Electronic health record year and country of birth testing and patient navigation to increase diagnosis of chronic viral hepatitis.

The United States Preventive Services Task Force recommends hepatitis C testing people born from 1945 to 1965, "birth cohort" as well as hepatitis C and hepatitis B testing people from countries of birth with endemic infection risk. We automated the hospital electronic health record system to test birth cohort and those born in countries with endemic infection risk. A script is launched searching the laboratory database upon registration for any hepatitis C antibody, hepatitis C RNA and/or hepatitis B surface antigen result. If no positive result was found, a hepatitis C antibody/reflex RNA and/or hepatitis B surface antigen were ordered. A patient navigator received weekly results and assisted patients with positive serology to schedule an appointment with their primary care provider or treatment specialist. A total of 10 726 participants were hepatitis C antibody tested, with 6.9% antibody positive. Monthly hepatitis C testing from January to July 2016 compared to August 2016-August 2017 increased 342% as a result of "birth cohort" testing. Following country of birth testing, monthly hepatitis B and hepatitis C testing increased 91%, and 44%, respectively, during June-August 2017 compared to September 2017-March 2018. 67% of hepatitis C-positive patients were linked to care. If the navigator contacted the patient, 92% were linked to care, and 32% were treated. Of hepatitis B surface antigen-positive patients, 43% were linked to care, 5% were on treatment, and 15% started treatment. Automated electronic health record ordering of hepatitis C and/or hepatitis B testing is feasible and increases testing. In the population tested, much improvement is needed with linkage to care and treatment.

Full annotation of serum virome in Chinese blood donors with elevated alanine aminotransferase levels.

BACKGROUND: A serum alanine aminotransferase (ALT) test is currently demanded for blood donation in China. One of the major reasons to include such a test is possible etiology of known or unknown hepatotropic viruses. However, this hypothesis has never been examined convincingly. STUDY DESIGN AND METHODS: The study recruited 90 Chinese blood donors that were divided into three groups based on their ALT values. Serum virome from these donors was explored using a metagenomics approach with enhanced sensitivity resolved at single sequencing reads. RESULTS: Anellovirus and pegivirus C (GBV-C) were detected among these donors. None of them were found solely in donors with abnormal liver enzyme. Anellovirus was highly prevalent (93.3%) and the co-infection with multiple genera (alpha, beta, and gammatorquevirus) were more common in the donors with normal ALT values in comparison to those with elevated ALT (single/double/triple Anellovirus genera, 1/3/24 vs. 7/7/14 or 6/7/13, p = 0.009). For unmapped reads that accounted for 15 ± 14.9% of the data, similarity-based (BLASTN, BLASTP, and HMMER3) and similarity-independent (k-mer frequency) analysis identified several circular rep encoding ssDNA (CRESS-DNA) genomes. Direct PCR testing indicated these genomes were likely reagent contaminants. CONCLUSION: Viral etiology is not responsible for elevated ALT levels in Chinese blood donors. The ALT test, if not abandoned, should be adjusted for its cutoff in response to donor shortage in China.

Acute Liver Failure of Indeterminate Etiology: A Comprehensive Systematic Approach by An Expert Committee to Establish Causality.

OBJECTIVES: In the United States, the Acute Liver Failure Study Group (ALFSG) registry lists approximately 11% of cases as of indeterminate etiology (IND-ALF) as determined by the respective local site principal investigator (PI). Traditionally, IND-ALF has prompted concern that other viruses or toxins might be implicated. We hypothesized that many IND- ALF cases would have an identifiable etiology upon further investigation. Improving the identification process should reduce the number of truly indeterminate cases. METHODS: Specific definitions for each etiology ("etiology-specific algorithms") were developed by a Causality Adjudication Committee that included six reviewers (each with 20 or more years of experience). Of 2718 patients with ALF, 303 initially deemed IND-ALF by site PIs underwent committee review guided by the algorithms. Acetaminophen (APAP) protein adducts were measured in sera when available, additional HEV testing was performed, and viral sequences sought by microarray analysis and metagenomic next-generation sequencing (mNGS). Study sites were asked to provide liver biopsy and/or explant reports and to update serological findings not reported previously. RESULTS: Nearly half (142, 46.9%) of the 303 IND-ALF cases could be reassigned to a single, defined etiology and rated as highly likely or probable; 11 additional cases, upon review, did not meet ALF criteria. Amongst reassigned etiologies, 45 were previously unrecognized APAP, 34 autoimmune hepatitis (AIH), 24 drug-induced liver injury (DILI), 13 various viral causes, 12 ischemia, and 14 miscellaneous other etiologies. The remaining 150, deemed true IND-ALF, represented just 5.5%. CONCLUSIONS: The indeterminate etiology in ALF includes patients with a diagnosis that is discernible after closer examination. Revision of etiologic diagnoses of indeterminate cases using added testing and expert opinion is useful in understanding all aspects of ALF.

Viral Surveillance in Serum Samples From Patients With Acute Liver Failure By Metagenomic Next-Generation Sequencing.

BACKGROUND: Twelve percent of all acute liver failure (ALF) cases are of unknown origin, often termed indeterminate. A previously unrecognized hepatotropic virus has been suspected as a potential etiologic agent. METHODS: We compared the performance of metagenomic next-generation sequencing (mNGS) with confirmatory nucleic acid testing (NAT) to routine clinical diagnostic testing in detection of known or novel viruses associated with ALF. Serum samples from 204 adult ALF patients collected from 1998 to 2010 as part of a nationwide registry were analyzed. One hundred eighty-seven patients (92%) were classified as indeterminate, while the remaining 17 patients (8%) served as controls, with infections by either hepatitis A virus or hepatitis B virus (HBV), or a noninfectious cause for their ALF. RESULTS: Eight cases of infection from previously unrecognized viral pathogens were detected by mNGS (4 cases of herpes simplex virus type 1, including 1 case of coinfection with HBV, and 1 case each of HBV, parvovirus B19, cytomegalovirus, and human herpesvirus 7). Several missed dual or triple infections were also identified, and assembled viral genomes provided additional information on genotyping and drug resistance mutations. Importantly, no sequences corresponding to novel viruses were detected. CONCLUSIONS: These results suggest that ALF patients should be screened for the presence of uncommon viruses and coinfections, and that most cases of indeterminate ALF in the United States do not appear to be caused by novel viral pathogens. In the future, mNGS testing may be useful for comprehensive diagnosis of viruses associated with ALF, or to exclude infectious etiologies.

Effect of scavenger receptor class B type I antagonist ITX5061 in patients with hepatitis C virus infection undergoing liver transplantation.

Hepatitis C virus (HCV) entry inhibitors have been hypothesized to prevent infection of the liver after transplantation. ITX5061 is a scavenger receptor class B type I antagonist that blocks HCV entry and infection in vitro. We assessed the safety and efficacy of ITX5061 to limit HCV infection of the graft. The study included 23 HCV-infected patients undergoing liver transplantation. The first 13 "control" patients did not receive drug. The subsequent 10 patients received 150 mg of ITX5061 immediately before and after transplant and daily for 1 week thereafter. ITX5061 pharmacokinetics and plasma HCV RNA were quantified. Viral genetic diversity was measured by ultradeep pyrosequencing (UDPS). ITX5061 was well tolerated with measurable plasma concentrations during therapy. Although the median HCV RNA reduction was greater in ITX-treated patients at all time points in the first week after transplantation, there was no difference in the overall change in the area over the HCV RNA curve in the 7-day treatment period. However, in genotype (GT) 1-infected patients, treatment was associated with a sustained reduction in HCV RNA levels compared to the control group (area over the HCV RNA curve analysis, P = 0.004). UDPS revealed a complex and evolving pattern of HCV variants infecting the graft during the first week. ITX5061 significantly limited viral evolution where the median divergence between day 0 and day 7 was 3.5% in the control group compared to 0.1% in the treated group. In conclusion, ITX5061 reduces plasma HCV RNA after transplant notably in GT 1-infected patients and slows viral evolution. Following liver transplantation, the likely contribution of extrahepatic reservoirs of HCV necessitates combining entry inhibitors such as ITX5061 with inhibitors of replication in future studies.

Prevention of hepatitis C virus infection using a broad cross-neutralizing monoclonal antibody (AR4A) and epigallocatechin gallate.

The anti-hepatitis C virus (HCV) activity of a novel monoclonal antibody (mAb; AR4A) and epigallocatechin gallate (EGCG) were studied in vitro using a HCV cell culture system and in vivo using a humanized liver mouse model capable of supporting HCV replication. Alone, both exhibit reliable cross-genotype HCV inhibition in vitro, and combination therapy completely prevented HCV infection. In vitro AR4A mAb (alone and combined with EGCG) robustly protects against the establishment of HCV genotype 1a infection. EGCG alone fails to reliably protect against an HCV challenge. In conclusion, AR4A mAb represents a safe and efficacious broadly neutralizing antibody against HCV applicable to strategies to safely prevent HCV reinfection following liver transplantation, and it lends further support to the concept of HCV vaccine development. The poor bioavailability of EGCG limits HCV antiviral activity in vitro.

Safety and efficacy of simeprevir plus sofosbuvir with or without ribavirin in patients with decompensated genotype 1 hepatitis C cirrhosis.

Combination antiviral therapy involving sofosbuvir (SOF) and simeprevir (SIM) is a treatment option in patients with genotype 1 chronic hepatitis C; however, the safety of this regimen in patients with decompensated cirrhosis is not established. Data from a combined treatment cohort of 2 large hepatology referral centers were evaluated to assess for safety and efficacy of SIM plus SOF with or without ribavirin (RBV) in patients with Child B or C cirrhosis. All (n = 42) patients included in the analysis had Child B (n = 35) or C (n = 7) cirrhosis and received 400 mg daily of SOF plus 150 mg daily of SIM, with (n = 7) or without (n = 35) RBV, for 12 weeks. Of the 42 patients in this cohort, 31 (74%) were male, 22 (52%) had failed prior treatments, and 28 (67%) were genotype 1a. Prior decompensating events included encephalopathy (57%), fluid overload (88%), or variceal hemorrhage (24%). Median Model for End-Stage Liver Disease score was 12 (range, 6-25). Treatment was well tolerated overall with more than one-half (57%) reporting no adverse events. In those reporting adverse events, the most common were fatigue (n = 6), insomnia (n = 4), headache (n = 5), nausea (n = 4), and grade 1 rash (n = 1). One patient developed chemical pancreatitis that did not require treatment discontinuation. Three of 7 patients who received RBV developed anemia, with 2 requiring blood transfusions and 1 requiring a dose reduction. No episodes of decompensation requiring hospitalization or deaths occurred on treatment. Of 42 patients, 38 (90%) patients had negative viral load at end of treatment (EOT), and 31 of 42 patients (74%) achieved sustained virological response 12 weeks after EOT; 10 of 10 patients (100%) with HCV genotype 1b achieved sustained virological response for 12 weeks (SVR12). In conclusion, SOF plus SIM was very well tolerated in patients with advanced Child B/C decompensated cirrhosis. Overall, 74% of patients achieved SVR12; 100% of patients with genotype 1b decompensated cirrhosis achieved SVR12.

Cutaneous Granulomas Associated With Interferon Therapy.

Treatment with interferon (IFN) could be associated with variable cutaneous adverse reactions. The aim of this study was to describe the clinicopathological spectrum of cutaneous granulomas associated with IFN therapy and identify the causal relation between IFN therapy and granulomatous reactions. The study included 18 patients (16 males and 2 females) with an average age of 48 years. Clinically, most of the lesions were solitary (83.3%) and located on the face (44.4%) and/or trunk (38.9%). The lesions were commonly presented as nodules (33.3%) or plaques (27.8%) with a common size of 5-10 cm. Granulomatous reactions were localized to the injection site in 4 cases, distributed on other body areas (remote granuloma) in 11 cases, and associated with lung involvement (systemic granuloma) in 3 cases. Histologically, injection site granuloma showed suppurative reaction in 75% and sarcoidal reaction in 25%. Remote granuloma showed tuberculoid reaction in 27.3%, interstitial in 27.3%, and sarcoidal in 45.4%. Systemic granuloma showed sarcoidal reaction in all cases. After withdrawal of IFN, only 3 lesions showed spontaneous complete clearance, whereas most of the lesions (83.3%) showed only partial improvement. Our results suggested that IFN is not a causal agent of all associated cutaneous granulomas but it mostly provokes the appearance of granulomatous reactions in susceptible individuals. Findings that prove this concept include the formation of granuloma in body sites away from the injection site, the heterogeneous pattern of granuloma both clinically and histologically, and incomplete clearance of most of the lesions after withdrawal of IFN.

Hepatic DNA Methylation Is Affected by Hepatocellular Carcinoma Risk in Patients with and without Hepatitis Virus.

OBJECTIVES: Several studies revealed that the proportion of hepatocellular carcinoma (HCC) without hepatitis virus infection (NBNC-HCC) is increasing. On the other hand, epigenetic alterations are reportedly responsible for HCC development. Here, we identified HCC risk factors that are associated with DNA methylation in the background liver tissue of NBNC-HCC patients. METHODS: We performed methylation analysis in 37 pairs of virus-positive and 22 pairs of NBNC-HCC and non-cancerous livers using a HumanMethylation450 BeadChip array. After the selection of differentially methylated CpGs (DM-CpGs) in cancerous and non-cancerous livers, we analyzed DNA methylation of DM-CpGs within the adjacent non-cancerous liver tissue that is affected by specific HCC risk factors. RESULTS: A total of 38,331 CpGs were selected as DM-CpGs using the following criteria: difference of ß-value between HCC and non-cancerous liver ≥0.15 and false discovery rate (FDR) q < 1.0E-12. We subsequently selected the DM-CpGs that had methylation differences with the background liver tissue (that has FDR q < 0.35). Among the virus-positive patients, the type of hepatitis virus was mostly associated with differences in methylation within the background liver tissues. However, we found that background methylation patterns were most significantly associated with aging in NBNC patients. Interestingly, age-related methylation differences in DM-CpGs were also observed in NBNC-HCC tissues. CONCLUSIONS: Hepatitis viruses affect the methylation profiles within background liver tissues. However, difference in background methylation was mostly associated with age in NCBC-HCC patients; some age-related methylation events could contribute to emergence of NBNC-HCC in elderly individuals.

Current perspectives of viral hepatitis.

Viral hepatitis represents a major danger to public health, and is a globally leading cause of death. The five liver-specific viruses: Hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus, and hepatitis E virus, each have their own unique epidemiology, structural biology, transmission, endemic patterns, risk of liver complications, and response to antiviral therapies. There remain few options for treatment, in spite of the increasing prevalence of viral-hepatitis-caused liver disease. Furthermore, chronic viral hepatitis is a leading worldwide cause of both liver-related morbidity and mortality, even though effective treatments are available that could reduce or prevent most patients' complications. In 2016, the World Health Organization released its plan to eliminate viral hepatitis as a public health threat by the year 2030, along with a discussion of current gaps and prospects for both regional and global eradication of viral hepatitis. Today, treatment is sufficiently able to prevent the disease from reaching advanced phases. However, future therapies must be extremely safe, and should ideally limit the period of treatment necessary. A better understanding of pathogenesis will prove beneficial in the development of potential treatment strategies targeting infections by viral hepatitis. This review aims to summarize the current state of knowledge on each type of viral hepatitis, together with major innovations.

VIRsiRNApred: a web server for predicting inhibition efficacy of siRNAs targeting human viruses.

BACKGROUND: Selection of effective viral siRNA is an indispensable step in the development of siRNA based antiviral therapeutics. Despite immense potential, a viral siRNA efficacy prediction algorithm is still not available. Moreover, performances of the existing general mammalian siRNA efficacy predictors are not satisfactory for viral siRNAs. Therefore, we have developed "VIRsiRNApred" a support vector machine (SVM) based method for predicting the efficacy of viral siRNA. METHODS: In the present study, we have employed a new dataset of 1725 viral siRNAs with experimentally verified quantitative efficacies tested under heterogeneous experimental conditions and targeting as many as 37 important human viruses including HIV, Influenza, HCV, HBV, SARS etc. These siRNAs were divided into training (T1380) and validation (V345) datasets. Important siRNA sequence features including mono to penta nucleotide frequencies, binary pattern, thermodynamic properties and secondary structure were employed for model development. RESULTS: During 10-fold cross validation on T1380 using hybrid approach, we achieved a maximum Pearson Correlation Coefficient (PCC) of 0.55 between predicted and actual efficacy of viral siRNAs. On V345 independent dataset, our best model achieved a maximum correlation of 0.50 while existing general siRNA prediction methods showed PCC from 0.05 to 0.18. However, using leave one out cross validation PCC was improved to 0.58 and 0.55 on training and validation datasets respectively. SVM performed better than other machine learning techniques used like ANN, KNN and REP Tree. CONCLUSION: VIRsiRNApred is the first algorithm for predicting inhibition efficacy of viral siRNAs which is developed using experimentally verified viral siRNAs. We hope this algorithm would be useful in predicting highly potent viral siRNA to aid siRNA based antiviral therapeutics development. The web server is freely available at http://crdd.osdd.net/servers/virsirnapred/.

Effects of antiviral therapy on hepatitis B virus reactivation and liver function after resection or chemoembolization for hepatocellular carcinoma.

BACKGROUND: How hepatitis B virus (HBV) infection react to hepatocellular carcinoma (HCC) treatment remains unclear, and the roles of anti-HBV therapy were seldom reported in HCC. AIMS: To evaluate changes of HBV replication and liver function after hepatectomy or transarterial chemoembolization (TACE) for HCC, also the short-term effects of anti-viral therapy were analyzed. METHODS: Totally, 590 HBsAg (+) HCC patients were recruited into two groups: only surgical resection, and only TACE, and subgrouped according to anti-HBV therapy or none. Clinical data were analyzed for statistical significance and risk factors for adverse events. RESULTS: In the no antiviral therapy groups, rates of HBV reactivation were 15.7% and 17.5% in patients who underwent hepatectomy and TACE, respectively, while the rates of deterioration of liver function were 4.1% and 8.1%, respectively. In contrast, in the antivirus group, the rates of reactivation were 0% and 1.5% after hepatectomy and TACE respectively, while the liver function deterioration rates were 2.4% and 1.5%, respectively. For patients who underwent hepatectomy, no antiviral therapy, and long hepatic inflow occlusion times increased the risk of HBV reactivation. For TACE, no antivirus and HBeAg negativity were the risk factors for reactivation. HBV reactivation was significantly correlated to liver function exacerbation after hepatectomy, while HBV reactivation, baseline ALT (alanine aminotransferase), and α-fetoprotein levels were significantly correlated to liver function exacerbation after TACE. CONCLUSIONS: HBV reactivation can occur after hepatectomy or TACE. Anti-HBV therapy can reduce the risk of reactivation, thus reducing the risk of liver failure especially in patients undergoing TACE.

Metagenomic Detection of Divergent Insect- and Bat-Associated Viruses in Plasma from Two African Individuals Enrolled in Blood-Borne Surveillance.

Metagenomic next-generation sequencing (mNGS) has enabled the high-throughput multiplexed identification of sequences from microbes of potential medical relevance. This approach has become indispensable for viral pathogen discovery and broad-based surveillance of emerging or re-emerging pathogens. From 2015 to 2019, plasma was collected from 9586 individuals in Cameroon and the Democratic Republic of the Congo enrolled in a combined hepatitis virus and retrovirus surveillance program. A subset (n = 726) of the patient specimens was analyzed by mNGS to identify viral co-infections. While co-infections from known blood-borne viruses were detected, divergent sequences from nine poorly characterized or previously uncharacterized viruses were also identified in two individuals. These were assigned to the following groups by genomic and phylogenetic analyses: densovirus, nodavirus, jingmenvirus, bastrovirus, dicistrovirus, picornavirus, and cyclovirus. Although of unclear pathogenicity, these viruses were found circulating at high enough concentrations in plasma for genomes to be assembled and were most closely related to those previously associated with bird or bat excrement. Phylogenetic analyses and in silico host predictions suggested that these are invertebrate viruses likely transmitted through feces containing consumed insects or through contaminated shellfish. This study highlights the power of metagenomics and in silico host prediction in characterizing novel viral infections in susceptible individuals, including those who are immunocompromised from hepatitis viruses and retroviruses, or potentially exposed to zoonotic viruses from animal reservoir species.

Risk factors for infection with different hepatitis C virus genotypes in southern Brazil.

OBJECTIVES: To investigate the proportion of different genotypes in countryside microregions in southern Brazil, and their association with risk factors. METHODS: Cross-sectional study including a convenience sample of patients who tested positive for HCV-RNA and were referred to a regional health center for genotyping, from December 2003 to January 2008. Data were obtained through the National Disease Surveillance Data System, from laboratory registers and from patient charts. Identification of genotypes was carried out using the Restriction Fragment Length Polymorphism "in house" technique. Independent associations with genotypes were evaluated in multinomial logistic regression and prevalence rates of genotypes were estimated with modified Poisson regression. RESULTS: The sample consisted of 441 individuals, 41.1 ± 12.0 years old, 56.5% men. Genotype 1 was observed in 41.5% (95% CI 37.9-48.1) of patients, genotype 2 in 19.3% (95% CI 15.0-23.6), and genotype 3 in 39.2% (95% CI 35.6-43.0). HCV genotype was significantly associated with gender and age. Dental procedures were associated with higher proportion of genotype 2 independently of age, education, and patient treatment center. CONCLUSIONS: The hepatitis C virus genotype 1 was the most frequent. Genotype 2 was associated with female gender, age, and dental procedure exposition.

Isolation of novel virus-like sequences associated with human hepatitis.

Two viruses, GB virus A (GBV-A) and GB virus B (GBV-B), were recently identified in the GB hepatitis agent. Human sera containing antibodies that recognize GBV-A and/or GBV-B recombinant proteins were subjected to polymerase chain reaction studies with degenerate oligonucleotides capable of amplifying a segment of the putative helicase genes from GBV-A, GBV-B or hepatitis C virus. Novel sequences related to members of the Flaviviridae were identified in sera from 12 individuals including 4 individuals with hepatitis. The limited nucleotide sequence identity between GBV-A, GBV-B and HCV sequences suggests that a novel virus, tentatively named GB virus C, may be responsible for some cases of non-A, non-B, non-C, non-D, non-E hepatitis.

[Genotyping and molecular marking of bacteria and viruses in epidemiological surveillance of actual infections].

AIM: Determination of genetic and molecular features of pathogens circulating in Russia, in the northwest of the country and in St. Petersburg to resolve the problems of spread of diseases caused by these pathogens. MATERIALS AND METHODS: Complete and limited gene sequencing, DNA restriction fragment length polymorphism analysis, spoligotyping, VNTR-typing, resistotyping and other methods were used. RESULTS: Data on population structure and dominant genotypes of tuberculosis mycobacteria, corynebacteria, helicobacteria, hepatitis A, B, C, human papilloma viruses circulating in Russia, in the northwest of the country and in St. Petersburg were obtained. Genetic divergence of rubella virus and poliovirus vaccine strains under mass vaccination conditions was detected. Evidence of higher effectiveness of pathogen genotyping methods in epidemiologic diagnostics compared with traditional epidemiological investigation was obtained. CONCLUSION: Microorganism genotyping methods were helpful in resolving strategic problems of contemporary epidemiology. Perspectives of further development of these methods are related to obtaining data on circulating genotypes in all regions of the world, establishment of complete databases on circulating genotypes and integration of this methodology into daily diagnostics and epidemiological surveillance.

Special Issue "Structural Variations and Molecular Genetics of Hepatitis Virus and Related Viruses".

In this special issue, we present collected updated data on the hepatitis viruses [...].

The impact of the timely birth dose vaccine on the global elimination of hepatitis B.

In 2016 the World Health Organization set the goal of eliminating hepatitis B globally by 2030. Horizontal transmission has been greatly reduced in most countries by scaling up coverage of the infant HBV vaccine series, and vertical transmission is therefore becoming increasingly dominant. Here we show that scaling up timely hepatitis B birth dose vaccination to 90% of new-borns in 110 low- and middle-income countries by 2030 could prevent 710,000 (580,000 to 890,000) deaths in the 2020 to 2030 birth cohorts compared to status quo, with the greatest benefits in Africa. Maintaining this could lead to elimination by 2030 in the Americas, but not before 2059 in Africa. Drops in coverage due to disruptions in 2020 may lead to 15,000 additional deaths, mostly in South-East Asia and the Western Pacific. Delays in planned scale-up could lead to an additional 580,000 deaths globally in the 2020 to 2030 birth cohorts.

Drugs of Abuse and Their Impact on Viral Pathogenesis.

Commonly misused substances such as alcohol, cocaine, heroin, methamphetamine, and opioids suppress immune responses and may impact viral pathogenesis. In recent years, illicit use of opioids has fueled outbreaks of several viral pathogens, including the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). This review focuses on the myriad of mechanisms by which drugs of abuse impact viral replication and disease progression. Virus-drug interactions can accelerate viral disease progression and lead to increased risk of virus transmission.