isolates were collected from 85 patients that confirmed to have cutaneous leishmaniasis (CL) based on parasitological examination. To identify the Leishmania isolates, speciesspecific primer sets were applied for molecular identification. The presence of LRV2 was performed by RdRp-semi nested-PCR. The genetic diversity were calculated using MEGA and DnaSP. To assess haplotype diversity, 31 LRV2 strains in different regions were surveyed using analysis a 292-bp section of the RdRp sequences. Results: Out of 85 patients, 83 (97.6 %) were diagnosed with L. major and 2 (2.4 %) with L. tropica. LRV2 virus was detected in 59 (69.4%) of the CL cases. For the first time, LRV2 was reported in one L. tropica strain in Iran. The current LRV2 sequences indicated the highest similarities to an Old World LRV2. Moreover, 10 unique haplotypes were identified based on the analyzed sequences of the RdRp gene. Conclusions: Our results indicated the highest occurrence of Leishmania/LRV2 co-circulation in this known ZCL focus from northeastern Iran. Phylogenetic analyses of LRV2 sequences confirmed that these isolates belong to the order of LRV2 from the Old World. This study offered an insight into LRV2 haplotype that the informative issue can be used for genetic research of LRV2 in other regions.