Intrauterine viruses can infect the decidua and placenta and cause adverse effects on the fetus during gestation. This review discusses the contribution of various viral infections to miscarriage and the molecular mechanisms by which viruses can cause devastating effects on healthy fetuses and induce miscarriage. Severe acute respiratory syndrome coronavirus 2 as newly emerged coronavirus was considered here, due to the concerns about its role during pregnancy and inducing miscarriage, as well.In this narrative review, an extensive literature search was conducted to find all studies investigating viral infections in miscarriage and their molecular mechanisms published over the past 20 years. The results of various studies investigating the roles of 20 viral infections in miscarriage are presented. Then, the mechanisms of pregnancy

Background Human adenovirus (HAdV) is an important viral agent in children which can lead to severe acute respiratory infection (SARI). Reports on molecular epidemiology of HAdVs in Iran are limited. This case-control study is conducted to compare the HAdV infection rate and molecular epidemiology among two groups of children with and without respiratory symptoms in Tehran, Iran during 2018–2019. Methods Nested PCR was performed on 120 oropharyngeal swabs taken from children aged five and younger with SARI who were hospitalized as the case group, and 120 oropharyngeal swabs were collected from children of the same age without respiratory symptoms as the control group. For positive samples Sanger sequencing was done and a phylogenetic tree was drawn afterward. Results Out of 120 cases, 8 (6.6%) tested positive for eachHAdV types including 6 (75%) HAdV-B7, 1 (12.5%) HAdV-C2, and 1 (12.5%) HAdV-C6. Among the control group, out of 120 samples, 8 (6.6%) were positive comprising 5 (62.5%) HAdV-C5, 2 (25%) HAdV-F41, and 1 (12.5%) HAdV-C6. Conclusion The present study indicated a different viewpoint of HAdV molecular epidemiology in which the genotypes were compared in children with and without respiratory symptoms. HAdV prevalence was equally common in cases and controls but different genotypes were detected in these two groups. HAdV-B7 was the main type among children with SARI, dissimilar to children with no respiratory symptoms where HAdV-C5 was the predominant type. Detecting HAdV-F in oropharyngeal swabs was a rare finding, which requires further investigation.

Background SARS‐CoV‐2 genomic surveillance is necessary for the detection, monitoring, and evaluation of virus variants, which can have increased transmissibility, disease severity, or other adverse effects. We sequenced 330 SARS‐CoV‐2 genomes during the sixth wave of the COVID pandemic in Iran and compared them with five previous waves, for identifying SARS‐CoV‐2 variants, the genomic behavior of the virus, and understanding its characteristics. Methods After viral RNA extraction from clinical samples collected during the COVID‐19 pandemic, next generation sequencing was performed using the Nextseq and Nanopore platforms. The sequencing data were analyzed and compared with reference sequences. Results In Iran during the first wave, V and L clades were detected. The second wave was recognized by G, GH, and GR clades. Circulating clades during the third wave were GH and GR. In the fourth wave, GRY (alpha variant), GK (delta variant), and one GH clade (beta variant) were detected. All viruses in the fifth wave were in GK clade (delta variant). In the sixth wave, Omicron variant (GRA clade) was circulating. Conclusions Genome sequencing, a key strategy in genomic surveillance systems, helps to detect and monitor the prevalence of SARS‐CoV‐2 variants, monitor the viral evolution of SARS‐CoV‐2, identify new variants for disease prevention, control, and treatment, and also provide information for and conduct public health measures in this area. With this system, Iran could be ready for surveillance of other respiratory virus diseases besides influenza and SARS‐CoV‐2.

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Many evidence suggests that long‐lasting infection can develop with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). This occurrence has been widely described in immunocompromised individuals. In these patients, ineffective clearance of virus infection provides an opportunity for developing immune escape mutants. This study aimed to characterize SARS‐CoV‐2 intrahost evolution in five immunocompromised in comparison with five immunocompetent COVID‐19 patients during treatment. We performed next‐generation sequencing (NGS) on collected two oropharyngeal samples from immunocompromised and immunocompetent COVID‐19 patients before and after treatment. In this study, we detected alpha and delta variants of SARS‐CoV‐2. The most common substitutions in structural proteins in patients with alpha variant were S‐ΔY143‐144, A570D, D614G and D1118H, and N‐R203K and G204R, and in delta variant S‐T19R, G142D, E156G, 157‐158del, L452R, T478K, D614G, D950N and N‐D63G, R203M and D377Y were dominant. The common variations in nonstructural and accessory proteins including nsp3‐A488S, P1228L, nsp6‐T77A, nsp12‐P323L, G671S, nsp13‐P77L, NS3‐S26L, and NS7a‐T120I were detected. Also some infrequent substitutions were seen in immunocompromised and immunocompetent patients. After treatment, nsp12‐V166A was emerged as a remdesivir resistance and S‐L452M in a patient with common variable immunodeficiency. S‐E484Q was detected in a patient with acute lymphoma leukemia. This study showed the possibility of the genetic diversity and development of some new mutations in immunocompromised patients. Therefore, surveillance of these patients to characterize any new variants is necessary.