Torque teno virus (TTV) is a promising novel marker for quantifying the immune function in solid organ recipients, whose diagnostic accuracy of acute rejection (AR) and infection after kidney transplantation (KT) has not been evaluated. We performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of TTV for discriminating AR and infection after KT. Eleven studies were included in the meta-analysis. Seven studies focused on the diagnostic accuracy of TTV for AR, and the pooled analysis indicated patients who developed AR had a significant lower TTV viral DNA load (log10 copies/mL, MD: -0.74, p < 0.01). The pooled sensitivity, specificity, and area under the receiver operating characteristics curve for TTV in AR differentiation were 0.61 (0.36-0.82), 0.81 (0.64-0.91), and 0.79 (0.75-0.82), respectively. The overall diagnostic odds ratio (DOR) was 6.74 (2.60-17.50), positive likelihood ratio (PLR) was 3.22 (1.75-5.95), and negative likelihood ratio (NLR) was 0.48 (0.27-0.84), respectively. Similarly, seven studies investigated the infection discrimination and found that patients who subsequently developed posttransplant infection had higher plasma TTV DNA loads (log10 copies/mL, MD: 0.65; p < 0.01) than those remaiing infection-free. Pooled sensitivity, specificity, and area under the receiver operating characteristics curve for TTV in infection differentiation were 0.72 (0.39-0.91), 0.57 (0.30-0.80), and 0.68 (0.64-0.72), respectively. The overall DOR was 3.28 (95% confidence interval [CI]: 2.08-5.17), the pooled PLR and NLR were 1.65 (95% CI: 1.25-2.18) and 0.50 (95% CI: 0.29-0.86), respectively. TTV might be a modest indicator for risk stratification of AR after KT, but it is a poor to discriminate posttransplant infection.

Viruses enter host cells via several mechanisms, including endocytosis, macropinocytosis, and phagocytosis. They can also fuse at the plasma membrane and can spread within the host via cell-to-cell fusion or syncytia. The mechanism used by a given viral strain depends on its external topology and proteome and the type of cell being entered. This comparative review discusses the cellular attachment receptors and entry pathways of dsDNA viruses belonging to the families Adenoviridae, Baculoviridae, Herpesviridae and nucleocytoplasmic large DNA viruses (NCLDVs) belonging to the families Ascoviridae, Asfarviridae, Iridoviridae, Phycodnaviridae, and Poxviridae, and giant viruses belonging to the families Mimiviridae and Marseilleviridae as well as the proposed families Pandoraviridae and Pithoviridae. Although these viruses have several common features (e.g., topology, replication and protein sequence similarities) they utilize different entry pathways to infect wide-range of hosts, including humans, other mammals, invertebrates, fish, protozoa and algae. Similarities and differences between the entry methods used by these virus families are highlighted, with particular emphasis on viral topology and proteins that mediate viral attachment and entry. Cell types that are frequently used to study viral entry are also reviewed, along with other factors that affect virus-host cell interactions.

BACKGROUND: Oncogenic viruses have recently been allied with lung carcinoma, however, the causal association has not been established till date. The study was conducted to determine the prevalence of high-risk Human papillomavirus (HPV; subtypes 16, 18, 31, 33 and 45), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) in lung carcinoma using polymerase chain reaction (PCR) on fine needle aspirates.
METHODS: Fine needle aspirates of patients with lung carcinoma were included as cases. The control samples included normal lung tissue, collected at the time of medico legal autopsies. DNA was extracted from samples of both cases and controls and analysed by PCR for the presence of HPV, EBV and CMV.
RESULTS: A total of 5/73 (6.8%) cases demonstrated the presence of HPV. Of these, 3 were positive for HPV-16 and one each for HPV-18 and HPV-45. A significant association of HPV with squamous cell carcinoma (SCC) (P = 0.01) was observed. Two cases were positive for EBV; however, the difference was not statistically significant for EBV (P = 0.5) as well as CMV. None of the controls were positive for HPV, EBV or CMV.
CONCLUSIONS: We conclude that fine needle aspirates can serve as reliable sample for PCR based detection of viruses. A significantly higher prevalence of HPV in lung cancer and a significant association with SCC was observed, thereby, indicating a positive link between HPV and etiopathogenesis of lung carcinoma. Diagn. Cytopathol. 2016;44:987-993. © 2016 Wiley Periodicals, Inc.

Numerous studies have found the presence of viral DNA in colorectal tumor tissues. However, whether viral infections contribute to the risk of colorectal cancer (CRC) is still under debate. We aimed to provide an overview of published epidemiological studies on the association between viral infections and CRC. A systematic literature search was performed in PubMed to find relevant studies published until 8 May 2014. Information collected included study population, sample type, laboratory method and prevalence of viral infection in cancer or precancer patients and controls. We found 41 studies that fulfilled the selection criteria, all of which had cross-sectional or case-control designs, and most of which were of small to moderate size. Viral infections included human papillomaviruses (HPV), human polyomaviruses, human herpesviruses, human bocavirus and Inoue-Melnick virus. Inconsistent results were observed across studies. Many studies reported higher viral DNA prevalence in tumor tissues than in normal noncancerous tissues either in the same patients or in CRC-free controls. However, potential contamination or temporal sequence of the infection and cancer development were often unclear. Seroprevalence studies assessing antibody titers indicative of viral infections did not find statistically significant differences between CRC cases and healthy controls. Overall published evidence on the role of viral infections in CRC etiology remains limited. Given the potential importance of viral infections and their implication for prevention, there is a strong need for large, methodologically rigorous epidemiological studies.

Viruses in three genera of the family Iridoviridae (iridoviruses) affect finfish. Ranaviruses and megalocytiviruses are recently emerged pathogens. Both cause severe systemic disease, occur globally and affect a diversity of hosts. In contrast, lymphocystiviruses cause superficial lesions and rarely cause economic loss. The ranavirus epizootic haematopoietic necrosis virus (EHNV) from Australia was the first iridovirus to cause epizootic mortality in finfish. Like other ranaviruses, it lacks host specificity. A distinct but closely related virus, European catfish virus, occurs in finfish in Europe, while very similar ranaviruses occur in amphibians in Europe, Asia, Australia, North America and South America. These viruses can be distinguished from one another by conserved differences in the sequence of the major capsid protein gene, which informs policies of the World Organisation for Animal Health to minimize transboundary spread of these agents. However, limited epidemiological information and variations in disease expression create difficulties for design of sampling strategies for surveillance. There is still uncertainty surrounding the taxonomy of some putative ranaviruses such as Singapore grouper iridovirus and Santee-Cooper ranavirus, both of which cause serious disease in fish, and confusion continues with diseases caused by megalocytiviruses. In this review, aspects of the agents and diseases caused by ranaviruses are contrasted with those due to megalocytiviruses to promote accurate diagnosis and characterization of the agents responsible. Ranavirus epizootics in amphibians are also discussed because of possible links with finfish and common anthropogenic mechanisms of spread. The source of the global epizootic of disease caused by systemic iridoviruses in finfish and amphibians is uncertain, but three possibilities are discussed: trade in food fish, trade in ornamental fish, reptiles and amphibians and emergence from unknown reservoir hosts associated with environmental change.

The present review gives an updated overview of transfusion transmitted virus (TTV), a novel agent, in relation to its molecular characteristics, epidemiological features, modes of transmission, tissue tropism, pathogenesis, role in various diseases and its eradication from the body. TTV, a DNA virus, is a single stranded, non-enveloped, 3.8 kb long DNA virus with a small and covalently closed circular genome comprising 3852 bases. It was tentatively designated Circinoviridae virus. TTV genome sequence is heterogeneous and reveals the existence of six different genotypes and several subtypes. TTV has been reported to transmit not only via parenteral routes, but also via alternate routes. This virus has been detected in different non-human primates as well. At present, TTV is detected by polymerase chain reaction (PCR) with no other available diagnostic assays. It shows its presence globally and was detected in high percent populations of healthy persons as well as in various disease groups. Initially it was supposed to have strong association with liver disease; however, there is little evidence to show its liver tropism and contribution in causing liver diseases. It shows high prevalence in hemodialysis patients, pointing towards its significance in renal diseases. In addition, TTV is associated with several infectious and non-infectious diseases. Though, its exact pathogenesis is not yet clear, TTV virus possibly resides and multiplies in bone marrow cells and peripheral blood mononuclear cells (PBMCs). Recently, attempts have been made to eradicate this virus with interferon treatment. More information is still needed to extricate various mysteries related to TTV.

In the past 10 years, hepatitis C and G viruses have been identified, and in the last two years a further parenterally transmitted agent, termed TT virus (TTV), has been discovered. These viruses have a worldwide distribution and frequently cause chronic infection. The purpose of this article was to promote an understanding of these viral agents and their relevance in dental practice. Infected patients may develop a chronic carrier state without clinical disease or may develop liver disease, and may have related oral conditions. Dental providers will see a growing number of patients with HCV/HGV and possibly TTV infection. All of these patients require appropriate infection control measures during dental treatment.

In 1997, a new DNA virus was cloned by a Japanese team and designated TT virus (TTV). This virus seemed to be associated with non-A, non-G post-transfusion hepatitis. It was isolated by polymerase chain reaction (PCR) and was presumed to be human Circoviridae. The virus is heterogenous; 16 different genotypes are currently registered, and it can be classified as a \"swarm\" of at least 5 different viruses. Depending on the PCR technique used, the prevalence of infection ranges from 1.9 to 36% among blood donors, from 11.5 to 71% in hemodialysis patients, from 47 to 82% among patients with non-A, non-B or non-C fulminant hepatic failure, and the most elevated percentage is found in hemophiliacs. Epidemiological studies have established that the routes of TTV infection might be parenteral, oral-fecal, and possibly salivary. Mother-to-infant transmission is controversial. TTV may play a role in the pathogenesis of non-A, non-B or non-C fulminant hepatic failure. Patients co-infected with hepatitis C virus (HCV) and TTV have a significantly higher histological grade score than patients with isolated HCV infection. Treatment with interferon seems to decrease TT viremia, according to results obtained outside the context of clinical trials. TTV seems to be a light pathogenic virus. Its widespread presence in the blood of infected subjects contrasts with the apparent absence of pathological symptoms. PCR standardization is needed to clearly establish its real prevalence worldwide.

TT virus is a recently discovered virus, of which the pathogenetic potential is still uncertain. The present paper describes the histopathological features of a case of TT virus-related acute recurrent hepatitis. The patient is a 28-year-old woman with no history of drug or alcohol abuse, presenting with repeated episodes of hypertransaminasemia evidenced during the last 4 years. No other markers of viral or autoimmune disease were found. On histological analysis, the liver parenchyma showed a preserved architecture. The histological features were those of a mild acute hepatitis. The clinicopathological findings suggest th

Cidofovir is a potent nucleoside analog antiviral drug approved for the treatment of cytomegalovirus (CMV) retinitis in patients with the Acquired Immune Deficiency Syndrome (AIDS). It is currently available only for intravenous infusion. Several small studies and case reports describe the successful use of cidofovir applied either topically or by intralesional injection in several virally induced cutaneous diseases. Available information demonstrates that cidofovir is a potent antiviral agent with activity against several DNA viruses that cause cutaneous disease when applied topically or administered by intralesional injection. No significant systemic side effects have been noted, although application site reactions are common and can occasionally be severe. The effective use of topical and intralesional cidofovir for the treatment of diseases of the skin caused by DNA viruses has been demonstrated in animals and a limited number of patients including those infected with human immunodeficiency virus (HIV). This article reviews the pharmacology of cidofovir and the utility of topical and intralesional cidofovir for the treatment of viral infections caused by human papillomavirus, herpesviruses (including acyclovir resistant strains), Kaposi\'s sarcoma-associated herpesvirus, molluscum contagiosum and monkeypox.