21,663 research outputs found
Chronic hepatitis B infection in sub-Saharan Africa: A grave challenge and a great hope
No full textIn sub-Saharan Africa, chronic infection with the hepatitis B virus (HBV) is a profoundly important public health issue characterised by high prevalence, frequent co-infection with HIV, and sub-optimally applied ascertainment and management strategies. Prevalence of hepatitis B surface antigen (HBsAg) in the general population varies geographically, with the highest rates (>8%) measured in West Africa.1 Among people living with HIV, between 6% and 25% are co-infected with HBV, and co-infection accelerates fibrosis and increases the risk of liver-related mortality and development of hepatocellular carcinoma (HCC) compared to HIV-negative controls.2
In part, as a consequence of reduced HIV-related mortality, both HCC and cirrhosis are increasing in sub-Saharan Africa.3 The proportion of deaths due to cirrhosis increased by 31% between 1990 and 2010.3 Lemoine et al. argue that if HCC and cirrhosis were grouped together, chronic viral hepatitis would rank within the top 10 causes of global mortality, above malaria and TB.4 However, accurate epidemiological data on liver-related mortality in sub-Saharan Africa are lacking, and verbal autopsy remains the predominant method of ascertaining the cause of death, which is highly likely to underestimate the true burden of disease.
Herpes simplex virus type 2: epidemiology and management options in developing countries
No full textGenital herpes simplex virus type 2 (HSV2) is highly prevalent worldwide and an increasingly important cause of genital ulcer disease (GUD). Continued HSV2 transmission is facilitated by the large number of undiagnosed cases, the frequency of atypical disease and the occurrence of asymptomatic shedding. The lack of easy, affordable diagnostic methods and specific antiviral treatment in countries with low and middle income is of great concern, given the ability of GUD to enhance HIV transmission and acquisition. With rising HSV2 prevalence contributing to an increase in the proportion of GUD attributed to genital herpes in high-HIV prevalence settings, a safe and effective HSV vaccine is urgently needed. Meanwhile, multifaceted interventions are required to improve recognition of genital herpes, to prevent its spread and also to prevent its potential to promote HIV transmission in developing countries
Epidemiology of antiretroviral drug resistance in drug-naïve persons
No full textPURPOSE OF REVIEW: An update is given on the epidemiology of transmitted antiretroviral drug resistance among HIV-1-infected adults. RECENT FINDINGS: Reported prevalence surveys show inter-region and intra-region variability, in part as a result of methodological differences. Temporal trends are difficult to define as rates appear stable or declining in some cohorts but increasing in others. While the highest prevalence continues to be observed in North America, Western Europe and areas of South America, transmitted antiretroviral drug resistance is emerging in countries where access to therapy is being scaled up, including regions of sub-Saharan Africa. Resistance patterns in drug-experienced and drug-naïve persons, transmission efficiency of resistant variants and their ability to persist as dominant species in the absence of drug pressure determine the prevalence of resistance mutations in persons with transmitted antiretroviral drug resistance. The most frequently detected mutations are in reverse transcriptase, especially thymidine analogue mutations, whereas protease mutations other than natural polymorphisms are generally less prevalent. SUMMARY: A consensus is required internationally on how transmitted antiretroviral drug resistance should be investigated and reported. Although routine testing methods provide only minimal estimates of the prevalence of transmitted antiretroviral drug resistance, successful treatment outcomes are observed in patients with resistance receiving first-line therapy guided by baseline resistance testing. © 2007 Lippincott Williams & Wilkins, Inc
HIV-1 subtypes: epidemiology and significance for HIV management
No full textPurpose of review: This review presents an update on the molecular epidemic patterns of HIV-1 infection and the effects of subtype-related genetic variability on transmission, disease progression, response to antiretroviral therapy and drug-resistance pathways. Recent findings: The molecular epidemiology of HIV-1 infection is complex and evolving. The emergence of new variants reflects HIV-1 prevalence, subtype epidemiology and risk-behaviour patterns in different geographical areas. Evidence indicates that certain subtypes may have a transmission advantage while others display higher replicative efficiency. The molecular mechanisms underlying these differences are being identified and include both virus- and host-related factors. Although drug susceptibility varies and clinical evidence remains limited, current antiretroviral regimens appear to have comparable efficacy in patients infected with B and non-B subtypes. Subtype-related variability influences resistance pathways. However, the major treatment-associated resistance mutations seen in subtype B also confer resistance in non-B subtypes and vice versa. Summary: Genetic differences among HIV-1 variants can influence the virus biological properties, susceptibility to existing and candidate antiretroviral drugs, and evolution of antiretroviral drug resistance. Further studies are required to define the impact of this variability on risk of transmission, disease outcomes, responses to antiretroviral therapy and resistance pathways. Meanwhile, plasma viral load and CD4 count remain the important predictors of disease outcome, regardless of the infecting subtype. Current antiretroviral regimens can be used reliably to treat patients with both B and non-B subtypes, and resistance interpretation algorithms provide adequate guidance. The limitations of current evidence should be acknowledged and instigate ongoing vigilance. © 2006 Lippincott Williams & Wilkins
Essential benefits of nucleoside analogue regimens in failing therapy
No full textSince the introduction of highly active antiretroviral therapy, nucleoside and more recently nucleotide reverse transcriptase inhibitors (NRTIs) have provided a highly effective backbone to antiretroviral regimens based on non-nucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs). Nonetheless, treatment failure can result from poor adherence, unfavourable pharmacokinetics, advanced disease or infection with a drug-resistant virus. Recent data have also indicated a high risk of virological failure with triple NRTI regimens, reflecting overall lower potency compared to combinations of NRTIs with either NNRTIs or PIs. Resistance mutations emerging upon failure can cause extensive cross-resistance among available NRTIs, and potentially affect susceptibility to newly developed antiretroviral drugs. However, despite the emergence of resistance, NRTIs can retain significant antiviral activity in treatment-experienced patients. This may reflect residual direct viral load suppression, as well as indirect effects related to impaired viral fitness of NRTI-resistant mutants and antagonist interactions between resistance mutations
- …
