Telbivudine and hepatitis B infection rate in infants tested
News statistics from UNAIDS show that the number of HIV-infected individuals worldwide fell slightly this year for the first time.
New statistics recently released by the UN suggest that the HIV/AIDS epidemic is declining. The statistics suggest that, globally, new cases of HIV and deaths attributable to the infection are falling for the first time. Although this finding is an encouraging one, the news statistics released by the UN’s program on HIV/AIDS show that progress in fighting the infection is a mixed picture.
These new statistics suggest that there were 2.6 million new HIV infections last year; this is 20% less than in 1999 when the epidemic was at its peak. “We are breaking the trajectory of the Aids epidemic with bold actions and smart choices,” commented Michel Sidibe the executive director of UNAIDS. Encouragingly, treatment for HIV infection is becoming accessible to more people, with an estimated 5 million people using antiretroviral (ARV) drugs in 2009 as compared with just 700,000 in 2004. With an estimated 33 million people living with HIV worldwide, however, making ARV drugs available to infected individuals worldwide, particularly in poorer countries, is still a key challenge.
It is suggested that among young people in the 15 most affected countries in the world, rates of HIV infection have dropped by more than 25% in recent years, showing that intensive safe sex campaigns in these countries are paying off. Although overall the statistics show that globally new HIV cases are falling and appreciable declines have been seen in South Africa, Zambia, Zimbabwe and Ethiopia among others, the picture is very different elsewhere such as in the countries of Eastern Europe and central Asia where sharp increases in HIV cases were found. This increase has been partly blamed on discriminating laws against homosexuals and drug users in some of these countries.
Although for every one person starting ARV treatment there are two new HIV infections Sidibe notes that “Just a few years ago, there were five new infections for every two people starting treatment. We are closing the gap between prevention and treatment.” With recent comments from the pope suggesting that the use of contraception could be tolerated in the catholic faith to “avoid passing a grave risk on to another” it is hoped that this gap can be closed further in the near future.
These statistics show that the huge investment into HIV/AIDS prevention and awareness campaigns is having a measurable impact this should bolster hopes that the UNAIDS vision of “zero new HIV infections, zero discrimination and zero AIDS-related deaths” may one day be achieved. But Sidibe stresses that there is still a long way to go noting that, “Investments in the AIDS response are paying off, but gains are fragile – the challenge now is how we can all work to accelerate progress.”
Source: UNAIDS global report: www.unaids.org/GlobalReport/Global_report.htm
New clinical trial results for severe malaria
Study results from the largest ever clinical trial investigating hospitalized patients with severe malaria suggest that artesunate should be the preferred treatment worldwide for all age groups.
The African Quinine versus Artesunate Malaria Trial (AQUAMAT) was carried out in ten centers across nine African countries over a 5-year period. It found that the number of deaths caused by severe malaria was reduced by 22.5% when treated with artesunate as compared with quinine. A total of 8.5% of patients admitted to hospital with severe malaria died when treated with artesunate compared with 10.9% of those treated with quinine. Results from this open-label randomized trial have led experts to recommend a change to the treatment guidelines of severe malaria, which currently advise quinine as the first-choice treatment.
“For over a century, quinine administered by injection has been the best treatment available for treating severe malaria, but thanks to the development of the artemisinin compounds, we now have a safer and much more effective treatment. We recommend that artesunate should now replace quinine for the treatment of severe malaria in both children and adults everywhere in the world,” commented Nick White (Bangkok, Thailand) the lead author of the study.
Source: Dondorp AM, Fanello CI, Hendriksen IC et al. Artesunate versus quinine in the treatment of severe falciparum malaria in African children (AQUAMAT): an open-label, randomised trial. Lancet 376(9753), 1647–1657 (2010).
Cholesterol-reducing statins linked to bacterial killing cells
New research from the University of California, San Diego School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences (San Diego, CA, USA) suggests that statins, drugs taken chronically worldwide for their cholesterol lowering properties, have the added health benefit of protecting against severe bacterial infection. In their latest study, the group describes for the first time the mechanism by which statins lower the risk of bacterial infections such as sepsis and pneumonia.
Recent data from a number of clinco-epidemiologic studies have suggested a link between patients taking statins which exert their cholesterol-lowering actions through inhibition of the rate-limiting enzyme in the biosynthesis of cholesterol (3-hydroxy 3-methylglutaryl coenzyme A [HMG-CoA] reductase), and reduced mortality from severe bacterial infections. In this latest study the group co-led by Victor Nizet and Christopher Glass (San Diego, CA, USA) investigated this link further. The group investigated how statins altered the innate immune capacity of phagocytic cells working to clear Staphylococcus aureus pathogens, the group noted that the statins had a beneficial effect on S. aureus clearance although this was not due to increased phagocytosis and oxidative burst as these were both inhibited. The group were able to show instead an increase production of antibacterial DNA based extracellular traps by neutrophils and monocytes in the presence of statins.
“We found these drugs fundamentally alter how white blood cells behave upon encountering bacteria” noted Nizet. Glass added that, “Clinical research indicates that perhaps 100 million Americans have elevated cholesterol levels that could benefit from statin therapy, thus any statin-associated changes to immune system function are certain to impact millions of people.”
The group suggest that their findings could prompt further research to investigate whether statins combined with antibiotics could help to optimize treatments for severe bacterial infections such as sepsis and pneumonia which, owing in part to increased levels of bacterial resistance to antibiotics, are becoming harder to treat.
Source: Chow OA, von Köckritz-Blickwede M, Bright AT et al. Statins enhance formation of phagocyte extracellular traps. Cell Host Microbe 8(5), 445–54 (2010).
Telbivudine and hepatitis B infection rate in infants tested
Results from a recent study presented at the 61st Annual Meeting of the American Association of the Study of Liver Diseases have demonstrated that limited use of telbivudine in highly viremic pregnant women can reduce perinatal hepatitis B virus (HBV) transmission to infants. HBV is currently difficult to eradicate as no treatment modalities exist which can cure the disease. However, it is hoped that blocking the transmission of the virus from mother to infant will decrease the burden of disease, particularly in Southeast Asia, where perinatal transmission of HBV is common.
In an open-label, case-controlled study, highly viremic hepatitis B e-antigen-positive pregnant women were administered 600 mg/day telbivudine beginning between weeks 20 and 32 of gestation, and this was continued for at least 4 weeks after delivery. Patients in the treatment arm achieved a sustained virologic response of 53% prior to delivery and 62% 4 weeks after delivery. None of the patients in the control arm achieved sustained virologic response at either point. “At baseline, both the control arm and the telbivudine arm had HBV DNA of about 8 logs, but at delivery, the mothers in the treatment arm had a tremendous reduction, of approximately 2.3 logs. Approximately 30% of those on treatment had undetectable (HBV DNA levels) or less than 1000 copies/ml,” summarized Calvin Pan (Mount Sinai Services at Elmhurst Hospital, New York, NY, USA).
In addition, only 4% of newborns in the treatment arm tested positive for hepatitis B whereas 23% of newborns from the control group tested positive. The safety profile of the patients treated with telbivudine was also good as none of the patients had to stop treatment as a result of adverse events. “Because we are struggling in combating the pandemic of hepatitis B worldwide, and frustrated in the limited resources we can allocate for treating our patients … Maybe we should be putting more efforts and allocating more resources on preventing HBV vertical transmission”, concluded Pan.
Sources: American Association of the Study of Liver Diseases: www.aasld.org/Pages/Default.aspx; PR Newswire: http://media.prnewswire.com/en/jsp/latest.jsp?resourceid=4433394&access=EH
New nanosensor device could help in the fight against bioterrorism
Adapted with permission from Yanik AA, Huang M, Kamohara O et al. An optofluidic nanoplasmonic biosensor for direct detection of live viruses from biological media. Nano Lett. 10(12), 4962–4969 (2010).
A group of scientists working at Boston University (MA, USA) have developed a diagnostic tool which could be used to quickly detect viruses such as Ebola virus from blood samples. The tool could help to contain a virus in the case of an outbreak by quickly identifying the virus responsible and individuals infected.
The tool utilizes plasmonic arrays which contain apertures of around 300 nm on metallic films that transmit light at varying intensities depending on the wavelengths. When a virus in a blood sample binds to a sensor this causes the refractive index nearby to change, resulting in a detectable change to the resonance frequency of light transmitted through the apertures. As Hatice Altug, co-lead author of the study notes, “At certain wavelengths, these nanohole arrays can transmit light much more strongly than the classical aperture theory prediction. This phenomenon is called ‘extraordinary optical transmission (EOT)’ effect … The resonance wavelength of EOT signal is strongly correlated with the effective dielectric constant of the adjacent medium around the plasmonic sensor. As pathogens bind to the sensor surface, the effective refractive index of the medium increases, and the red-shifting of the plasmonic resonance occurs.” It is the magnitude of this change in resonance which can be used to determine the concentration of virus present. As shown in , Altug notes that, “Selectivity is achieved by surface immobilized highly specific antiviral immunoglobulins showing strong affinity to the viral membrane proteins. Correspondingly, with the use of antibodies, we specifically capture viruses from a sample solution on the surface of our sensor.”
In their paper, the group note that using their device they have successfully detected both poxviruses and hemorrhagic fever surrogates. The device is able to detect live viruses at clinically significant concentrations without the need for sample preparation. The fact that no sample preparation is needed means that the device has the potential to be highly portable and produce results quickly in the field. This would make it ideally suited in epidemic situations and particularly in the defense against bioterrorism. In recent years, the threat of biowarfare has grown and RNA viruses such as Ebola have been highlighted as a particular risk. In addition to being highly contagious these viruses often present with nonspecific symptoms, making diagnosis and treatment difficult.
As the authors note “Our platform can be easily adapted for point-of-care diagnostics to detect a broad range of viral pathogens in resource-limited clinical settings at the far corners of the world, in defense and homeland security applications as well as in civilian settings such as airports customs.”
Further development of the tool is underway and it is hoped that the technology will be developed into a portable device that can be used worldwide in the diagnosis of outbreaks of infectious disease.
Source: Yanik AA, Huang M, Kamohara O et al. An optofluidic nanoplasmonic biosensor for direct detection of live viruses from biological media. Nano Lett. 10(12), 4962–4969 (2010).